Health officials in New Jersey are investigating a case of malaria, the potentially deadly mosquito-transmitted disease, in a Morris County resident with no international travel history.
That means it is possible the infection happened locally, authorities say, which would be rare.
Malaria isn't endemic to the United States, which means it doesn't regularly occur or spread here. If confirmed, it would be the first known locally acquired case of malaria in more than three decades, since 1991.
In 2023, the CDC just identified nine cases of malaria that people contracted in Texas and Florida -- the first documented cases of local infection in the U.S. in 20 years. The CDC is assisting New Jersey officials in their investigation.
Most of the 2,000 U.S. cases or so a year are in people who get malaria while traveling to a country where the disease spreads.
There are about 100 travel-associated cases of malaria reported in New Jersey each year, health officials say. The disease is caused by a parasite that infects a certain kind of mosquito.
Locally acquired malaria typically occurs when a mosquito bites a person infected with travel-associated malaria, acquiring the parasite, and then bites another person, passing the infection. Successful treatment of individuals confirmed to have malaria significantly reduces or eliminates the risk of further transmission.
Malaria can't be transmitted person-to-person. Most people get malaria from the bite of an infected mosquito. Starting treatment as early as possible can often prevent severe illness and death, according to the CDC.
Not all mosquitoes can transmit malaria, but if they bite a person with the disease, they can become infectious, according to the CDC. The mosquitoes that carry the disease are present in New Jersey, health officials say, but the risk of locally acquired malaria remains low.
Malaria infected nearly 250 million people globally in 2022 and killed more than 600,000, mostly children. Common symptoms include fever and flu-like illness, chills, headache, nausea, vomiting and diarrhea.
More severe symptoms can lead to kidney failure, seizures, mental confusion or coma.
Malaria is especially pronounced in Africa. Prescription drugs can treat and cure it, and most cases are preventable. A vaccination campaign has been launched in recent months that health officials hope will help reduce cases and deaths. Malaria is confirmed via blood test.