Clinicians: For 24/7 diagnostic assistance, specimen collection guidance, shipping instructions, and treatment recommendations, please contact the CDC Emergency Operations Center at 770-488-7100. More detailed guidance is under Information for Public Health & Medical Professionals.
Clinicians: CDC no longer provides miltefosine for treatment of free-living ameba infections. Miltefosine is now commercially available. Please visit impavido.com for more information on obtaining miltefosine in the United States. If you have a patient with suspected free-living ameba infection, please contact the CDC Emergency Operations Center at 770-488-7100 to consult with a CDC expert regarding the use of this drug.
Although most cases of primary amebic meningoencephalitis (PAM) caused by Naegleria fowleri infection have been fatal 1, there have been five well-documented survivors (one from the U.S. in 1978 2,3 , one from Mexico in 2003 4, two from the U.S. in 2013 5,6, and one from the U.S. in 2016) who received the following treatment courses:
Based on the treatment regimens used in the survivors, including the 2013 case-patients, the following combination of drugs is recommended for treatment of PAM:
Recommended Treatment for Primary Amebic Meningoencephalitis Caused by Naegleria fowleri
* Conventional amphotericin (AMB) is preferred. When AMB was compared with liposomal AMB against Naegleria fowleri, the minimum inhibitory concentration (MIC) for AMB was 0.1 µg/mL, while that of liposomal AMB was 10x higher at 1 µg/ml. Liposomal AMB was found to be less effective in the mouse model and in in vitro testing than the more toxic form of AMB 6,2. AMB methyl ester was also found to be less effective in the mouse model 7,8. Because of the extremely poor prognosis of Naegleria fowleri infection, it’s worth considering aggressive treatment.
** Miltefosine 9, a breast cancer and anti-leishmania drug, has shown some promise against the free-living amebae in combination with some of these other drugs. Miltefosine has shown in vitro and mouse model amebicidal activity against Balamuthia, Naegleria fowleri, and Acanthamoeba10-12 and has been used to successfully treat patients with Balamuthia infection 13 and disseminated Acanthamoeba infection 14. The standard miltefosine dosing in adults is as follows:
Miltefosine (oral)
Up to 45 kg body weight: 100 mg daily (i.e., one 50 mg cap po BID, given with food if possible to reduce gastrointestinal side effects)
45 kg body weight and higher: 150 mg daily (i.e., one 50 mg cap po TID, given with food if possible to reduce gastrointestinal side effects )
These standard doses are the maximal tolerated with respect to gastrointestinal symptoms. A higher dose would lead to increased nausea, vomiting, or diarrhea. Miltefosine is mildly nephrotoxic and the dosing might need to be adjusted for patients with impaired kidney function. However, because few data are available about the effective dose for amebic infection, the risk for nephrotoxicity should be balanced with the risk for mortality from PAM. If you have a patient with suspected Naegleria or other free-living ameba infection, please contact the CDC Emergency Operations Center at 770-488-7100 to consult with a CDC expert regarding the use of this drug.