West Nile Virus

In the marshy woods of Secaucus, N.J., a mosquito can make a happy home.

With water and shade under a canopy of maple trees, you could barely ask for more to start your own bloodsucking family.

For Gary Cardini, though, this is a battleground.

"You want to get them in the water before they're flying," explains Cardini, who supervises the field team for Hudson County Mosquito Control. "In the water, they're captive. You know where they are."

Wikimedia Commons

In 1999, West Nile virus snuck into the United States. Like many border-crossing diseases, the virus wreaked more havoc in its new home, where those it infected hadn't developed immunity. While the virus infects humans, and can be fatal, it was deadliest in a different population: North American birds.

When the virus first appeared, Luke George, a researcher at Colorado State University who studies birds, said there were reports of dead birds. Lots of them.

"That was how people knew it had showed up in North America is they were seeing lots of dead crows and jays, especially in suburban areas."

George and other scientists knew West Nile killed other birds too, but many thought after an initial die-off most populations recovered. No one really knew the true effect on North American birds, until George and some other researchers decided to take a closer look.

Centers for Disease Control and Prevention

Researchers with the National Center for Atmospheric Research and the Centers for Disease Control and Prevention found that increased West Nile outbreaks correlated strongly with above-average temperatures in the preceding year.

They also found wet weather influenced outbreaks – although the actual impact varied by region. In much of the West, wetter-than-average winters correlated with above average outbreaks. Researchers found a different picture in the eastern U.S., where West Nile outbreaks correlated with fall and spring seasons that were drier than average.

That may seem counterintuitive; after all, doesn't a wet spring usually mean more mosquitoes in the summer, since they need water sites to reproduce?

Centers for Disease Control and Prevention

Insecticide spraying for West Nile infected mosquitoes will begin Friday, August 15 in the highest risk portion of Larimer County, an area that overlaps with part of southeast Fort Collins.

It will be the county spraying, not the city of Fort Collins.


Weld County public health officials say a wet summer has lead to more of the mosquitoes that carry the West Nile virus.

Centers for Disease Control Division of Vector Borne Diseases

While most Americans probably haven't heard of Chikungunya, Ann Powers, a research microbiologist at the Centers for Disease Control, has been studying the virus for 15 years.

The mosquito-carried virus made the news recently when the first locally-transmitted case of it appeared in Florida, July 17. Now, the public and medical researchers are wondering if it may spread further into the United States, and how serious it might be.

The research that Powers does at the CDC's Division of Vector Borne Diseases in Fort Collins may help answer some of those questions.


For the first time in the 2014 season, West Nile infected mosquitoes have been found in 5 Colorado counties.

Fifteen years ago an unwelcome viral visitor entered the U.S., and we've been paying for it ever since.

The U.S recorded its first case of West Nile virus back in 1999. Since then, the disease has spread across the lower 48 states and cost the country around $800 million, scientists reported this week in the American Journal of Tropical Medicine and Hygiene.

The Centers for Disease Control and Prevention

Across Colorado thousands of federally funded lab workers remain furloughed due to the government shutdown. At the Centers for Disease Control and Prevention’s Division of Vector-Borne Diseases in Fort Collins, just 10 percent of staff remain on duty.

Centers for Disease Control and Prevention

Since West Nile Virus was first identified more than a decade ago, applying bug spray became a must for summer outings. But sprays containing DEET can be a turn off. They can be smelly and feel greasy.