Preparing for the exotic mosquito invasion of Australian backyards


While Australia has hundreds of “home-grown” mosquitoes, it is just a few from overseas that have authorities on alert. Preparing for these new risks is critical if the future pest and public health risks associated with mosquitoes are to be effectively managed. Citizen scientists may hold the key to success!

A project underway in the Northern Rivers region of NSW is set to build a framework for responding to the threats of exotic mosquitoes. This is in association with the Building Resilience to Climate Change program, a partnership program between Local Government NSW (LGNSW) and the NSW Office of Environment and Heritage (OEH) to address identified climate change risks and vulnerabilities facing NSW councils.

Lead by Tweed Shire Council, the program “Developing and trialing a Northern Rivers Emerging Vector Response Plan” is designed to build capacity among local stakeholders in the region to better respond to possible introductions of exotic mosquitoes from overseas (or perhaps travelling south from Queensland).

The mosquitoes that pose the greatest risk are Aedes aegypti and Aedes albopictus. As well as being severe nuisance-biting pests, these mosquitoes can transmit pathogens of serious public health concern such as Zika, dengue and chikungunya viruses. The mosquitoes aren’t found in local wetlands, they prefer backyard water-holding containers. This means that should these mosquitoes make their way to NSW, local authorities must shift their focus from the swamps to the suburbs.

There is already a program in place monitoring mosquitoes and the pathogens they carry in NSW. This program is primarily focused on Ross River virus and the mosquitoes that transmit this pathogen. As a consequence, mosquito collections are typically in bushland or wetland areas adjacent to urban areas and may not readily pick up exotic mosquitoes that have moved into local backyards.

Authorities must expand their approach and develop strategic responses to these exotic threats.


Representatives of local stakeholders help survey 300 backyards in Tweed Heads!

This work is already underway. A workshop for local stakeholders was held in December 2017 in Tweed Heads along with a two day field exercise in which around 300 residential backyards were surveyed for potential mosquito habitats. A wide range of potential sources of mosquitoes was identified, the most common were water-filled plants (particularly bromeliads), pot-plant saucers, buckets, wheel burrows, garden ornaments, and rainwater tanks.

The survey highlighted how important community involvement in the program is and “citizen science” is currently being employed to assess some mosquito surveillance technologies in backyards across the Tweed Heads region.

Supported by a grant from the Human Health and Social Impacts Node, a partnership between the Office of Environment and Heritage, NSW Health and The University of Sydney, over 150 mosquito traps were deployed and it is hoped that the mosquitoes they collect will help inform the development of strategic mosquito surveillance in the future.


An example of the mosquito traps deployed across two suburbs in Tweed Heads to collect eggs from mosquitoes buzzing about backyards

Whats needed now is a better understanding of how the community thinks about mosquitoes and how they’re trying to make their backyard less favourable for these pests.

Residents in the Local Government Areas of Tweed, Byron, Ballina, Richmond Valley, Clarence Valley, Lismore and Kyogle are invited to participate in a short survey. It is a great way to learn how to reduce the risks of mosquito bites in your backyard (there is also an iPad that can be won!).

If you live in the areas mentioned, or know friends or family who do, please complete and/or share the details of the survey.

You can start the survey now!

There are many factors contributing to the future threat of  mosquitoes and mosquito-borne disease in Australia. Climate change or exotic mosquito introductions may be game changes but one of the most important considerations is the importance of community awareness and willingness to assist local health authorities.

Perhaps the new mosquito emoji will help too?







A flood of festive season media coverage


Spring is gone and with the arrival of summer comes the mosquitoes. Calls from the media inevitably follow shortly after. I have no doubt many journalists, broadcasters and producers have my name in their diaries, circled brightly in red, on the first day of summer!

It is a fun part of my job to deal with the media. Its more than just getting a chance to talk about mosquitoes and their role in the local environment, it also provides an opportunity to do some important public health communications around the issues of mosquito bite prevention and management of mosquito-borne disease.

