Mosquito Management: State Mosquito Program Begins Mosquito Testing for West Nile and Eastern Equine Encephalitis Viruses

June 10, 2014
 
State Mosquito Program Begins Mosquito Testing for West Nile and Eastern Equine Encephalitis Viruses
 
First case of EEE identified in the state during 2013; public, clinicians reminded of EEE risk
 

The State of Connecticut Mosquito Management Program today announced it is monitoring mosquitoes for the presence of viruses that can cause illness in people including West Nile virus (WNV) and eastern equine encephalitis virus (EEE). The mosquito trapping and testing program, coordinated by the Connecticut Agricultural Experiment Station (CAES), began June 2nd. Test results to date are negative.
 
The program also released surveillance results from the 2013 season. The results include the first confirmed human case of eastern equine encephalitis (EEE) in a Connecticut resident. In April, the Centers for Disease Control and Prevention (CDC) confirmed that an adult resident of eastern Connecticut who had been hospitalized with encephalitis and died in the Fall, was positive for EEE.
 
The resident had been tested for WNV, but was not tested for EEE before death. Fortunately, through the astute actions of a physician at a local hospital, further testing was initiated that lead to the post mortem diagnosis of EEE infection.
 
“While rare, EEE is serious and underscores the importance of taking personal precautions to avoid mosquito bites,” said DPH Commissioner Dr. Jewel Mullen. “The presence of this virus in Connecticut should also remind clinicians to include EEE, along with WNV, among their possible diagnoses so that appropriate tests can be done.”
 
Dr. Mullen said that DPH is preparing an advisory to Connecticut clinicians regarding the current epidemiology of EEE and WNV as well as testing options for diagnosing mosquito-borne diseases.
 
EEE Surveillance
Mosquitoes infected with EEE virus transmit the virus by biting humans. EEE is a rare illness in humans, and only a few cases are reported in the United States each year. Most cases occur in the Atlantic and Gulf Coast states.
 
Last season there was significant EEE virus circulation in eastern Connecticut, including infected mosquitoes, a horse, and pheasant flocks. Mosquitoes with EEE virus were identified in five
 
Connecticut towns: Haddam, Hampton, North Stonington, Plainfield and Voluntown. A horse stabled in Griswold died from EEE-associated illness during the second week of September. In early to mid-September, pheasants in a farm flock in Killingly and a flock in Sprague died from EEE infections.
 
The numbers and types of mosquitoes with EEE identified in the Pachaug State Forest in Voluntown prompted the Department of Energy and Environmental Protection to temporarily close part of the forest to recreational activities and to conduct ultra-low volume ground spraying to reduce the number of mosquitoes.
 
WNV Surveillance
Last season, the Connecticut Agricultural Experiment Station (CAES) identified WNV-positive mosquitoes at trap sites in 22 towns: Branford, Bridgeport, Darien, East Haven, Fairfield, Glastonbury, Greenwich, Groton, Manchester, New Haven, North Branford, Norwalk, Plainfield, Stafford, Stamford, Stratford, Voluntown, Wallingford, Waterford, West Haven, Westport and Wilton. Four Connecticut residents from the towns of Stamford, Stratford, and Bridgeport were diagnosed with WNV-associated illnesses. There were no fatalities.
 
Connecticut Mosquito Management Program
The management of mosquitoes in Connecticut is a collaborative effort involving the Department of Energy and Environmental Protection (DEEP), the Connecticut Agricultural Experiment Station (CAES) and the Department of Public Health (DPH), together with the Department of Agriculture and the Department of Pathobiology at the University of Connecticut (UCONN). These agencies are responsible for monitoring and managing the state’s mosquito population levels to reduce the potential public health threat of mosquito-borne diseases.
 
The CAES maintains a network of 91 mosquito-trapping stations in 72 municipalities throughout the state. CAES began its mosquito trapping and testing season last week. Mosquito pools that test positive for WNV and EEE, as well as human cases of these illnesses, will be posted on the Connecticut Mosquito Management Program website.
 
For information on West Nile virus and EEE, including what you can do to prevent getting bitten by mosquitoes and the latest mosquito test results, visit the Connecticut Mosquito Management Program Web site at www.ct.gov/mosquito.