A Guam visit to battle Zika virus and discover new mosquitoes

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There are few places on earth where you can search in water-filled canoes for one of the most dangerous mosquitoes on the planet less than a stone’s throw from tourists posing for selfies alongside their inflatable novelty swans in the nearby lagoon.

Guam is the place to go if you need to tick that off your “to do” list!

I was fortunate to be invited to speak at the Pacific Island Health Officers Association (PIHOA) Regional Zika Summit and Vector Control Workshop in Guam 25-29 June 2017. The theme of the summit was “Break Down the Silos for Preparedness and Management of Emergencies and Disasters in United States Affiliated Islands” and had objectives to critical analyze the regional responses to recent mosquito-borne disease outbreaks while developing policies to strengthening public health emergency response and preparedness systems and capabilities within the region.

The tranquil lagoons of the Pacific Islands may seem a very long way from the hustle and bustle of the busy South American cities that held the 2016 Olympics but just as Zika virus was grabbing the attention of sports reporters everywhere, health authorities active in the Pacific were growing concerned too.

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The Pacific has been far from free of mosquito-borne disease outbreaks. Previous outbreaks of dengue, chikungunya and even Ross River virus had struck numerous times. While sometimes widespread, at other times outbreaks were more sporadic or isolated. As is the case for many non-endemic countries, outbreaks are prompted by movement of infected travelers and the prevalence of local mosquitoes.

Across the region there are four mosquitoes of primary concern, Aedes aegypti, Aedes albopictus, Aedes polynesiensis and Aedes hensilli. The greatest concerns are associated with Aedes aegypti and in those countries where the mosquito is present, the risks of mosquito-borne disease outbreak are greatest. For this reason alone, it is imperative that good entomological surveillance data is collected to confirm the distribution of these mosquitoes but also to develop strategies to eradicate, where possible, Aedes aegypti should it be introduced to new jurisdictions.

With a growing interest in developing mosquito surveillance and control programs for exotic mosquitoes here in Australia, it was a perfect opportunity for me to get a closer look at how the threats of these mosquitoes and associated outbreaks of disease are managed.

On the third day of the meeting, vector control took centre stage. A brilliant day of talks from each of the jurisdictions on the disease outbreaks they’ve faced and how they’re preparing for future threats. There were presentations from the United States Affiliated Pacific Islands (USAPI) including Guam, the Federated States of Micronesia (Yap, Kosrea, Chuuk, Pohnpei), the Commonwealth of the Northern Marianas (CNMI), the Republic of Palau, the Republic of Marshall Islands (RMI), and American Samoa.

Hearing from these teams doing their best to protect their local communities from the threat of mosquito-borne disease, with only limited resources, was quite eye opening. There was passion and dedication but each territory faced unique challenges to ensure the burden of disease is minimised.

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Just outside the workshop venue were a series of water-filled canoes. Most contained larvae!

There is little doubt that climate variability will have a strong role to play in the impacts of mosquito-borne disease across the region in the future but there are so many other issues that could be contributing to increased risk too. One of the biggest problems is rubbish.

Time and time again, the issue of accumulated waste, especially car bodies and discarded tyres, was raised as a major problem. As many of the key pest mosquitoes love these objects that trap water, treatment of these increasing stockpiles becomes more of a concern. Community wide cleanups can help reduce the sources of many mosquitoes but the rubbish more often than not remains on the island and requires continued management to ensure is not becoming a home to millions of mosquitoes.

It is a reminder that successful mosquito control relies on much more than just insecticides. An integrated approach is critical.

There was a “hands on” session of surveillance and control. Coordinated by PIHOA’s Eileen Jefferies and Elodie Vajda, the workshop was a great success. It provided an opportunity for many to see how to prepare ovitraps and BGS traps (one of the most widely used mosquito traps) and discuss the various considerations for choosing and using the right insecticides to reduce mosquito-borne disease risk. Workshop attendees were also the luck recipients of a selection of cleaver public awareness material produced in Guam, from personal fans and anatomically incorrect plush mosquitoes to Frisbees and mosquito-themes Pokemon cards!