Scorchers, sun protection, and buzzing bloodsuckers

What got the ball rolling this year was a joint media briefing arranged by ausSMC. Alongside colleagues talking about heat waves, summer storms, sun protection and bushfire, I shared some tips on protecting yourself from mosquito bites and mosquito-borne disease this summer. It was interesting speaking alongside Professor Sanchia Aranda, CEO of Cancer Council Australia, and comparing the ways we promote safe and effective use of sunscreens and mosquito repellents. This was picked up on in additional media coverage. Overall, there was over 300 local and international articles following this media briefing!

The briefing provided an opportunity to fill a gap in public health communication I’ve identified (and tried to fill) in recent years. Health authorities are pretty good at providing advice on choosing mosquito repellents but less so on using them effectively. Ensuring repellents are actually used effectively is the best way to increase the protection of the community against mosquito-borne disease.

In early December we held our “Sydney Ideas: Mosquitoes in the City” event at Westmead. This was a great opportunity to speak to the community and the well attended event prompted some broader interest in the work of presenters.

It was a pleasure being able to visit the studios of ABC Radio National with Prof Tony Capon, Professor of Planetary Health at the University of Sydney, to discuss with Philip Adams how urbanisation and a changing climate may influence local mosquito populations and mosquito-borne disease risk. I’m working more and more with Tony so nice to share the opportunity to talk about this initiative with him on national radio. You can listen back here. This work is strongly linked to the theme of the “Mosquitoes in the City” event and there is clearly much to learn regarding the place of mosquitoes, wetlands, wildlife and mosquito-borne disease at the fringes of our metropolitan regions under the influence of a changing climate and the ways urban design responds to the threat.



Why me? I wish mozzies would bite my friends instead!

There was another boost in interest resulting from a spot on ABC News 24 Weekend Breakfast. The accompanying online article explaining why mosquitoes are more likely to bite some people more than others then sparked considerable interest! What followed was a bunch of radio and television interviews.

There was also a follow up article at and this was also picked up on “Kids News” who republished a modified version of the story together with some suggestions for classroom learning exercises. Nice.

There were two different experiences with ABC News. The appearance on Weekend Breakfast was great. I’ve done segments with Andrew Geoghegan and Miriam Corowa before, have always been impressed with their knowledge and interest. I really enjoy the relaxed feel on the show. Was also a pleasure working with Dale Drinkwater, the producer, who put together the segment and accompanying article.

A couple of days later I appeared on News Breakfast with Virginia Trioli. As the program is produced out of Melbourne, I had to do a live cross from the Sydney studios. I always find these interviews a little uncomfortable as I’m tucked away in a small, dark recording booth staring down a camera and hoping my ear piece doesn’t fall out! I’m sure there is an art to these but I’m not sure I’ve mastered that just yet.


Once the mozzies start biting…

With the warm weather arriving and everyone’s minds turning to summer, there is always a flood of festive season-related media stories. Once the mozzie stories started popping up, many more media outlets starting running segments.

There were also warnings about the health threats of mosquitoes over the festive season from local health authorities.

I had the chance to visit many radio and television studios to conduct interviews, this time it was the first opportunity to visit the Macquarie Radio (home to 2UE and 2GB) for what turned out to be a relatively long (by commercial radio standards) interview with Tim Webster on Talking Lifestyle/2UE including a few callers asking about mosquito repellents, disease risk and what the “purpose” of mosquitoes actually is! Listen back via the Holiday and Home podcast.

Taking talkback can be tricky. I’m fortunate enough to have had an opportunity to do this reasonably routinely. I appreciate the opportunity to get a feel for what the community wants to know about mosquitoes, we should be taking these things into account when designing fact sheets and other communication material. There is no point in simply systematically repeating what has come before.

