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New York|New Malaria Case Prompts Testing of Mosquitoes in New Jersey
https://www.nytimes.com/2025/08/20/nyregion/new-jersey-mosquitoes-malaria.html
A Morris County resident may have contracted the illness locally, which would be the first known instance in decades of someone being exposed while in the state.
Aug. 20, 2025, 4:53 p.m. ET
New Jersey scientists are testing mosquitoes after a Morris County resident may have contracted malaria locally, which health officials said would be the first known instance in decades of someone being exposed while in the state.
About 100 cases of malaria are reported annually in New Jersey by people who have recently traveled. Officials said that the patient who was recently diagnosed with the illness had not traveled internationally, suggesting the possibility of a locally acquired infection.
The patient, who has not been identified, is recovering, health officials said.
The New Jersey Department of Health and the U.S. Centers for Disease Control and Prevention are working jointly to identify potential sources of infection.
Malaria is a mosquito-borne disease caused by a parasite and is widespread in many tropical and subtropical areas. A type of mosquito that spreads the disease, Anopheles, exists in New Jersey, but locally acquired cases are rare. One scenario in which that can happen involves someone who has been infected while traveling abroad and then returns home and is bitten by another mosquito. That insect can then acquire the parasite and spread it to other people.
According to the C.D.C., the United States eliminated malaria in the early 1950s. Each year, about 2,000 people return home from international travel with malaria infections. After 20 years without a report of a locally acquired case in the United States, nine cases were reported to the C.D.C. in Arkansas, Florida and Texas in 2023.
The New Jersey Department of Environmental Protection and a local mosquito-control program in Morris County, which is about 35 miles west of New York City, are collecting mosquitoes for testing.
New Jersey’s state epidemiologist, Dr. Tina Tan, said that such testing was standard when there was a report of a mosquito-borne illness.
A New England Journal of Medicine report in 1994 recounted the cases of a 29-year-old woman and 3-year-old boy from different parts of the state who were believed to have contracted malaria in New Jersey in 1991. In 1998, a 19-year-old college student who had not traveled was reported to have been exposed locally.
While cases of local exposure are rare, Jeff Brown, the acting state health commissioner, still advised residents to take precautions to prevent mosquito bites.
“While risk to the general public is low, it’s important to take the necessary precautions to prevent locally acquired malaria in New Jersey,” Mr. Brown said in a public statement. “The most effective ways are to prevent mosquito bites in the first place and to ensure early diagnosis and treatment of malaria in returning travelers.”
The state’s Health Department said that mosquito-borne diseases such as West Nile virus and eastern equine encephalitis tended to peak in the state during the summer and early fall months.
Dr. Tan suggested avoiding mosquito bites by using government-approved insect repellent, wearing long-sleeve shirts, pants and socks while outdoors. She also urged residents to be on the lookout for areas that collect water around their homes to reduce the mosquito population.
“You do that mainly by eliminating standing water, and that helps mosquito-proof because mosquitoes love to breed in stagnant water,” Dr. Tan said.
Samantha Latson is a Times reporter covering New York City and a member of the 2025-26 Times Fellowship class, a program for journalists early in their careers.