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Guam “mozzie” team: Elodie Vajda, Claire Baradi, Michelle Lastimoza, Eileen Jefferies and me

Following the summit, there was a chance to visit the new Guam “Mosquito Laboratory”, newly established as part of the Guam Environmental Public Health Laboratory (GEPHL). I’ll go out of my way to visit any mosquito laboratory but I was particularly keen to see this one as one of my previous students was playing a key role in establishing the mosquito rearing and identification laboratories. Elodie has been doing an amazing job and it was brilliant to geek out with her over some hard core mosquito taxomony as we tried to ID a couple of tricky specimens. [Make sure you check out our recent paper on the potential impact of climate change on malaria outbreaks in Ethiopia]

It actually turned out that one of their “tricky specimens” was a new species record for Guam – an exotic mosquito Wyeomyia mitchellii! The paper reporting this finding has just been published “New Record of Wyeomyia mitchellii (Diptera: Culicidae) on Guam, United States“.

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Mosquito-borne disease in the Pacific isn’t going anywhere and it’s important that once the focus fades from Zika virus, dengue and chikungunya viruses will again take centre stage and their potential impacts are significant. With the added risks that come with gaps in the understanding of local pest and vector species, the prevalence of insecticide resistance among local mosquitoes, climate variability and a struggle to secure adequate funding, challenges lay ahead in ensuring the burden of mosquito-borne disease doesn’t increase.

A modified version of this article appears in the latest issue (Winter 2017; 12(1)) of Mosquito Bites Magazine, (a publication of the Mosquito Control Association of Australia)

 

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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.

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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!

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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.

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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:

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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.

Mosquitoes, Gold Coast and the latest arbovirus research

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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!


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

Suzi B. Claflin1 and Cameron E. Webb2,3

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.


Do urban wetlands increase mosquito-related public health risks?

Jayne K. Hanford1, Cameron E. Webb2,3, 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.


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.


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

Cameron E Webb1,2

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.


So, you want to write a field guide?

Cameron E. Webb1,2, 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.


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.


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

Cameron E Webb1,2 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.


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

Cheryl S. Toi1, Cameron E. Webb1,2, 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.


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.


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 Mah1,2, 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?

 

 

Summer summary of mosquito media madness

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Summer is always a busy time for me. As well as plenty of time sloshing about in the wetlands, there is often lots of interest from mosquito-curious media. There has been some intense bursts of activity in previous summers but the 2015-2016 was particularly interesting.

I certainly covered some new ground this summer. I responded to over 160 individual media requests in the past 6 months. From flies and food safety to the emergence of Zika virus. Here is a wrap from my media adventures and some valuable lessons learned for future science and public health communication.

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The good news of new virus discoveries

Usually, the discovery of a new mosquito-borne virus brings with it new concern for public health. This time though, there was some good news.

Towards the end of 2015, a paper reporting on a collaborative research project between University of Queensland, QLD Health and University of Sydney was published in Virology. This was the first publication detailing the discovery of Parramatta River virus, an insect specific virus that exclusively infects the mosquito Aedes vigilax. This virus does not infect people and poses no health risk.

A joint media release was issued by University of Queensland and University of Sydney and there was plenty of media attention. Not surprising given the usual negative associations with mosquito-borne pathogens!

There were dozens of articles, much of the attention focused on the team at University of QLD. Dr Jody Hobson-Peters was kept busy with local media including ABC and Brisbane Times. It was a great experience sharing the research with colleagues in Queensland, particularly great seeing so much exposure for PhD student Breeanna McLean and her newly published research.

