First Cases of West Nile Virus Reported in New Jersey

The New Jersey Department of Health is reporting the state’s first human cases of West Nile virus (WNV) this year. A child tested positive for West Nile virus neuroinvasive disease in Atlantic County with symptoms reported the third week of July. An adult in Middlesex County also tested positive for West Nile virus neuroinvasive disease with symptoms reported in the first week of August. Both residents have been discharged from the hospital and are recovering at home.   

Most WNV cases occur between mid-August and mid-September. In a typical year, there are 14 human WNV infections reported, although that number can vary substantially year-to-year. Last year, New Jersey had 41 human cases of WNV, including eight fatalities.  

“While the number of WNV human infections is lower than last year, we are seeing high levels of virus circulating in mosquitoes,” said Acting New Jersey Health Commissioner Jeff Brown. “As mosquito season can last into early November, depending on weather conditions, bite prevention will be essential in protecting yourself and your family against mosquito-borne diseases like West Nile virus into the fall. This means avoiding mosquito bites through tried-and-true methods, like using insect repellents, wearing long sleeves and pants, and taking steps to keep mosquitoes outside the home.”  

For many people, WNV causes asymptomatic infection. One in five persons will develop a mild to moderate illness, typically with a fever, chills, headache, body aches, joint pains, vomiting, diarrhea, or rash.  

Less than one percent of people infected will develop a more severe form of the disease that affects the central nervous system, requires hospitalization, or results in death. People over age 50 with certain chronic medical conditions and with weakened immune systems are at greater risk of developing severe illness. Symptoms include a severe headache, high fever, neck stiffness, stupor, disorientation, coma, tremors, convulsions, muscle weakness and paralysis. Recovery from severe illness can take several weeks or months. 

Early symptoms of WNV may be confused with COVID-19 or several other common viral illnesses. Specific laboratory tests are needed to confirm WNV, but there is no specific treatment. The best way to prevent the disease is to avoid mosquito bites. Persons who think they might have WNV or another mosquito-borne disease should contact a health care provider.  

To protect against mosquito-borne diseases, residents should: 

• Wear EPA-registered insect repellent. 

• Treat clothing with permethrin or use pre-treated clothing. 

• Wear long sleeves and long pants and cover exposed skin. 

• Cover cribs, strollers, and baby carriers with mosquito netting. 

• Mosquito-proof your yard and home by dumping standing water.  

• Use air conditioning, when possible, and use well-maintained window and door screens to keep mosquitos outside. 

“We are urging the public to not let their guard down and protect themselves from mosquito bites by turning over or removing items that collect water in order to eliminate standing water,” said Environmental Protection Commissioner Shawn LaTourette. “Standing water that pools in yard items such as empty planters serves as breeding grounds that cause the number of mosquitoes to grow rapidly and increase your risk of mosquito-borne diseases.”   

This year, the first detection of WNV in mosquitoes was in April. WNV has been detected in 776 mosquito pools, which is higher than this time last year. WNV has been detected in all New Jersey counties.  

Residents, business owners, and contractors can take steps to reduce mosquito populations on their properties by emptying or changing outdoor standing water at least weekly. Areas that may need attention include flowerpots, pet food and water dishes, birdbaths, swimming pool covers, clogged rain gutters, plastic wading pools and wheelbarrows, and any containers or trash that may be difficult to see, such as under bushes, homes, or around building exteriors. 

 An interactive vector-borne disease dashboard and weekly reports on WNV-related activity are available at nj.gov/health