The West Nile virus continues to be a threat — and has been discovered in more places and earlier in the season than last year. But it has not yet resulted in any new human cases, according to New Jersey officials, who urge residents to take precautions to avoid mosquito bites.
State data from earlier this month shows that the virus, which is transmitted to humans through bites from an infected mosquito, was found so far this year in 35 pools of water — breeding grounds for the insects — across 13 counties; last year 25 freshwater sources had tested positive in nine counties by the same point in the season.
In addition, the weekly surveys conducted during the late spring and summer also revealed the West Nile virus (WNV) had appeared an average of two weeks earlier in ten of the 13 counties. In Atlantic County, it showed up a full six weeks earlier than it did in 2017.
But these changes — departures from the five-year averages — have not translated into any human infections, at this point. In all of 2017, New Jersey identified eight individuals who had contracted West Nile virus, which can cause symptoms that range from mild to severe and include fever, chills, body aches and rashes. If untreated, the infection can cause seizures, bleeding and brain swelling, coma and paralysis.
Dr. Tina Tan, the state epidemiologist, who works for the Department of Health, said this is not necessarily surprising, since “August and September are when human cases ramp up.” That said, she called it a “precautionary tale” that should underscore the importance of preventive measures: using proper insect repellent, wearing long sleeves, pants and socks, and removing standing water from the yard.
Watch out for symptoms year-round
“We need to monitor people and people need to take precautions all year,” Tan said. “But it is especially important now, with the nice weather, when people are spending a lot of time outside.”
West Nile virus has been endemic to New Jersey for nearly two decades, Tan said, and, while mosquito season is limited in the Garden State to the warmer months, doctors should be on the lookout for the symptoms all year. Tan said it is possible for residents to contract the disease while overseas, an issue given the state’s diverse citizenry, many of whom are regular travelers.
New Jersey monitors a number of mosquito-borne diseases, including WNV and Zika, which are carried by insects that can live in this climate. It also tracks others, like malaria and dengue, which are not native to the area, but are regularly detected and pose public health threats. (In fact, 125 cases of malaria were diagnosed here last year, and 32 so far this year.) The New Jersey Communicable Disease Service, within the DHS, publishes weekly reports of vector-borne illnesses — or human diseases caused by pathogens or pests — throughout the season.
The system also tracks half a dozen illnesses — including Lyme disease and spotted fever — that are transmitted by ticks, which are also native to the region. Some 1,200 residents have already been diagnosed with Lyme disease this year (more than 5,000 were identified with the infection in 2017). Officials monitor the presence of several of these diseases in horses as well.
Get rid of standing water
The state has expanded its vector-borne disease tracking systems in recent years, in part thanks to a $2.5 million grant from the federal Centers for Disease Control and Prevention in July 2016. The funding allowed New Jersey to beef up surveillance, testing, and mosquito prevention and was part of $60 million distributed nationwide in response to the rise of the Zika virus in the Americas.
Much of the mosquito-control work is done by county agencies, with guidance from the state Department of Environmental Protection. Larry Hajna, a DEP spokesperson, said mosquito populations can fluctuate based on a variety of factors and stressed it is important for property owners to help eliminate any sources of standing water, which provide breeding grounds for the insects and drive up the likelihood of infections.
“Common sources include garbage cans and lids that are upside down, empty planters and flower pots, clogged rain gutters, birdbaths, pet food bowls and water dishes, and buckets,” Hajna said. “Even an empty drinking cup can collect enough water to provide mosquito breeding habitat.”