Naegleria fowleri found in hot springs across three national park sites
Updated
Updated · Outside · May 6
Naegleria fowleri found in hot springs across three national park sites
5 articles · Updated · Outside · May 6
USGS and Montana State University sampled 40 waterways at five western NPS sites, finding the amoeba in 34% of samples, including Yellowstone, Grand Teton and Lake Mead.
Polecat Hot Springs in Grand Teton showed the highest concentrations, while Yellowstone’s Boiling River, Lewis Lake and Firehole areas and four Lake Mead hot springs also tested positive.
The nearly always fatal pathogen infects through the nose in warm freshwater; researchers say warming waters may expand its range northward, prompting calls for monitoring, awareness and precautions such as nose clips.
As climate change pushes pathogens north, what other invisible dangers might be lurking in our favorite summer spots?
Brain-eating amoeba is in our national parks. Why are there no universal safety standards for U.S. recreational waters?
34% of Water Samples in Major Western US National Parks Test Positive for Deadly Naegleria fowleri Amoeba
Overview
A multiagency study (2016-2024) confirmed the presence of the deadly amoeba Naegleria fowleri in 34% of water samples from Yellowstone, Grand Teton, and Lake Mead national parks, with the first viable detection in Grand Teton hot springs due to improved sampling. This pathogen causes a rare but almost always fatal brain infection called PAM, which occurs only when contaminated water enters the nose during water activities. Climate change is expanding the amoeba's habitat northward, increasing the need for enhanced environmental monitoring and public education. In response, the National Park Service has implemented visitor precautions and improved water testing, while policy debates continue on balancing recreation with safety.