The Rhode Island Department of Environmental Management (DEM) and the Rhode Island Department of Health (RIDOH) today announced a mosquito sample collected on Tuesday, Sept. 5 in Warren has tested positive for West Nile Virus (WNV).
This is the third finding of WNV in Rhode Island this year; the first occurred in Warren on Monday, Aug. 7 and the second occurred in Barrington on Tuesday, Aug. 15. The remaining 85 mosquito samples from traps set on the 5th tested negative for both WNV and Eastern Equine Encephalitis (EEE).
The positive finding is not unexpected. Mosquito-borne diseases are more prevalent in late summer and early fall, and risk typically lasts until the first frost. Personal protection is the first line of defense against mosquitoes that may carry WNV, EEE, or other diseases – and the most effective way to avoid infection. Throughout the summer season, the public is encouraged to:
• Remove anything around your house and yard that collects water; just one cup of water can produce hundreds of mosquitoes.
• Clean gutters and downspouts to ensure proper drainage, and repair holes in window screens.
• Remove any water from unused swimming pools, wading pools, boats, planters, trash and recycling bins, tires, and anything else that collects water, and cover them.
• Change the water in birdbaths at least two times a week, and rinse out birdbaths once a week.
• Use EPA-approved bug spray with one of the following active ingredients: DEET (20-30% strength), picaridin, IR3535, and oil of lemon eucalyptus or para-menthane-diol. Do not use bug spray on infants under 1 year of age.
• Minimize outdoor activity at dawn and at dusk when mosquitoes are most active.
• Put insect netting over strollers and playpens.
• Wear long sleeves and long pants whenever possible, particularly if you are outdoors during dawn and dusk.
To date, in Rhode Island, there have been three findings of EEE in mosquito samples. There are no confirmed human cases of EEE in Rhode Island. However, because summer and fall are peak seasons for mosquito-borne disease transmission to people, Rhode Islanders should be aware of the symptoms of EEE.
Severe cases of EEE (involving encephalitis, an inflammation of the brain) begin with the sudden onset of a headache, high fever, chills, and vomiting. If you think you or a family member may have EEE, it is important to consult your healthcare provider for proper diagnosis.
Horses are particularly susceptible to WNV and EEE. Horse owners are advised to vaccinate their animals early in the season and practice the following:
• Remove or cover areas where standing water can collect.
• Avoid putting animals outside at dawn, dusk or during the night when mosquitoes are most active.
• Insect proof facilities where possible and use approved repellants frequently.
• Monitor animals for symptoms of fever and/or neurological signs (such as stumbling, depression, loss of appetite) and report all suspicious cases to a veterinarian immediately. If you are unsure if your horse is properly vaccinated you should consult with your veterinarian.
• Horses are the most susceptible domestic animal, but other, less common species such as ratites (emus, ostriches, etc.) and camelids (alpacas and llamas) are occasionally infected. Owners of ratites and camelids should consult with their veterinarian regarding vaccination of their animals.
Mosquitoes are trapped weekly by DEM and tested at the RIDOH State Health Laboratories. The RIDOH State Health Laboratories have recently changed their testing methodology to use a more sensitive testing method which may account for an increase in positive results going forward. DEM issues advisories on test results from late June through September, with additional reports as necessary. Test results are pending for traps set on Monday, Sept. 11 and will be included in future announcements. Typically positive mosquito test results will trigger additional trapping to assess risk.