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.

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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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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Why don’t mosquitoes spread Ebola?

Authorities are quick to remind the community that Ebola virus is spread by blood and bodily fluids so it is hardly surprising that many are asking, “can mosquitoes spread Ebola”?

The 2014 Ebola outbreak in West Africa is the largest in history. As of mid-October, there have been approximately 9,000 cases and 4,500 deaths. The World Health Organisation warned that the infection rate could reach 5000 to 10000 new cases a week by the end of the year.

The virus is primarily transmitted from sick to healthy people by blood or body fluids (including but not limited to urine, saliva, sweat, feces, vomit, breast milk, and semen). In addition, objects contaminated with the virus (including needles and syringes) and direct contact with infected animals also play a role. Given this knowledge, it is not an unreasonable question to ask if blood feeding mosquitoes could spread the virus from infected people or animals.

Mosquitoes are just flying syringes aren’t they?

Mosquitoes are not flying syringes. They don’t transmit pathogens by transferring small infected droplets of blood. There is a complex biological process between the mosquito and the pathogen that must be completed before transmission can occur. In addition, there are ecological questions regarding the diversity, abundance, distribution and host-feeding patterns of local mosquitoes that can all influence the importance of mosquitoes in outbreaks of disease.

Unraveling these biological factors can be a complex process.

The saltmarsh mosquito (Aedes vigilax) (Photo: Stephen Doggett)

What happens inside the mosquito?

The mouth parts of a mosquito are made up of small tubes that either suck or spit. For a mosquito to effectively transmit a virus, the virus must make its way from the mosquito gut to the mosquito saliva.

If a mosquito takes a blood meal from an infected animal that contains the virus, the virus must infect the cells of the gut and then pass through to the body of the mosquito, replicate and then disseminate throughout the mosquito until the salivary glands are infected. This process is known as the extrinsic incubation period and can take anywhere from a few days to over two weeks. Once the salivary glands are infected, the mosquito may pass the virus to a new host through the saliva she injects while taking a blood meal.

There can be many barriers in this process. It may simply be the case that the virus cannot survive long enough in the gut of a mosquito. If it does survive, the virus may not “escape” the gut of the mosquito. In this case, the pathogen is excreted and the mosquito does not become infected.  Even if most of the body of the mosquito becomes infected, the salivary glands may remain uninfected and the pathogen is not transmitted through the bite of the mosquito.

To test the ability of mosquitoes to become infected and transmit pathogens requires laboratory studies (Source: Stephen Doggett, Pathology West – ICPMR Westmead)

Experiments to determine the ability of individual mosquito species to transmit pathogens are known as “vector competence” experiments. Hundreds of these have been conducted in many countries to assess the ability of local mosquito species to transmit endemic and exotic pathogens. These studies typically involve the exposure of mosquitoes to an infected blood meal and then testing, at various times following infection, the legs, wings and body of the mosquito (to determine infection) and salivary glands or saliva specifically.

There are very few published vector competence studies on Ebola. In one, three species of mosquito (Aedes albopictus, Aedes taeniorhynchus, and Culex pipiens) were infected with Ebola Reston virus but no virus replication was recorded. What was interesting about this study was that, by attempting to inoculate the mosquitoes through intrathoracic injection rather than orally (i.e. via an infected blood meal), the researchers were able to bypass the mid-gut barrier. It gave the virus the best chance of infection. However, the lack of virus replication in the mosquitoes suggests they are unlikely to be natural hosts of the virus.

What happens outside the mosquito?

When assessing the role of mosquitoes in outbreaks of disease, it is important to look at not only how competent the mosquito is at becoming infected and transmitting a virus. What happens in the laboratory may not reflect what is happening in the field.

For example, a mosquito that preferentially feeds on birds may be an effective vector but will play a minor role in transmission of the pathogen to humans as it will rarely, if ever, bite a person. These mosquitoes, however, may play an important role in spreading the pathogens amongst wildlife and this may indirectly increase the risk of exposure to humans. There may also be mosquitoes that are effective vectors but are naturally found at such low densities (due to reliance on specific environmental conditions) they rarely bite humans.

