NYC Reports First Human Case of West Nile Virus This Season

West Nile virus season typically occurs from June through September, and although the month of August is waning, state health departments around the country continue to report new human cases of the virus as well as associated deaths.

At least 42 states along with the District of Columbia have reported bird, mosquito, or human infections of West Nile virus so far in 2017, according to data from the Centers for Disease Control and Prevention (CDC), with 28 states reporting human cases of the virus as of August 8, 2017. In 2015, all but 7 states and Puerto Rico reported human cases of West Nile, and there were 2,175 cases across the United States. That year, the country saw 146 deaths from West Nile, 142 of which occurred from neuroinvasive disease, the most severe symptom of the virus. While up to 80% of individuals infected with West Nile virus will experience no symptoms, less than 1% of infections can result in serious neurological illness such as encephalitis or meningitis. Symptoms of a severe West Nile infection include headache, high fever, neck stiffness, disorientation, coma, tremors, seizures, or paralysis.

In Louisiana, a resident of Alexandria in Rapides Parish recently died after contracting West Nile virus. According to local news reports, the case involved a 71-year-old man who had battled the infection for 2 weeks before dying on August 10, 2017. As of August 5, the Louisiana Department of Health’s weekly arbovirus surveillance summary reported 19 human cases of West Nile virus so far in the state this season resulting in 2 deaths, both of which occurred in adults between the ages of 60 and 74. In 2016, Louisiana saw a total of 2 West Nile-associated deaths. Following heavy rains and flash flooding in the state’s Orleans Parish — which earlier this season reported West Nile-positive mosquitoes — the governor declared a state of emergency for the parish. To limit breeding areas for mosquitoes and prevent mosquito bites, health officials in the area have reminded residents to remove standing water whenever possible and to keep window screens maintained.

On August 14, 2017, Mississippi’s State Department of Health reported 6 new human cases of West Nile virus, bringing the state’s total number of laboratory-confirmed cases to 25 so far this season. Last year Mississippi reported 43 human cases of West Nile, resulting in 2 deaths. On July 31 the state reported its first West Nile-associated death in a Grenada County resident for 2017. “This sadly serves as a reminder that the threat of West Nile virus should be taken very seriously,” said state epidemiologist Paul Byers, MD, at the time. “While many people may be infected with West Nile and not show symptoms, in a small number of cases, the infection can cause very serious complications, even death.”

In addition to these cases, on August 11, 2017, New York City’s Health Department reported the city’s first human case of West Nile this season. According to local health officials, the case involves a patient under the age of 50 who is in serious condition at an area hospital, and comes as the area is seeing a record number of West Nile-positive mosquito pools, most of which are on Staten Island. New York City’s health commissioner Mary T. Bassett, MD, MPH, is urging area residents to avoid mosquito bites by wearing mosquito repellent, covering arms and legs when outdoors, getting rid of standing water, and installing window screens. “We will not be able to completely eradicate West Nile virus from the mosquito population, but we can reduce human transmission and save lives.”