The New York City Department of Health and Mental Hygiene is reporting five human West Nile virus (WNV) cases in the city, the first of the current season.

All the patients are residents over the age of 50 from the following boroughs:  Two patients were from Brooklyn, and one each was from Queens, Staten Island and Manhattan. Three of the patients required hospitalization and have since been released.

New York City map/Public domain image/Franklin Baldo via Wikimedia Commons

According to the Centers for Disease Control and Prevention (CDC), approximately 80 percent of people (about 4 out of 5) who are infected with WNV will not show any symptoms at all.

Up to 20 percent of the people who become infected have symptoms such as fever, headache, and body aches, nausea, vomiting, and sometimes swollen lymph glands or a skin rash on the chest, stomach and back.Symptoms can last for as short as a few days, though even healthy people have become sick for several weeks. About one in 150 people infected with WNV will develop severe illness.

The severe symptoms can include high fever, headache, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness, vision loss, numbness and paralysis. These symptoms may last several weeks, and neurological effects may be permanent.

Since first seen in the United States in 1999, over 37,000 WNV disease cases have been reported to the CDC, and this number likely underestimates the total number of infections. In addition to the human toll, an analysis published in the American Journal of Tropical Medicine and Hygiene (AJTMH) in February shows thathospitalized cases of WNV disease have cost a cumulative $778 million in health care expenditures and lost productivity over a 14 year period. For more infectious disease news and information, visit and “like” the Infectious Disease News Facebook page

Health officials offer the following recommendations to protect themselves from mosquitoes: Wear insect repellent and covering up outside in the late afternoon and evening, Check toys and play houses for standing water, Turn over containers, wading pools and wheelbarrows when not in use, Change the water in birdbaths at least twice weekly, Sweep puddles off driveways after it rains, Clear storm drains and gutters and Clean and chlorinate pools and hot tubs and drain water off their covers.