Why has mosquito-borne disease hit Tasmania?

Are there even mosquitoes in Tasmania?

You could be forgiven thinking that Australia’s southern most state, Tasmania, is probably free of mosquitoes and certainly the chances of an outbreak of mosquito-borne disease would be rare. Is it even possible?

Health authorities in Tasmania have recently warned residents and visitors to avoid mosquito bites following reports of locally acquired infections of Barmah Forest virus.

Ross River virus may be the best known of Australia’s local mosquito-borne pathogens but Barmah Forest isn’t far behind. Infection can cause an illness similar to Ross River virus disease, its typically marked by joint pain and inflammation, fatigue, rash, headaches, muscle pain, fever and chills.

Fortunately the disease is not fatal.

There have been outbreaks of Barmah Forest virus in many parts of Australia, not just in the tropical north. Significant outbreaks have occurred in NSW and southern Western Australia.

While Tasmania may be cold, that doesn’t mean there aren’t mosquito problems. There is a range of mosquitoes found in Tasmania, including Aedes camptorhynchus, a key species of pest and public health concern. This mosquito is closely associated with coastal estuarine wetlands, especially saltmarsh environments.

Tasmania has also had outbreaks of mosquito-borne disease. More than 100 people were infected with Ross River virus in the coastal region just to the east of Hobart in 2002. Specimens of Aedes camptorhynchus collected in the region tested positive to the virus making transmission risk most likely influenced by an abundance of this mosquito.

Like Ross River virus, Barmah Forest virus is spread by mosquitoes to people from local wildlife. It is likely that the virus quietly circulates between native animals, such as birds and mammals, but when favorable conditions for mosquitoes occur and populations increase, the risks of transmission to people increase.

While there is only a hand full of cases confirmed to date, a total of five with an additional two to be confirmed, it may not seem significant. However, it is a reminder that wherever mosquitoes, wetlands, and wildlife occur, there can also be a risk of mosquito-borne disease transmission.

With a warmer Tasmania possibly resulting from climate change and a concomitant extension of the “mosquito season” in coming years, perhaps the public health risks associated with mosquitoes will be something for health authorities to keep a closer eye on in the future. Importantly, is it time for local authorities to proactively monitor mosquitoes and the activity of mosquito-borne pathogens?

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The image used at the top of this post comes from John Tann via Flickr; a mosquito (possibly Aedes alboannulatus) from Strahan, Tasmania.

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Find out more about the amazing mosquitoes of Australia by picking up a copy of the award winning “A Guide to Mosquitoes of Australia” from CSIRO Publishing.

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West Aussies versus the local mozzies

This is a special guest post from Dr Abbey Potter, Senior Scientific Officer, Environmental Health Hazards, WA Health. I’m currently mentoring Abbey as part of The Public Health Advocacy Institute of WA (PHAIWA) Mentoring Program. Its been a great experience as we navigate through some of the strategies to raise awareness of mosquito-borne disease and advocate for better approaches to addressing the public health risks associated with mosquitoes.

Living in WA, we’re all too familiar with the pesky mosquito. We know they bite but what we often don’t consider is that they can transmit serious and sometimes deadly diseases. In fact, a recent survey of locals indicated that knowledge of mosquito-borne disease is pretty limited, particularly among younger adults aged 18-34 years and those living in the Perth Metro. It’s pretty important we’re aware of the risks posed by these pint-sized blood suckers and how you can avoid them… and here’s why!

The Facts

On average, more than 1,000 people will be infected with a mosquito-borne disease in WA every year. Our mossies can transmit Ross River virus, Barmah Forest virus, West Nile virus (Kunjin substrain) and Murray Valley encephalitis virus. All four cause diseases that are debilitating at best, causing weeks to months of symptoms. Murray Valley encephalitis is limited to the north of the State but is so serious it can result in seizures, coma, brain damage and even death.

Forget the bush, most people bitten in their own backyard. West Aussies are all very prone to getting eaten alive while socialising outdoors but if you’re up in the north of the State, you’ve also got a much higher likelihood of being bitten while boating, camping or fishing or working outside, compared to the rest of the state.

And don’t think you’re off the hook when you head off on holidays. A further 500 WA residents return from overseas travel with an exotic mosquito-borne disease every year. Heading to Bali? Beware of dengue, especially young adult males who return home with the illness more than others. There is limited mosquito management in many overseas countries where disease-transmitting mozzies can bite aggressively both indoors and throughout the day. This catches West Aussies off guard, as we are accustomed to mozzies biting outdoors, around dusk and dawn. When you’re in holiday mode it’s likely that you’ll be relaxing, having a couple of drinks and not thinking about applying repellent. Oddly enough, mosquitoes may actually be more attracted to people whose body temperature is higher. This happens naturally when you consume alcohol, so best pull out the repellent before you crack your first beer.

Despite our attractiveness to mosquitoes, we aren’t really aware of the most effective ways to avoid bites or how we can do our bit to reduce breeding in our own backyards. If you live by the mantra Cover Up. Repel. Clean Up you’ll have no problems!

Western Australia has some amazingly beautiful wetlands but these saltmarshes around Mandurah can produce large populations of nuisance-biting mosquitoes!

Cover Up

If you know you are going to be outdoors when mosquitoes are active, wear loose, long-fitting clothing that is light in colour. Believe it or not, mosquitoes can bite through tight pants as tough as jeans – I’ve witnessed it!

If you’re staying in accommodation that isn’t mosquito-proof, consider bed netting.

Try to keep children indoors when mosquitoes are most active. If exposure can’t be avoided, dress them appropriately and cover their feet with socks and shoes. Pram netting can also be really useful.

Admittedly, it’s not always practical to wear long sleeves during our warm summer nights, so there are going to be times when you need to use repellent. Choose a product that actually works and apply it appropriately so it does the job. Despite our best intentions, this is where we often go wrong. There are a few basic things to cover here, so stick with it!

Ingredient: Science tells us that the best active ingredient for repelling mosquitoes is diethyltoluamide (DEET for short) or picaridin. You need to look for either one of these names on the repellent label under the ‘active constituents’ section.

Unfortunately, natural repellents and anything wearable (e.g. bands, bracelets or patches) have very limited efficacy. Experts don’t recommend you use them and I consider this very wise advice. It only takes a single mosquito bite to become infected and chances are you will receive at least one if you rely solely on a product of this nature. It just isn’t worth the risk.

Percentage: The next thing to consider is the percentage of the active ingredient. This can range anywhere from 7% to 80% which can make choosing a repellent confusing. Just remember, the higher the percentage, the LONGER the product will remain active for. It doesn’t mean it will repel mosquitoes better.

A repellent containing 16-20% DEET will provide around 4-6 hours of protection, and is a good place to start. Repellents labelled ‘tropical strength’ usually contain greater than 20% DEET – they are useful when you spend longer periods exposed to mosquitoes or if you are heading to a region where dengue, malaria or Zika is problematic. Kids repellents usually contain picaridin or <10% DEET.

Sometimes it can be tricky to work out the percentage of the active ingredient. You can see the Bushmans example below states this clearly, but the other bottles list the ingredient in grams per litre (g/L). No need for complex maths – just divide by 10 and you have the magic number! For example, the RID label below reports the product contains 160g/L of DEET. This would convert to 16% DEET – easy!

You can see a few examples here of effective repellents:

How to Apply: No doubt we would all prefer if repellents didn’t feel quite so gross on our skin or didn’t smell so bad. Even I have to admit that before I moved into this field, I was guilty of putting just a dab here and a dab there. Unfortunately, this is flawed logic that will only result in you being bitten!

Repellents must be applied correctly to be effective. That means reading the label and applying it evenly to all areas of exposed skin. Remember to reapply the product if you are exposed to mosquitoes for longer than the repellent protects you for. You’ll also have to reapply the repellent after sweaty activity or swimming.

For more information on repellent use in adults and children, click here.

Clean Up

Mosquitoes need water to breed, but only a very small amount. Water commonly collects in a range of things you may find in your backyard including pot plant drip trays, toys, old tyres, trailers and clogged up gutters. Mosquitoes also love breeding in pet water bowls, bird baths and pools if the water is not changed weekly or they are not well maintained. Rain water tanks can also be problematic so place some insect proof meshing over any outlets. When you’re holidaying, cover up or remove anything that may collect water.

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If you need more official info from WA Health about mosquito-borne disease or simple ways to prevent being bitten click here. And if you want to read more about how much West Aussies know (or don’t know) about mossies, check out Abbey’s excellent paper here! Joint the conversation too on Twitter by following Abbey and Cameron.

Taking Australian wetland research to China

My PhD student Jayne Hanford has been super busy this year. Not much more than a year into her candidature and she has already locked away a summer of research and has been presenting her findings at conferences here in Australia as well as overseas.

After recently sharing our research at the Society for Wetland Scientists Annual Conference held in Corpus Christi, Texas, USA and the Mosquito Control Association of Australia conference on the Gold Coast, Jayne is off to China for the 10th INTECOL International Wetlands Conference.

