The New York City Health Department is confirming the first human cases of West Nile virus this season.

Health officials said Monday the virus was detected in five New York City residents, all over the age of 50. Two patients were from Brooklyn, the others were from Queens, Staten Island and Manhattan.

Three of the patients were hospitalized and have since been discharged. The other two cases did not require hospitalization.

Most people infected with the mosquito-borne virus either show no symptoms or suffer a flu-like illness. A small number develop a serious illness that can lead to neurological damage.

Protective measures against mosquitoes include eliminating standing water, using repellent, wearing long-sleeve shirts and long pants, and repairing doors and screens for tight fits.

(AP)