The New York City Department of Health and Mental Hygiene has announced that mosquitoes at two sites in its area were found to be infected with the West Nile Virus. The sites are Glen Oaks, Queens and New Dorp Beach, Staten Island.

While no cases of human infections have been reported this year, officials urged citizens to be proactive and take precautionary measures to be on the safe side.

According to NBC New York, five people from the four boroughs were infected with the virus last summer, and three of them had to be sent to the hospital.

West Nile infections can cause symptoms that resemble flu and neurological disease, but not all those who get bitten by infected mosquitoes get sick.

Mosquitoes get infected when they feed on birds that carry the virus. The mosquitoes can also infect other animals, with dogs and horses as the common victims.

The Centers for Disease Control and Prevention says there is as yet no vaccine available to combat the West Nile Virus, adding that scientists are still working on it and a cure will hopefully be available in the future.

Meanwhile, the department is intensifying its efforts to fight mosquitoes in affected neighborhoods by putting up more mosquito traps and treating basins used to catch them.

Measures are also being carried out to prevent mosquito larvae from maturing.

According to health commissioner Mary Bassett, people should take simple precautions to prevent infections.

"The most effective way to keep mosquito populations low is to remove standing water from items like buckets, gutters, planters, or any other receptacles that might be outdoors," TIME quoted Basset as saying.

People are also advised to put on mosquito repellant and be fully clothed when in areas populated by mosquitoes, especially at dawn or dusk.