Her research is focused on understanding the links between wetland vegetation, aquatic biodiversity and mosquito populations. Better understanding of these links will assist management strategies that minimise actual and potential pest and public health risks associated with mosquitoes and urban wetlands.

Our abstract for the conference is below:

Is the Biodiversity Value of Constructed Wetlands Linked to their Potential Mosquito-Related Public Health Risks?

Jayne Hanford¹, Cameron Webb², Dieter Hochuli¹

¹School of Life and Environmental Sciences, The University of Sydney, Australia; ²Department of Medical Entomology, Westmead Hospital and The University of Sydney, Westmead, Australia

 Stormwater treatment wetlands constructed in cities can enhance the sustainability of urban biodiversity by providing wildlife refuge areas and habitat connectivity. However, the creation of wetlands for stormwater infrastructure can increase risks to public health and wellbeing by proliferating nuisance-biting and pathogen-transmitting mosquitoes. In severe cases, this proliferation can erode goodwill in the community for creating and protecting valuable wetland systems.  We compared mosquito assemblages at 24 natural and constructed urban wetlands in the greater Sydney region, Australia. Our aim was to determine if stormwater wetlands constructed with the goal to support high biodiversity value also had reduced associated mosquito risks. Wetlands were located across a gradient of urbanisation determined by surrounding human population density, and included sites with different aquatic and riparian habitat complexity and availability. Adult and larval mosquitoes and aquatic macroinvertebrates were sampled on two occasions through summer and autumn. Aquatic macroinvertebrates were used to derive health indices, as well as being a relative measure of aquatic diversity.  Diversity of adult mosquito species was high, and abundance varied greatly between wetlands. Macroinvertebrate assemblages were also highly variable between sites. Wetlands with greater habitat complexity had lower adult mosquito abundance and greater mosquito species diversity, compared to stormwater-specific wetlands with minimal available habitat. As expected, mosquito assemblages did not respond to urbanisation and aquatic macroinvertebrate assemblages per se, but appeared to respond to a complex suite of coarse and fine-scale features that may affect a wetland’s biodiversity value.  Effectively integrating wetlands into cities requires balancing their design for water infrastructure purposes, biodiversity resources and public health and wellbeing requirements. Understanding the risks as well as the benefits will enhance the value of constructed urban wetlands in sustainable cities while minimising public health risks posed by mosquitoes.

Jayne will be speaking in the “The next generation of wetland science: ecosystems, applications, and engineering” session in the Nanhu Room 1520-1530 on Wednesday 21 September.

You can keep an eye on whats happening in China by following Jayne on Twitter and checking the hashtag #IWC10

The Society for Wetland Scientists Annual Conference held in Corpus Christi, Texas, USA back in May included a paper by Jayne titled “Risky Wetlands? Conflicts between biodiversity value and public health” and prompted some great feedback and discussion among wetland scientists at the meeting. It was a successful trip and a timely reminder that I must get to one of the SWS meetings sometime soon, perhaps Puerto Rico?

Keep an eye out for Jayne’s research publications soon!

 

 

 

Mosquitoes, Gold Coast and the latest arbovirus research

This week I’ve been on the Gold Coast for the 12th Mosquito Control Association of Australia and Arbovirus Research in Australia Symposium. The theme of the meeting was “Managing challenges and threats with new technology” and included presentations covering a range of topics, from remote piloted aircraft for mosquito control to the discovery of insect-specific viruses and their potential to stop outbreaks of mosquito-borne disease.

You can check out some of the tweets shared during the meeting here.

I found myself on ten papers presented at the meeting and I’ve provided the abstracts below!

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Does surrounding land use influence the mosquito populations of urban mangroves?

Suzi B. Claflin¹ and Cameron E. Webb^2,3

¹Department of Entomology, Cornell University, Ithaca, NY, USA; ²Marie Bashir Institute of Infectious Diseases and Biosecurity, University of Sydney, Sydney, NSW; ³Department of Medical Entomology, NSW Health Pathology, Westmead Hospital, NSW 2145, Australia

Mosquitoes associated with mangrove habitats pose a pest and public health risk. These habitats in urban environments are also threatened by urbanisation and climate change. As a consequence, urban mangrove management must strike a balance between environmental conservation and minimising public health risks. Land use may play a key role in shaping the mosquito community within urban mangroves through either species spillover or altering the abundance of mosquitoes associated with the mangrove. In this study, we explore the impact of land use within 500m of urban mangroves on the abundance and diversity of adult mosquito populations. Carbon dioxide baited traps were used to sample host-seeking female mosquitoes around nine mangrove forest sites along the Parramatta River, Sydney, Australia. Specimens were identified to species and for each site, mosquito species abundance, species richness and diversity were calculated and were analyzed in linear mixed effects models. We found that the percentage of residential land and bushland in the surrounding area had a negative effect on mosquito abundance and species richness. Conversely, the amount of mangrove had a significant positive effect on mosquito abundance, and the amount of industrial land had a significant positive effect on species richness. These results demonstrate the need for site-specific investigations of mosquito communities to assist local authorities develop policies for urban development and wetland rehabilitation.

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Do urban wetlands increase mosquito-related public health risks?

Jayne K. Hanford¹, Cameron E. Webb^2,3, Dieter F. Hochuli¹

¹ School of Life and Environmental Sciences, The University of Sydney, Sydney; ² Medical Entomology, NSW Health Pathology, Level 3 ICPMR, Westmead Hospital, Westmead; ³Marie Bashir Institute of Infectious Diseases and Biosecurity, The University of Sydney, Sydney

Wetlands in urban areas are frequently constructed or rehabilitated to improve stormwater quality and downstream aquatic health. In addition to improving water quality, these wetlands can provide aesthetic, recreational and biodiversity values to communities. However, urban wetlands are often perceived to proliferate nuisance-biting and pathogen-transmitting mosquitoes which can, in severe cases, erode goodwill in the community for protecting these valuable ecosystems.  We compared mosquito assemblages at 24 natural and constructed wetlands in the greater Sydney region, Australia. Our aims were to determine if wetlands with high aquatic biodiversity posed reduced mosquito-related public health risks, and if these links vary across the urban-rural gradient. At each wetland we sampled adult and larval mosquitoes, aquatic macroinvertebrates and physical habitat variables on two occasions through summer and autumn.  Although larval mosquito abundance was low across all sites, there was a high diversity of adult mosquito species, and assemblages varied greatly between sites and seasons. Species of wetland-inhabiting mosquitoes showed vastly different responses to aquatic biodiversity and physical habitat variables. There were strong relationships between the abundance of some mosquito species and aquatic macroinvertebrate richness, while others mosquito species showed strong relationships with the percentage of urbanisation surrounding the wetland.  Effectively integrating wetlands into cities requires balancing wetland design for water infrastructure purposes, biodiversity resources and public health and wellbeing requirements. Understanding relationships between biodiversity value and mosquito-related public health risks will enhance the value of constructed urban wetlands in cities while minimising risks posed by mosquitoes.

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Aedes aegypti at Sydney Airport; the detections and response

Doggett, S.L. and Webb C.E

Department of Medical Entomology, CIDMLS, Pathology West, ICPMR,
Westmead Hospital, Westmead, NSW.

Despite a huge increase in the detections of exotic vectors at ports around Australia, up until 2016 there had been no detection of Aedes aegypti at the Sydney International Airport. However, this changed on 14/Jan/2016 when two larvae were observed in an ovitrap serviced by the Department of Agriculture and Water Resources (formerly AQIS), as part of their routine surveillance activities for the detection of exotic vectors. These larvae were confirmed as being Ae. aegypti. Thereafter, there were a further nine separate detections of Ae. aegypti up until 4/Mar/2016. Six were via BG traps, one in an ovitrap, and there were two separate instances of an adult mosquito being collected in open areas. The majority of detections occurred in areas of the airport known as the ‘basement areas’. This is where the bags are unloaded from the air cans onto convey belts for collection directly upstairs by the passengers. Response measures undertaken included: (1) enhanced surveillance; BG traps were increased in number from 2 to 12, and traps inspected at more frequent intervals; (2) insecticide treatments; thermal fogging and surface sprays were conducted of the relevant areas; (3) vector surveys; a comprehensive audit of the airport was undertaken to examine the potential for localized mosquito breeding. In the case of the vector surveys, some 107 potential sites were identified and grouped into risk categories. No Ae. aegypti were discovered breeding, although Cx. quinquefasciatus and Ae. notoscriptus were found, and recommendations to prevent future localized breeding were made.

