Primary amebic meningoencephalitis (PAM) is a rare and often fatal brain infection caused by the free-living ameba Naegleria fowleri. It is associated with recreational water exposure and poorly maintained recreational and municipal water systems. The CDC recommends using sterile, boiled, or distilled, and cooled tap water for nasal irrigation. This study reports a fatal case of PAM resulting from the improper use of a nasal irrigation device with contaminated tap water from a recreational vehicle (RV).
A 71-year-old female in Texas experienced severe neurological symptoms like headache, altered mental status, and fever 4 days after using a nasal irrigation device filled with tap water from the RV’s water system at a campground. Despite receiving medical treatment for suspected PAM, she experienced seizures and died 8 days after symptom onset. Laboratory testing confirmed the presence of N. fowleri in her cerebrospinal fluid.
The Texas Department of State Health Services conducted an epidemiologic investigation and discovered that the patient had routinely performed nasal irrigation using non-boiled water from the RV’s portable water faucet. This practice raised concerns about two water sources. The 1st was RV’s portable tank faucet, which supplied water to the faucet and shower without a municipal connection. The 2nd was the municipal water system, which was connected via a hose and water filter to the RV’s portable water system, bypassing the tank during nasal irrigation.
To assess the water sources, researchers collected 12 environmental samples. These samples involved the patient’s nasal irrigation squirt bottle, 1 L of water from the RV water heater, swabs from the RV showerhead, kitchen, and bathroom sink faucets, a large volume (about 100 L) of ultrafiltered sample, and a swab from the campsite’s municipal water connection. Additional samples included a 15 L ultrafiltered sample and a swab of the RV’s potable water tank, the RV’s external water filter, the RV’s municipal connection hose, and another 100 L ultrafiltered water sample from a low-flow municipal water connection point at the campsite.
The water quality indicators were evaluated during sampling, and all samples were tested for N. fowleri at the CDC. No N. fowleri DNA or live amoebae were found in any environmental samples. However, the monochloramine and total chlorine levels in the low-flow municipal distribution system sample were under the Texas Commission on Environmental Quality’s recommended minimal disinfection residual levels. The presence of free ammonia, decreased pH, and inconsistent levels of active disinfectant and total chlorine suggested poor disinfection performance, which could contribute to biofilm formation.
Biofilms may serve as a protective barrier for harmful microorganisms, such as bacteria and amoebas, rendering them less vulnerable to disinfectants. Turbidity levels at the taps in the RV were significantly above the acceptable drinking water standard (<1.0 NTU), indicating a failure in water disinfection. The combination of low disinfectant levels and high turbidity may have allowed thermophilic amoebae to survive, but none were found in the tested samples.
This case remains under investigation due to a lack of additional documented exposures and the low quality of both campground municipal water and the RV’s tap water at the time of sampling. The pathogen may have been potentially present at the time of sampling, but at levels below detection thresholds. Although the exact source of contamination remains unclear, the RV’s potable water tank may have contaminated the system before it was connected to the campground’s municipal supply.
This case highlights the serious health risks associated with improper nasal irrigation, while also emphasizing the importance of maintaining RVs’ water quality and ensuring that municipal water systems meet legal standards. Following suggested nasal irrigation practices, such as using sterilized, boiled, distilled, and cooled water, is necessary to reduce the risk of infection.
Reference: Smith OA, Tillman W, Lewis JB, et al. Notes from the field: Primary amebic meningoencephalitis associated with nasal irrigation using water from a recreational vehicle – Texas, 2024. MMWR Morb Mortal Wkly Rep. 2025;74(19):334-335. doi:10.15585/mmwr.mm7419a4