The natural reservoir host for Ebola virus appears to be bats. However, it is suspected that one of the most likely routes of transmission from bats to humans could be via the spread of the virus to primates (who are infected by bat droppings or bodily fluids of diseased bats) and then to humans through expose to the infected primate. There are likely to be plenty of mosquitoes that readily bite both bats and various primates in regions where Ebola is endemic but there is no evidence that mosquitoes play a role in these endemic enzootic transmission cycles.

During an outbreak of Ebola in Kikwit (Democratic Republic of the Congo) in 1995, researchers collected approximately 35,000 arthropods and tested them for the presence of the virus. 15,118 mosquitoes were tested and no Ebola virus was detected.

Ebola virus transmission cycles between enzootic and epidemic conditions (Source: CDC)

While mosquito-borne pathogens have emerged (or reemerged) in various parts of the world, this has primarily been driven through the movement of vectors and infected individuals through international travel. There is no evidence that mosquitoes have played a role in the transmission of any of the emerging zoonotic pathogens that have jumped from animals to humans in recent times.

There are also other factors to take into consideration. One critical factor with regard to the current Ebola outbreak is the epidemiological data. As described in this review of transmission, human cases are driven by direct contact with the blood or other body fluids of infected patients. If mosquitoes were capable of transmitting Ebola virus, there would likely be a very different distribution of cases with many people becoming infected who hadn’t had prior contact with an infected person.

Unfortunately, while the mosquitoes in West Africa are not transmitting Ebola virus, they are transmitting malaria parasites. Malaria will kill many times more people in West Africa than Ebola this year. Perhaps the most significant public health impact of the Ebola outbreak in West Africa will be the disruption of anti-malaria campaigns?

The photo at the top of this piece is taken from European Commission Humanitarian Aid & Civil Protection.

Should we mix mosquito repellents and sunscreens?

Combining mosquito repellents with sunscreens, as well as other cosmetics, sounds like a great idea but perhaps it isn’t to best way to protect ourselves from exposure to both the sun and mosquitoes.

There are formulations that combine mosquito repellents with various skin moisturizers but the most common combination formulations contain sunscreen and repellents. A combined formulation make sense given that Australia has one of the highest rates of skin cancer anywhere in the world. Even the Cancer Council have their own “Repel Sunscreen” formulations.

Combined formulations but conflicting risks

As well as questions regarding the efficacy of these formulations, there have also been some questions regarding their safety. Do they lessen the protection against the sun? Do they lessen the protection against mosquitoes? Do they increase the potential risk of toxic reactions to mosquito repellents?

One study found that the inclusion of mosquito repellent in sunscreen actually reduced the sun protection factor of the sunscreen. In 2009, I published a paper in Australian and New Zealand Journal of Public Health that investigated the efficacy of combined sunscreen and insect repellent formulations. The key finding was that no loss of protection from mosquito bites was provided by these combined formulations when compared to low and high dose “mosquito repellent only” formulations. The finding supported previous studies that indicated sunscreen does not reduce the efficacy of insect repellent. However, where we went further was to try and provide some guidelines for use of these products to maximise mosquito bite protection but also to minimise any potential adverse reactions to repellents.

I’ve provided plenty of detail of how to choose and use mosquito repellents in the “Beating the Bite” guidelines freely available for download

This issue of conflicted use was highlighted in a review of sunscreen labelling recommendations and combination sunscreen/insect repellent products that outlined concerns that “the application of a combination product too frequently poses the risk of insect repellent toxicity, whereas application too infrequently invites photodamage”.

Could combined formulations raise potential over exposure to mosquito repellents?

It is important to note that many published studies and reviews have shown that DEET does not pose a significant health concern (see here too). A recent review of safety surveillance from extensive humans use reveals no association with severe adverse events. In short, if a DEET-based mosquito repellent is used as recommended, there are no major concerns for health risk.

What if the use of a combined repellent and sunscreen formulations results in the application rate of repellent above and beyond recommended rates?

How much repellent are you using with sunscreen?

The recommended use of sunscreens and repellents are quite different. As well as the frequency of reapplications (sunscreen every two hours; repellent reapplication is determined by the “strength” but may be up to four hours for mid-range formulations), the quantity used will vary. Mosquito repellents require a thin application over all exposed skin to provide effectiveness. When the applications rates providing effective protection in mosquito repellent studies are compared to those for sunscreen use (i.e. approximately 30ml applied across the forearms, legs, torso and back 20 minutes before going outside and reapplied every two hours), application rates for sunscreens are approximately 3-5 times greater.

