(HealthDay News) – Two patients who died of an amebic infection had no history of freshwater exposure but had ameba in their household plumbing and used a nasal irrigation device for sinus problems.

Jonathan S. Yoder, MPH, from the U.S. Centers for Disease Control and Prevention in Atlanta, and colleagues describe the cases of a 28-year-old man and a 51-year-old woman in Louisiana who were hospitalized for infectious meningoencephalitis in 2011, and died after a brief illness.

The researchers found that both patients had been diagnosed with primary amebic meningoencephalitis (PAM). Neither patient had recent freshwater exposure, with their only reported water exposure being tap water used for routine activities, including in neti pots for regular sinus irrigation. The thermophilic ameba Naegleria fowleri (N. fowleri) was present in water samples in the homes of both patients. No amebae were detected in samples from the municipal water treatment plant and distribution system serving the homes.

“These are the first reported PAM cases in the United States associated with the presence of N. fowleri in household plumbing served by treated municipal water supplies and the first reports of PAM potentially associated with the use of a nasal irrigation device,” Yoder and colleagues conclude. “These infections introduce an additional consideration for physicians recommending nasal irrigation and demonstrate the importance of using appropriate water (distilled, boiled, filtered) for nasal irrigation.”

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