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Communicating the risks of local and exotic mosquito-borne disease threats to the community through social and traditional media

Cameron E Webb^1,2

¹Department of Medical Entomology, NSW Health Pathology, Level 3, ICPMR, Westmead Hospital, WESTMEAD NSW 2145 AUSTRALIA; ²Marie Bashir Institute of Infectious Diseases and Biosecurity, University of Sydney, NSW 2006, AUSTRALIA

Mosquito-borne disease management in Australia faces challenges on many fronts. Many gaps exist in our understanding of the drivers of exotic and endemic mosquito-borne disease risk but also the pathways to ensuring the community embrace personal protection measures to avoid mosquito bites. While traditional media has been the mainstay of public health communications by local authorities, social media provides a new avenues for disseminating information and engaging with the wider community. This presentation will share some insights into how the use of social media has connected new and old communications strategies to not only extend the reach of public health messages but also provide an opportunity to promote entomological research and wetland conservation. A range of social media platforms, including Twitter, Instagram and WordPress, were employed to disseminate public health messages and engage the community and traditional media outlets. Engagement with the accounts of traditional media (e.g. radio, print, television, online) was found to be the main route to increased exposure and, subsequently, to increased access of public health information online. With the increasing accessibility of the community to online resources via smartphones, researchers and public health advocates must develop strategies to effectively use social media. Many people now turn to social media as a source of news and information and those in the field of public health, as well as entomological research more generally, must take advantage of these new opportunities.

See the slides here.

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So, you want to write a field guide?

Cameron E. Webb^1,2, Stephen L. Doggett¹ and Richard C. Russell²

¹Department of Medical Entomology, NSW Health Pathology, Level 3, ICPMR, Westmead Hospital, WESTMEAD NSW 2145 AUSTRALIA; ²Marie Bashir Institute of Infectious Diseases and Biosecurity, University of Sydney, NSW 2006, AUSTRALIA

We know a lot about Australian mosquitoes. They’re one of the most studied insects in the country. Their pest and public health threats warrant a better understanding of their biology and ecology. There is still plenty we don’t know. We may not understand their ecological role in the local environment very well and there are many mosquitoes we know exist but have very little information about them. We still need to give many mosquitoes a formal scientific name. There is a reason why so many field guides are written by retired scientists. It’s not just about expertise, it’s about time too! In early 2016, “A Guide to Mosquitoes of Australia” to was published by CSIRO Publishing and marked the culmination of many years work. This work involved chasing mosquitoes from coastal rock pools to snow melt streams. We carried eskies of buzzing mosquitoes on airplanes from northern Australia to laboratories in Western Sydney and there were many late nights of wrangling those mosquitoes to get the perfect photo. Lots of mosquito bites too. Many, many mosquito bites. Putting together this field guide wasn’t an easy task and for all those involved it proved a challenge in many different ways. Digging out old papers to colour-correcting digital photographs proved time consuming but the biggest delays in finishing this project was a problem that plagues many field guide writer, “species creep”! Completing the guide was only possible with the kindness, generosity and co-operation of many mosquito researchers around the country.

See the slides here.

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Arbovirus and vector surveillance in NSW, 2014/15-2015/16

 Doggett, S.L., Clancy, J., Haniotis, J., Webb C. and Toi, C.

Department of Medical Entomology, CIDMLS, Pathology West, ICPMR,
Westmead Hospital, Westmead, NSW.

The NSW Arbovirus Surveillance and Vector Monitoring Program acts as an early warning system for arbovirus activity. This is achieved through the monitoring of mosquito abundance, detection of arboviruses from mosquitoes, and the testing for seroconversions to MVEV and KUNV in sentinel chickens. A summary of the last two seasons will be presented. The 2014-2015 season started early with elevated temperatures through late 2014, however conditions were relative dry with neither Forbes’ nor the Nicholls’ hypothesis being suggestive of an MVEV epidemic. Despite this, for the inland region, human notifications were close to average, with 260RRV & 11BFV). There were 12 arboviral detections from the inland including 5BFV, 6RRV & 1STR, with no seroconversions. In contrast, the coastal strip experienced the largest epidemic of RRV in recorded history. The 1,225 cases were close to double the average, with much of the activity occurring in the far north coast. There were 41 isolates from the mosquitoes trapped along the coast and included 6BFV, 29RRV, 4EHV and 2STRV. An intense El Niño occurred during the 2015-2016 season and thus it was extremely dry across the state. Again the Forbes’ and the Nicholls’ hypothesis were not suggestive of an MVEV outbreak. For the inland, mosquito numbers were well below average and there were only two arboviral detections from the mosquitoes (1RRV & 1 BFV), with no seroconversions. Similarly, mosquito collections were below average and there were also two arboviral detections from the trapped mosquitoes (1BFV & 1EHV). Human cases were below average.

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Are remote piloted aircraft the future of mosquito control in urban wetlands?

Cameron E Webb^1,2 Stephen L. Doggett¹ and Swapan Paul³

¹Department of Medical Entomology, NSW Health Pathology, Level 3, ICPMR, Westmead Hospital, WESTMEAD NSW 2145 AUSTRALIA; ²Marie Bashir Institute of Infectious Diseases and Biosecurity, University of Sydney, NSW 2006, AUSTRALIA; ³Sydney Olympic Park Authority, 8 Australia Ave, Sydney Olympic Park NSW 2127, AUSTRALIA

Mosquito control in urban wetlands will become increasing important. The expansion of residential areas will continue to encroach on natural mosquito habitats, particularly coastal wetlands, and expose the community to the health risks associated with mosquitoes. In many existing areas, ever increasing density of human populations associated with high rise residential developments will further expose people to mosquitoes. The increasing urban development adjacent to wetlands can restrict the ability to use traditional larvicide and insect growth regulator application methods. In 2016 a trial of larvicide application via remote piloted aircraft was undertaken in an area of estuarine wetlands at Sydney Olympic Park. An existing mosquito control program involving helicopter application of larvicides has been in place for over a decade. Post-treatment mortality of Aedes vigilax and Culex sitiens larvae was compared between bioassay and long-term surveillance sites within the wetlands. While there was a substantial reduction in larval densities post-treatment, the treatments via remote piloted aircraft were less effective than those of traditional piloted aircraft. The results of this preliminary trial suggest that the use of remote piloted aircraft has potential but the operational aspects of this application method requires careful consideration if there are to be as effective as existing strategies.

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Seasonal Activity, Vector Relationships and Genetic Analysis of Mosquito-Borne Stratford Virus

Cheryl S. Toi¹, Cameron E. Webb^1,2, John Haniotis¹, John Clancy¹ and Stephen Doggett¹

¹Department of Medical Entomology, Centre for Infectious Diseases and Microbiology Laboratory Services, Pathology West – Institute for Clinical Pathology and Medical Research, Westmead Hospital, NSW; ²Marie Bashir Institute for Infectious Diseases and Biosecurity, University of Sydney, Institute for Clinical Pathology and Medical Research, Westmead Hospital, NSW;

There are many gaps to be filled in our understanding of mosquito-borne viruses, their relationships with vectors and reservoir hosts, and the environmental drivers of seasonal activity. Stratford virus (STRV) belongs to the genus Flavivirus and has been isolated from mosquitoes and infected humans in Australia. However, little is known of its vector and reservoir host associations. A total of 43 isolates of STRV from field collected mosquitoes collected in NSW between 1995 and 2013 were examined to determine the genetic diversity between virus isolates and their relationship with mosquito species by year of collection. The virus was isolated from six mosquito species; Aedes aculeatus, Aedes alternans, Aedes notoscriptus, Aedes procax Aedes vigilax, and Anopheles annulipes. While there were distinct differences in temporal and spatial activity of STRV, with peaks of activity in 2006, 2008, 2010 and 2013, there was a high degree of sequence homology (89.1% – 97.7%) found between isolates with no evidence of mosquito species, geographic, or temporal divergence. The result suggests the virus is geographically widespread in NSW (albeit only from coastal regions) and increased local STRV activity is likely to be driven by reservoir host factors and local environmental conditions influencing vector abundance. While STRV may not currently be associated with major outbreaks of human disease, with the potential for urbanisation and climate change to increase mosquito-borne disease risks, and the potential for genomic changes which could produce pathogenic strains, understanding the drivers of STRV activity may assist the development of strategic response to public health risks posed by zoonotic flaviviruses in Australia.

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Insect specific flaviviruses suppress West Nile virus replication and transmission

Sonja Hall-Mendelin¹, Breeanna McLean², Helle Bielefeldt-Ohmann³, Cameron E. Webb⁴ Jody Hobson-Peters², Roy Hall², Andrew van den Hurk¹

¹Public Health Virology, Forensic and Scientific Services, Department of Health, Queensland Government, PO Box 594, Archerfield 4108, Queensland, Australia; ²Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, St Lucia 4072, Queensland, Australia; ³School of Veterinary Science, The University of Queensland, Gatton Campus, Gatton 4343, Queensland, Australia; ⁴Medical Entomology, Marie Bashir Institute of Infectious Diseases and Biosecurity, The University of Sydney, NSW, Australia

Diseases caused by mosquito-borne flaviviruses, including dengue (DENV), Zika and West Nile viruses (WNV), are a global problem. New molecular tools have led to recent discoveries of a plethora of insect-specific flaviviruses (ISF) that infect mosquitoes but not vertebrates. Preliminary reports have suggested that transmission of WNV can be suppressed by some ISFs in co-infected mosquitoes, thus the ecology of ISFs and their potential as natural regulators of flaviviral disease transmission is intriguing. In vitro studies with two ISFs discovered in Australia, Palm Creek virus (PCV) and Parramatta River virus (PaRV), demonstrated suppression of WNV, Murray Valley encephalitis virus (MVEV) and DENV replication in mosquito cells (C6/36) previously infected with either of these ISFs. Further in vivo experiments indicated that these ISFs were not transmitted horizontally in the saliva, and that PaRV relied on vertical transmission through the mosquito egg to the progeny. Additional studies revealed a significant reduction of infection and transmission rates of WNV when Culex annulirostris were previously infected with PCV, compared to control groups without PCV. Of particular interest was the specific localisation of ISFs to the midgut epithelium of mosquitoes infected via natural route (vertical transmission – PaRV) or by intrathoracic injection (PCV). Overall these results confirm a role for ISFs in regulating the transmission of pathogenic flaviviruses by mosquitoes and that this interference may occur in the midgut where initial infection occurs. Further research is needed to determine the precise mechanism of this phenomenon and its potential for mosquito-borne disease management.