I was surprised at how little attention there was in the news from Sydney media. The lesson here though was more about bad timing than uninteresting research. A couple of weeks after the initial media release, I forwarded around a few emails and sent out a couple of tweets and next thing you know, we made the front page of the local newspaper, the Parramatta Advertiser (see above). It was some great local coverage, not only about the virus discovery but it also provided an opportunity to raise awareness of mosquitoes and mosquito-borne disease on the eve of summer!

Lesson learned: A good reminder that if your research isn’t picked up immediately, give it another shot a few weeks later. Timing may make all the difference but perseverance does too!

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To stop sickness, swat or spray

Just in time for Christmas lunch and summer holiday picnics, I published an article on flies and food safety at The Conversation. I really expected this article to slip under the radar of most people. Coming out on Christmas eve doesn’t seem likely many would be clicking about on the internet but within a few days over 600,000 people had clicked on the piece!

Many of those clicks were thanks to the article being shared by IFLS but there was also plenty of interest from local media and I was busy with interview requests from ABC Local Radio across the country. Who doesn’t love hearing about how flies poop and vomit on your food? I was even interviewed by Grey Nomad Magazine!

Lesson learned: Applying a little science to seasonal urban myths and common uncertainties can prove popular and may be a good opportunity to promote a little science!

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Rain, rain everywhere with mozzies soon to come

With all the talk of El Nino and predictions of a hot and dry summer for the east coast of Australia, the summer was actually reasonably mild and extremely wet. Sydney was particularly battered by a series of storms and intense rainfall early in 2016.

More water generally means more mosquitoes. In response to the rain, many media outlets were interested in chatting about the prospects of a bumper mosquito problem. As well as talking about the prospects of an increase in mosquito-borne disease risk, it was a great opportunity to talk about personal protection measures.

There were some radio, print and tv spots that provided opportunities to talk about how to choose and use the right repellents.

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In 2015 I published a paper in the Medical Journal of Australia explaining that health authorities need to provide more guidance on how the community can get mosquito repellents working more effectively.

Typical health warnings and media release from health authorities (usually limited to grabs on news bulletins) but when there is an opportunity to do longer form radio interviews, there is a chance to put an emphasis on aspect of public health messages. The hook to get these longer spots is giving more than just warnings, by mixing up some interesting things about mosquitoes, you can catch a little extra attention and sneak in the public health messages between the fun and fascinating facts about mosquitoes!

One news outlet was really insistent in grabbing a hold of me for some comments ahead of the evening bulletin. They even sent a crew to meet me in the city while I was taking the kids along to the Sydney Festival!

Lesson learned: When doing tv for the evening news, it is ok to wear a t-shirt, shorts and runners just so long as you have a rain jacket handy to make you like like you could have just stepped straight out of the wetlands!

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From African forests to South American cities

While many of us were keeping our eyes on the developing outbreak of mosquito-borne Zika virus in South America towards the end of 2015, it wasn’t until February 2016 that the situation really grabbed the attention of the world’s media.

In late January, I published a piece at The Conversation titled “Does Zika virus pose a threat to Australia?” It prompted a little interest but it was the media conference coordinated by University of Sydney Media and Communications together with Australian Science Media Centre (AusSMC) that coincided with the announcement of the World Health Organization that the Zika virus outbreak was a Public Health Emergency of International Concern.

Together with colleagues from the University of Sydney’s Marie Bashir Institute of Infectious Disease and Biosecurity, I spoke at a media conference broadcast nationally on ABC News 24. There was a huge amount of media stories stemming from this media conference with over 500 individual articles identified across radio, tv, print and online. During the days and weeks following, I felt like I was spending more time at the ABC studios in Ultimo than I was in our lab! There were days when I spent hours on the phone doing radio interviews.

There were a couple of great longer form interviews that I really appreciated the opportunity to contribute to such as ABC Radio National’s Health Report and Rear Vision. There were also a couple of podcasts too, check out Science on Top and Flash Forward.

