Detecting Naegleria fowleri in Alabama lakes and ponds

Distribution and Prevalence of Naegleria fowleri in Freshwater from Alabama Lakes and Ponds

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Naegleria fowleri, the “brain-eating amoebae,” is a pathogen found in freshwater ecosystems and soil. Upon exposure to the pathogen via water-related activities, the amoebae enters the nose and invades the brain, causing primary amoebic meningoencephalitis (PAM), which has a 95-99% mortality rate. While rare, PAM cases occur worldwide and, in the US, mostly occur in southern-tier states. Strangely, no PAM cases have been reported in Alabama. However, the presence of N. fowleri in Alabama waters was documented from a single location in a 1991 environmental survey. Based on the lack of environmental surveys and the previous N. fowleri detection in Alabama, my research aims to determine the distribution and presence of N. fowleri in Alabama lakes and ponds, including whether environmental factors affect its presence. For this study, water samples were collected from 34 sites in the spring and 46 sites in the summer of 2019. Environmental parameters were also measured. Triplicate 200 ml water samples from each site were vacuum filtered through sterile 0.45 mm mixed cellulose ester filters, and the filters were frozen until DNA extraction. Following DNA extraction, polymerase chain reaction (PCR) was used to amplify a fragment of the N. fowleri 18S rRNA gene and gel electrophoresis was used to evaluate the presence of N. fowleri. To date, PCR triplicates of 23 samples from 8 ponds tested negative for N. fowleri. In the remaining sample, N. fowleri was detected in one of the PCR triplicates, indicating N. fowleri was present in at least one Alabama pond.