A Staten Island man with West Nile virus has died, the city’s health department confirmed.

City health officials, who did not identify the 65-year-old, said he became ill and died earlier this month. “An investigation into whether the death was in fact related to the virus is ongoing,” officials said in a statement. According to the health department, there have been five other cases of West Nile virus this season. Last week, the department confirmed that a 73-year-old Queens woman and a 60-year-old Bronx man were infected.

The Staten Island man would be the city’s first known fatal case this year. In Nassau County, health officials confirmed two deaths linked to the virus, of a 75-year-old man and an 80-year-old woman.

West Nile virus, which is transmitted by mosquitoes during the summer months, can cause flu-like symptoms. In severe cases, the virus can infect a person’s brain or spinal cord.

With origins in Africa, Asia, and the Middle East, the virus was first reported in North America in 1999. In New York, there was a surge of cases in 2003, when 71 were reported statewide and 31 were reported in New York City. That year, six cases in New York City were fatal.

Last year, three city residents died after contracting West Nile virus, and 15 others became ill. This summer, city health officials said infected mosquitoes have been found in Brooklyn, Staten Island, Queens, and the Bronx. The city has been spraying affected areas with larvicides.