While increased exposure to the Zika virus is a valid concern among Baton Rouge residents after the recent flooding in the region, three University experts agree that West Nile, not Zika, is what people should focus their attention on.
The Zika virus is spread by the bite of infected Aedes aegypti and Aedes albopictus mosquitos, also known as the yellow fever mosquito and Asian tiger mosquito respectively. Mosquitos breed in standing water from flooding and heavy rainfall, leading some to believe Louisianians could be more vulnerable to contracting Zika.
Residents should refocus their concerns about Zika, according to Rebecca Christofferson, an assistant professor in pathobiological sciences at the LSU School of Veterinary Medicine. Christofferson conducts her research in the Vector-borne Disease Laboratory at the vet school.
“For Zika, at this point, there’s no risk because there’s no local transmissions in Louisiana,” Christofferson said. “For floodwaters and those types of things, you actually have to be more concerned about West Nile, because West Nile is in Louisiana, and floodwaters do affect those mosquitos.”
For Zika to be locally transmitted, the mosquito would have to contract the illness from a human or animal host who has the disease and then spread it to others. An imported Zika case occurs when one travels to an area with infected Aedes mosquitos and is bitten, bringing the disease back with them.
Louisiana has 26 reported cases of imported Zika, but no locally transmitted cases.
As a precaution against West Nile, Christofferson advises people to wear bug repellent with DEET, dump out standing water and wear protective clothing when possible.
Christofferson’s research centers on the transmissions that drive arboviruses and how temperature affects the efficiency of the virus in a mosquito. Christofferson was recently awarded a $1.2 million grant from the National Institutes of Health (NIH) and the National Institute of General Medical Sciences. The grant will last until Aug. 21, 2019.
Christofferson is looking to characterize some of the variability of Zika in mosquitos by using math modeling to regulate transmission outputs. With predictive modeling, she can compare data and see how the simulated transmission differs.
“Depending on temperature, there was this interesting interplay between how long the mosquito lives and how long it takes for the virus to get out. It wasn’t as one-to-one as we expected,” Christofferson said. “The cool thing about this project is that our math models will be directly tied to experimental data.”
Christofferson’s research could predict what seasons would have an intense concentration of mosquitos and where to effectively get rid of them.
Another University expert on Zika, Kristen Healy is a mosquito biologist and assistant professor in medical entomology and public health entomology at the LSU AgCenter.
Rather than looking at the virus like Christofferson, Healy studies the mosquito itself. She looks at variables including mosquitos’ temperature dependency, development rates and the effectiveness of pesticides.
With over 60 species of mosquitoes in Louisiana alone and 3,000 worldwide, not every mosquito is a potential vector, or carrier of the disease, so Healy looks at the reasons why some insects are infected and others aren’t.
To test this, she infects mosquitos with the virus and collects data on which are capable of transmitting the virus, and the reasons behind why or why not.
“It’s like a numbers game,” Healy said. “We look at the individual population of species and what those pressures are that are on those mosquitos that contribute to that factor, and what goes into that.”
In past research projects, Healy studied different strategies to better control mosquitos — how to better trap them, what types of habitats they prefer to lay eggs in and source reduction.
Healy’s stance was similar to her colleague’s, in that Louisiana residents shouldn’t be worried about contracting Zika because of floodwaters.
“To have increased risk, you need more imported cases and a higher population of those mosquitos. In this area, we’re really just not seeing that many. We don’t have the virus, and we don’t even have those high levels of mosquitos,” she said. “We should always think about mosquito-borne viruses annually anyway, because that risk is always there, and it’s never going away.”
Alma Roy is the assistant director of the Louisiana Animal Disease Diagnostic Laboratory, which works to improve public health and prevent mosquito-borne infections in people.
LADDL collects mosquito pools found in areas across the state and tests them for three different viruses: West Nile, Encephalitis and Eastern Equine Encephalitis. West Nile is more prevalent than any other mosquito-borne illness in Louisiana right now, Roy said.
Testing yields a positive or negative result, and if positive, the lab reports back to the parish which pool is infected. The parish is able to identify exactly where the sample originated from and from there, take preventative measures such as spraying the affected areas.
“We don’t have it here in our mosquito population, so we’re not too concerned about the flood increasing that potential. Zika’s really not on our radar right now,” Roy said. “Floodwater’s bad for increasing the number of mosquitoes and the potential for the same infections we have, like West Nile and Encephalitis.”
LSU experts say West Nile, not Zika, is Louisiana’s concern
By Lauren Heffker
September 6, 2016
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