Meet the Zika Expert: Dr. Grayson Brown

University of Kentucky Entomologist Dr. Grayson Brown's research includes the Aedes aegypti mosquito at the University of Kentucky in Lexington, Ky.

University of Kentucky Entomologist Dr. Grayson Brown’s research includes the Aedes aegypti mosquito at the University of Kentucky in Lexington, Ky.

July 20, 2016

Q: Why is the Zika virus getting traction now? What is contributing to its spread?

A: The virus arrived in Brazil in April, 2015.  In October of last year, the first microcephalic babies were born.  Over the remaining months of the mosquito season in Latin America, many other effects of the virus, heretofore not seen, began to appear.

The mosquito season is still early in the Northern Hemisphere so there is increased concern that the virus will soon appear here and cause similar problems to that experienced in Latin America.  Factors that contribute to its spread are returning travelers, long-term viremia that is sexually transmissible, and an unknown vector range.

Q: Would Zika spread as fast in the United States as it has in South America?

A: No.  In the US, we do not spend as much time outdoors, we are much more likely to use air conditioning in our homes (with the doors/windows closed), we have better drainage and sanitation systems, we have better municipal mosquito control programs, and we are more likely to use effective mosquito repellents and other controls on our own property.

Q: Why are you focusing on mosquitoes – what you call the “vector” – as the best way to combat Zika?

A: There is no vaccine for Zika nor is there a cure.  The best way to deal with it is through prevention.  The best preventative approach to a vectored pathogen like this is through control of the vector – in this case mosquitoes.

Q: With the Olympics in Rio approaching, what are the health risks for residents of Rio and visitors?

A: The residents of Rio are already exposed to the risks of Zika so the Olympics will not have much impact on them.  The highest incidence of Zika is found in the poorer favelas, not in the Olympic Village area.

The biggest vectored-disease health risks for visitors to Rio is going to be dengue and chikungunya, both of which are also at epidemic levels in Rio right now.  Both of these viral diseases are vectored by the same mosquito as Zika but their symptoms are much more severe.

That said, visitors staying in upscale hotels in the vicinity of the Olympic Village and who use repellents and other common-sense measures to avoid mosquito bites will have a lower risk of contracting any of these three viruses.

Q: What other precautions can one take to avoid contracting Zika?

A: Personal Protection: Repellents, wearing protective clothing (e.g. long pants, long sleave shirts), avoid being outside in the dusk hours (4 – 9 pm).  Property Protection:  Dump any standing water that might breed mosquitoes, fix any sagging gutters, remove thick vegetation (especially the invasive Japanese honesuckle).  Consider having a backyard mosquito control treatment applied to your suburban backyard.

Q: Why is a large-scale response important, and what are the risks of inaction?

A: A high percentage, up to 80%, of patients infected with Zika never show any symptoms even though they become viremic and can pass the virus to mosquitoes.  Consequently, for every diagnosed patient, there are many more not diagnosed.  So when viremic patients begin showing up, you have to assume there a many others who could be anywhere.  Thus, once the virus appears, a wide-area approach is necessary.


Q: What long-term, sustainable control options have you discovered in your research?

A: We were a founding laboratory in the development of Natular, a bacterial fermentation product that is highly effective at killing mosquito larvae yet environmentally benign.  It is now one of the principal larvicides used by municipalities throughout the US.

We have had fairly good success with distributing copepod eggs.  These eggs are highly resistant to desiccation and can be spread out any time of the year.  The copepods that hatch from them build up very rapidly and eat the youngest mosquito larvae.

In conjunction with several corporations, we are currently developing a system for mass releasing mosquitoes from fixed wing aircraft.  This will be necessary when using sterile males, GMO’s, Wolbachia-infected, or other autocidal methods as they become available.

Q: Does a solution lie in terms of mosquito control or public health funding? 

A: Unless we’re prepared to take on a world-wide eradication effort, the best solution is knows as Integrated Vector Management.  This approach uses a combination of surveillance, mosquito control, and community engagement to manage the mosquito population such that it minimizes the public health threat.  The protocols for doing this are well known but not widely followed because it requires a sustained commitment by local authorities.  Mosquito management is really a local affair but once a vectored disease drops out of the headlines, local governments loose interest in mosquito management which then declines in quality.  This means that, when the public health threat eventually re-emerges, the management teams and programs have to play catch up and be rebuilt during the critical first year or so when the health threat could best be avoided.

Q: How do you propose officials make long-term progress with short term funding?

A: The short term funding should be used to re-establish mosquito management programs according to sustainable practices mentioned above.  Thereafter, local governments need to understand that we are in for more mosquito-borne disease threats in the future and that they need to find the resources to protect their citizens.

A top notch mosquito control program is not that expensive for most municipalities.  It can be funded with a very small assessment on real estate, tire tax, or other permanent local funding source.


Q: The BBC recently ran a story posing the question, “would it be wrong to eradicate mosquitoes” worldwide. Is that a possible solution?

A: It is technically possible to eradicate a target mosquito species.  However, there are too many places in the world where this would not be possible due to ecological concerns, security/political concerns, etc.  The cost would be enormous and, in the end, it would likely be unsuccessful.

Q: Do you think the media and public is overly concerned, or under concerned about the threat of Zika in the US and abroad?

A: I think the media have overhyped the Zika threat in the Continental US.  However, we do need more sophisticated mosquito surveillance and management in this country so, to the extent that is accomplished, the hype is beneficial.

Epidemics of mosquito-borne disease will not end with Zika – there’s more coming.  We are going to need better mosquito management programs in place when these future threats appear.  It is part of the way things are now.



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