How do I know if an animal is infected with West Nile Virus?
Signs of infection in wildlife, like in humans, can range from no symptoms to severe symptoms of neurologic illness. Commonly reported signs in animals include weakness, stumbling, trembling, head tremors, inability to fly/walk, and a lack of awareness that allows them to be easily approached and handled. These symptoms, however, can also have other causes. The only way to positively confirm West Nile Virus infection is by laboratory testing of the animal’s tissues.
Researchers dip sampling for mosquitoes along the Alaka‘i Swamp Trail, Kaua‘i
A female mosquito (Aedes japonicus) reared from larvae collected from the Kawaikoi Stream, Kauai.
Researcher working in the laboratory.
Culex species mosquito biting a human hand.
A U.S. Geological Survey analyst performs DNA extractions on enriched cultures of water from the study area. Once the DNA was extracted it was used to detect pathogen gene markers using polymerase chain reaction (PCR). Scientists have found that the presence of indicator bacteria, hepatitis E virus (HEV), and numerous bacterial pathogen genes increased following precipitation-induced runoff events in streams draining adjacent land surfaces in Iowa where swine manure was recently applied.
USGS scientists capture and release wild birds while monitoring for West Nile.
Mosquito, Aedes aegypti
Curlews are very attentive parents and fly close to intruders and alarm call to distract them from their young broods. USGS scientists take advantage of this behavior by using a mist net to sweep birds out of the air when they approach. In June 2007, USGS scientists used this approach to tag 13 curlews with satellite transmitters at their southern breeding area in Alaska. They use satellite telemetry to track these birds, in order to map their migration routes and find the location of their nonbreeding areas.