Are you using repellent when you don’t need to?

It is interesting to note the differences in the use pattern of sunscreen and mosquito repellent use. In many instances, nuisance-biting mosquitoes will generally be more active during periods when sun exposure risk is low (e.g. late afternoon, evening and early morning). However, as I pointed out in this paper on mosquito repellent use to reduce the risk of dengue, protection against these day-biting mosquitoes could call for the use of both products simultaneously. There is also no doubt that under some circumstances in coastal regions of Australia, mosquitoes can be out and about biting in shaded environments (places like mangrove forests and coastal swamp forests) during the day.

The Yellow Fever Mosquito, Aedes aegypti (Photo: Stephen Doggett)

What should you do?

I’m not aware of any review in Australia to reconsider the registration or recommendations surrounding the use of combined mosquito repellent and sunscreen formulations. In most instances, the advice provided by local authorities is simply to “follow label instructions”.

Combined mosquito repellent and sunscreen formulations are not recommended by the CDC. It is worth noting that also in Canada, combined sunscreen and insect repellents are not recommended. It is suggested to apply the sunscreen first, then the insect repellent over the top. The only problem is that as repellent will generally last longer than sunscreen, you end up alternating application of the two products.

We tested the idea that repellents should be applied first and then sunscreen over the top. While testing the efficacy of sunscreen wasn’t in the scope fo our study, we found that the efficacy of repellent (as measured by the duration of protection) was actually reduced. The reduction, we concluded, was probably due to physical disruption of the original mosquito repellent application during subsequent sunscreen application.

It should be noted once again that repeated reviews have concluded that DEET-based repellents pose a very low risk of adverse health impacts. However, if you were to take a cautious approach, if there is a risk of possible adverse reaction to repellents, this may be more likely to happen when using high dose DEET-based repellents (e.g. “tropical strength” repellents that may contain over 80% DEET) in combination with sunscreen. If you want to lower the risks as much as possible, using a low-dose DEET-based (e.g. containing less than 10% DEET), or picaridin-based, repellent will more closely align the recommended reapplication times of the two products.

If you’re looking for sunscreen advice, visit the Cancer Council website here.

The full reference for our 2009 paper is below:

Webb, C. E. and Russell, R. C. (2009) Insect repellents and sunscreen: implications for personal protection strategies against mosquito-borne disease. Australian and New Zealand Journal of Public Health, 33: 485–490.

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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Can we genetically modify malaria mosquitoes to extinction?

Malaria no more? A new study has provided a pathway to possibly driving one of the most important malaria transmitting mosquitoes to extinction by using genetically modified mosquitoes that produce almost entirely male offspring. Without many females, the mosquito population will crash. A decline in the number of malaria cases should similarly follow.

There has been much research, as well as community discussion, regarding the use of genetically modified mosquitoes (and sometimes the pathogens themselves) to reduce the impacts of mosquito-borne disease. The recent proposals around the use of genetically modified mosquitoes to assist in the control of dengue outbreaks have been attracting many headlines, including both excitement and concern.

The new study, “A synthetic sex ratio distortion system for the control of the human malaria mosquito” (published in Nature Communications), reports on the genetic modification of mosquitoes that only produce sperm that result in (mostly) only male offspring. The researchers used a modified enzyme that attacks a specific region of the X-chromosome, preventing it being passed onto the next generation. Mating between GM mosquitoes and “wild type” mosquitoes produced up to 97.4% male mosquitoes.

In addition, the researchers demonstrated that once the wheels are set in motion, there is the potential that the spread of these  mosquitoes carrying “male only sperm” pass on the trait to their offspring and then their offspring. It is hoped that as these mosquitoes spread throughout the environment, eventually, the population of mosquitoes will crash as female mosquitoes are removed. The theory was tested in the laboratories and the researchers found that it took about 6 generations for the populations to crash (but they did need to start off with three times as many genetically modified mosquitoes to “wild type” mosquitoes).

While the technology is new, the idea was first proposed in the 1950s. The idea that you can distort the sex ratio of insect populations to control pest impacts had been proposed with various approaches to achieve it. The latest approach provides a novel way to apply the strategy to mosquitoes.