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Neges, Nidos and Nings – so that’s what’s killing my mossie cells!

Roy Hall¹, Jody Hobson-Peters¹, Helle Bielefeldt-Ohmann¹, Caitlin O’Brien¹, Breeanna McLean¹, Agathe Colmant¹, Jessica Harrison¹, Thisun Piyasena¹, Natalee Newton¹, Waylon Wiseman¹, Marcus Mah^1,2, Natalie Prow², Andreas Suhrbier², David Warrilow³, Andrew van den Hurk³, Sonja Hall-Mendelin³, Cheryl Johansen⁴, Steven Davis⁵, Weng Chow⁶, Stephen Doggett⁷, John Haniotis⁷ and Cameron Webb⁷.

¹Australian Infectious Diseases Research Centre, School of Chemistry and Molecular Biosciences, The University of Queensland, Australia; ²QIMR Berghofer Medical Research Institute, Herston, Brisbane, Australia; ³Public Health Virology, Forensic and Scientific Services, Coopers Plains, Queensland, Australia; ⁴Arbovirus Surveillance and Research, Infectious Diseases Surveillance Unit, PathWest Laboratory Medicine WA, Western Australia; ⁵Berrimah Veterinary Laboratories, Department of Primary Industry and Fisheries, Darwin, Northern Territory, Australia; ⁶Vector Surveillance and Control, Australian Army Malaria Institute, Enoggera, Queensland, Australia; ⁷Department of Medical Entomology, West Westmead Hospital, Westmead, NSW, Australia.

Isolation of viruses from mosquitoes is an important component of arbovirus surveillance and virus discovery programs. In our lab, these viruses are detected in inoculated cultures by the appearance of cytopathic effects (CPE) in mosquito cell monolayers or by reactivity of monoclonal antibodies to viral antigens or dsRNA intermediates. Isolates are then identified by RT-PCR or deep sequencing.  We detected extensive CPE in many mosquito cell cultures inoculated with mosquito homogenates from several regions of Australia, however these isolates were not identified by specific mAbs or RT-PCRs designed to detect known arboviruses.  When we investigated their identity by deep sequencing, a new species (Castlerea virus – CsV) in the unclassified taxon Negevirus, was identified in several mosquito species from WA and Brisbane. Two viruses in the newly established Mesoniviridae family (order Nidovirales) were also identified; a novel species named Casuarina virus (CASV) from Coquillettidia xanthogaster in Darwin and from Culex annulirostris in Cairns, and the first Australian isolates of Nam Dinh virus from several mosquito species in Brisbane and Perth. Many isolates of a new genetic lineage of Liao Ning virus, a member of the Seadornavirus genus (family Reoviridae), were also obtained from several mosquito species from different regions of Australia.  These new viruses were isolated at very high frequency in some mosquito collections, and were often found to co-infect isolates of other mosquito-borne viruses making it difficult to obtain pure cultures. We have now developed neutralising antibodies to each virus to facilitate selective removal of these viruses from mixed cultures.

 

That was a busy meeting. I’m exhausted but cannot wait until the next meeting in 2018. Are you a member of the Mosquito Control Association of Australia?

 

 

Moving pictures and managing mosquitoes

For a few months now I’ve been thinking through some future options for the blog and my science communications activities. I’ve been toying around with starting a podcast or video blog about my work in local wetlands.

#MosquitoWeek has just happened in the U.S. and as it coincided with the close of entries with the Entomological Society of America YouTube competition, I thought what better time to play around with putting together a video.

A year or so ago I had the chance to see Karen McKee (aka The Scientist Videographer) talk about social media and the ways she uses video as a critical component of her community engagement and communications. Since I’m already using Instagram to connect followers with my various wetland sites and mosquito studies (as well as other things), I’ve thought video could be a way to go.

Interesting too since images and video are (or are soon to be) increasingly dominant in social media.

I’m an advocate for mosquito control to be part of overall wetland management. I think I’m sometimes seen as the enemy of wetland and wildlife conservation, not surprising given the perception of mosquito control still influenced by the DDT debate. As we push for the construction and rehabilitation of urban wetlands, the pest and public health risks associated with mosquito populations do need to be considered by local authorities.

I’m often arguing that ecologically sustainable mosquito management is actually critical to wetland conservation. If you’re encouraging the community to visit your wetlands, what happens when they’re chased away by mosquitoes? What about the community living around the wetland? Will nuisance-biting erode the good will of the community for wetland conservation?

You can watch my video, “Why is mosquito management important in our local wetlands?”, at YouTube or below:

You can check out some of my other posts of wetlands, mosquitoes and social media below:

Should we start pulling out mangroves to save our wetlands?

Does wetland rehabilitation need mosquito control?

Can social media help track environmental change?

Mosquitoes, constructed wetlands, urban design and climate change: Some workshop resources

Let me know if you’d be interested in seeing more videos! Send me a tweet.

Can social media help translate research to practice and promote informed public health messages?

I’m a Senior Investigator with the Centre for Infectious Diseases and Microbiology – Public Health. One of our primary focuses is translating research into improved public health outcomes. With NSW Population Health and Health Services Research Support Program assisting our work, we’re exploring new ways to achieve this objective. My experience of using social media was selected to be showcased among other case studies in 2015. 

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Nuisance-biting mosquitoes and mosquito-borne disease are concerns for local authorities in Australia. 2015 saw the largest outbreak of mosquito-borne Ross River virus disease for more than 20 years with over 9,500 cases nationwide. In NSW, there were 1,633 cases compared to the annual average since 1993 of 742 cases per year. Notwithstanding the current outbreak, other endemic, as well as exotic, mosquito-borne pathogens represent future threats to public health.

As there is no large-scale mosquito control program in NSW, reducing the contact between mosquitoes and people is primarily achieved through the promotion of personal protection measures. NSW Health promotes the use of topical insect repellents in combination with behavioural change to avoid natural mosquito habitats and the creation of mosquito habitats around the home. This information is typically provided in the form of posters, brochures, online factsheets, and seasonal or outbreak-triggered public health messages issued by Local Health Districts or the NSW Ministry of Health.

With the emergence of new communications technologies, particularly the rise in popularity of social media, there are new opportunities for public health communications.

The aim of the current research was to determine the reach of public health messages through social media by tracking engagement, audience and relative value as assessed by media monitoring organisations and metrics provided by hosting services of social media platforms.

Assessing activities and processes

Dr Cameron Webb (CIDM-PH) has focused much attention on filling the gaps between current public health messages and findings from recent research into topical mosquito repellents.[1] For example, while public health messages provide accurate information on the insect repellents that provide the best protection, there is a paucity of information provided on how best these products should be used by individuals and those they care for.

Dr Webb’s engagement with mass media, online media (e.g. The Conversation), a personal blog (e.g. Mosquito Research and Management) and social media (e.g. Twitter) has resulted in substantial exposure of focused and informed public health messages. From mid-2014 through to the end of 2015, Dr Webb participated in over 80 mass media articles and interviews in print, online, radio and television media with public health information reaching an estimated audience of over 10 million people.[2] The focus of his messaging around mosquito-borne disease was to highlight the best way for the community to choose and use mosquito repellents; stressing the importance of active ingredients and application methods. This fills a gap in the current provision of public health information while also augmenting public health alerts and messages associated with the 2015 outbreak of Ross River virus disease.

Social media has become a “go to” source of information for much of the community. Information shared on Facebook, Twitter, Instagram, and YouTube has the potential to shape the habitats and behaviour of the community. Dr Webb is active on Twitter (currently followed by over 4,500 people); he uses the platform to engage with the social media accounts of journalists and broadcasters to establish a voice of authority in the field of mosquito-borne disease prevention and extend the reach and exposure of public health messages broadcast through mass media. Using Twitter to share links to informed articles following interviews reached hundreds of thousands of people by being shared by the social media accounts of journalists, media outlets, government organisations and community groups. During the 2014-2015 summer, tweets by Dr Webb reached an estimate 1.28 million people.[3]

Dr Webb regularly writes open access articles on his website, attracting around 250 daily visitors with over 117,000 article views.[4] In addition to his personal website, Dr Webb regularly contributes articles to The Conversation (a website for academics to share expert opinion and write about their latest research). His articles have attracted over 120,000 readers. However, one article “why mosquitoes seem to bite some people more” (published 26 January 2015) has alone been read by over 1.3 million people.[5] This “non-scholarly” writing not only establishes CIDM-PH scientists as authorities in public health matters but can also assist in directing the public to official health guidance provided on official websites and other sources.