This flood of media requests also exposed me to a few more new experiences. There were live tv appearances on Sunrise, ABC News 24 and Sky News but probably one of the most interesting was my spot on Channel Ten’s The Project. It was interesting for a number of reasons.

Firstly, I was warned early on that one of the guests on the panel was comedian Jimmy Carr, a somewhat controversial figure notorious for jokes a little too close to bad taste. I’m not typically one to play the “wacky scientist” during interviews but what I was most cautious of was not being seen to be treating a very serious disease outbreak too lightly. I was determined to play the straight guy. In the end the interview turned ok but there were a couple of awkward moments that, luckily, ended up being edited out.

Secondly, simply doing the interview was unusual. It was a pre-recorded interview with me in a tiny room at the Channel Ten studio in Sydney and the panel in the Melbourne studio. I was sitting in front of a green-screen, staring down the camera with an earpiece blasting away in my ear. I have done live crosses before but they’re all been one-on-one interviews. This time it was with the panel and I found it incredibly difficult to get the feel for each of the panelists when they were asking questions. Missing that eye-to-eye contact was a disconcerting experience. Luckily, all turned out well in the end.

Lesson learned: Lots (I mean LOTS) learned while dealing with the interest in Zika virus! Probably another post in itself…but I would say that managing this volume of media wasn’t easy and it did eat up a lot of time (even though communicating public health messages is central to my “day job”) but this was important work.

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A morning with Dr Karl!

When it comes to science communicators in Australia, there are few with a higher profile than Dr Karl Kruszelnicki. We’d spoken on a number of occasions about mosquitoes but I’d never actually met him in person before. “Dr Karl” invited me to hang out for a morning recording interviews for ABC News 24, ABC Local Radio and also guest on his national “Science Talk” segment on Triple J’s Mornings Show with Zan Rowe.

The experience of a behind-the-scenes perspective on Karl’s hectic schedule and how he manages the frenetic pace of work at the ABC was an eye opener. Doing the hour long segment on Triple J was great, enlightening to get questions from a slice of the Australian community I don’t usually cross paths with when doing the usual community engagement. I good reminder of just how much anxiety there can be within the community when news of international disease outbreaks occur. Not surprising given the thousands of Australians travelling to South America each month….with more to come later this year when the Rio Olympic Games kick off!

You can listen to the segment here and you can also follow Dr Karl on Twitter.

Lesson learned: From a public health perspective, this is a great reminder that the concerns and anxieties around infectious disease can change depending on the sector of the community you’re dealing with. The core messages may remain the same but you’ll always need to consider your audience when fine tuning your public health messages.

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So, was all this worth it?

It was stressful. It was fun. It eroded much of my time that may have been spent in other ways but I see this as “doing my job” perhaps a little more than pure research scientists do. But how does all this convert into tangible metrics. How do you measure the reach and economics of all these media activities?

I’m fortunate to be supported by the University of Sydney media and communications team that helps out by providing some data on the metrics of my media activities each summer. What was all this time and effort worth?

Between November 2015 and Match 2016, I was quoted in over 160 media items. This adds up to a cumulative audience of around 8.9 million people, that is quite some reach! How much was it worth? Based on current advertising rates, about $1.6 million.

I’ve written before about how we can better value science and public health communication. Collecting these types of metrics can be useful for a range of purposes. Recently, I’ve been including media engagement as an “in kind” contribution to grant applications with valuation calculated on average media coverage that may be expected.

The lesson here is to take the time to record your media activities, not just so you have a list to demonstrate quantity but also so you can assess audience and value to your media activities. Work with your media and communications departments to see what extra information you can collect.

Got any other tips? Share them via Twitter!

 

 

 

 

 

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. 


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)

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.

Zika virus: Resources, references and recommendations

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The following is a collection of almost 100 links to news stories, resources, references and recommendations associated with mosquito-borne Zika virus and the current outbreak in the Americas.

What is Zika? What are the health threats and why an outbreak now?

