Mosquito Sample Tests Positive For Deadly Equine Encephalitis Virus

MANORVILLE, NY — A deadly new public health threat has been posed in Suffolk County as a mosquito sample tested positive for the eastern equine encephalitis virus.

The New York State Department of Health told Suffolk County health officials that the sample, Culiseta melanura, which tested positive for the virus — also referred to as "Triple E" — was collected on August 16 in the Manorville area.

Officials warn that the the presence of EEE in a mosquito sample poses a potential health risk; Suffolk County Commissioner of Health Services Dr. James Tomarken has requested the Health Commissioner of the New York State Department of Health to confirm a declaration of an imminent threat to public health for Suffolk County.

The designation will allow the county to move forward with critical steps to control mosquito populations.

According to the county, eastern equine encephalitis is "a rare but deadly illness for humans."

The disease is also a concern for horses, though a vaccine is available and recommended for horses. Both Triple E and West Nile virus are transmitted by the bite of an infected mosquito, county officials said Thursday.

“The reason EEE is less common in humans is that the primary mosquito vector, Culiseta melanura, does not typically feed on humans,” Dr. Tomarken said. “However, the virus may be transmitted to humans and horses by bridge vectors, which are other kinds of mosquitoes that have contracted the virus by feeding on infected birds.”

Eastern equine encephalitis is "a rare but deadly illness for humans"

Approximately 5 to 10 human cases of EEE are reported annually in the U.S. — but New York State has only reported 12 cases of EEE since 1952.

To date, there have been no human cases of EEE in Suffolk County. The last reported positive mosquito for EEE in Suffolk County was in 2008.

In severe cases, a person with EEE may experience encephalitis, or swelling of the brain — that may result in death.

The mortality rate of those that develop EEE is about 33 percent, the highest among human arboviruses — a virus transmitted by arthropod vectors — cases reported in the United States.

Currently, there is no human vaccine for EEE and patients are treated with supportive care, officials said in a release.

Horses are particularly vulnerable if they contract EEE, county sources said.

The equine mortality rate due to EEE ranges from 75 to 90 percent.

In 2016, the USDA reported 118 cases of EEE in horses from 15 states, including two from upstate New York.

Suffolk County reported three cases of EEE in horses in 2003. Owners of horses have an essential role in preventing EEE from spreading, health experts say.

Horse owners are encouraged to vaccinate their animals and put safeguards in place that prevent animals exposure to mosquitoes as well as report any suspicious signs of EEE in animals to a veterinarian.

In addition to that news, an additional 16 mosquito samples have tested positive for West Nile virus, Suffolk County said.

The samples, all Culex pipiens-restuans, were collected on August 15 and August 16. One sample tested positive from Farmingville, Port Jefferson Station, Setauket, North Babylon, Copiague, Lindenhurst, Melville, Dix Hills, East Hampton and Aquebogue.

Three tested positive in West Babylon and two in Southold.

So far this year, Suffolk County has reported 92 mosquito samples that were confirmed positive for West Nile virus; 9 birds confirmed positive for West Nile virus, as well.

No humans or horses have tested positive for West Nile virus in Suffolk this year, county officials said.

West Nile virus may cause a range of symptoms, from mild to severe, including fever, headache, vomiting, muscle aches, joint pain, and fatigue.

There is no specific treatment for West Nile virus. Patients are treated with supportive therapy as needed.

Residents are asked to help stem the mosquito population by eliminating standing water on their property.

"With the finding of eastern equine encephalitis virus in the county, Dr. Tomarken is asking the public to take steps to be even more vigilant, especially those who live in or visit the Manorville area," a release from Suffolk County said Thursday.

Individuals, especially those aged 50 or over, or those with compromised immune systems, are urged to take precautions to avoid being bitten by mosquitoes. To avoid mosquito bites, residents are advised to:

• Minimize outdoor activities between dusk and dawn.
• Wear shoes and socks, long pants and long-sleeved shirts when mosquitoes are active.
• Use mosquito repellent, following label directions carefully.
• Make sure all windows and doors have screens, and that all screens are in good repair.
• Keep mosquitoes from laying eggs inside and outside of your home. Once a week, empty and scrub, turn over, cover, or throw out containers that hold water, such as vases, pet water bowls, flowerpot saucers, discarded tires, buckets, pool covers, birdbaths, trash cans and rain barrels.
• Download a copy of Suffolk County’s informational brochure “Get the Buzz on Mosquito Protection,” available in English and Spanish, and share it with the community.

In addition, dead birds may indicate the presence of West Nile virus in the area. To report dead birds, call the Public Health Information Line in Suffolk County at 631-787-2200 from 9 a.m. to 4:30 p.m., Monday through Friday. Residents are encouraged to take a photograph of any bird in question.

To report mosquito problems or stagnant pools of water, call the Department of Public Works’ Vector Control Division at 631-852-4270.

For further information on mosquito borne illnesses, visit the Department of Health Services’ website by clicking here.