AgCenter mosquito control efforts aim to minimize effects of Zika virus


This is a female Aedes aegypti mosquito while she is in the process of acquiring a blood meal from a human host. Commonly known as the yellow fever mosquito, it has a smaller distribution in Louisiana than the Asian tiger mosquito (Aedes albopictus). Both can potentially transmit diseases to humans. Photo by James Gathany, Center for Disease Control

(03/02/16) BATON ROUGE, La. – An LSU AgCenter medical entomologist is working with mosquito control efforts in Louisiana to minimize the effects of tropical diseases such as the Zika virus.

Kristen Healy said that Zika virus will probably be less of a threat in Louisiana than other mosquito-borne diseases in the area, including West Nile virus or eastern equine encephalitis.

Healy, who primarily focuses her research on mosquitoes and mosquito-borne pathogens, said West Nile virus and eastern equine encephalitis rely on birds for transmission. “These diseases are more difficult to control because you cannot easily access local bird populations,” she said.

With Zika virus an animal reservoir is not required in the transmission cycle, she said, so transmission can be reduced by having people protect themselves from mosquito bites.

Healy said protective measures that can be taken include:

– Use of repellents registered with the U.S. Environmental Protection Agency and applying them according to label instructions.

– Wearing long sleeve shirts and long pants that are light-colored.

– Checking yards and businesses weekly for standing water in containers such as tires and buckets where mosquitoes lay eggs.

– Repair of window and door screens to prevent entry of mosquitoes into homes.

– Support for local mosquito control programs.

So far, Healy said, Zika has been detected in individuals in the U.S. who have traveled abroad, including a handful in Louisiana.

“Since it is still early in the mosquito season, it would be unlikely to see any local transmission at this time. However, there is still much we do not know about which mosquito species will be important for transmission in this area,” Healy said.

The symptoms of Zika include a mild flu-like illness, she said, with fever, joint pain, conjunctivitis and a skin rash that alerts health care workers to the possibility of the disease, in addition to recent travel abroad.

“The greatest risk at this time is by traveling to countries where local transmission is occurring,” Healy said. “It is not unusual to expect imported cases coming into the U.S., but an imported case in the area does not mean that local transmission will occur.”

Only 20 percent of the people exposed to the disease will show any symptoms, she said.

“The main concern at this time is the current link between infants born with microcephaly to mothers infected with Zika virus during pregnancy. However, there is still much we do not know regarding this link,” she said.

Currently, the Centers for Disease Control (CDC) is recommending that women who are pregnant or might become pregnant avoid travel to areas of known Zika transmission. More information about travel warnings and restrictions can be found at

Protection from mosquito bites is not only important because of the potential threat of Zika, but also because of existing disease-causing pathogens spread by mosquitoes in Louisiana, Healy said.

“West Nile virus continues to be important in our area, as well as sporadic cases of eastern equine encephalitis, Saint Louis encephalitis and La Crosse encephalitis,” Healy said.

Also, mosquitoes are the sole means of transmitting heartworms to pets, she said.

Two species of mosquitos, the Asian tiger (Aedes albopictus) and the yellow fever mosquito (Aedes aegypti), have been identified as potential vectors of pathogen transmission. Healy said graduate students in her lab are working to find out more about the behaviors of these two species to help fight disease spread.

The Asian tiger mosquito is highly abundant in this area, especially during the summer months, she said, while the yellow fever mosquito has a much smaller distribution in the state.

“Unfortunately, both Aedes albopictus and Aedes aegypti will bite during the day as well at dusk, dawn and evening hours,” Healy said.

Healy has three researchers in her lab who are studying different aspects of mosquitoes.

Research associate Emily Boothe is working in six parishes to study the mosquito responsible for transmitting West Nile virus. This includes evaluating collection techniques for trapping adult mosquitoes and monitoring of insecticide resistance in the state. Also, her research interests extend to the Asian tiger mosquitoes, and her work will determine how temperature affects larval development, metabolism and larvicide efficacy.

Graduate student Nick Delisi is evaluating susceptibility of mosquito larvae to different larvicides that target these immature mosquitoes. He is currently in the process of comparing field-collected mosquitoes to an established lab colony strain with no resistance.

Graduate student Shiloh Judd is studying the feeding habits of the Asian tiger mosquito that feeds on plant nectar as well as blood. All mosquitoes feed on plant nectars as a source of energy. By determining which species of plants are most attractive to mosquitoes, there is potential to target these plants as another avenue for control of mosquitoes.

Healy and her lab work closely with mosquito control programs around the state and are implementing several applied research projects.

Todd Walker, director of the East Baton Rouge Parish Mosquito Abatement and Rodent Control, said his office works closely with Healy and the LSU AgCenter.

“They do tests to evaluate the effectiveness of our applications and pesticides,” Walker said.

Walker said Healy obtained a grant from the EPA to study the potential effects of using pesticides against mosquitoes on honeybees. The results of the study have been favorable, he said. “Properly done, mosquito control operations do not have to be harmful to honeybees.”

Walker said efforts are being made with the LSU AgCenter to design a drone, or unmanned aerial vehicle, to scout for potential mosquito breeding sites that would be difficult to access, such as a pile of discarded tires in a wooded area.

Walker said Healy assists the Louisiana Mosquito Control Association, and she serves on the board of directors.

Healy also is participating in the national Extension Disaster Education Network to compare different state responses to Zika. She said several parishes have developed their own campaigns to spread public awareness of how the disease can be prevented.

Cornell University in New York has developed an extensive website about the disease. It can be accessed at

Also, the University of Florida has information about the virus, mosquito vectors and prevention at

The LSU School of Veterinary Medicine has several mosquito research projects underway. Rebecca Christofferson, assistant professor in pathobiological sciences, with the Vector-borne Disease Laboratory at the school, is studying the virus to see how it presents itself in different forms.

Christofferson, working with veterinary science doctoral students Ania Kawiecki and Handly Mayton, said the team’s goal is to improve the ability to diagnose the virus.

5/18/2016 2:02:18 PM
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