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PATHOGENIC 'NAEGLERIA': DISTRIBUTION IN NATURE
Citation:
Wellings, F., P. Amuso, A. Lewis, M. Farmelo, AND D. Moody. PATHOGENIC 'NAEGLERIA': DISTRIBUTION IN NATURE. U.S. Environmental Protection Agency, Washington, D.C., EPA/600/1-79/018.
Description:
Infection in man with pathogenic Naegleria, a free-living soil amoeba, results in a usually fatal disease entity known as primary amoebic meningoencephalitis. Epidemiological data usually included exposure to freshwater lakes or streams within the week prior to onset. However, no confirmed isolations had been made from the suspected exposure sites. The major obligation of this study was to determine the presence or absence of pathogenic Naegleria in freshwater lakes in Florida which had been associated with human cases of PAM. Secondary objectives were to elucidate the source of these amoebae, i.e., soil, avian, and/or mammals and to determine the environmental and/or ecological factors related to the presence of pathogenic Naegleria in lake waters. Results showed conclusively that pathogenic Naegleria amoebae are widely distributed in Florida's freshwater lakes. Examination of samples obtained from freshwater lakes in Georgia also showed extensive distribution of these amoebae. Samples submitted from a lake in South Carolina, which was associated with a PAM case, also yielded pathogenic Naegleria, indicating that these organisms are not unique to Florida's subtropical climate. These studies indicate that pathogenic Naegleria are ubiquitous and over winter in lake bottom sediments or at the sediment/lake water interface. No significant differences have been established among lakes supporting large populations of pathogenic Naegleria and those supporting very limited or undetectable populations.