As of last Tuesday, 537 cases of West Nile virus (WNV) disease have been reported in the US from 45 states, according to the Centers for Disease Control and Prevention (CDC).

Culex quinquefasciatus/CDC
Culex quinquefasciatus/CDC

Now a case is reported from where it all began in the US in 1999–New York City.

The New York City Health Department today confirmed the season’s first human case of West Nile virus in a Brooklyn man who was diagnosed with encephalitis. The patient was over the age of 40 and has underlying medical conditions. Human cases of West Nile virus occur each year in New York City, typically between July and October.

This first case of West Nile in NYC was identified about two weeks later in the season compared to previous years. A total of 318 New Yorkers have been diagnosed with West Nile virus since it was first found in the United States in 1999.

“This season’s first case of West Nile virus is a reminder to protect ourselves against mosquito bites,” said Health Commissioner Dr. Mary T. Bassett. “Wearing mosquito repellent when you are outdoors, getting rid of standing water, and installing window screens will reduce your risk of getting bitten. New Yorkers age 60 and older or people with weakened immune systems should be especially careful as they are more likely to become seriously ill, and in rare cases die, if infected.”

West Nile virus infection can cause a mild or moderate flu-like illness, or sometimes no symptoms at all. In some people, particularly those 60 and older, West Nile virus can cause a serious and potentially fatal infection of the brain and spinal cord. The most common symptoms are headache, fever, muscle aches, and extreme fatigue. Symptoms of more severe illness can also include changes in mental status and muscle weakness.