Live TV can also be tricky. I also had the chance to do segments on Channel Nine’s Today and Today Extra programs. These are always fun and I do find it fascinating to see how the behind-the-scenes production of these shows get put together.

Even the local newspaper, the Parramatta Sun, ran a nice story with great shot of me among the mangroves of the Parramatta River. It is also fun dragging photographers out into the wetlands. This time a fun shot of me from a different perspective other than simply standing beside a mosquito trap!


There was certainly plenty of “buzz” (or should that be “hum”) about mosquitoes over recent weeks. Great to see other articles pop up by fellow science communicators as well as the occasionally celebrity. There can never be too many ways to get the message out!

The mosquito coil conversation

At the point where I thought everyone was getting sick of mosquitoes, my latest article on the safe and effective use of mosquito coils was published at The Conversation (as well as being republished by ABC News). To date there have been about 90,000 clicks on the article, highlighting just how interested people are in the topic.

There were a bunch of other interview requests on the back of this including ABC Sydney, ABC Brisbane and ABC Adelaide. You can listen back to my chat with James Valentine on ABC Nationwide Afternoons here.

It isn’t always easy managing media requests

To finish up, I think it is important to share some of the reality of wrangling all these media requests. Most importantly, it takes time. It takes time to prepare and it takes much more time to actually do these activities.

For live television appearances, that often only last a few moments, you’re typically asked to arrive at the studios 30-40min prior to scheduled interview. Notwithstanding the travel time back and forth from studios (often very early in the morning), this means the interruption to the day isn’t insignificant. There was one day that I participated in two different teleconferences while in transit to and between interviews at ABC in Ultimo and Channel Nine in Willoughby!

The other thing is that sometimes you’ll get bumped. I was scheduled to chat on a live television program that requested I bring along a cage of live mosquitoes. This is generally not a problem but it does take time, especially when I have to actually collect field caught mosquitoes especially for this purpose. Unfortunately, the segment got bumped on one day, rescheduled for the next and then bumped again for a second time.

It would be easy to get really upset in these circumstances but it is a reality of dealing with the media. Don’t take it personally as these things are mostly out of your control. If you’re keen to engage with the media, this is just one of the many challenges you’ll need to learn to manage.

Spot any other cool mozzie media things? Join the conversation on Twitter or Facebook!


Ross River virus in Melbourne, how did that happen?


Health authorities in Victoria have been warning of mosquito-borne Ross River virus for much of the summer. The state is experiencing one of its worst outbreaks of the disease but cases have mostly been across inland regions. Now it’s hit Melbourne. How has this happened?

Ross River virus is the most commonly reported mosquito-borne disease in Australia. There are usually about 5,000 cases across Australia. However, in 2015 there was a major spike in activity with around 9,000 cases reported. It is a common misconception that the disease is only found in northern regions of Australia. I’m often told “I heard the disease is moving south from QLD?” That’s not the case.

The virus is just as much a natural part of the Australian environment as the mosquitoes and the wildlife that maintain transmission cycles.

While there are generally more cases in northern Australia, nowhere is safe. Some of the largest outbreaks have occurred in southern regions of Western Australia, South Australia, Victoria and even Tasmania.

The virus is widespread but is generally associated with rural regions. A driving factor in determining the activity of Ross River virus is that more than just mosquitoes are involved in outbreaks. The virus is maintained in the environment in native wildlife, especially kangaroos and wallabies. Even when and where there are high numbers of mosquitoes, without wildlife, outbreak risk is low. This is the reason why any clusters of locally infected cases in metropolitan regions are typical in areas where there are wetlands, wildlife and mosquitoes occurring together. We’ve seen this on the urban fringe of Sydney and Perth in recent years.

The announcement of locally acquired cases in the suburbs of Frankston and Casey, in Melbourne’s south-east, has taken many by surprise. Should it have?

