Last weekend’s cold snap has ended the threat of Eastern equine encephalitis for this year. That’s according to Dr. Theodore Andreadis, director of the Connecticut Agricultural Experiment Station.
“The weather is certainly cold enough now that the mosquito numbers have declined dramatically, and the risk of anyone being bitten by an infected mosquito is virtually zero at this point,” said Andreadis. “And we haven’t detected any further virus activity, in fact we stopped our surveillance program last week.”
Andreadis said this year’s EEE outbreak was unusual and probably due to migrating birds from the South that carried the virus to freshwater swamps in the Northeast.
“There’s one particular species of mosquito that develops in these swamps, and we know that that mosquito was the one that really drives the whole transmission cycle,” said Andreadis. “And when we have very high populations of that mosquito, that creates the kind of conditions that would be conducive for a rapid buildup of the virus.”
Andreadis is almost certain that EEE will reemerge next year, but he doesn’t expect it to be as widespread.
“We know this virus is spread by mosquitoes and birds,” said Andreadis. “We assume a large number of birds must have been infected with this virus, otherwise we wouldn’t have seen so many human cases. I suspect that there is some herd immunity in the bird population, so next year we may not have as many susceptible birds.”
One factor that will determine the severity of EEE next year is the weather this winter.
“If we have a mild winter with heavy snowfall and rain that will inundate these swamps with a lot of water, it will increase the likelihood these mosquitoes survive the winter, as well as the virus,” said Andreadis.
Connecticut reported four human cases of EEE this year, three of which were fatal.