Balamuthia mandrillaris Transmitted Through Organ Transplantation --- Mississippi, 2009
Weekly
September 17, 2010 / 59(36);1165-1170
On December 14, 2009, a physician in Mississippi contacted CDC to report possible transplant-transmitted encephalitis in two kidney transplant recipients who shared the same organ donor. Histopathologic testing of donor autopsy brain tissue at CDC showed amebae, and subsequent testing of specimens from the donor and the two kidney recipients confirmed transmission by transplantation of Balamuthia granulomatous amebic encephalitis (GAE), a rare disease caused by Balamuthia mandrillaris, a free-living ameba found in soil (1). One kidney recipient, a woman aged 31 years, died; the other recipient, a man aged 27 years, survived with neurologic sequelae. Recipients of the heart and liver from the same donor received preemptive therapy and have shown no signs of infection. The donor, a previously healthy boy aged 4 years, was presumed to have died from acute disseminated encephalomyelitis (ADEM), an autoimmune neurologic disease, after infection with influenza A. An investigation was conducted by the state health departments in Mississippi, Kentucky, Florida, and Alabama and CDC to characterize the cases, elucidate possible exposures in the donor, and develop recommendations for early detection and prevention. This is the first reported transmission of Balamuthia by organ transplantation. Clinicians should be aware of Balamuthia infection as a potentially fatal cause of encephalitis. Organ procurement organizations (OPOs) and transplant centers should be aware of the potential for Balamuthia infection in donors with encephalitis of uncertain etiology, and OPOs should communicate this elevated risk for infection to transplant centers so they can make an informed risk assessment in the decision to accept an organ.
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This report is the first to describe transmission of Balamuthia through organ transplantation. However, a second cluster of patients with transplant-transmitted Balamuthia was confirmed at CDC on August 27, 2010 (2). Balamuthia infection is extremely rare, with fewer than 200 human cases recognized worldwide since Balamuthia was found to be a human pathogen in 1990 (3,4). The true magnitude of disease caused by Balamuthia is unknown because Balamuthia GAE often is misdiagnosed as other neurologic diseases (1,3). Once infection progresses to encephalitis, it is almost always fatal. Infection occurs in both immunocompromised and otherwise healthy persons, and often in children, although cases have occurred in patients across the age spectrum (5). Because of the rarity of Balamuthia GAE, risk factors are poorly defined, but might include exposure to soil or stagnant water, young age, and Hispanic ethnicity (3).
