According to an official of Vermont Agriculture Agency.
“We begin our mosquito monitoring from July 5,” said Patti Casey, director of the environmental monitoring program. “I’m disappointed. In my opinion, it’s too late. We usually started at the beginning of June.”
Casey said she thinks it’s important to track mosquito populations as they emerge to see trends.
“With climate change, we see differences in populations as weather patterns change,” she said. “It is important to follow the start of the season to detect changes.”
Cary Giguere, director of public health at the Agricultural Resource Management Division, said Wednesday that while he appreciates Casey’s “passion” for his work, the late start was caused by a few factors beyond his control. the Agriculture Agency.
First, said Giguere, the Vermont Department of Health and the Centers for Disaster Control and Prevention, which provides half of the $170,000 needed for the program, said he was most concerned about mosquito-borne eastern equine encephalitis, which doesn’t start showing up until July and lasts until September. Therefore, the late start of the monitoring program corresponds to the priorities of both agencies.
The last death in Vermont from eastern equine encephalitis was in 2016. Giguere said the disease occurs in cycles of seven to 10 years when it becomes more prevalent.
“Nobody knows why,” he said.
Second, Giguere said he was unable to obtain the five vehicles he needed for field technicians from the state vehicle fleet until July, and that leasing the vehicles more early from Enterprise, which has a contract with the state, would have cost about $10,000, or five times more than securing them from the state fleet. Vehicles have been hard to come by in the age of COVID, according to Giguère.
“It was actually a good exercise to look at what we were doing and make it more consistent with what the CDC wants us to do with their money,” Giguere said.
The Department of Agriculture’s involvement in the mosquito surveillance program dates back to the early 2000s when the West Nile virus first emerged, according to Giguere.
“The CDC was giving money to the state to do surveillance, and we had previously been monitoring mosquitoes in the mosquito control districts of Brandon, Pittsford, and Salisbury,” Giguere said. “We already had the traps and the people. They just said, ‘Can you do more of what you’re already doing?'”
How does the monitoring program work?
Casey said the mosquito monitoring program includes about 100 sites statewide where insects are captured using three types of traps. The team of six summer technicians look for mosquitoes that could cause problems for people or livestock.
“This year we’re back to gravid (mosquito) trapping, which means pregnant and susceptible to West Nile virus,” Casey said.
The Department of Health had ordered Casey to stop trapping pregnant mosquitoes a few years ago, she said, because West Nile virus was thought to be spreading statewide, with no dots. hot.
“Me, being the person on the ground, I always advocate knowing,” Casey said. “Fortunately this year they decided to have us hand over these gravid traps, or at least some of them.”
Mosquitoes are collected from the traps at least once a week and taken back to a laboratory to identify species and sex. Only females count for the spread of the disease, according to Casey.
“The collected females are identified by species,” she said. “We have a priority list based on ability to carry disease. Not all mosquitoes bite humans.”
Mosquitoes that carry eastern equine encephalitis, for example, like to feed on birds and are less likely to feed on mammals. But there are also other mosquitoes called “bridge vectors”, which feed on birds and mammals, transmitting the disease to humans.
“It’s kind of a closed loop until the virus heats up,” Casey said. “Bridge vectors can take it out of the cycle (of the bird) and humans.”
Although monitoring mosquitoes carrying eastern equine encephalitis is his biggest study this year, Casey said his team is also monitoring Asian tiger mosquitoes, which appear to have an established population in southern and western Vermont. These mosquitoes caused “a bit of a splash” when they were discovered in Vermont several years ago, Casey said, because they can carry diseases such as dengue fever and yellow fever.
“These are tropical diseases and they’re not going to take hold in Vermont anytime soon,” Casey said. “At this point, they pose no risk to Vermonters.”
Contact Dan D’Ambrosio at 802-660-1841 or [email protected] Follow him on Twitter @DanDambrosioVT. This coverage is only possible with the support of our readers.