Jamestown Canyon virus found in Suffolk mosquito for first time this year

The Jamestown Canyon virus, which is transmissible to humans via an infected mosquito’s bite, has been detected in a sample in Suffolk for the first time this year, the county health department said Thursday.

That mosquito was collected in Sayville on July 18 as part of standard sampling in the county, which also found the West Nile virus in five other samples, taken in Lindenhurst, Northport and Greenlawn on July 26, and in Mastic Beach on July 25.

So far this year, at least 12 mosquito samples have tested positive for West Nile.

There have been no known cases of West Nile in humans in Suffolk this year so far — last year there were 11 — and there has never been a known case of Jamestown Canyon in the county, according to health department spokeswoman Grace Kelly-McGovern.

West Nile — first identified, in 1937, in Uganda’s West Nile district, and first detected in Suffolk in 1999 and each year since — is the top cause of mosquito-borne disease in the continental United States, according to the Centers for Disease Control and Prevention.

For most infected people — 8 out of 10 — there are no symptoms, but 1 in 5 develop a fever with other symptoms such as headache, body aches, joint pains, vomiting, diarrhea or rash. Severe illness occurs in 1 in 50 people, the CDC says.

With Jamestown Canyon virus — first identified in 1961 in mosquitoes from Jamestown Canyon, Colorado, and typically reported in the upper Midwest — initial symptoms can include fever, fatigue and headache, and some also have respiratory symptoms, the CDC says.

It can also cause severe disease "including infection of the brain (encephalitis) or the membranes around the brain and spinal cord (meningitis),” the CDC says.

The virus was found in mosquitoes in Suffolk in 2008, 2017 and last year, the department’s news release said.

Recommended precautions against mosquito bites include protective clothing — long-sleeved shirts, socks and long pants — and insect repellent with at least 30% DEET.

Local municipalities in the region sometimes spray to kill mosquitoes.

The Jamestown Canyon virus hasn’t been found this year in any mosquitoes in Nassau but was last year, according to Chris Boyle, a spokesman for Nassau County Executive Bruce Blakeman. 

Boyle said West Nile virus was found in one mosquito this year in Nassau, but no human has been infected.