An illustration taken from “This is Ann, she’s dying to meet you” produced by US War Department, 1943

Doesn’t this latest research mean, in theory, you could make mosquitoes extinct?

The results from the current study are fascinating but it is still very early days before it is known if this approach works under field conditions and can actually reduce malaria, let alone drive mosquitoes to extinction. Keep in mind that this study focuses on just one of the thousands of mosquito species found throughout the world.

The mosquito the researchers from the Imperial College of London used was one of the key vectors of malaria parasites, Anopheles gambiae. This species belongs to a group of mosquitoes that contain up to 40 different species that may play a role in the transmission of malaria parasites. The fact that there are so many mosquito species capable of transmitting malaria parasites makes developing a “silver bullet” approach to control difficult.

Global distribution of potentially important malaria vectors (Taken from: Kiszewksi et al., 2004. American Journal of Tropical Medicine and Hygiene 70(5):486-498 via CDC)

There are many ecological and operational issues surrounding the release of genetically modified mosquitoes. Notwithstanding any fitness cost (e.g. less effective mating with “wild type” mosquitoes, lower fecundity, lower survival of immature stages, smaller dispersal ranges) that may put the genetically modified mosquitoes at a competitive disadvantage in the field, there are the issues of determining when, how many, and how frequently, genetically modified mosquitoes must be released into the environment. Some of these issues are discussed in this discussion paper and I’ve written about regulation here.

Even if the laboratory technique is translated to the field, and it worked, what would happen if you drove local populations of Anopheles gambiae to extinction?

I’m not sure that there is any research that identifies the ecological role of these mosquitoes. There certainly hasn’t been any work, to my knowledge, that addresses the issue in the same way we studied the ecological role of the Australian mosquitoes that spread Ross River virus. However, the potential ecological impacts of genetically modified mosquitoes have been identified.

Putting aside the issues of ecological impact (perhaps there wouldn’t be any significant ecological impact?), what would be the impact on human health? This is the critical issue. We know that by reducing the contact between mosquitoes and humans through the use of bed nets and insecticides can reduce the incidents of malaria, what if populations of Anopheles gambiae were significantly reduced or eradicated?

Malaria eradication campaigns have been with us for decades but are they now transitioning from spraying insecticides to releases genetically modified mosquitoes? (Source: National Library of Medicine)

One of the problems may be that the ecological niche exploited by Anopheles gambiae is simply taken up by another of the mosquitoes able to transmit malaria. Anopheles gambiae is a pretty good competitor and if you take it out of the environment, another Anopheles species may move in. There is no doubt that Anopheles gambiae is one of the most important vectors of malaria parasites but even if a “replacement” species moves in, outbreaks of disease may still be less than before. However, health authorities will still need to call on traditional mosquito control and malaria prevention strategies. A balance is required when assessing the cost effectiveness of the new and old strategies.

Amongst the wave of new technologies purported to aid in the battle against malaria, it is worth noting that current methods of prevention (e.g. bed nets) and control (e.g. insecticides), in combination with better diagnosis and treatment, have contributed to a reduction in world wide malaria mortality rates by 42% since 2000. Combining different mixes of approaches (e.g. bed nets and residual insecticide treatments) has been shown to be potentially significant. In the future, perhaps genetically modified mosquitoes should be added to this mix too.

You can listen (stream or download) to me chat with James Carleton about the implications of the research on Radio National’s Breakfast. There has also been plenty of news coverage following the publication of the research, a good overview is here.

Why not join the conversation by following me on Twitter?

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The photo of the malaria vector, Anopheles gambiae, at the top of this post is taken from here (CDC/James Gathany)

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World Health Day 2014: An Australian perspective

Monday 7 April is World Health Day. Every year, to mark the anniversary of the founding of WHO in 1948, the World Health Organization draws attention to a public health problem of global proportions and what needs to be done to address it. The theme is vector-borne disease with the key message that a small bite can be a big threat.

There are some wonderful resources available at the WHO website including information on the key vector-borne diseases internationally and what can be done to combat the vectors and reduce the burden of disease. One of the key messages is that while more than half of the world’s population is at risk of vector-borne diseases and increased travel, trade and migration make even more people vulnerable, these diseases are preventable.

What about Australia?