Dr Webb’s activities provide a framework for how health authorities may engage with social media to extend public health messages. Organisations or individuals can connect health authority information with the community through media outlets. He has been invited to share his experiences in this field at local and international conferences and workshops including those coordinated by the Public Health Association of Australia, Australian Entomological Society and Entomological Society of America. In addition, Dr Webb has been invited to provide lectures on the benefits of social media for public health advocacy to undergraduate and post-graduate students at the University of Sydney.

While traditional messaging provided by health authorities will remain a staple in public health campaigns, social media provides a connection between traditional and emerging media and communication organisations. This increased connectivity between public health advocates, the media and community has the potential to greatly improve the awareness of mosquito-borne disease and increase the rate of uptake and application of strategic personal protection measures.

References

1. Webb C.E. (2015). Are we doing enough to promote the effective use of mosquito repellents? Medical Journal of Australia, 202(3): 128-129.
2. Estimated audience reported by Kobi Print, Media and Public Relations, University of Sydney, 23 April 2015, based on data provided by media monitoring organisation isentia.
3. Estimated from total “tweet impressions” for the period October 2014 through April 2015 provided by Twitter Analytics (https://analytics.twitter.com/user/Mozziebites/home accessed 30 April 2015)
4. Data provided by WordPress statistics (accessed 18 December 2015)
5. Data provided by The Conversation metrics (accessed 18 December 2015)

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This article was originally published by NSW Health showcasing some of the work within the NSW Population Health and Health Services Research Support Program. You can see the original article here.

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Should we start pulling out mangroves to save our wetlands?

You have no idea how badly I wanted to jump down into the thick black mud.

I don’t remember much about primary school but I do have strong recollections of an assignment on the importance of mangroves to the ecology of the Parramatta River. Perhaps not the assignment itself, but I do remember Mum and Dad taking me down to the river and I drew some pictures of the twists and turns of branches and trunks and the finger-like pneumatophores punching up through the thick dark grey mud. It may only have been 10 minutes drive from home in Western Sydney but it was a glimpse into a world so strange and alluring, how could it not have made an impact on me?

I remember the great disappointment of my parent’s stern words keeping me from jumping down below the high water mark and into the mud. The same feelings of frustration and disappointment when stopped from doing other fun things like playing in stormwater drains, letting off firecrackers or swimming in rips!

Mangroves don’t just attract the attention of young environmental scientists. Exploiting a unique place between the land and sea, mangroves have intrigued and fascinated many before me with the first descriptions, by Greek mariners, thought to date back to 325BC. What were these plants that seemed to defy logic, growing half submerged in salty water?

Almost thirty years after my primary school assignment, with sandshoes replaced by gumboots, that childhood disappointment of adventure squashed is now matched by the realisation that mangroves aren’t perfect. In fact, they’re a threat to some of the other plants and animals found in our local local estuaries.

Now I spend most of my summer coated in that same dark grey mud, covered in mosquito bites and thinking about how important mangrove management will be for the future of our coastal wetlands.

More than mangroves

There is little doubt mangroves are an ecologically important habitat. They provide a home for a wide range of creatures, from bacteria to birds. Rich in nutrients and hiding places, mangroves are perfect nurseries for fish and crustaceans. Bird and bats and rodents and reptiles all find a home here too.

They’re threatened by climate change but they may also play a critical role in protecting our shoreline against sea level rise and storm surges. Sea level rise itself may knock out mangrove forests too but mangroves could also mitigate the impacts of climate change by storing carbon. In fact, the role estuarine wetlands may play in keeping carbon dioxide out of the atmosphere could be critical.

Make no mistake, mangroves are important. Thing is, it is also important to also remember that estuarine wetlands are more than just mangroves.

When we talk about estuarine wetlands, we’re grouping together a number of habitats that  include seagrass, saltmarsh, sedgelands and mudflats as well as mangroves. Each of these habitats play an important role in the functioning of the estuary as a whole but they each, individually, provide something specific to the wildlife that utilise the wetlands.

Saltmarshes are critically important and are in desperate need of conservation. In NSW they’re listed as Endangered Ecological Communities. As well as urbanisation and pollution, a changing climate and sea level rise risk severely degrading the quality of these habitats.

One of the key threats facing saltmarshes is a native plant. A native estuarine wetland plant. Mangroves.

The encroachment of mangroves into saltmashes is a serious problem. This is happening in many parts of the world. It is a strange situation in which one native plant is taking over another and with these ecological shifts, there are knock-on effects to other components of the wetland ecosystem. Most importantly, nesting and feeding shorebirds.

Are mangroves really a threat?

The mangroves are just doing what mangroves do. The reason they’re threatening saltmarshes is due to our modification of local environments.

Urban runoff reduces the salinity of these wetlands and this reduced salinity not only removes the ecological advantages of salt-tolerent saltmarsh plants, such as Sarcocornia quinqueflora and Sporobolus virginicus, but it helps mangrove seeds and seedlings survive the otherwise harsh environmental conditions of saltmarshes. Lower the salinity, increase the invasive potential of mangroves.

Frequent dryness and highly salty conditions are a saltmarsh’s best defense against invading mangroves.

Filling in wetlands and the construction of seawalls, roadways and other infrastructure give saltmarshes little refuge or respite from these threats. While mangroves encroach from the sea, there is nowhere for saltmarshes to migrate to when dealing with sea level rise.

They’re cornered and under attack but even where the plants are persisting, the quality of habitat they provide for local wildlife is slowly degraded by colonising mangrove seedlings.

There are many waterbirds that use our local estuaries that are under threat. Saltmarshes are great habitats for migratory shorebirds. There are plentiful resources in the form of insects and other invertebrates within the sediments. The birds can nest on the marsh and as they can see all around, predators are easy to spot. They feel safe.

There have been declines in the White-fronted Chat populations around Sydney. Many other populations of wading birds associated with Australia’s coastal wetlands are in decline too. Mangrove invasion isn’t the only thing to blame but it is an issue that needs to be addressed.

For many of these birds, the encroachment of mangroves into mudflats and saltmarshes is a problem. Its a problem for their foraging and nesting. Once mangrove seedlings start popping up on the middle of the saltmarsh, all those advantages of a wide open habitat in which predators are easy to spot are lost.

Imagine you’re a black-winged stilt. You’re trying to find a safe place to nest. A perfect place would be a raised area of saltmarsh surrounded by water. A dead flat saltmarsh with clear lines of sight for dozens of meters around. You’ll be able to see an approaching predator (like a fox or a feral cat) from far enough way to escape with plenty of time to spare. Now, stick a few mangrove seedlings here and there. They start to obscure your view. They’ll give sneaky predators a place to hide. Even if there are not predators about, you’ll probably get nervous. You’ll probably spend more time thinking about the threat of predators and less time foraging for food.

As mangroves move in, the birds will leave. Long before the saltmarsh is over run by mangroves, out-competed by the shade of establishing young mangroves, the quality of the habitat for many shorebirds will have already been lost. There may be some plants remaining but the ecological role of the habitat is gone.

Do historic paintings provide conflicting evidence to the commonly held view that mangroves have always been present along the Parramatta River? (Parramatta River, c. 1837, Conrad Martens (1801-78) via Australian Art Auctions)

Painting the picture of change in the local wetlands

How can we predict what will happen in the future if we haven’t learned from the past?

Tracking change in these wetlands is important. The use of photography has played an important role in tracking environmental change for a long time. Aerial photography and satellite imagery have helped reveal dramatic changes in vegetation associated with Australia’s coastal wetlands. This analysis has demonstrated the encroachment of mangroves into saltmarshes and this encroachment is considered a key threatening process of this endangered ecological community.

How can we track the encroachment of mangroves? While technology has helped reveal current changes in mangrove encroachment, other uses of imagery can explore relatively recent “urban myths” about historic mangrove distribution.

Thinking back to that school assignment, I remember being told how important mangroves were to the local environment. We we taught that, here in Sydney, that mangroves were always part of the Parramatta River estuary, that they have alwasy been a critical component of the river’s ecology. Was this really the case?

There has been some brilliant detective work done to determine the historic distribution of mangroves along the Parramatta River in this paper titled “Estuarine wetlands distribution along the Parramatta River, Sydney, 1788–1940: implications for planning and conservation“. The authors have used old photos and, in particular, some of the earliest paintings from the Sydney region (together with notes from settlers at the time) and found that the estuary was dominated by mudflats and saltmarsh habitats and that extensive areas of mangroves did not occur until the 20th Century.

To quote the author, Lynette C. McLoughlin:

“These historical sources indicate that in the 19th century extensive mudflats and saltmarsh communities dominated the inter-tidal zone, with mangroves more limited to creek fringes and some patches in bays for much of the period. In the upper river from Subiaco Creek to Parramatta, there is no evidence for the presence of mangroves until the 1870s. Following settlement and increased sedimentation, inter-tidal mudflats expanded, mangroves colonised up river and out onto mudflats in bays in the latter part of the 19th century, followed by expansion into saltmarsh in the 20th century.”

