### Microbiology A free-living freshwater amoeba. *N*. *fowleri*. [^1] ### Epidemiologic Risks Swimming in warm freshwater lakes. It runs up the 1^st^ nerve through the cribriform plate and thence into the brain. Most cases have come from the warm, wet Southern US as it grows best at 115 degrees and can be found in a variety of hot waters. It can be found in tap water, including in the US. [^2] Thanks to global warming, it is now as far north as Minnesota, oh yeah sure doncha know. [^3] Washing out your sinus with a Netti pot with tap water is another way to get the bug into your brain. [^4] [^5] There was a case from a water rafting park. [^6] And there are rare cases from hot springs. [^7] Bottom line: try to avoid fresh water going up the nose. Like many infections, it is moving north as the world warms. [^8] ### Syndromes Acute meningoencephalitis. Diagnose the infection by seeing it wriggling in the CSF with a microscope. ### Treatment It is mostly case reports of people throwing the amoebic kitchen sink at the bug. Miltefosine plus hypothermia plus amphotericin B plus rifampin plus fluconazole? If you have a patient with suspected free-living amoeba infection, contact the CDC Emergency Operations Center at 770-488-7100 to consult with a CDC expert. ### Notes Most patients die. 143 cases, 4 survivors, those who live usually have extensive brain damage. It isn't pretty. But based on a few case reports perhaps early treatment with miltefosine and hypothermia (a thermophile, the cooler the body, the harder it will be for it to grow) will lead to a good outcome. Early is less than 36 hours after the onset of symptoms. ### Rationalizations [^1]: Siddiqui R, Khan NA. Primary amoebic meningoencephalitis caused by Naegleria fowleri: an old enemy presenting new challenges. PLoS Negl Trop Dis. 2014 Aug 14;8(8):e3017. doi: 10.1371/journal.pntd.0003017. PMID: 25121759; PMCID: PMC4133175. [^2]: Ward L, Sherchan SP. Surveillance of Naegleria fowleri in Louisiana's public water systems. J Water Health. 2023 Nov;21(11):1627-1631. doi: 10.2166/wh.2023.040. PMID: 38017594. [^3]: Kemble SK, Lynfield R, DeVries AS, Drehner DM, Pomputius WF 3rd, Beach MJ, Visvesvara GS, da Silva AJ, Hill VR, Yoder JS, Xiao L, Smith KE, Danila R. Fatal Naegleria fowleri infection acquired in Minnesota: possible expanded range of a deadly thermophilic organism. Clin Infect Dis. 2012 Mar;54(6):805-9. doi: 10.1093/cid/cir961. Epub 2012 Jan 11. PMID: 22238170. [^4]: Jonathan S. Yoder, Susanne Straif-Bourgeois, Sharon L. Roy, Thomas A. Moore, Govinda S. Visvesvara, Raoult C. Ratard, Vincent R. Hill, Jon D. Wilson, Andrea J. Linscott, Ron Crager, Natalia A. Kozak, Rama Sriram, Jothikumar Narayanan, Bonnie Mull, Amy M. Kahler, Chandra Schneeberger, Alexandre J. da Silva, Mahendra Poudel, Katherine L. Baumgarten, Lihua Xiao, Michael J. Beach, Primary Amebic Meningoencephalitis Deaths Associated With Sinus Irrigation Using Contaminated Tap Water, _Clinical Infectious Diseases_, Volume 55, Issue 9, 1 November 2012, Pages e79–e85, [https://doi.org/10.1093/cid/cis626](https://doi.org/10.1093/cid/cis626) [^5]: Yoder JS, Straif-Bourgeois S, Roy SL, Moore TA, Visvesvara GS, Ratard RC, Hill VR, Wilson JD, Linscott AJ, Crager R, Kozak NA, Sriram R, Narayanan J, Mull B, Kahler AM, Schneeberger C, da Silva AJ, Poudel M, Baumgarten KL, Xiao L, Beach MJ. Primary amebic meningoencephalitis deaths associated with sinus irrigation using contaminated tap water. Clin Infect Dis. 2012 Nov;55(9):e79-85. doi: 10.1093/cid/cis626. Epub 2012 Aug 22. PMID: 22919000. [^6]: Jennifer R Cope, Jennifer Murphy, Amy Kahler, Daniel G Gorbett, Ibne Ali, Brandi Taylor, Lisa Corbitt, Shantanu Roy, Nicole Lee, Dawn Roellig, Scott Brewer, Vincent R Hill, Primary Amebic Meningoencephalitis Associated With Rafting on an Artificial Whitewater River: Case Report and Environmental Investigation, _Clinical Infectious Diseases_, Volume 66, Issue 4, 15 February 2018, Pages 548–553, [https://doi.org/10.1093/cid/cix810](https://doi.org/10.1093/cid/cix810) [^7]: Vugia DJ, Richardson J, Tarro T, Vareechon C, Pannaraj PS, Traub E, Cope JR, Balter S. Notes from the Field: Fatal Naegleria fowleri Meningoencephalitis After Swimming in Hot Spring Water - California, 2018. MMWR Morb Mortal Wkly Rep. 2019 Sep 13;68(36):793-794. doi: 10.15585/mmwr.mm6836a3. PMID: 31513557; PMCID: PMC6753969. [^8]: Gharpure R, Gleason M, Salah Z, et al. Geographic Range of Recreational Water–Associated Primary Amebic Meningoencephalitis, United States, 1978–2018. _Emerging Infectious Diseases_. 2021;27(1):271-274. doi:10.3201/eid2701.202119.