Hypothesis: Waterfowl may be important intermediary reservoirs of Naegleria fowleri

Primary Amebic Meningoencephalitis (PAM) caused by Naegleria fowleri is a rare, usually fatal disease. It is thought that PAM occurs most often in southern US states because of the warmer surface waters in these states. To better understand the epidemiology of this disease we converted the raw number of cases reported in each state from 1962 to 2022, to an estimate of cases per individual at potential risk. Our relative risk estimates paint a slightly different picture, suggesting that in addition to the temperature of surface waters other epidemiologic factors are also at play, and that there may be an association between waterfowl nesting areas and risk of disease acquisition. We hypothesize that waterfowl serve as reservoirs that maintain the environmental sources of human infection. If this can be shown, control measures can be implemented to reduce the risk of disease acquisition.