Mosquitoes are carriers (vectors) for many diseases, most commonly of West Nile Virus and Eastern Equine Encephalitis (EEE). Mosquitoes bite until the first heavy frost (usually end of October). Everyone participating in outdoor activities should take actions to protect themselves from mosquito bites.
The risk of transmitting West Nile Virus (WNV) or Eastern Equine Encephalitis (EEE) to humans is linked to the presence of the mosquitoes which carry the diseases and the number of birds which contract them. Mosquitoes are therefore routinely collected and tested for the presence of these diseases from June through October in a cooperative effort with the Department of Environmental Management (DEM). DEM traps mosquitoes at various locations throughout Rhode Island and later separates the mosquitoes of each trap into 'pools' according to species. The State Health Laboratory tests each pool for the presence of virus. The Rhode Island State Biological Laboratory performs testing for West Nile Virus and EEE virus infection in human specimens year-round.
|Variable||Low Risk Indicators||Medium Risk Indicators||High Risk Indicators|
|Temperature @ dusk||< 55° F||55° - 70° F||> 70° F|
|Wind Velocity||> 20 mph||10-20 mph||< 10 mph|
|Habitat||Open, unshaded||Partial Sun||Woods, deep shade|
|Proximity||> 2 miles||1-2 miles||< 1 mile|
|Time of Day||Mid-day||[Other times]||Dusk|
|Mosquito Density*||< 20 / CDC Trap||20-50 / CDC Trap||> 50 / CDC Trap|
|Infected Mosquitoes||None||WNV; Highland J||EEE|
|Infected Mammals, including humans||None||WNV||EEE|
|Age of Mosquitoes||Newly emerged adults||Newly emerged - 2 wks||> 2 wks***|
|- Month||November - June||July, October||August, September|
Rhode Island Department of Health in collaboration with the Department of Environmental Management and University of Rhode Island