Australia may be fortunate in that we’re free of some of the nastiest pathogens spread by mosquitoes, we still have our own home grown viruses. Exotic pathogens are also increasingly knocking at our door. While countries in our region battle with outbreaks of mosquito-borne dengue, chikungunya and zika viruses, and Australian travellers are increasingly returning home either infected with these pathogens, or potentially carrying exotic mosquitoes.

In recent years we’ve had a case of “airport dengue” in Darwin, the first case of locally acquired dengue in Western Australia for 70 years, the first imported human case of zika virus, detection of yellow fever mosquitoes in Melbourne and activity of Ross River virus making its way into residential areas of Sydney.

Notwithstanding our “home grown” pathogens, that circulate amongst endemic mosquitoes and local wildlife,  exotic threats continue to threatened our shores.

It wasn’t until the 1980s that Australia was declared free of malaria. Historically, there were cases throughout the country but now the risks are considered minimal. It is, however, important to note that there are small risks of local outbreaks as highlighted by a small cluster of cases in Far North QLD in 2002. While there remains a risk to travellers, the availability of effective prophylaxis reduces those risks. However, the number and type of imported cases of malaria into Australia in the future may be determined by a range of factors including the resettlement of people from endemic countries, as well as military and civilian activities.

The Yellow Fever mosquito, Aedes aegypti (Photo: Stephen Doggett)

Yellow Fever hasn’t impacted Australia to the extent of many other regions of the world. While we’ve seen increasing numbers of imported dengue and chikungunya, there have been very few imported cases of Yellow Fever reported with only two since 1991. However, recent studies have suggested that Australian mosquitoes readily become infected with and can transmit representative African and South American strains of Yellow Fever virus. The question remains as to the potential for local outbreaks to be triggered by returning travellers but perhaps we are fortunate that the availability of an effective vaccine and quarantine reviews of travellers returning from yellow fever endemic regions (Australians visiting yellow fever-endemic countries may be required to show proof of vaccination with a WHO International Certificate of Vaccination ) assists in reducing outbreak risk. Be careful if you’re heading to the World Cup in Brazil!

Japanese encephalitis virus has been knocking on our door for a while. While it is not considered a high risk for short-term travellers to endemic regions, northern Australia may be impacted. Most notable was an outbreak in the Torres Strait in 1995. While the availability of a vaccine can greatly reduce the risks, given the similarities between the mosquito populations of Torres Strait and northern Australia, concerns were raised as to the risks that may exist for transmission to occur more widely on mainland Australia. Studies assessing the risk to mainland Australia revealed some fascinating factors that may drive public health risks, from high altitude wind dispersed mosquitoes to genetic differences between local mosquito species. Despite the virus being isolated from mosquitoes collected on mainland Australia and debate continues as to any likely activity in northern mainland Australia there generally appears to be very low risk that transmission will occur more widely. Perhaps the greatest risk will be if human population grows in northern Australia?

Although imported cases in travellers, as well as refugees, are occasionally reported, until recently, Australia was considered free of Leishmaniasis. However, the discovery of parasites in red kangaroos (as well as a black wallaroo and agile wallabies) and subsequent incrimination of biting midges has changed the way local health authorities look at Australia’s susceptibility to these parasites. One of the most interesting aspects of recent research is the identification of biting midges as playing a potential role in local transmission. Biting midges (Diptera: Ceratopogonidae) are commonly known as sand flies in Australia but true sand flies (Diptera: Phlebotominae) are considered the primary vectors of Leishmania parasites. The absence of human biting species of Australian sand flies has often been cited as a reason the disease poses little risk here. More research is needed to better understand the local risks factors. However, like many of the pathogens discussed here, increased global travel from endemic regions is likely to be the biggest future risk factor.

It is probably dengue that poses the biggest threat to Australia. Historically, dengue posed a risk to communities along the east and west coasts of the country but since the 1950s, activity has been limited to Far North QLD. The current risk areas of dengue are determined by the presence of the only mosquito species in Australia currently capable of transmitting the viruses, Aedes aegypti. Local outbreaks are triggered by travellers introducing the pathogen to local mosquito populations and the number of cases reported can range from less than 100 to around 10000 each year. The future risks posed to Australia by dengue will be driven by the introduction of new vector species, such as the Asian Tiger Mosquito, Aedes albopictus, as well as increasing activity of dengue viruses in our region.

