LSU Diagnostics tracks mosquito-borne diseases like Easter Equine Encephalitis and West Nile viruses

—As part of its mission to safeguard both animal and human health, the LSU School of Veterinary Medicine plays a critical role in disease surveillance, prevention, and research. LSU Diagnostics (Louisiana Animal Disease Diagnostic Lab), a key component of the school, tests over 30,000 mosquito pools annually from 32 parishes/locations across Louisiana, targeting three deadly encephalitis viruses in humans: West Nile Virus (WNV), Eastern Equine Encephalitis (EEE), and St. Louis Encephalitis (SLE). LSU Diagnostics can expand its surveillance efforts to proactively tackle emerging mosquito-borne viruses such as the Zika virus in 2016. In addition to this vital work, LSU Vet Med boasts infectious disease experts like Rebecca Christofferson, Ph.D., who studies the emergence and transmission patterns of zoonotic and mosquito-borne viruses. Together, the LSU Vet Med team maintains situational awareness for emerging mosquito-borne viruses and works towards readiness in the event of an outbreak.

So far in 2024, LSU Diagnostics has detected WNV in 324 mosquito pools, with no detection of EEE or SLE. The mosquito species that tested positive for West Nile virus include 318 Culex quinquefasciatus (known as the southern house mosquito), one Culex erraticus (a small, dark mosquito), and five Aedes albopictus (known as the Asian tiger mosquito).

LSU Diagnostics also tests clinical samples from domestic animals for exposure to these viruses. In the past year, four out of 26 tested horses were positive for EEE antibodies, and out of the 28 horses tested, none were positive for WNV antibodies. This means that there is likely little exposure to both viruses in horse populations to these viruses. Molecular testing has identified one horse and one goat positive for EEE out of eight total tested.

This combination of tests in mosquito pools and animals indicates that while overall exposure remains low, there is still a risk–albeit low–of acute illness in domestic animals due to ongoing transmission of these viruses in Louisiana.

The mosquito surveillance program is not just about monitoring but also about taking proactive steps. It involves the weekly reporting of positive mosquito pools in close collaboration with local mosquito abatement districts and related governments. This proactive approach allows for timely insecticide spraying in areas that test positive for any of the three viruses, providing protection as well as a sense of safety and security to the community.

LSU Diagnostics conducts Mosquito (Arboviral) Surveillance Testing throughout the year. All mosquito test results are reported to the Mosquito Abatement Districts and the Louisiana Department of Health (LDH), Office of Public Health. Equine test results are reported to the State Animal Health Officials, LDH, and the submitter's veterinarian, which creates an efficient information dissemination network, and instills confidence in the program's thoroughness from client to government.

Dr. Christofferson is an associate professor in Pathobiological Sciences and is an expert in disease transmission and epidemiology (incidence, distribution, and control of diseases). The goal of her lab’s research is to identify and investigate the factors that drive transmission of arthropod-borne and other emerging viruses (examples of arthropods are mosquitoes, ticks, and fleas). She and her team investigate mosquito-transmitted viruses such as Zika, dengue, chikungunya, West Nile, and some Bunyaviruses. Understanding how viruses such as are transmitted (including how they spread through the mosquito) can provide valuable information for prevention and treatment.

LSU Vet Med is protecting Louisiana against mosquito-borne diseases on two fronts: surveillance, research, and public outreach. To protect yourself against these viruses, avoid contact with mosquitoes. This means wearing EPA-approved mosquito repellent as per the directions and making sure window screens are in good condition. In addition, dump out standing water around your house where mosquitoes might breed, including gutters that might hold water due to accrued debris and saucers under potted plants. If you have a swimming pool, make sure to maintain proper water chemistry to discourage breeding, even in the cooler months; and stock ornamental water features with mosquito larva-eating fish. Refer to your local mosquito abatement for offered services and further tips on how to control mosquitoes around your house.

About LSU Vet Med: Bettering lives through education, public service, and discovery

The LSU School of Veterinary Medicine is one of only 33 veterinary schools in the U.S. and the only one in Louisiana. LSU Vet Med is dedicated to improving and protecting the lives of animals and people through superior education, transformational research, and compassionate care. We teach. We heal. We discover. We protect.