West Nile virus can cause a range of symptoms, from mild flu-like symptoms, headache and fever, to severe illness. In the most serious cases, infection can result in encephalitis, or inflammation of the brain. To date in 2000, there have been no confirmed human cases of encephalitis caused by West Nile virus , although the State Health Department continually tests for West Nile virus in encephalitis cases for which there is no known cause. Nearly 300 such specimens have been tested so far this year at Wadsworth Laboratory. Health officials stress that dead bird reports are the best way of tracking the spread of West Nile virus, and they encourage New Yorkers who observe dead crows to contact their local health departments.
Crows are particularly vulnerable, and the vast majority of infected crows die.
For that reason, they are considered to be an important early warning sign that infection could be present in a specific area. Birds serve as the reservoir for West Nile virus, after being bitten by an infected mosquito. Because the virus may well be in parts of the State where it has yet to be confirmed, Dr. Novello urged all New Yorkers to be vigilant about personal protection. The State will purchase time to air the spot. That message, which features several children and adults working together to remove standing water and items that collect water from around the home, also has been running as a public service announcement since late March.