Victoria is no stranger to mosquitoes and outbreaks of mosquito-borne disease. There are mosquito surveillance and mosquito control programs in place in many regions and historically there have been major outbreaks of mosquito-borne disease. From freshwater flood plains of the inland to the tidally flooded estuarine wetlands of the coast, Victoria has diverse and often abundant mosquitoes. But cases in the metropolitan region are rare.

Victorian mosquitoes are not all bad but over a dozen different mosquito species can spread Ross River virus.

The region where these cases have been identified are in proximity to bushland and wetland areas. There is no doubt plenty of mosquitoes and suitable wildlife too. While this is the first time local transmission has been documented, that doesn’t mean the virus hasn’t circulated in the past, or even that cases may have occurred.

For individuals infected but only suffering mild symptoms, the illness can be easily discounted as nothing more than a mild case of the flu. Without appropriate blood tests, these cases never appear in official statistics. For this reason, many mosquito researchers believe that the number of notified cases across the country is just the tip of the iceberg with many milder infections going diagnosed.

But why in Melbourne now?

It is difficult to know for sure. The two most likely explanations are that either environmental conditions were ideal for mosquitoes and suitable populations of wildlife were present so that the virus was much more active in the local environment than previously. The second explanation is that the virus may have been introduced to the region by a traveller or movement of wildlife. In much the same way Zika virus made its way from SE Asia to South America in the last few years, mosquito-borne viruses move about in people and animals, much less so than mosquitoes themselves (but that isn’t impossible either).

Victoria (as well as inland NSW) is experiencing one of its largest outbreaks of Ross River virus on record following significant flooding of inland regions. With so much activity of the virus in the region, perhaps an infected bird or person travelling to the metropolitan region brought the virus with them. When bitten by local mosquitoes, the virus started circulated among local mosquitoes and wildlife.

Most people infected by Ross River virus are bitten by a mosquito that has previously fed on a kangaroo or wallaby.

Once it’s made its way to metropolitan regions, the virus can be spread from person to person by mosquitoes. Common backyard mosquitoes, especially Aedes notoscriptus, can transmit the virus but as these mosquitoes are not particularly abundant, don’t fly vary far and will just as likely bite animals as humans, they’re unlikely to drive major urban outbreaks of the disease. This mosquito doesn’t pack the same virus-spreading-punch as mosquitoes such as Aedes aegypti that spreads dengue, chikungunya and Zika viruses. Aedes aegypti isn’t in Victoria.

We’re unlikely to see significant spread of Ross River virus across Melbourne but that doesn’t mean Victorians should be complacent. As there is no cure for Ross River virus disease, the best approach is to avoid being infected in the first place. Preventing mosquito bites is the best approach. For my tips and tricks on avoiding mosquito bites see this recent paper in Public Health Research and Practice as well as my article for The Conversation.

Keep an eye on the website of Victoria Health for more information.







Social media and blood suckers showcased at the International Congress of Entomology


Digital technology is changing a lot about how we undertake entomological research and communicate the results of that research to the community and policy makers.

This week in Orlando, Florida, is the International Congress of Entomology (ICE). A huge gathering of entomologists from around the world. While it was a great pleasure to be invited to participate, I couldn’t get over there this time.

I will, however, have a chance to present my work in the Symposium “Entomology in the Digital Age”  Friday, September 30, 2016 (01:30 PM – 04:45 PM), Convention Centre Room W222 A.

In the presentation I’ll share some of the reasoning behind my use of social media to engage the community with both entomological research and public health communication. Most importantly, it will focus on some of the metrics I’ve recorded alongside my use of social media, maintaining a blog of research and writing for outlets such as The Conversation.

I’ve written about my use of social media and how it can help extend the reach of public health messages and presented on the topic alongside a range of great speakers at the 2014 Entomological Society of America meeting in Portland.

This time around, technology is playing an even more direct role in my presentation! I’ve pre-recorded my presentation and it will be shown to the audience on the day among other presentations. I’ll also be checking into the session to answer questions. Despite the fact I’ll need to be up around 1:30am due to time differences, it should be fun.

