A man in southwest Florida died after becoming infected with a rare brain-eating amoeba, which state health officials say was "possibly as a result of sinus rinse practices utilizing tap water."

The Florida Department of Health in Charlotte County confirmed Thursday that the unidentified man died of Naegleria fowleri.

State and local health and environmental agencies "continue to coordinate on this ongoing investigation, implement protective measures, and take any necessary corrective actions," they added.

The single-celled amoeba lives in warm fresh water and, once ingested through the nose, can cause a rare but almost-always fatal brain infection known as primary amebic meningoencephalitis (PAM).

The Centers for Disease Control and Prevention has tallied 157 PAM infections in the U.S. between 1962 and 2022, with only four known survivors (a fifth, a Florida teenager, has been fighting for his life since last summer, according to an online fundraiser by his family).

Agency data suggests this is the first such infection ever reported in February or March.

Infections are most common in Southern states and during warmer months, when more people are swimming — and submerging their heads — in lakes and rivers.

But they can also happen when people use contaminated tap water to rinse their sinuses, either as part of a religious ritual or an at-home cold remedy.

The CDC says the disease progresses rapidly and usually causes death within about five days of symptom onset.

The first symptoms of PAM can include headache, fever, nausea and vomiting, and they typically start about five days after infection (though they can begin anywhere within one to 12 days). Later symptoms can include stiff neck, confusion, seizures, hallucinations and coma.

Naegleria fowleri has not been shown to spread through water vapor, aerosol droplets, person-to-person transmission or drinking water, a fact that Florida health officials emphasized this week.

"Infection with Naegleria fowleri is RARE and can only happen when water contaminated with amoebae enters the body through the nose," they said. "You CANNOT be infected by drinking tap water."

That said, there are steps you can take to reduce your risk.

How safe are sinus rinses?

Many people use neti pots — or nasal irrigation devices like bulb syringes and squeeze bottles — to flush out their clogged sinuses when feeling under the weather.

The Food and Drug Administration says those are "usually safe and effective ... when used and cleaned properly."

That means no rinsing with tap water, which may contain low levels of organisms that are safe to swallow but not ingest through the nose.

Instead, use distilled or sterile water, which is sold in stores, or tap water that has been boiled for 3-5 minutes and then cooled until lukewarm (it can then be stored in a clean, closed container and used within 24 hours).

You could also use a special water filter — labeled "NSF 53" or "NSF 58" — designed to remove those germs.

Then make sure both your hands and the device are clean and completely dry, and follow the manufacturer's directions for use.

Afterward, the FDA suggests washing the device, drying the inside with a paper towel or letting it air dry before you use it again.

Splish, splash and stay cautious

The CDC warns that people should "always assume" there's a risk for infection when entering warm fresh water.

"The only sure way to prevent an infection is to avoid water-related activities in warm fresh water, especially during summer months," officials say.

If you are going swimming, try to prevent water from going up your nose.

That means no jumping or diving into bodies of warm fresh water, and avoid putting your head underwater in hot springs and other untreated geothermal waters.

You should also avoid digging in or stirring up sediment in shallow waters, since that's where amebae are more likely to live.

And either hold your nose shut, use nasal clips or keep your head above water while swimming.

People should also try not to let water into their nose while bathing, showering, or washing their face, Florida health officials say.

They recommend keeping plastic or inflatable pools clean by emptying, scrubbing and letting them dry after each use, and disinfecting swimming pools with chlorine before and during use.

Officials also warn not to let kids play with hoses or sprinklers unsupervised, and to avoid slip-n-slides or other similar activities where it's hard to prevent water from getting in the nose.