It is only relatively recently that mangroves have really flourished along the river.

There is absolutely no doubt they were always present, tucked away in the tiny bays and inlets of what became known as Sydney Harbour but it was the mudflats and saltmarshes that dominated much of the estuary. These habitats, no doubt, provided a rich and productive habitat for shorebirds and other wildlife.

So, where to from here?

Globally, mangroves are a critical component of wetland ecosystems. There is little doubt of that, and little doubt that in many parts of the world, even here in Australia, they are under threat. But so is saltmarsh and, saltmarsh is far less likely to be given the chance to demonstrate the resilience that mangroves will to continued changed environmental conditions results from a rising sea level and surging urbanisation.

Not just saltmarsh but mudlfats too.

Coastal authorities are increasingly aware of the need to balance protection of mangrove forests and the benefits they provide but also the conservation of saltmarsh and mudflats that are so critical to shorebirds.

The reality is, there will need to be a program of mangrove culling to sustain conservation of saltmarsh habitat. You need a permit to remove mangrove seedlings but a seasonal program of removal would be greatly beneficial in stopped the spread of mangroves into saltmarsh habitats. Local authorities are incorporating mangrove removal programs in their local wetland rehabilitation programs.

Removing young seedlings is easy, you can pull them straight out of the wet mud. Wouldn’t take much to organise a team of volunteers to move through the local saltmarsh removing seedlings. Perhaps in Autumn when the migratory shorebirds have left and the mosquito populations aren’t so bad?

The idea that native vegetation should be actively removed from habitats sounds at odds with environmental conservation. However, we need to maintain our wetlands for our future generations and the next generations of birds, and fish and crustaceans that rely on them now where few other opportunities exist.

2 February is World Wetlands Day. Please get out into your local wetlands, or at least make a pledge to visit your nearby wetlands sometime soon.

Learn more about Australia’s amazing mangroves by dropping by MangroveWatch and picking up the excellent Australia’s Mangroves by Norm Duke. There is also an extremely useful text on Australian Saltmarshes that is essential.

Finally, check out one of the most extensive resources on urban wetland management, including estuarine wetlands, via the free eBook produced by the Sydney Olympic Park Authority titled “Workbook for Managing Urban Wetlands in Australia“. Read a brief article on our analysis of the use of this resource in the latest issue of Wetlands Australia, see “Insights from the use of an online wetland management resource” by Webb and Paul (pages 26-27).

What are you doing for World Wetlands Day? Join the conversation on Twitter!

Want to learn more about the amazing world of Australian mosquitoes? Check out “A Field Guide to Mosquitoes of Australia” out now through CSIRO Publishing. Over 200 pages containing a pictorial guide to almost 100 different mosquitoes along with tips on beating their bite and protecting your family from the health risks of mosquitoes. You can order online or through your favourite local bookstore or online retailer.

 

Safely avoiding mosquito bites when pregnant

Hundreds of millions of people fall ill due to mosquito-borne pathogens every year but the recent rise in birth defects associated with Zika virus emerging in the Americas has health authorities on alert.

Zika virus is transmitted by mosquitoes, primarily by the Yellow Fever mosquito, Aedes aegypti. Since its discovery in Africa around 70 years ago it has avoided the public health spotlight due to the relatively mild illness it causes. Throughout Africa and Asia it is overshadowed in importance by the diseases caused by malaria parasites as well as dengue and chikungunya viruses.

For background on the rise of Zika virus, see my article for The Conversation.

Zika and the health risks to those pregnant and their unborn children

While Zika virus has yet to be fully confirmed as the causative agent in birth defects (such as microcephaly), there is clearly enough concern among health authorities in many parts of the world to issue warnings to those pregnant to avoid travel to countries experiencing an outbreak of Zika virus.

Authorities in Columbia and El Salvador have even gone so far as to advise residents to avoid falling pregnant for up to two years.

The Australian Government issued the following advice via their SmartTraveller website:

“Until more is known about Zika virus, and taking a very cautious approach, we advise women who are pregnant (in any trimester) or who plan to become pregnant to consider postponing travel to any area where Zika virus transmission is ongoing. If you do decide to travel, talk to your doctor first and strictly follow steps to prevent mosquito bites during your trip.”

For many, the option of not travelling will be easy. But what if you still want to travel? What if you’re doing business in some of these countries? What if you need to travel to visit family? Cancelling a trip isn’t always the easiest options.

Reducing risk of mosquito-borne disease while travelling

Irrespective of the current Zika outbreak, travelling while pregnant brings various health and safety risks.  Other mosquito-borne diseases, such as malaria and dengue, also pose a risk to pregnant women and their unborn children. These serious risks existed long before Zika virus grabbed the public health spotlight.

Unfortunately, there is no vaccine currently available for Zika virus. Vaccines are in development for dengue viruses and anti-malaria drugs are available so consult your local travel health clinic.

While travelling, staying indoors as much as possible, particularly air-conditioned accommodation, will greatly reduce exposure to mosquitoes. This may not be how you expected to spend your time during a South American holiday!

Many people associate mosquito-borne disease with wetland or jungle environments but as Zika virus is spread by mosquitoes found in urban habitats (e.g. water-filled containers), travellers should not be complacent if only visiting cities. Some of the biggest recent outbreaks of mosquito-borne disease have been in major metropolitan regions in the Americas and Asia.

Mosquito control in Brazil, a striking image of the battle against container-inhabting mosquitoes (Image: Ernesto Benavides via International Business Times)

If you’re staying at a high end resort, chances are there will be a well established insect control program. This typically includes widespread spraying for insecticides to knock down any mosquito populations. This may not completely remove risk but it will substantially lower potential exposure to mosquitoes. Again, don’t be complacent and take special care to avoid mosquitoes if taking a day trip to local villages or other tourist attractions.

Sleeping under a bed net is usually recommended in regions where malaria is an annual problem but this may not offer that much protection against Zika virus as the mosquitoes that spread the virus primarily bite during the day. If you’re planning on taking some afternoon naps, make sure it is under a bed net. A range of insecticide treated bed nets are available from your local camping store.

There is also an ever increasing range of “pre-treated” insect repellent clothing but evidence is scarce on just how effective these are at preventing bites. Treating clothing with insecticide (e.g permethrin) yourself would be a better option but don’t expect that wearing treated clothing means you don’t have to put insect repellents on exposed skin.

Safe and effective use of mosquito repellents

There will be anxiety among many about using insect repellents while pregnant. Are they safe? Will they impact the baby?

Without doubt, the most commonly used, safe and effective mosquito repellents is DEET (I’ve written about these repellents extensively, see here and here but I’ll summarize below). This is found in lots of major commercial brands and is a mainstay in the recommendations issued by health authorities the world over. Problem is, it can be hard to find information on how to choose and use the repellent that’s right for you and your situation.

The first point to remember is that the the strength of the formulation determines how long you’re protected against mosquito bite, not how many mosquitoes are kept away. For example, a 10% DEET based repellent may provide 2h protection, a 20% formulation may provide 4h protection. When choosing a repellent, think about how long you need protection for and how frequently you’re happy to reapply.

Secondly, the repellent must be applied as an even coverage on all exposed skin. If there are “gaps” in the application, mosquitoes are sneaky enough to pick a spot to bite. In the case of the mosquitoes that spread Zika, dengue and chikungunya viruses, pay special attention to application around the lower legs and feet, that’s where they like to bite.

Be sure to reapply repellent after swimming or sweaty exercise too.

There is no need to apply mosquito repellents to skin under clothing.

Are repellents safe to use when pregnant?

Health authorities and regulatory agencies rarely provide specific warnings on the use of insect repellents by those pregnant. While there haven’t been many clinical trials, these papers (here and here) demonstrate a lack of documented significant health risk associated with the used of DEET-based repellents. Most notably, a study of almost 900 women using mosquito repellent in the second or third trimester and no adverse neurologic, gastrointestinal, or dermatologic effects were observed in women or their infants for a year after birth.

It is important to balance the distinct lack of evidence of major health risks associated with repellents to the rapid rise in microcephaly in Brazil. Repellents can stop mosquitoes bites, stop mosquito bites and remove the risk of infection. If you use registered mosquito repellents as directed on the label, they are effective and safe.

Common sense must prevail. Even if you’re concerned about the use of repellents, make some compromises while still protecting yourself for infection. Choose a lower dose DEET-based repellent and reply more often. This is a better approach than trying a repellent that hasn’t been proven effective.

I’m often asked what formulation works best. There are aerosol sprays, roll-ons, pump-pack sprays, creams, gels, lotions and even towelettes. There really haven’t been many scientific studies looking at which if these formulations work best, and for good reason. As the active ingredients in these formulations are the same, it doesn’t really matter. The critical issue is to choose a formulation that you’re most comfortable using to ensure you get a good coverage over exposed skin. I like creams and pump-pack sprays but I generally apply the product to my hands first and them spread across skin.

Always ensure you avoid getting repellent in your eyes or any cuts or abrasions.

I don’t like the smell or feel of mosquito repellents!