See the abstract below…

Taking entomological research from the swamps to the suburbs with social media

Cameron E Webb

Connecting scientists and the community is critical. This is particularly the case for medical entomologists working in the field of mosquito-borne disease where the translation of entomological research into improved public health outcomes is a priority. While traditional media has been the mainstay of public health communications by local authorities, social media provides 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. doi: 10.1603/ICE.2016.94611

If you’re at ICE, you can also catch up with my PhD student David Lilly who’ll be presenting our research into the development of insecticide resistance in bed bugs as part of the symposium “New Insights into Biology, Resistance Mechanisms, and the Management of the Modern Bed Bug” Friday, September 30, 2016, 01:30 PM – 04:45 PM, Convention Center, West Hall F4 (WF4).

Novel insecticide resistant mechanisms in the common bed bug, Cimex lectularius

David Lilly, Cameron E Webb and Stephen Doggett

Introduction: Research on field strains of Cimex lectularius from Australia has identified widespread resistance to pyrethroid insecticides, but variability in the magnitude expressed. To determine if differences in resistance mechanisms exist, collected strains were examined for the presence of metabolic detoxification and/or cuticle thickening. Methods: The presence and relative contribution of detoxifying esterases or cytochrome P450 monooxygenases were assessed. Bed bugs collected from Parramatta (NSW), Melbourne (VIC) – 2 strains, ‘No.2’ and ‘No.4’, and Alice Springs (NT) were exposed in topical bioassays employing deltamethrin and two pyrethroid synergists: piperonyl butoxide (PBO) and EN16/5-1. PBO inhibits both monooxygenases and esterases, whereas EN16/5-1 will inhibit esterases only. Thus in a comparative bioassay, the results can infer the dominant enzyme system. The Parramatta strain was then selected to study the potential presence of cuticle thickening. Nine-day-old male bed bugs were exposed to filter papers treated with the highest label rate of Demand Insecticide®(200mL/10L of 25g/L lambda-cyhalothrin) and were grouped according to time-to-knockdown (< 2 hours, ≥ 4 hours, and survivors at 24 hours). Measurements of mean cuticle thickness at the transverse midpoint of the second leg tarsus were taken under electron microscope. Results/Conclusion: All strains possessed resistance that was inhibited by the synergists, with the Parramatta and Melbourne No.2 indicating esterase-dominance, and Alice Springs and Melbourne No.4 indicating cytochrome P450 monooxygenase-dominance. Cuticular measurements demonstrated that bed bugs surviving deltamethrin exposure had significantly thicker cuticles, denoting a novel form of resistance in these insects. doi: 10.1603/ICE.2016.92553


You can also see Stephen Doggett (co-author and photographer of A Guide to Mosquitoes of Australia) speaking on photographing mosquitoes to in the symposium “Insect Photography Symposium: Bringing the Small to the World.

You can join the conversation on Twitter and keep an eye on all the fun in Orlando by keeping an eye on the tweet stream!



Moving pictures and managing mosquitoes


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

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

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

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

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

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

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

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

Should we start pulling out mangroves to save our wetlands?

Does wetland rehabilitation need mosquito control?

Can social media help track environmental change?

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

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


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

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

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.


  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 ( 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.


Does Zika virus pose a threat to Australia?

They’re small, spindly insects but their threat never dwindles – the bites of mosquitoes threaten death and disease in many parts of the world. The emergence of a little-known virus, Zika, from an African forest, is the latest to alarm the public, politicians and health authorities because of its potential link to birth defects.

What is Zika virus?

Zika virus is a mosquito-borne virus closely related to dengue and Yellow Fever viruses. Discovered almost 70 years ago in a Ugandan forest, the virus generally only causes a mild illness. Symptoms include rash, fever, joint pain and conjunctivitis.

Severe symptoms aren’t common and the illness was never thought to be fatal.

