Environment/Climate Change
Climate signals in the ecology of Naegleria Fowleri Raheleh Mohammadi* Raheleh Mohammadi Mohammadi Mohammadi Mohammadi Mohammadi UNMC, Rollins
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Background: Naegleria fowleri, the causative agent of Primary Amebic Meningoencephalitis (PAM), is a rare but nearly always fatal infection (95–99% case fatality). Although traditionally linked to warm freshwater, emerging evidence suggests its cysts may persist in cooler, drier conditions, potentially expanding its ecological range. This study explores temporal and spatial patterns of PAM cases in the U.S. and their association with climate-sensitive predictors.
Methods: PAM case data (1962–2023) were obtained from CDC at the county level, including month and year of occurrence. Climate variables—temperature, anomalies, and drought index—were sourced from NOAA datasets, along with regional climate classifications. We compared climate conditions during case-months versus non-case-months and applied generalized estimating equation models to assess associations.
Results: Initially concentrated in southern states (Texas, Florida), PAM cases expanded to western and midwestern regions over time. Decadal trends show increasing frequency, with recent peaks. Case-months exhibited higher temperatures across all regions, even cooler/drier areas. Positive temperature anomalies and drier conditions were more common during case-months. Models indicated temperature anomaly significantly increased PAM incidence (IRR=1.13, CI: 1.11–1.14), while SPI-12 suggested a 12% decrease in incidence per unit increase (IRR=0.88, CI: 0.86–0.90).
Conclusion: Climate variability plays a critical role in PAM emergence. Comparing case-month climate conditions to non-case-months provides insight into pathogen ecology and informs targeted public health interventions.