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Notes from the Field: Primary Amebic Meningoencephalitis Associated with Hot Spring Exposure During International Travel — Seminole County, Florida, July 2014

Please note: An erratum has been published for this article. To view the erratum, please click here.

Peggy J. Booth1; Dean Bodager MPA2; Tania A. Slade, MPH1; Swannie Jett, DrPH1

On July 2, 2014, the Florida Department of Health was notified of a suspected case of primary amebic meningoencephalitis (PAM). PAM is a rare, devastating infection of the brain caused by Naegleria fowleri, a free-living ameba found in warm, fresh water bodies throughout the world. Amebae are aspirated into the nasal cavity through swimming, splashing, or nasal irrigation, and after attaching to the nasal mucosa, migrate across the cribriform plate to the brain via the olfactory nerves, causing extensive damage to the frontal lobes of the brain (1). In August 2013, miltefosine, an antiparasitic drug with activity against N. fowleri, became available from CDC as an investigational drug used for the treatment of free-living ameba infections in combination with other antimicrobial drugs (2).

On June 27, 2014, the patient, a boy aged 11 years, had experienced a headache, low grade fever, stiff neck, nausea, and vomiting. He was hospitalized on June 29, with a presumptive diagnosis of viral meningitis. The initial cerebral spinal fluid (CSF) analysis was negative for motile ameba. All other routine tests were negative. His condition deteriorated, progressing to altered mental status, slurred speech, and seizures. On July 1 the patient required intubation and mechanical ventilation. A second CSF specimen was collected in the evening of July 1, and motile ameba were observed and reported in the early morning of July 2. Physician consultation with CDC was immediately facilitated by the Florida Department of Health to arrange for the release and delivery of miltefosine from Atlanta, Georgia, to Orlando, Florida; however, the patient died before its arrival on July 2. On July 9, CDC confirmed the presence of N. fowleri in the CSF by real-time polymerase chain reaction.

An interview of the patient's parents conducted by the Florida Department of Health in Seminole County revealed that the family had traveled to Costa Rica during June 19–June 27, 2014, where they had engaged in swimming, zip lining, and water slide use at a resort hot springs on June 23. The parents reported having avoided exposure to bodies of fresh water in Florida, because of public awareness of N. fowleri, but said they were unaware of the risk for PAM internationally. No other swimming or nasal insufflation of water was reported either in Costa Rica or in Florida during the week before illness onset. N. fowleri was detected in water samples from the hot springs and river pond located at the resort (3).

PAM is typically fatal; only three nonfatal cases have ever been reported in the United States (4). Miltefosine was administered as part of the successful treatment of a case of PAM in 2013 (5). Miltefosine can be requested from CDC upon clinical suspicion of PAM infection and before laboratory confirmation. Physicians should consider a diagnosis of PAM in persons with a clinically compatible illness who have a history of fresh water exposure 1–9 days before illness onset. Early diagnosis and prompt treatment are thought to be essential because of the high mortality rate. Strategic placement of miltefosine in Texas and Florida, where approximately half of all cases in the United States have been reported, is being considered and might reduce the time to initiating treatment associated with transport of the medication, thereby increasing the possibility of patient survival. Health care professionals and the public need to be aware that N. fowleri can be found in any warm, fresh water body throughout the world, including latitudes in the northern United States previously thought to have a climate incompatible with ameba activity (6).


Donna Walsh, Gladys Fernando, Florida Department of Health, Seminole County; Benjamin G. Klekamp, Debra Mattas, Dain Weister, Mirna Chamorro, Florida Department of Health, Orange County; David Atrubin, Jamie DeMent, Division of Disease Control and Health Protection, Florida Department of Health; Ibne Ali, Jonathan Jackson, CDC.

1Florida Department in Health-Seminole County; 2Florida Department of Health.

Corresponding author: Tania Slade,, 407-665-3266.


  1. Visvesvara GS. Free-living amebae as opportunistic agents of human disease. J Neuroparasitology 2010;1:61–73. Available at
  2. CDC. Investigational drug available directly from CDC for the treatment of infections with free-living amebae. MMWR Morb Mortal Wkly Rep 2013;62:666.
  3. Abrahams-Sandi E, Retana-Moreira L, Castro-Castillo A, Reyes-Batlle M, Lorenzo-Morales J. Fatal meningoencephalitis in child and isolation of Naegleria fowleri from hot springs in Costa Rica. Emerg Infect Dis 2015;21:382–4.
  4. CDC. Naegleria fowleri—primary amebic meningoencephalitis (PAM). Atlanta, GA: US Department of Health and Human Services, CDC; 2014. Available at
  5. Linam WM, Ahmed M, Cope JR, et al. Successful treatment of an adolescent with Naegleria fowleri primary amebic meningoencephalitis. Pediatrics 2015;135:e744–8.
  6. Kemble SK, Lynfield R, DeVries AS, et al. Fatal Naegleria fowleri infection acquired in Minnesota: possible expanded range of a deadly thermophilic organism. Clin Infect Dis 2012;54:805–9.

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