Zika virus (CDC). Essential resource. Click.

Zika virus (WHO). Essential resource. Click.

Zika virus spreading explosively, says World Health Organisation (The Guardian). Coverage of statement by WHO Director General that the explosive outbreak of Zika virus in the Americas as “deeply concerning” and that an emergency committee has been convened. Click.

WHO Director-General summarizes the outcome of the Emergency Committee regarding clusters of microcephaly and Guillain-Barré syndrome (WHO). Click.

Zika virus declared a global health emergency by WHO (ABC News). Click.

Zika Virus Spreads to New Areas — Region of the Americas, May 2015–January 2016 (CDC). Click.

WHO early response to Zika virus praised by Australian experts (The World Today). Click.

First report of autochthonous transmission of Zika virus in Brazil (Memórias do Instituto Oswaldo Cruz). Click.

How a Medical Mystery in Brazil Led Doctors to Zika (New York Times). A summary of how health officials investigating a spike in cases of birth defects put together the link to a mosquito-borne disease. Click.

Explainer: where did Zika virus come from and why is it a problem in Brazil? (The Conversation). A good, brief summary of the emergence of Zika virus in Brazil and the health risks it poses. Click.

Zika virus outbreak: What you need to know (New Scientist). A good summary of issues associated with Zika virus outbreak. Click.

Zika outbreak: What you need to know (BBC). A good summary of what is known of Zika virus and its health risks. Click.

What to Know About Zika Virus (The Atlantic). Click.

Zika virus, explained in 6 charts and maps (Vox). Useful collection of infographics on Zika virus, current and historic outbreak distributions and health impacts. Click.

An Illustrated Guide To The Zika Outbreak (Huffington Post). Click.

Why it’s wrong to compare Zika to Ebola (The Conversation). Whats the difference between Ebola and Zika viruses? What are the implications of outbreaks and declarations of public health emergencies? Click.

Zika fever: panic won’t help us (The Guardian). Editorial highlighting the horror and unexpectedness of the Zika virus outbreak in Brazil and how we should move forward in mosquito control. Click.

What we still don’t know about Zika virus (Mashable). There are plenty of gaps in our understanding of Zika virus. Click.

The human cost of Zika is clear, but will Brazil’s economy suffer too? (The Conversation). Outbreaks of infectious diseases can have greater impacts than the human illness alone. Click.

aedes_albopictus_SteveDoggett

Zika virus and its vectors

Mosquitoes: The Zika vector (Radio National). Why do we need to know how many mosquitoes can spread Zika virus and what is it about the mosquitoes that do that make them such an important pest? Click.

Natural-born killers: mosquito-borne diseases (SMH). What is it that makes mosquitoes such effective vectors of pathogens? Click.

Zika Virus in Gabon (Central Africa) – 2007: A New Threat from Aedes albopictus? (PLOS Neglected Tropical Diseases). Click.

Oral Susceptibility of Singapore Aedes (Stegomyia) aegypti (Linnaeus) to Zika Virus (PLOS Neglected Tropical Diseases). Click.

Aedes (Stegomyia) albopictus (Skuse): A Potential Vector of Zika Virus in Singapore (PLOS Neglected Tropical Diseases). Click.

Potential of selected Senegalese Aedes spp. mosquitoes (Diptera: Culicidae) to transmit Zika virus (BMC Infectious Diseases). Click.

Genetic Characterization of Zika Virus Strains: Geographic Expansion of the Asian Lineage (PLOS Neglected Tropical Diseases). Click.

Molecular Evolution of Zika Virus during Its Emergence in the 20th Century (PLOS Neglected Tropical Diseases). Click.

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The spike in cases of microcephaly and its suspected links to Zika virus infection of those pregnant has been raising greatest concern. (Image: BBC)

Zika virus, pregnancy and microcephaly

Possible Association Between Zika Virus Infection and Microcephaly — Brazil, 2015 (CDC). Click.

