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.
Transmission of Balamuthia infection has occurred via organ transplantation from infected donors on three documented occasions . Clinicians should consider Balamuthia as a cause of encephalitis in transplant recipients, particularly in those recipients who received organs from a donor who died from a neurologic or unknown cause of death. Transplant centers and organ procurement organizations should be aware of the potential for Balamuthia infection in donors with encephalitis of uncertain etiology.
Summary Table for Balamuthia Outbreaks Associated with Organ Transplantation in the United States
|Year(s)||Donor||Transplant Recipients||Symptomatic Recipients||Recipient Deaths||Asymptomatic Recipients Treated Prophylactically|
|2009||4 year-old male||4||2||1||2|
|2010||27 year-old male||4||2||2||2|
|2011-2012||39 year-old male||5||1||1||4|
To date, among three transplant clusters, symptomatic organ recipients have received chemotherapy for treatment of transplant-transmitted granulomatous amebic encephalitis and asymptomatic organ recipients have received prophylactic chemotherapy, guided by serology, for presumed Balamuthia mandrillaris exposure. In the latter scenario, asymptomatic organ recipients in the 2011–2012 cluster were considered exposed and received chemotherapy if their antibody titer reached ≥1:64 and continued therapy, adjusted for side effects, until their titer fell to 1:16 or lower . Although the serological treatment points were experimental and require further confirmation and optimal preemptive therapy regimens are undefined, asymptomatic organ recipients in these three clusters who had initial titers ≥1:64 and who were managed in this way did not develop granulomatous amebic encephalitis.