The Department of Environmental Management (DEM) and the Rhode Island Department of Health (HEALTH) announced Wednesday that test results from two mosquito pools from a trap set in the Great Swamp in West Kingston have been confirmed positive for Eastern Equine Encephalitis (EEE) and West Nile Virus (WNV).
It is the first time this year that EEE has been positively identified in Rhode Island, although it is presumed likely to be present in other areas of the state. The positive EEE result was found in a pool of 37 mosquitoes trapped on Aug. 26 and was of the Culex species that bites both birds and mammals.
In addition to the EEE finding, WNV was found the same day in a pool of 50 mosquitoes in Great Swamp. The infected insect was of the Culiseta species that feeds almost exclusively on birds.
As a result, DEM will be setting extra mosquito traps in the South County area for increased assessment.
A third mosquito pool, which was from a trap set in Chapman Swamp in Westerly, has been confirmed positive for Highlands J Virus. The positive Highlands J result was from a species of mosquitoes that bites birds. Highlands J is a bird disease that doesn't affect humans, but is an indicator that environmental conditions are appropriate for the transmission of other mosquito-borne viruses.
According to both DEM and Health, these findings are not unexpected at this time of the year. Test results on the remaining 147 mosquito pools from 33 traps set statewide during the week of Aug. 26 are pending at the Department of Health laboratory.
This year, to date in Rhode Island, four pools of mosquitoes have tested positive for West Nile Virus and one pool of mosquitoes has tested positive for EEE. There have been no reported 2013 cases of WNV or EEE in humans in the state at this time.
Throughout the mosquito season, which typically lasts through the first hard frost, residents are encouraged to protect themselves by eliminating mosquito breeding grounds and avoiding mosquito bites. Personal protection is the first line of defense against mosquitoes that can carry diseases such as WNV and EEE and is by far the most effective way of avoiding infection.
DEM staff trap and test mosquitoes weekly and will normally report mosquito test results once a week on a routine basis, with additional reports as necessary. Test results from mosquitoes trapped this week will be included in next week's announcement. Positive mosquito test results will generally trigger additional trapping to assess risk.