Microcephaly in Brazil: is it occurring in greater numbers than normal or not? (Virology Down Under). Great post highlighting the gaps in our understanding of links between microcephaly and Zika virus. Click.

Proving that the Zika virus causes microcephaly (The Conversation).  What questions must be answered to confirm a link between Zika virus and microcephaly. Click.

Interim Guidelines for Pregnant Women During a Zika Virus Outbreak — United States, 2016 (CDC). Click.

CDC: Link between Zika, microcephaly looks “stronger and stronger” (Reuters). Click.

Facts about Microcephaly (CDC). What are the impacts, causes and treatments associated with microcephaly? Click.

Zika virus outbreak raises Pacific, Americas travel concerns for pregnant women (Stuff NZ). Implications for those travelling in Pacific while pregnant. Click.

Safely avoiding mosquito bites when pregnant (Mosquito Research and Management). My tips on safe and effective avoidance of mosquito bites while pregnant. Click.

13 Things Pregnant Women Should Actually Know About Zika (Buzzfeed). Some good advice, most importantly, don’t panic. Don’t even panic if you’re pregnant and bitten by a mosquito. Click.

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Zika virus and the threat to Australia

Does Zika virus pose a threat to Australia? (The Conversation). An overview of why, and why not, Zika virus poses a risk to Australia. Click.

The Threat to Australia: The Rise Of Zika Virus (Popular Science). Article from 2014 highlighting potential risk to Australia of Zika virus following detection of imported cases. Click.

Zika Virus Explained: Aussie Mozzies, Bali Risks And Pregnancy (Huffington Post). Good summary of risks posed to Australia and Australian travellers. Click.

Zika virus: Risk of a widespread outbreak in Australia ‘low’, experts say (ABC News). A summary of reasons why there won’t be a major outbreak of Zika virus in Australia. Click.

Zika talkback with Dr Karl on Triple J (ABC). I join Dr Karl for talkback on Zika virus, advice to travellers and the risks of outbreak in Australia. Click.

Zika virus alert (NSW Health). Factsheet on Zika virus and risk to NSW. Click.

Little chance of Zika outbreak in NSW (Sky News). There is unlikely to be a major outbreak of Zika virus across Australia’s most populated region. Click.

Two Aussies confirmed with Zika as US records first case of virus transmitted through sex (The Mercury). Click.

Zika virus mosquitoes found in Sydney: Airport increases insecticide spraying of incoming passengers (Daily Telegraph). Report of recent detection of Aedes aegypti at Sydney airport by Department of Agriculture and Water Resources. Click.

Queensland announces $1.4 million program to fight Zika. (Brisbane Times). Queensland authorities announce response plan; increasing monitoring and research into Zika virus.  Click.

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Zika virus entering Australia

Zika virus and Travel Alert for Australians (Smart Traveller). Click.

Imported Zika Virus Infection from the Cook Islands into Australia, 2014 (PLOS Current Outbreaks). Click.

Zika Virus Infection Acquired During Brief Travel to Indonesia (Am J Trop Med Hyg). Published report from 2013 of Australian traveller exposed to Zika virus in Indonesia. Click.

Aussie diagnosed with Zika after Bali monkey bite, experts warn of missed cases (SMH). Report of 2015 case os suspected infection following monkey bite in Bali. Click.

Zika Virus Infection In Australia Following A Monkey Bite In Indonesia (Southeast Asian Journal of Tropical Medicine and Public Health). Abstracted from published case report of suspected Zika virus infection following monkey bite. Click.

Six cases of Zika virus in Australia last year as pregnant women warned not to travel (SMH). Summary of recent imported cases of Zika virus infection in Australian travellers. Click.

Health Department confirms WA Zika case (The West Australian). Report of imported case of Zika virus infection in returning traveller to Western Australia. Click.

Zika virus: Queensland woman, child confirmed as contracting illness (ABC News). Imported cases of Zika virus infection with travellers returning to QLD from El Salvador. (ABC News). Click.

