FAIRFIELD COUNTY, Conn. – An aggressive species of mosquito that can spread several diseases including West Nile and Zika is expanding in the state of Connecticut, according to a study from the Connecticut Agricultural Experiment Station.
The Asian tiger mosquito (Aedes albopictus) is an invasive species that originated in East Asia and is undergoing a northward expansion in the United States, according to CAES. Connecticut had previously been seen as near the northern boundary of its potential range, but this new study that covered a 20-year period from 1997 to 2016 found that they are becoming more abundant, particularly in urban and suburban locations along the state's southwestern shoreline.
Winter temperatures play an important role in the expansion of the species, with mild temperatures allowing the Asian tiger mosquito to survive through the winter.
"This is the first documentation of Ae. Albopictus overwintering in New England,” said Dr. Philip Armstrong, lead author and Medical Entomologist at CAES. “Furthermore, our date demonstrates how mild winters affect the seasonal abundance and overwintering success of this mosquito.”
Two different viruses, Cache Valley and West Nile virus, were isolated in the mosquitos, which officials say further indicate that it poses a disease threat to humans. The Asian tiger mosquitos are human biters than can also carry chikungunya and dengue.
“We would anticipate further expansion and build-up of this species with projected climate change,” said Dr. Theodore Andreadis, co-author and Director of CAES. “Its aggressive biting behavior and ability to transmit a cadre of human disease causing viruses clearly warrant further study and close monitoring through our statewide surveillance program.”
The Connecticut Post reported that the state will begin its annual trapping and testing of mosquitoes on Monday. While it is difficult to predict what each season will bring, state officials told the Connecticut Post that they predict there will be some West Nile activity this year.
There have been 131 cases of West Nile virus in humans since 2000, including three fatalities, according to the Connecticut Post. While last year was a quiet one for West Nile, officials told the Connecticut Post that wet springs like we've seen this year, followed by hot, dry summers, can result in more West Nile activity.
The state also began testing for Zika last year, and though the Asian tiger mosquito is the main carrier of the disease, officials don't predict any local transmission of Zika this year, the Connecticut Post reported.