Think global and think local

It is easy for Australians and Australian authorities to become complacent of these vector-borne diseases. When we read news of outbreaks on a massive scale overseas, it is difficult to connect a threat to our local suburb. However, the critical factor across many of these pathogens is that increasing globalisation and fast international travel can expose Australia to both the pathogens and their vectors. We need to appreciate the risks and anticipate the threats. Ensuring that we maintain the capacity for quarantine surveillance and strategic responses to the detection of pathogens and vectors will be critical.

This wonderful info-graphic below from WHO on the simple steps you can take to reduce the risks of mosquito-borne disease to you and your family apply just as much to Australia as any other country on earth. It only takes one bite and over half the world’s population at risk of these pathogens. With cases of mosquito-borne Ross River virus reported from every state and territory in Australia, that includes us!

For more information, visit the official World Health Day site.

 

 

 

 

Don’t let the “love bugs” bite this Valentine’s Day

What are you taking on your Valentines Day date? Flowers? Chocolates? Clean undies? Don’t forget to pack the insect repellents! There may be more than just “love bugs” about.

I’ve got you under my skin

The human scabies mite (Sarcoptes scabei) is the only arthropod to truly get under our skin. The tiny mite burrows in and feeds on dissolved human tissue in the tunnels they excavate. Itchy yet? Don’t start scratching as that is one way to release mites and infect your friends.  The other way is when mites come to the skin surface to mate. Newly “knocked up” females are usually quick to burrow into the skin but for those that don’t, they’re prime candidates for transfer.

Skin to skin contact is the typical way the mites are spread from person to person. A hand shake probably won’t do it but sexual contact will. Serious problems with scabies are also not uncommon in aged care facilities and can be a serious problem in Aboriginal communities. Even wombats can be infected.

Once infected, symptoms can take up to a month to develop. At that point, the infected person develops an allergic reaction to the mite’s faeces, skin moults, saliva or moulting fluids. The “mite tunnels” may appear as pale grey threadlike marks and often follow natural creases in the skin in areas such as the hands, particularly the webbing between the fingers, but also on the wrists, elbows, genitals and breasts. Large areas of the body can also be covered by a rash that is not specifically associated with the mite’s burrows but rather is thought to be a generalised allergic reaction. Severe itching all over the body can be experience with the intensity of irritation especially noticeable at night.

Typical scabies infestations are easily treated with an insecticide cream. Problem is, to confirm infection, you need to have a “skin scraping” taking to look for the mites, their eggs or faeces. Taking a “skin scraping” can be pretty nasty and the bulk of scabies infestations are diagnosed on symptoms alone. I think scabies infection is one of the most over diagnosed illness doing the rounds. From the calls I take (at least a couple a week), anyone who presents to their doctor or pharmacist with an itch appears to end up smearing a cream like this all over themselves. The problem is, when the cream doesn’t fix the itch (because the itch is caused by something other than mites), people may repeat the course of treatment once or twice more (as well as trying “other” solutions). That then leads to self inflicted skin irritation and the cycle continues. Correct diagnosis would avoid these problems!

Scabies infection can be even more serious in immunocompromised or elderly individuals when mite populations explode. Known as “crusted” or “Norwegian” scabies, the skin can take on a thicken appearance and contain huge numbers of mites. In these situations, the condition can be highly contagious and barrier nursing is required.

Intense activity of scabies mite in a case of “crusted” scabies (Photo: Stephen Doggett, Medical Entomology, Pathology West)

The “deadliest catch” on the dating scene or just “butterflies of love”?

Pubic lice, Pthirus pubis, (commonly known as crabs) have found a home on the pubic hair of humans (after apparently making the leap from gorillas around 3.3 million years ago). Different to head lice (Pediculus capitis), the claws of pubic lice are adapted to courser hair pubic region and lice and rarely (but occasionally) travel far from those regions. Unsurprisingly, they spread primarily through sexual contact. In many countries they’re classified as a sexually transmitted infection. However, they don’t really pose a significant health risk. They can cause severe itchiness in the infested regions but there are no known pathogens spread by their bites (interestingly though, there has been some suggestion that the presence of pubic lice may indicate the presence of more serious STIs).

