How Does West Nile Virus Travel and how did it get to Westchester County NY?

Author: Mosquito Squad of Fairfield, Westchester, and Rockland County

One common misconception many people have is that mosquitoes are able to fly long distances. Yes, they do have wings and always seem to be around us anytime we are outdoors. So they must fly a lot, right? The fact is mosquitoes are very poor fliers. They rarely travel more than a few hundred feet in their lifetime. In fact, the wind rather than their wings causes them to move the greatest distance.

If all that is true, how did West Nile spread so quickly in the US? West Nile spread into all of the contiguous United States in just 6 short years after being first detected in Queens NY in 1999. Research showed that birds were the vector, or cause, for West Nile spreading so rapidly. This is especially true of jays and crows.

As the birds flew to new areas, West Nile went with them. Once a bird is infected, it can transmit the disease to every other mosquito that bites it. Although horses and humans can both be infected with the virus, they are infected with the disease but do not pass it to mosquitoes that bite them later.

Now is the time of year when we begin hearing about the first cases of West Nile virus. The Connecticut Post recently reported the first case of West Nile in the US this year. This case was just diagnosed in Wisconsin. Westchester County is no stranger to West Nile virus. Last year the NY State Department of Health confirmed two people were infected. Seven batches (samples) of mosquitoes taken by our Health Department showed the presence of the West Nile virus. A recent article by The Atlantic reported that scientists believe with longer, wet summers and shorter winters across the US, mosquito and tick diseases will be on the rise.

The number of occurrences of West Nile will rise shortly in Westchester County as we get further into Spring and mosquitoes start to feast on infected birds. In 2012, 5,674 cases and 286 deaths were reported to the CDC. Since only one in five people infected will show any symptoms of having contracted the disease, the number of people infected is likely to be 5 times greater than reported.

We spend most of our time outdoors in our back yards. Experts recommend that mosquito protection is best when it includes a barrier spray to reduce the number of mosquitoes on the property. An effective barrier spray will dramatically reduce the mosquito population on a property, thereby reducing exposure to the virus.