There is often a temptation for those who dislike DEET to use a “natural“, plant-based repellents. Notwithstanding that these products provide shorter periods of protection, tea-tree oil (particularly when used in home-made concoctions) also has the potential to cause skin irritation. While plant-based mosquito repellents may offer some protection against nuisance-biting mosquitoes, they shouldn’t be relied on to prevent mosquito bites in regions of mosquito-bore disease outbreaks.

Many health authorities recommend para-Menthane-3,8-diol (PMD), a product commonly known as “oil of lemon eucalyptus”. This is not an essential oil but rather the by product of the distillation process of Corymbia citriodora. The product does repel a range of biting insects and there is no evidence suggesting it should not be used in pregnancy. However, in Australia, this product is generally more difficult to find in grocery stores and pharmacies than DEET- or picaridin-based repellent formulations.

It would be brilliant if there was a non-topical options for stopping mosquito bites. Unfortunately, there is nothing that has been proven effective. Do not rely on mosquito repellent wrist bands as they do not provide adequate protection against mosquitoes. Also, remember that there is nothing you can eat or drink that will stop you being bitten by mosquitoes.

Rounding out the advice on mosquito repellents, make sure you pack some before you leave. You can never be sure of what products will be available at your destination or whether it has gone through the process of registration (e.g. APVMA in Australia or EPA-registered in the U.S.). It is not unheard of for mosquito repellent stock to sell out during outbreaks of disease.

Lastly, if you’re travelling to regions experiencing dengue, chikungunya and Zika virus outbreaks, don’t necessarily expect to be swarmed by mosquitoes in the same way you will around many of Australia’s coastal wetlands. Don’t be complacent if there are only a few about, remember, it only take one bite to transmit a pathogen. Don’t wait until you notice mosquitoes biting, wake up and put on that repellent.

There is a great set of questions with answers provided by the CDC for pregnant travellers on Zika risk and prevention and here is another reminder of the travel advice provided by the CDC and Australian Government for pregnant women.

If planning to travel while pregnant, consult your local doctor or travel health clinic for advice.

Want to learn more about the amazing world of Australian mosquitoes? Check out “A Field Guide to Mosquitoes of Australia” out now through CSIRO Publishing. Over 200 pages containing a pictorial guide to almost 100 different mosquitoes along with tips on beating their bite and protecting your family from the health risks of mosquitoes. You can order online or through your favourite local bookstore or online retailer.

 

 

Putting a value on science communication

For many scientists, communicating the ideas that underpin their areas of expertise to the public and policy makers is critical. Sharing the findings of research could make a difference to people’s lives, even if it is just to increase their appreciate of science and the world around them. But how do we value the communication of science by scientists?

Scientists often bemoan the lack of acknowledgment of their scientific communications and community engagement efforts. There is little doubt that these “outreach” activities receive far less “academic credit” than publication in high impact journals.

Writing for “popular science” outlets is often perceived to be a career negative. While some argue there needs to be capacity for the community engagement efforts of scientists to be acknowledged in the assessment of academic accomplishment, others argue against it. Regardless of your motivations, if you’re going to engage in science communication, it is best to make the most of your activities but even when your research goes vial, how can you put a value on this?

How can you value your science communications in a way that may be recognised for employment, promotion, grant applications etc?

One of my recent articles for The Conversation, why mosquitoes seem to bite some people more, went a little bit viral. Almost 1.3 million people clicked on that article. Would I swap it for an article in Nature (or any other scholarly publication with a high impact factor) that only 20 people read? Probably as it would make a far more valuable contribution to my career…but would it have the same potential to change people’s awareness and behaviour in avoiding mosquito bites? Probably not.

I’ve written before about the importance of social media in getting the public health messages informed by my research out to the public. A blog post I wrote about the shortcomings of mosquito repellent wrist bands in protecting people against mosquito bites is the most read post on my blog. Since first published, the article “Do mosquito repellent wrist bands work?” has been read by around 47,000 people. The original paper, published in a journal without an impact factor, may have been read by only dozens of people if I hadn’t written about it on my blog.

I’m increasingly asked to provide evidence of “engagement” or “translation” activities associated with my research. This is particularly the case for my activities with Centre for infectious Disease and Microbiology Public Health where translating research for improved public health outcomes is a key objective. Those outcomes have generally been focused on providing informed guidance to local authorities on infectious disease surveillance, diagnosis and treatment.

What about community engagement?

I wanted to share how I’ve been trying to value my science communication activities in recent years. My general approach to this is to document as much detail as possible about individual activities, try to quantify the reach of activities (as much as possible) and to try to use my experience with these activities into what could be best described as my “core” activities.

In the same way you may incorporate a new laboratory technique or statistical analysis into your research, why not incorporate your science communication activities similarly?

Every summer I find myself standing in the mangroves talking to a camera (while being bitten by mosquitoes)

Media activities

In the summer past, I’ve been interviewed about 50 times on research findings, disease outbreaks and topical issues associated with mosquitoes and mosquito-borne disease. This level of activity clearly holds the potential to engage the wider community with important public health messages as well as (hopefully) improve their understanding of local scientists and their research.

While keeping a track of the interviews and their details (date, topic, journalist, outlet etc) is handy, it is also possible to go beyond that to record audience reach and assign a relative value. This is where you’ll need the help of your institute’s media and communications unit. They should be able to obtain reports from media monitoring organisations that keep track of details (interview summary points and duration, audience size, estimated value) associated with media activities.

For example, on 16 January 2015 I did a live cross to Channel 7’s Sunrise program. The interview ran for just over 3 minutes, issues about mosquito-borne disease risk and personal protection measures were covered, it had an estimated audience of over 500,000 and was valued at around $200,000.

Over the course of a year (or perhaps a research project), it is possible to assign both a financial and engagement value? For me, the media activities over the 2014-2015 summer had an estimate audience of around 8 million and value of over $600,000. This extra level of detail adds so much extra weight to the value of science communications activities.

Mosquito Bites is the bulletin of the Mosquito Control Association of Australia. Distributed to members throughout Australia and many other countries, it provides information on the operational aspects of mosquito and mosquito-borne disease management.

Popular science writing

I regularly contribute articles to non-scholarly publications, these include newsletters, bulletins and magazines produced by local community groups, industry bodies and scientific associations. As well as recording the specific details about each article, it is also possible to record circulation as a measure of engagement.

If you need to add a financial value to these articles, why not consider what the current rates are for freelance journalists? They seem to be around $0.40-1.00 per word, that makes any (non-scholarly journal) writing associated with research projects as an “in kind” contribution valued at around $500-600? Planning on writing an article associated with an upcoming research project, why not include this extra value as an “in kind” contribution?

I regularly write for The Conversation. The website provides excellent data on the readership of individual articles (including with respect to other contributors from your institution) in addition to republication and social network sharing. Most of my articles receive around 6,000-8,000 reads but many have also reached around 20,000. Again, this is typically substantially greater exposure than received by my articles in scholarly journals. Recording this additional information would help make a handy argument that non-academic writing holds value, especially when arguing about research translation.

Output from @mozziebites Twitter Analytics for February 2015 showing data on impressions and engagement with my Tweets during the month.

Social media activity

Got a Twitter account or Facebook page? It is obviously great to keep track of your follower numbers, retweets, likes and shares of tweets and posts. It is a way to demonstrate engagement with the community. I started tracking my activity on Twitter early on. I was partly interested in whether people would engage with tweets about mozzies but I also wanted to demonstrate to my “bosses” that using social media for “work purposes” had some benefits in line with the public health objectives of my research activities. There was also a very nice paper published in 2012 that provided a framework for assessing the engagement of health authorities with social media and I wanted to gather similar data.

For Twitter users, you can access data on your own account via Twitter Analytics. It provides plenty of useful information, especially engagements (i.e. total number of times a user interacted with a Tweet, including retweets, replies, follows, favorites, links, cards, hashtags, embedded media, username, profile photo, or Tweet expansion), impressions (i.e. times a user is served a Tweet in timeline or search results) and link clicks (i.e. clicks on a URL in the Tweet). This kind of data can help demonstrate the extent to which the online community is interacting with your own social media activity.

It will also help if you engage with your institution on social media. Help promote their activities and those of your colleagues and collaborators. In turn they’ll help raise your profile too.

Speaking at public events provides opportunities to meet a wide cross section of the community….even celebrities such as Jimmy Giggle at the ABC community event at Parramatta Park, April 2014.

Community presentations

Every year i speak at a range of community events. In the past year or so I’ve spoken at such diverse events as Sydney Olympic Park Authority’s Life in the Park, Australian Skeptics in the Pub, Cumberland Birds Observer’s Cub meeting, Oatley Flora and Fauna Conservation Society meeting and Pint of Science. This provides an opportunity to speak to a wide cross section of the community but is also an opportunity to document experience in communicating to different audiences.

As well as keeping track of these speaking engagements (date, title, location, hosting organisation), I also try to record the number of attendees and most of the time I make a note of questions asked. This, again, is a way to document engagement/translation of research. It can also form a foundation for how you may shape research, it has particularly been the case for me reviewing the way we share public health information relating to the promotion of insect repellent use.