You’ve probably seen the headlines. Prompted by this paper, there has been a lot of attention paid to the rise of the Brazilian waxing trend and the threat it poses to the natural habitat of pubic lice. Are the parasite’s days numbered? This probably isn’t the case. No, probably not.

Although there is some data on prevalence rates in Australia from the 1980s (about 1.5% of individuals visiting STI clinics), there really isn’t much more information available about just how widespread are pubic lice infestations (not much quantitative data on pubic hair trends amongst the general population is available either but there have been some attitudinal studies carried out in Australia). Cases of pubic lice is clearly rare but specimens do occasionally pop up in pathology samples submitted to our laboratory. I once tried to look into some data from local sexual health clinics but there just hasn’t been enough data collected to make any meaningful assessment on any changes in prevalence rates.

These days, with information more readily available online, individuals are probably more likely to buy treatments from chemists than attend sexual health clinics. Avenues to collect reliable data on prevalence rates may be difficult to find. Doesn’t seem to matter anyway as the “Brazillian” trend is apparently over. I can hear the tiny applause of crab claws the world over.

Life cycle of the pubic louse (taken from CDC)

Beware the sleepover stowaways

Bed bugs may not specifically be a sexually transmitted arthropod but nevertheless a parasite that may take advantage of some Valentine’s Day sleepovers. Bed bugs have been grabbing the headlines for the past 10-15 years as that make a stunning resurgence in many parts of the world. This resurgence has been attributed to, in some ways, by greater availability of cheap, fast international travel and resistance in bed bugs to commonly used insecticides (I currently have a PhD student investigating this).

Bed bugs don’t live on the body. They don’t just live in beds either. They live in almost any crack or crevice available that is also close to humans. Bedrooms obviously. Planning a special Valentine’s Day sleepover at the local hotel? Don’t be fooled into thinking bed bugs are only found in cheap accommodation, they’re just as likely to be lurking in five star hotels.

If bed bugs decide to make a meal of you, it isn’t just the bites that cause a problem. If they decide to hide away in your overnight bag, you may find yourself dealing with an expensive and inconvenient pest control operation in your home. Best avoid them in the first place.

Best check for any stowaways in Valentine’s Day gifts too.

Not the souvenir you were hoping for?

Is your partner rushing home from overseas for Valentine’s Day? Make sure they don’t bring home a less than special gift of mosquitoes or mosquito-borne disease!

As highly unusual as it sounds, transporting infected mosquitoes in luggage has been the cause of infections in non-endemic regions. There have been documented cases of “baggage malaria“. Even in Australia, we’ve had a suspected case of “baggage dengue” in Western Australia. While “airport” malaria and dengue cases have been reported in many regions, perhaps the same rapid international travel that appears to be driving the resurgence in bed bugs may increase the risk of baggage-assisted movement of infected mosquitoes?

Even if your partner manages to avoid bringing home any infected mosquitoes, perhaps a passionate reunion could lead to a highly unusual case of sexually transmitted infection. A scientist working in Senegal returned home to Colorado only to infect his wife with the (normally only) mosquito-borne Zika virus (a virus closely related to Japanese encephalitis virus and West Nile virus rarely recorded outside Africa). Interestingly, we’re currently seeing an outbreak of Zika virus in the Pacific so best be warned if your partner has just returned from French Polynesia!

So, does this mean mosquito-borne viruses like Zika, West Nile, dengue or Ross River could be sexually transmitted human-to-human? We know viruses are sexually transmitted between mosquitoes but apart from the case of Zika virus infection discussed here, I’m not aware of any other reported cases in humans. Strange given the huge numbers of cases that occur during dengue outbreaks. Perhaps nobody has thought to check? The semen of boars has been checked and they found Japanese encephalitis virus….

Wild pig (Sus scrofa) (Photo National Aeronautics and Space Administration)

Who would have thought there were so many entomological risks associated with Valentine’s Day?

To find out more about arthropods of public health concern in Australia, check out this document I put together for the Australian Federal Government Department of Health and Aging. It is available for free download as either PDF or WORD versions.

Webb CE, Doggett SL and Russell RC. (2013). Arthropod pests of public health significance in Australia. Department of Health and Aging, Canberra. ISBN: 9781742419770. [PDF]

(Photo of the Alaskan King Red Crab at the top of this post is taken from Wikipedia.)