The city confirmed on Sunday its first case of a New Yorker infected with the West Nile virus this season.
An unidentified Brooklyn man over the age of 60 has already been treated and released after he was hospitalized with viral meningitis.
Doctors already discharged the man, but city health officials advised New Yorkers to protect themselves from mosquito bites.
"New Yorkers age 60 and older or persons with weakened immune systems should be especially careful as they are more likely to become seriously ill, and in rare instances die, if infected," warned Health Commissioner Dr. Mary T. Bassett.
Since it was first found in the United States in 1999, the city reports 318 New Yorkers have been diagnosed with West Nile virus.
The Health Department also announced large swaths of Queens will be sprayed between Aug. 17 and Aug. 18 between 8:30 p.m. and 6 a.m. the following morning.
The agency said it treats 62,160 catch basins in Queens two to three times per year.