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Zika outbreaks in the Pacific

Zika Virus Outside Africa (Emerging Infectious Diseases). Summary of outbreaks in regions outside Africa with specific discussion of the first outbreak in Pacific. Click.

Zika Virus Outbreak on Yap Island, Federated States of Micronesia (New England Journal of Medicine). Click.

Zika virus: following the path of dengue and chikungunya? (The Lancet). Good paper, including useful maps, of activity of three critical mosquito-borne pathogens. Click.

Rapid spread of emerging Zika virus in the Pacific area (Clinical Microbiology and Infection). Publication reporting on the 2013 outbreak of Zika virus in the Pacific. Click.

Notes on Zika virus – an emerging pathogen now present in the South Pacific (Australian and New Zealand Journal of Public Health). An article assessing the risks of Zika virus to New Zealand. Although no suitable vectors exist there, a relatively larger volume of infected travellers would be expected to occur given the strong links to Pacific Islands. Click.

Tonga declares Zika outbreak (Sky News). Zika is impacting more regions than the Americas in 2016. Click.

Australia to help Pacific fight Zika (SBS News). How can Australian authorities take their expertise in mosquito monitoring, mosquito control and vaccine development to assist outbreak of Zika virus. Click.

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Zika virus and sex: An unusual route of transmission

Probable Non–Vector-borne Transmission of Zika Virus, Colorado, USA (Emerging Infectious Diseases). First documented case of transmission of Zika virus through direct contact between people. Click.

Potential Sexual Transmission of Zika Virus (Emerging Infectious Diseases). Publication from 2015 on suspected sexual transmission of Zika virus. Click.

Zika virus infection ‘through sex’ reported in US (BBC). Suspected case of sexually transmitted Zika virus in Texas in 2016. Click.

CDC: To avoid Zika exposure, consider no sex (The Washington Post). Coverage of CDC guidance on avoiding sexual transmission risk of Zika virus. Click.

Interim Guidelines for Prevention of Sexual Transmission of Zika Virus — United States, 2016 (CDC). Click.

Zika: Why the virus isn’t an STI despite being passed on after sexual contact (Independent).  Only where sex is the predominant route of transmission, and the infection is maintained in the human population by sexual transmission, is a pathogen considered a STI and that definition does not apply to Zika virus. Click.

Brazil finds Zika in saliva, urine; expert warns against kissing (SMH). Detection of Zika virus in saliva and urine doesn’t necessarily mean these are pathways of transmission. Authorities advising against kissing? Click.

Zika and the 2016 Rio Olympics

Zika Outbreak Means It Is Now Time To Cancel Rio Olympics (Forbes). Is the threat of Zika virus really so great that the Rio Olympics should be cancelled? Click.

NYU Bioethicist, Amid Zika Threat, Wants to Reschedule Rio Olympics: ‘What the Hell’s the Difference?’ (New York Magazine). With so many unanswered questions, and little confidence the outbreak is under control, is it really ethical to go ahead with the Rio Olympics? Click.

Brazil minister says no plans to cancel Rio Games (AP). Click.

Zika virus will not hamper Rio Olympics says IOC president Thomas Bach (ABC News). Click.

IOC says it will issue advisory on Zika virus spreading across South America ahead of Rio Olympics (ABC News). Click.

Zika crisis and economic woes bring gloom to Brazil’s Olympic buildup (The Guardian). Click.

Zika scare: Olympic athletes need mosquito nets as Bushman sponsors team (SMH). Click.

Zika Virus Rio Olympics: How Australian Athletes Will Fight Potential Infection (Huffington Post). Click.

Bushman named as official insect repellent of Australian Olympic team (mUmBRELLA). One of Australia’s leading mosquito repellent manufacturers to support the athletes and officials travelling to Rio Olympics. Click.