Communications and publications

Finally, think about ways you can parlay your experience with science communication into output that’s recognised by your organisation or institute. Why not write a perspectives piece, commentary or letter to the editor? I’m regularly seeing articles popping up in peer reviewed journals explaining the benefits of using social media, why not target a journal within your field that may not have covered the topic. You only need to see the metrics on this paper, ‘An Introduction to Social Media for Scientists‘, to realise that there is plenty of interest and having an extra journal article under your belt won’t hurt either.

Similarly, if you’re being asked to speak at conferences and workshops on your use of social media and/or science communication strategies, make sure you’re recording all those details too.

To conclude, there may not (yet) be a magic number to assign to your science communications activity in the same way impact factors and altmetrics help measure the success of traditional academic output. However, that doesn’t mean you cannot record a bunch of “metrics” associated with science communications, both online and off, that will hopefully better place you for that next job offer or promotion.

What do you think? How do you document your scientific communications activities? Join the conversation on Twitter.

Are mosquito coils making us sick?

We burn them to beat the bite of mosquitoes but could they actually be making us sick? Is breathing the smoke from a smouldering mosquito coil really the same as smoking a pack of cigarettes?

In summary, should I use mosquito coils to protect my family from mosquito bites?

• Only use commercial products that have been registered by local authorities
• Products that contain pyrethroids will provide better protection from mosquitoes than those that contain only botanical extracts
• The byproducts of combustion, not insecticides, associated with mosquito coils may pose a health risk in some circumstances
  
• Best to limit use of coils to outdoor or well ventilated indoor areas
• Don’t sleep next to a smouldering mosquito coil
• Consider plug-in “smokeless” mosquito repellent devices
• Sleeping under a mosquito net is the best non-chemical approach to overnight mosquito bite prevention

The Saltmarsh Mosquito (Aedes vigilax) (Photo: Stephen Doggett)

Here is the background…

For centuries we’ve burnt substances, particularly aromatic plants, to keep mosquitoes away. The clouds of smelly smoke can often ward off the swarms of blood sucking mosquitoes.

The use of pyrethrum in incense gained popularity and became common practice in Asia but it wasn’t until the early 1900s that the mosquito coil was born thanks to Japanese entrepreneurs Eiichiro and Yuki Ueyama and their katori senkō (mosquito-killing incense).

Modern mosquito coils, mostly containing the pyrethroid insecticides, are an almost permanent fixture at camp sites and backyard during summer. Millions of families across the tropics use them as their primary source of mosquito-borne disease prevention. They’re cheap and generally effective. We burn them to reduce the risks of mosquito-borne disease but could they actually be making us sick?

Health concerns of mosquito coils

There is growing concern about the adverse health impacts associated with the burning of mosquito coils and sticks indoors. A recently presentation to the 48th National Conference of Indian College of Allergy, Asthma and Applied Immunology has again raised the issue of potential health impacts associated with mosquito coils with media coverage given to Dr Sundeep Salvi in the lead up to the conference. He is quoted as saying “Burning one mosquito coil in a closed room amounts to smoking roughly 100 cigarettes”. The key point in Dr Salvi’s comment is “closed room”.

When assessing the real risks posed by mosquito coils, it is important to consider not just what is released by these smouldering products but actual likelihood it poses a serious health risk. How do you balance these potential health risks of burning coils with those posed by the bite of infected mosquitoes?

Do you really need to weigh up the risks of breathing in smoke from a mosquito coil with the risks of mosquito bites? (Image: Joel Sartore, National Geographic)

Who checks the safety of mosquito coils?

In Australia, all substances that purport to kill or repel mosquitoes must be registered by the Australian Pesticides and Veterinary Medicines Authority (APVMA). Similar regulatory authorities exist in other jurisdictions.

Mosquito repellents, whether they’re topical or spatial or whether they contain “chemical” or “natural” substances will need to be tested for efficacy and safety. Check the packaging for a registration number. There are dozens of different variations on “mosquito coils” including sticks, coils, candles and a variety of “plug in” devices. You’ll find the shelves of the local supermarket, camping and hardware store fully stocked almost all year round!

Despite the wide range of products available, the active ingredients (that is the mosquito repelling or killing products) don’t vary too much. There are either synthetic pyrethroids or botanical extracts (e.g. citronella oil, eucalytpus oil). You may be surprised to know that some contain a combination of the two. Just because “citronella” is written in bold on the packaging, it may still contain one of the synthetic pyrethroids. Check the label.

Does burning mosquito coils really make us sick?

A study of mosquito coils sold in the U.S. and found that some mosquito coils contain octachlorodipropyl ether (s-2) that, during the smouldering of the coils, produces an extremely potent lung carcinogen as a byproduct called (bis(chloromethyl)ether (BCME)). Fortunately, s-2 is banned in many countries. It is no longer used commercially in the U.S. and prompted by reports of the risks associated with mosquito coils, Hong Kong authorities released a statement in 2005 regarding the recall of mosquito coils containing s-2.

It is not listed as an active ingredient in mosquito coils registered for use in Australia. Given that in most circumstances, particularly in Australia, mosquito coils don’t contain s-2, it is the particulate matter that is of greatest concern.

An often quoted study published in 2003 titled “Mosquito coil emissions and health implications” analysed the components of commercially available mosquito coils from China and Malaysia and found that burning mosquito coils in an enclosed room may pose “significant acute and chronic health risks” with the fine and ultra fine particulate matter released from a single mosquito coil equaling that of up to 137 cigarettes!

In addition, they found that emission of formaldehyde (a by product of the combustion process) from burning one coil can be as high as that released from burning 51 cigarettes.

Doesn’t sound too good does it? The combustion of the coil itself is the main concern, not the insecticides used.

More recent studies have indicated that changing the base materials used in mosquito coils (i.e. switching to charcoal from other organic material) can reduce the volume of particulate matter substantially. Would these “smokeless” mosquitoes be more “healthy”? Probably.

Does what happens in the lab stays in the lab?

Billions of mosquito coils are sold across Asia every year. Millions of families use them as their primary mosquito bite prevention strategy. Why aren’t we seeing more substantial health impacts in local communities?

It is worth noting that two papers published in 2006 investigated the different methods used to assess the health risks associated with burning mosquito coils. The researchers tested different methods to expose laboratory rats to particulate matter from mosquito coils. They firstly reported that “protocols devised evaluate and assess the acute inhalation toxicity of mosquito coil smoke demonstrating that the nose-only mode of exposure of rats to the smoke of mosquito coils is suitable to assess the toxic potency of different coils.

The nose-only mode has clear advantages over the whole-body exposure mode.” Then, using the “nose-only” exposure method that they proposed, the researchers concluded that “overnight exposure to the smoke from burning mosquito coils (manufactured in Indonesia) is unlikely to be associated with any unreasonable health risk.” This is a noteworthy conclusion given that the level of exposure to those rats (6 h a day, 5 days a week for 13 weeks) was substantial.

What about “smokeless” mosquito coils?

There is a paucity of studies investigating the potential human health impacts of “smokeless” mosquito repellents. The few studies that do exist are inconclusive or use animals to test health impacts under conditions unlikely to occur in most circumstances.

A 2005 review of pyrethroid poisoning reported “Despite their extensive world-wide use, there are relatively few reports of human pyrethroid poisoning. Less than ten deaths have been reported from ingestion or following occupational exposure. Occupationally, the main route of pyrethroid absorption is through the skin. Inhalation is much less important but increases when pyrethroids are used in confined spaces.” Again, this highlights the critical issue here, exposure to insecticides in confined and/or enclosed situations.

It is worth remembering that pyrethroids are over 2000 times more toxic to insects than mammals. That means that the concentrations used to kill insects are unlikely to have adverse health impacts on humans, particularly if commercial formulations are used as recommended. Given the billions of people who use mosquito coils to prevent mosquito bites, perhaps the more important question to ask is, does burning mosquito coils actually prevent mosquito-borne disease? Perhaps that is a discussion for another time….

Perhaps one of the most interesting ideas this year was the “mosquito repellent beer carton”. More marketing than public health initiative but I like the idea. The carton is infused with citronella so that when you’re sitting about the campfire enjoying a few beers, you can toss bits of the carton into the fire and keep mosquitoes away. It is unlikely many mosquitoes will be actively repelled. However, I do like the idea of using the beer carton as an opportunity to raise awareness of mosquito-borne disease.

Perhaps it is this little bit of public health communication that will actually stop a few people becoming infected.

Do you use mosquito coils and sticks to prevent mosquito bites? Join the conversation on Twitter and let me know what you think.

Want to learn more about the amazing world of Australian mosquitoes? Check out “A Field Guide to Mosquitoes of Australia” out now through CSIRO Publishing. Over 200 pages containing a pictorial guide to almost 100 different mosquitoes along with tips on beating their bite and protecting your family from the health risks of mosquitoes. You can order online or through your favourite local bookstore or online retailer.

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Read more at The Conversation: Are mosquito coils good or bad for our health?

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Read more at The Conversation: What can I eat to stop mosquitoes biting me?

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Read more at The Conversation: The best (and worst) ways to beat mosquito bites

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