Despite detection throughout Africa and Asia, the virus rarely entered the spotlight of scientific research. It was overshadowed by the spread and impact of dengue and chikungunya viruses, which infect millions of people across the regions.

In the last decade, Zika virus outbreaks have occurred in the Pacific, with reports of severe illness. But again, Zika was considered a lesser threat than dengue and chikungunya viruses.

Everything changed in 2015 when Zika virus reached the Americas.

New outbreaks and severe symptoms

Since the first local Zika virus infection, cases have been reported from at least 19 countries or territories in the Americas, with more than one million suspected cases.

Rapid spread of an emerging mosquito-borne pathogen is news enough but people are also panicked by reports of more serious consequences of Zika virus infections, including post-viral Guillain-Barré Syndrome, an autoimmune condition where there person’s nerves are attacked by their own body.

Of most concern has been the rapid rise in rates of microcephaly, a birth defect which causes babies to be born with unusually small heads, in regions where Zika virus has been circulating.

While the role of Zika virus as the cause of microcephaly has not yet been confirmed, there is growing evidence of a connection between the two where pregnant women have been infected with the virus.

Babies born with microcephaly, and those who died shortly after birth, have tested positive for the virus, and there are close regional associations between clusters of birth defects and Zika virus.

There is enough concern for the Centres for Disease Control to issue health warnings to pregnant women planning to travel to these regions. [This also includes the Australian Government] Some health authorities are even advising people to postpone pregnancies.

There is no vaccine for Zika virus. Stopping mosquito bites is the only way to prevent infection.

Is Australia at risk of a Zika virus outbreak?

There is little doubt the virus can make it to Australia. There have already been a number of infections reported in travellers arriving in Australia from the Cook Islands and Indonesia.

Mosquito-borne viruses generally aren’t spread from person to person. Only through the bite of an infected mosquito can the virus be transmitted.

In the case of Zika, there have been some unusual cases of transmission, including through sex and the bite of an infected monkey. Despite these unusual circumstances, mosquitoes will still play the most important role in any local transmission.

While dozens of mosquitoes are capable of spreading local mosquito-borne pathogens, such as Ross River virus, only one of the 300 or so mosquitoes found in Australia can transmit Zika virus: Aedes aegypti, the Yellow Fever Mosquito, which is only found in north Queensland.

The Yellow Fever mosquito, Aedes aegypti, is critical to the spread of Zika virus in many regions of the world, including Australia.

For local Aedes aegypti to spread Zika virus, they must bite an infected traveller shortly after they return from a country where the virus is circulating.

While the chances of this happening are small, there is then a risk of a local outbreak occurring as the infected mosquito bites people who’ve never left the country.

This is the process that occurs in outbreaks of dengue in Far North Queensland. If we can get outbreaks of dengue, there is no reason we cannot, or won’t, get an outbreak of Zika in the future.

How to reduce the risk of transmission

Fortunately, authorities are well placed to contain an outbreak of Zika virus, as the required strategies are the same as management of dengue outbreaks.

Perhaps the real message here for Australian authorities is that they need to work diligently to keep exotic mosquitoes out of the country.

While Aedes aegypti may not become established in southern cities, even with a changing climate, there is great potential that Aedes albopictus, better known as the Asian Tiger Mosquito, could become established in southern cities. As well as a vector of Zika virus, it can spread dengue and chikungunya viruses and be a significant nuisance-biting pest. Keeping this mosquito out of our cities is critical.

Australians planning travel to South and Central America, including the Rio Olympics, should take precautions to avoid mosquito bites. Irrespective of Zika virus, mosquito-borne dengue and chikungunya viruses have infected millions of people, causing thousands of deaths, in the last few years and are reason alone to pack mosquito repellents. Be prepared to cover up with long sleeved shorts and long pants if in regions where risk is high.

The ConversationThis article was originally published on The Conversation. Read the original article.