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Battling mosquitoes and the Zika virus outbreak

How Can We Slow The Epidemic Of Zika Infections? (Forbes). Now that the outbreak of Zika virus has been documented, what strategies are available to slow the spread and increasing numbers of cases? Click.

The world needs a Zika vaccine: Getting one will take years (STAT). We won’t have a Zika virus vaccine anytime soon. Here is an explanation why. Click.

Brazil Zika virus: ‘War’ declared on deadly mosquitoes (BBC). How are authorities battling the outbreak of Zika virus in Brazil? Click.

Mosquito Wars Update: Would You Choose GMO ‘Mutants,’ Pesticides Or Dengue And Zika Viruses? (Forbes). The outbreak of Zika virus has focused the attention of health authorities on options for future mosquito-borne disease management strategies. Click.

Brazil sends in 200,000 soldiers to stop the spread of the Zika virus outbreak which has seen huge numbers of babies born with small heads and cast a shadow over the Olympics (Daily Mail). Click.

Here’s what it will take to stop the Zika virus (Vox). Summary of critical issues to address to better understand and stop the Zika virus outbreak. Click.

Curbing Zika Virus: Mosquito Control (Popular Science). Well supported article on options for mosquito control and mosquito-borne disease management. Click.

7 ways the war on Zika mosquitoes could be won (New Scientist). Overview of the different approaches available to beat the Zika virus outbreak and mosquito-borne disease more generally. Click.

In Australia, a New Tactic in Battle Against Zika Virus: Mosquito Breeding (New York Times). Overview of emerging technologies developed in Australia to battle dengue but could be incorporated into the Zika virus response. Click.

Zika virus: pesticides are not a long-term solution says leading entomologist (The Guardian). Spraying insecticides can sometimes be a blunt instrument unless there is an understanding of where best to target mosquito populations. Click.

Zika outbreak revives calls for spraying with banned pesticide DDT (STAT). Outbreaks of mosquito-borne disease often prompt calls to return to DDT as teh insecticide of choice to control mosquitoes. Click.

Insecticide to be sprayed inside planes from Zika affected regions (The Guardian). Aircraft should already be treated with insecticides to stop movement of mosquitoes from one country to the next, hitchhiking in planes but efforts have been boosted in wake of Zika virus fears. Click.

Bats and Mosquitoes

Illustration by Golly Bard

Be careful what you wish for

Let’s Kill All the Mosquitoes (Slate). Emergence of another mosquito-borne disease, another opportunity to call for killing mosquitoes off completely. Click.

Why Eradicating Earth’s Mosquitoes To Fight Disease Is Probably a Bad Idea (Vice). Don’t be so sure that eradicating mosquitoes is the answer, or at least it won’t have consequences. Click.

Would it be wrong to eradicate mosquitoes? (BBC). What could be the unexpected consequences of sending mosquitoes extinct? Click.

Sights on world’s deadliest animal as Zika virus spreads (The New Daily). Wiping out all mosquitoes is probably a bad idea but perhaps we could knock off just a few and greatly improve the health of the planet? Click.

There’s one (or more) in every crowd…

Is Zika Virus the Next Tool For Forced Sterilization, Vaccination and Depopulation? (Activist Post). Oh boy. Click.

Health experts slam anti-vaxxers’ zika virus conspiracy theory as ‘absurd’ (News.com.au). No, immunization programs didn’t cause the Zika virus outbreak and increases in microcephaly. Click.

Concerning Correlation: GMO Mosquitoes Caused Zika Virus Outbreak? (21st Centuray Wire). Bonkers. Click.

No, GM Mosquitoes Didn’t Start The Zika Outbreak (Discover Magazine). Wonderful article debunking one of the most common conspiracy theories associated with the Zika virus outbreak. Click.

Got any more useful links? Tweet them through to me!

Photo of sign from Zika Forest taken from here.

Safely avoiding mosquito bites when pregnant

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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.

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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.