After the state saw its highest rate of the West Nile Virus since 2012, experts said there are steps citizens can take to protect themselves, despite the increasingly low chances of transmission as temperatures drop in Connecticut.
Eight West Nile cases were confirmed between August and September this year, with one in New Haven, another in Shelton and six in Bridgeport, according to the State of Connecticut Mosquito Management Program in an Oct. 8 report on the human surveillance of West Nile Virus.
Though this rate is the highest Connecticut has seen in three years — with a record 21 cases confirmed in 2012 — experts and city officials said the risk going forward is relatively low. West Nile Virus, which is transmitted from birds to mosquitoes and then from mosquitoes to humans, is most common during the warmer months of the year, said Leonard Munstermann, senior research scientist in microbial disease at the School of Public Health and head curator of entomology at the Yale Peabody Museum.
“We’re really on the tail-end of the season, so it’s actually a little bit late to have a case [of West Nile Virus],” Colleen O’Connor, the special assistant to the New Haven Health Director, said. “But it’s been unseasonably warm so people have to remember that it’s still possible to catch West Nile.”
Humans cannot spread the illness to others and are more likely to contract West Nile Virus in the summer because there are more mosquitoes, Munstermann said.
He added that people who are immunocompromised or over the age of 65 are at a higher risk of experiencing serious symptoms. Most healthy people who contract the disease do not show symptoms any more severe than those of a mild cold.
“In terms of the Yale student community, I venture to say the risk of serious illness is [negligible],” Munstermann said.
Alexia Belperron, research scientist in medicine and lecturer in the Department of Molecular, Cellular and Developmental Biology, said the incubation period for West Nile Virus is usually 14 days, with cases that result in hospitalization taking longer to develop.
Belperron added that controlling transmission of West Nile Virus can be challenging because it is impossible to control where infected birds fly. But mosquitoes can be tested for infection, she said.
O’Connor said that when New Haven conducts its annual collection of mosquitoes, there are always a number of insects that test positively. She cited several ways that the public can protect themselves from being bitten, such as applying insect repellent and removing standing water from their property. O’Connor added that each year, New Haven provides insect repellent to elderly citizens, who are particularly susceptible to the virus. The city also applies larvicide to areas where standing water often collects, such as under manhole covers.
The West Nile Virus was first discovered in the West Nile subregion of Uganda. Its history in the United States can be traced back to a 1999 outbreak, during which more than a dozen cases were confirmed in New York City. An epidemic swept across the United States in the years following, Munstermann said, adding that there have been smaller waves of West Nile Virus outbreaks since then.
The latest case of West Nile Virus in Connecticut was confirmed on Sept. 27.
Clarification: A previous version of this article did not specify that mosquito larvae collects underneath manhole covers.