Managing Your Property to Reduce the Threat of West Nile Virus

Posted: June 1, 2015

Ah, summertime….picnics, barbeques, outdoor activities…unfortunately, also a time to be bugged by mosquitoes and an increased threat of West Nile Virus.
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The West Nile Virus was first found in the United States in the summer of 1999, in New York City. Prior to this, the disease was only found in Africa, Europe and Asia. The virus most-likely entered the United States in water from the holds of cargo ships or shipping containers originating from these countries. Since its first introduction, the virus has spread across the United States infecting birds, humans, and other mammals alike. 

The primary reservoirs for West Nile Virus are birds which facilitate the spread of the disease when the mosquito takes a blood meal from an infected bird and then bites another bird, animal or person. In humans, most cases of the infection are mild, and symptoms resemble the flu. In more serious cases, which are less common, the virus can cause encephalitis, which is an infection of the brain. Those who are most at risk for more serious complications from the virus include persons over age 50 and those with compromised immune systems, however, the virus can be contracted by anyone.

One of the best ways to combat the spread of West Nile Virus is to eliminate places that can harbor standing water where mosquitoes can breed. It takes less than a week for mosquitoes to complete their larval and pupal stages to become biting adults when optimal breeding conditions are present. Stagnant, warm water provides prime habitat for fueling the mosquito’s life cycle. Children’s wading pools left full overnight, wheelbarrows, flower pots, recycling bins, bird baths, discarded tires, and clogged rain gutters all present opportunities for water to collect. In addition, low spots in yards or fields with poor drainage, tire ruts, and abandoned pools are all ideal places for mosquito breeding.

Ornamental ponds can be a source of relaxation and add an aesthetically pleasing water feature to your yard. If these ponds are not properly maintained, however, they can become a perfect place for mosquitoes to breed. A pond with a pump and some means of moving the water through the pond should not cause problems as mosquitoes prefer still water in which to lay their eggs. Additionally, a pond with fish, frogs, turtles, and other aquatic life that eat mosquito larvae will not become a mosquito breeding ground.  

If sources collecting water can’t be eliminated, such as when using a rain barrel to collect roof water for gardening or other uses, products such as Mosquito Dunks exist which will treat standing water areas. Dunks are donut-shaped cakes made up of Bacillus thuringiensis israelensis – a bacteria that specifically targets the gut of mosquito larvae leaving them unable to survive. The dunks slowly dissolve over time and protect the water from becoming a mosquito habitat.

Be sure to protect yourself from a bite by limiting your time outdoors in the evenings, when mosquitoes tend to bite and by using an insect repellent containing 20-30% DEET. Products containing Picaradin have also proven effective against mosquito bites. When using any kind of pesticide, always follow the label instructions and use extra caution when applying repellent to children.

In many counties across the state, Penn State Extension works as the coordinator of the county mosquito surveillance and control program. These programs are funded by grant money from the Department of Environmental Protection and also involve a partnership with County government. These grants, in addition to the surveillance and control of mosquito populations, also provide public education and help to reduce the incidence of West Nile Virus in Pennsylvania communities.

For more information on Pennsylvania’s West Nile Surveillance Program, to report high mosquito populations, or dead birds, visit