What are the symptoms of infection?
Signs of infection include headache, nausea, vomiting and confusion — all typical for people with any type of meningitis, Dr. Cope said.
Patients who are admitted to the hospital with these symptoms should tell a doctor if they have recently been in a freshwater park, pool or body of water, she said.
How many people have died from it?
The infection is extremely rare but almost always leads to death, according to the C.D.C. In the United States, there were 143 infections between 1962 through 2017, the last year for which data is available. All but four of them were fatal. More than half of the infections occurred in Texas and Florida, the C.D.C. said.
The amoeba is not found in salt water.
How can I avoid being infected?
Most of the infections happened when swimming in warm lakes or rivers. Swimmers or divers should take steps to prevent infection, such as blocking water from entering the nose.
“Hold your nose or use nose clips,” said Dr. Tina Tan, epidemiologist for the New Jersey Department of Health. “Avoid putting your head under water, such as in hot springs, and stirring up the dirt or the mud.”
Most of the infections occurred in Texas and Florida because they have warm climates and large populations, and water sports are popular, Dr. Cope said. Precautions should be taken for activities like diving and water skiing that have the potential to force large amounts of water into the nasal cavity.
Is nasal rinsing safe?
It depends. At least one person contracted the infection through nasal rinsing: A 47-year old man in the Virgin Islands died in 2012 after becoming infected during a nasal ablution that he performed in preparation for Islamic prayer, the C.D.C. said. The amoeba was detected in untreated groundwater from a well and rainwater from a cistern that he had used as his household water sources.
At least two cases of infection have occurred in people who used neti pots, which are ceramic or plastic pots used to clear sinuses, the C.D.C. said. Water should be boiled for one minute (or three minutes at elevations higher than 6,500 feet), left to cool and filtered before rinsing, the C.D.C. advises. Otherwise, distilled, sterile or disinfected water should be used.
