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This content is taken from the London School of Hygiene & Tropical Medicine & ARCTEC's online course, Preventing the Zika Virus: Understanding and Controlling the Aedes Mosquito. Join the course to learn more.

Skip to 0 minutes and 14 seconds One of the things to remember about the Aedes mosquito is that it transmits more than one disease; so it transmits chikungunya, dengue fever, yellow fever as well. And so when it comes to controlling these mosquitoes there is a potential that we could have an impact on more than one disease. When people do research studies quite often that research study is very focused it’s a dengue study or it’s a chikungunya study and quite often the end points or the outcomes of that study are focused as well in those diseases and quite often it’s easy to to forget the wider impact of a control intervention.

Skip to 0 minutes and 52 seconds Even malaria mosquitoes in parts of the world, for example, in Southeast Asia or in South America, transmit malaria potentially during the day and outdoors so control methods that we use for Aedes mosquitoes may even have an impact on malaria as well. So, this is important when designing control programs and also research studies as well looking at the impacts of vector control technologies to consider the wider implications of the control interventions on other diseases not just Zika, but other diseases including dengue, chikungunya and even malaria. The story of Zika has a bigger message; we have to remember that Zika is coming on top of dengue that has been around a long time.

Skip to 1 minute and 33 seconds And after dengue, there was chikungunya sweeping through the Caribbean now sweeping through Latin America, another virus like Zika which we underestimated because its effects are generally nonfatal. But actually they turned out to be much more serious than we anticipated. They don’t kill, but these are very bad sequelae.

Skip to 1 minute and 57 seconds And what they have in common of course is Aedes aegypti. Aedes aegypti started in East Africa, spread throughout the world in the eighteenth nineteenth centuries, now being followed in the same way by Aedes albopictus from the far east – Korea, China – also now spreading throughout the world. And we’ve kind of let them go. But what we should remember is that after dengue and chikungunya and Zika, there’s a whole list of other viruses waiting to come and they probably will come. So, sooner or later we are going to have to take this mosquito seriously and with things like Zika, it emphasizes the idea that maybe we should be thinking a little more seriously again of the eradication measures.

Skip to 2 minutes and 44 seconds Otherwise we’re going to be doing this source reduction effort, suppressing it but not getting rid of it, forever and ever and ever. And even when when Latin America looks like Shanghai from ocean to ocean built over, everything else will be gone there’ll be no other mosquitoes but Aedes aegypti and Aedes albopictus will be there and happy. Those mosquitoes will be there and transmitting virus until we aim at the mosquito not just the viruses they transmit. The points illustrated I think by yellow fever as an example, yellow fever one of the first viruses we knew because it’s very fatal to people. Not many survive getting yellow fever.

Skip to 3 minutes and 26 seconds We don’t worry about it much in developed countries because there’s a good vaccine, lifelong protection from a good vaccine, but we don’t use much of that vaccine; there are stocks but they’re not large. So the question we always ask it’s a question for medical entomology students why has yellow fever never reached Asia? And ok some people think it might be because there’s some secret barrier.

Skip to 3 minutes and 50 seconds The mosquitoes there are somehow less able to carry that particular virus. But as far as we can see there is no justification for that; they look like the same mosquitoes and certainly if you feed them on the virus they get the virus, so probably most entomologists would say it’s waiting to happen. What’s going to happen? It’s going to be really bad. And are we ready? We are certainly not. No one is taking that possibility seriously it’s not planned for, so another reason to focus on the mosquito.

Lessons learned: What do these control methods mean for other diseases?

The Aedes mosquito transmits more than one disease, so could the control methods we’re using in an attempt to halt the spread of Zika affect transmission of other diseases too?

In the video Dr James Logan and Dr Jo Lines use examples of other vector borne diseases such as malaria, dengue, and yellow fever to discuss the impact of control interventions targeted specifically towards Aedes. What are the wider implications of our actions? Should we reassess the ways in which we evaluate our interventions?

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This video is from the free online course:

Preventing the Zika Virus: Understanding and Controlling the Aedes Mosquito

London School of Hygiene & Tropical Medicine

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