Swimming-related brain disease claims lives

From the Morbidity and Mortality Weekly Report (published by the CDC) May 30, 2008 Primary amebic meningoencephalitis (PAM) is a rare but nearly always fatal disease caused by infection with Naegleria fowleri, a thermophilic, free-living ameba found in freshwater environments. Infection results from water containing N. fowleri entering the nose, followed by migration of the amebae to the brain via the olfactory nerve. In 2007, six cases of PAM in the United States were reported to CDC; all six patients died. Preliminary results of a new study indicate that a total of 121 cases (range: 0–8 cases per year) occurred in the United States during 1937– 2007. The six cases of PAM reported in 2007 were among the six highest annual totals of cases reported during the study period; the other five highest totals were 1980 (eight cases), 2002 (seven cases), and 1978, 1986, and 1995 (six cases each). During 1937–2007, median age of the patients was 12 years (range: 8 months–66 years). Among the 119 cases for which sex of the patient was known, males accounted for 93 (78%) of the cases. Only one reported survivor met case criteria. Exposure primarily occurred in untreated, warm, freshwater lakes or rivers in 15 southern tier states (Arizona, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, Missouri, Nevada, New Mexico, North Carolina, Oklahoma, South Carolina, Texas, and Virginia); the state of exposure for four cases was unknown. Among the 112 cases for which month of exposure was known, 95 (85%) occurred during July–September. The extremely low incidence of PAM makes epidemiologic study difficult; why certain persons become infected with the amebae while millions of others exposed to warm recreational freshwaters do not is unknown. Risk reduction measures• The only certain way to prevent N. fowleri infections is to refrain from water-related activities. However, some measures that might reduce risk by limiting the chance of contaminated water going up the nose include: — Avoid water-related activities in bodies of warm freshwater, hot springs, and thermally polluted water such as water around power plants. — Avoid water-related activities in warm fresh water during periods of high water temperature and low water volume. — Hold the nose shut or use nose clips during activities in warm fresh water such as lakes, rivers, or hot springs. — Avoid digging in or stirring up sediment during waterrelated activities in shallow, warm freshwater areas.

From the Morbidity and Mortality Weekly Report (published by the CDC) May 30, 2008 Primary amebic meningoencephalitis (PAM) is a rare but nearly always fatal disease caused by infection with Naegleria fowleri, a thermophilic, free-living ameba found in freshwater environments. Infection results from water containing N. fowleri entering the nose, followed by migration of the amebae to the brain via the olfactory nerve. In 2007, six cases of PAM in the United States were reported to CDC; all six patients died. Preliminary results of a new study indicate that a total of 121 cases (range: 0–8 cases per year) occurred in the United States during 1937– 2007. The six cases of PAM reported in 2007 were among the six highest annual totals of cases reported during the study period; the other five highest totals were 1980 (eight cases), 2002 (seven cases), and 1978, 1986, and 1995 (six cases each). During 1937–2007, median age of the patients was 12 years (range: 8 months–66 years). Among the 119 cases for which sex of the patient was known, males accounted for 93 (78%) of the cases. Only one reported survivor met case criteria. Exposure primarily occurred in untreated, warm, freshwater lakes or rivers in 15 southern tier states (Arizona, Arkansas, California, Florida, Georgia, Louisiana, Mississippi, Missouri, Nevada, New Mexico, North Carolina, Oklahoma, South Carolina, Texas, and Virginia); the state of exposure for four cases was unknown. Among the 112 cases for which month of exposure was known, 95 (85%) occurred during July–September. The extremely low incidence of PAM makes epidemiologic study difficult; why certain persons become infected with the amebae while millions of others exposed to warm recreational freshwaters do not is unknown. Risk reduction measures• The only certain way to prevent N. fowleri infections is to refrain from water-related activities. However, some measures that might reduce risk by limiting the chance of contaminated water going up the nose include: — Avoid water-related activities in bodies of warm freshwater, hot springs, and thermally polluted water such as water around power plants. — Avoid water-related activities in warm fresh water during periods of high water temperature and low water volume. — Hold the nose shut or use nose clips during activities in warm fresh water such as lakes, rivers, or hot springs. — Avoid digging in or stirring up sediment during waterrelated activities in shallow, warm freshwater areas.