When water containing the Naegleria fowleri ameba, a single-celled organism, enters the nose, the organisms may migrate to the brain, causing primary amebic meningoencephalitis, a very rare-but usually fatal-disease. A new study published in Clinical Infectious Diseases describes the first reported cases in the United States implicating nasal irrigation using disinfected tap water in these infections. Now available online, the study highlights the changing epidemiology of this uncommon disease, as well as the importance of using appropriately treated water for nasal irrigation.
From 2002 to 2011, 32 N. fowleri infections were reported in the U.S., according to the Centers for Disease Control and Prevention (CDC). In this latest study, Jonathan Yoder, MPH, coordinator of waterborne diseases and outbreak surveillance at CDC, reports the work of the Louisiana Department of Health and Hospitals and CDC in investigating two cases in 2011 in Louisiana. Two unrelated patients, a 28-year-old man and a 51-year-old woman, each died within five days of being admitted to the hospital with meningitis-like symptoms. Both had used a neti pot for regular sinus irrigation. Because family members of both patients were certain the patients had no recent history of recreational freshwater contact, which is typically associated with the disease, sinus irrigation using disinfected (chloraminated) tap water was implicated.
"N. fowleri was found in water samples from both homes," Yoder said, but "not found in the treatment plants or distribution systems of the municipal water systems servicing the patients' homes." Although it was never clear how N. fowleri were introduced into the plumbing of the patients' houses, once there, the organisms were able to colonize the hot water systems.