The New York City Health Department says it has confirmed the season’s first human case of West Nile virus.

Health officials said Monday that the patient is a Brooklyn man who was diagnosed with encephalitis. He is over age 40 and has underlying medical conditions.

The health commissioner, Dr. Mary T. Bassett, says West Nile can especially affect people 60 and over, and those with weakened immune systems. In rare cases, it can be fatal.

The season typically runs between July and October.

The department has completed nine rounds of pesticide spraying and seven aerial larvicide treatments to reduce the risk of West Nile and Zika.

No Zika virus has been found in any mosquito in New York City.

(AP)