Mosquito Season Is Here: After Heavy Rain, Water Removal Can Reduce Mosquito Populations

Mosquito Season Is Here: After Heavy Rain, Water Removal Can Reduce Mosquito Populations

BREWSTER, NY—The water pools formed after the heavy rainfall of last weekend may soon be teaming with mosquito larva. Already this season, the Putnam County Department of Health (PCDOH) has found and identified Aedes Japonicus mosquitoes, the type that carries West Nile Virus, chikungunya, dengue, and other viruses.

“We have not had a case of West Nile Virus in the county since 2011,” says interim Health Commissioner Michael Nesheiwat, MD, but that could change. Taking measures to reduce mosquito populations is very important. Putnam residents are strongly advised to remove all standing water from their property.”  To date only three cases of chikungunya have been reported in Putnam, all since 2014. Four cases of dengue fever have been reported as well, the most recent in 2012. However, these seven cases were all travel related and not instances of locally acquired infections.

Mosquitoes can breed in anything that collects water in the yard, if left for more than four days. Some mosquitoes, including the Aedes Albopictus, prefer small items like a bottle cap, full of water, in which to breed. Only one lone specimen of A. Albopictus has ever been found in Putnam. While this mosquito has shown to be capable of carrying the Zika virus in a lab, it has not proven itself as a reliable carrier in the real world.

“Checking your yard now and after every rainfall is crucial,” says Robert Morris, PE, MPH, Director of Environmental Health at the Putnam County Department of Health. “Items that trap water—old tires, rain gutters, cups or cans, even leaves and tree holes—may provide a breeding spot. Drill holes in tires or dispose of them properly; clean gutters, and overturn all containers, however small.” Contrary to popular belief, smaller pools of water are more productive for mosquito breeding than larger bodies of water, which have natural mosquito predators such as fish or aquatic insects, such as dragonflies. The PCDOH continues to apply larvicide to targeted road catch basins around the county to reduce breeding locales. This season, like last year, mosquito tracking by the PCDOH and the New York State Department of Health will be increased as well.

Preventing bites of all kinds also should be a top priority.  Personal protection measures are advised for any outdoor activities. Shoes, socks, long pants and long-sleeved shirts are reliable methods. Clothing that is factory-treated with the insecticide permethrin has also been proven effective. Insect repellent containing DEET should also be used as well, paying close attention to the directions provided by the manufacturer. Children should not apply this product themselves—it should be applied for them.

The Department of Health’s mission is to improve and protect the health of the Putnam County community, composed of nearly 100,000 residents. Core services include community health assessment, disease surveillance and control, emergency preparedness, environmental health protection, family health promotion and health education. For more information, please visit the PCDOH website at or visit the social media sites on Facebook at, and Twitter @PutnamHealthNY.

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