Tick and mosquito-borne illnesses make early entrance

The Connecticut Agricultural Experiment Station is reporting higher-than-average numbers of ticks testing positive for Lyme disease and mosquitoes testing positive for West Nile virus in New Canaan.

According to Dr. Goudarz Molaei, who directs the experiment station’s tick testing program, “we have received over 2,600 ticks so far this year for testing and greater than 40% have tested positive for Lyme disease spirochetes. This is roughly 10% higher than what we have typically seen over the last five years.”

The experiment station is also reporting high tick infection rates with Babesia microti,the causative agent of babesiosis, a malaria-like illness (8%), and Anaplasma phagocytophilum, the causative agent of human granulocytic anaplasmosis (12%).

“We are in the midst of a peak activity for nymphal stages of blacklegged deer ticks, Ixodes scapularis, that are often difficult to detect because of their small size and propensity to quickly attach and feed,” said Dr. Theodore Andreadis, director of the experiment station. “Using tick repellants when hiking or camping and conducting tick checks remain the best ways to reduce the risk of contracting tick-borne diseases.”

According to the Centers for Disease Control and Prevention (CDC), Lyme disease is the most commonly reported vector-borne disease in the United States that affects an estimated 329,000 people annually and can cause severe damage to joints and the nervous system. The Connecticut Department of Public Health reported 2,022 cases of Lyme disease in 2017. Several hundred cases of babesiosis and human granulocytic anaplasmosis have also been diagnosed.


The first mosquitoes to test positive for West Nile Virus were trapped in New Canaan on June 19. It’s one of the earlier detections of virus recorded during the last 20 years of the statewide monitoring program, a press release from the experiment station said.

"The recent rainfall and warm weather forecast for this weekend and beyond are expected to increase mosquito activity and build-up of West Nile virus,” Andreadis said. “We encourage everyone to take simple measures such as wearing mosquito repellent and covering bare skin, especially during dusk and dawn when mosquitoes are most active."

To reduce the risk of being bitten by mosquitoes people should:

  • Minimize time spent outdoors between dusk and dawn when mosquitoes are most active.

  • Be sure door and window screens are tight-fitting and in good repair.

  • Wear shoes, socks, long pants, and a long-sleeved shirt when outdoors for long periods of time, or when mosquitoes are more active. Clothing should be light-colored and made of tightly woven materials that keep mosquitoes away from the skin.

  • Use mosquito netting when sleeping outdoors or in an unscreened structure and to protect small babies when outdoors.

  • Consider the use of mosquito repellent, according to directions, when it is necessary to be outdoors.

West Nile virus has been detected in the state every year since 1999. Last year, the experiment station trapped and tested nearly 200,000 mosquitoes and identified West Nile Virus-positive mosquitoes at trap sites in 30 towns in six counties (Fairfield, Hartford, Middlesex, New Haven, New London, and Windham). Three Connecticut residents were diagnosed and hospitalized due to West Nile infection. Since 2000, 134 human cases of West Nile virus have been diagnosed in Connecticut residents including three fatalities.

The experiment station maintains a network of 91 mosquito-trapping stations in 72 municipalities — including two in Wilton — throughout the state. Mosquito trapping and testing begins in June and continues into October. Positive findings are reported to local health departments and online at http://www.ct.gov/caes/mosquitotesting.

Information: www.ct.gov/mosquito