The State Department of Public Health (DPH) and the Connecticut Agricultural Experiment Station (CAES), both members of the Connecticut Mosquito Management Program (MMP), today announced that the seasonal mosquito trapping and testing program coordinated by the CAES has ended for the 2016 season. The program monitors the types, numbers and locations of mosquitoes and tests them for the presence of viruses that can cause illness, including West Nile virus (WNV), Eastern Equine Encephalitis virus (EEE) and Zika virus.
The CAES maintained a network of 91 mosquito-trapping stations in 72 municipalities throughout the state. Mosquito trapping for 2016 began May 31 and concluded October 14. The lower temperatures seen by mid-October, typically too low to sustain the mosquito population, signal the end of Connecticut’s mosquito season. The CAES trapped and tested over 170,000 mosquitoes. The mosquitoes were grouped (pooled) by species, location and date of collection. Mosquitoes were identified with WNV and EEE, but no mosquitoes tested positive for Zika virus.
"As we reach the conclusion of mosquito monitoring for the season, I would like to take the opportunity to thank the dedicated professionals of the State of Connecticut Mosquito Management Program who worked diligently to keep our residents safe and informed. At the same time, we must remain vigilant and I urge anyone travelling to Zika-affected areas to take the necessary precautions," Governor Dannel Malloy said.
"It is important to remember that while the threat of acquiring mosquito-borne infections in Connecticut has passed, travelers should be aware of the diseases that are circulating among mosquitoes in areas they visit and take the recommendations for prevention of illness seriously," said Department of Public Health Commissioner Dr. Raul Pino. "In the case of Zika virus, transmission can also occur as the result of sexual contact with someone who recently traveled to an affected area."
WNV was identified in 122 pools of mosquitoes. The positive mosquitoes were collected at trap sites in 20 towns in 4 counties (Fairfield, Hartford, New Haven and New London) collected July 6 to September 28. The first were collected in Stamford.
During 2016, one Connecticut resident was reported with WNV-associated illnesses. The patient, 70-79 years of age and a resident of Milford, was diagnosed with encephalitis and hospitalized. While WNV infections are not usually fatal, patients with meningitis or encephalitis may suffer lasting symptoms resulting from neurological damage.
EEE was identified in one pool of mosquitoes collected September 12 in Voluntown. No human or domestic animal infections were reported. EEE is a rare illness in humans, and only a few cases are reported in the United States each year, mostly in the Atlantic and Gulf Coast states. However, it often causes serious neurologic illnesses and fatalities. A Connecticut resident died of an EEE-associated illness in 2013.
Zika virus was introduced into the Western Hemisphere during 2015 spread rapidly in tropical regions of Latin America and the Caribbean Islands. Zika commonly causes fever, rash, conjunctivitis or other mild symptoms and rarely a neurological illness (Guillain-Barré syndrome) among infected people. It can also cause serious birth defects when a woman is infected during pregnancy.
The yellow fever mosquito (Aedes aegypti) is the primary mosquito species involved in the Latin American epidemic and does not occur in Connecticut. Another mosquito species, the Asian tiger mosquito (Aedes albopictus), may also transmit Zika virus. The Asian tiger mosquito has a more temperate distribution in the U.S. and has been identified in southern Connecticut.
As of October 25, 973 patients have been tested for Zika virus, including 698 (72%) pregnant women. Of those tested, 96 (10%) were positive for Zika virus or for an undetermined flavivirus of which Zika is one possibility; 27 (28%) were pregnant women. 95 of the positive patients had travelled to an area outside the continental U.S. with active Zika transmission and the remaining positive patient had travelled to the Miami-Dade County area of Florida, which also has active Zika transmission.
Enhanced mosquito surveillance conducted by the CAES collected 2,221 Aedes albopictus mosquitoes in 25 trap sites in 18 towns primarily in lower Fairfield and New Haven counties. No Zika -positive mosquitoes were identified.
Connecticut Mosquito Management Program
The response to mosquito transmitted diseases in Connecticut is a collaborative inter-agency effort involving the Department of Energy and Environmental Protection (DEEP), the Connecticut Agricultural Experiment Station (CAES), the Department of Public Health (DPH), the Department of Agriculture and the Department of Pathobiology at the University of Connecticut (UCONN). These agencies are responsible for monitoring mosquito populations and the potential public health threat of mosquito-borne diseases.
For more information on WNV and EEE, what can be done to prevent getting bitten by mosquitoes, and the latest mosquito test results and human infections, visit the Connecticut Mosquito Management Program web site at www.ct.gov/mosquito. For more information on Zika virus, please visit www.ct.gov/zika.