Serologic survey for exposure following fatal Balamuthia mandrillaris infection

Abstract

Granulomatous amebic encephalitis (GAE) from Balamuthia mandrillaris, a free-living ameba, has a case fatality rate exceeding 90% among recognized cases in the United States. In August 2010, a GAE cluster occurred following transplantation of infected organs from a previously healthy landscaper in Tucson, Arizona, USA, who died from a suspected stroke. As B. mandrillaris is thought to be transmitted through soil, a serologic survey of landscapers and a comparison group of blood donors in southern Arizona was performed. Three (3.6%) of 83 serum samples from landscapers and 11 (2.5%) of 441 serum samples from blood donors were seropositive (p = 0.47). On multivariable analysis, county of residence was associated with seropositivity, whereas age, sex, and ethnicity were not. Exposure to B. mandrillaris, previously unexamined in North America, appears to be far more common than GAE in Southern Arizona. Risk factors for disease progression and the ameba's geographic range should be examined.

Parasitic Infections Associated with Unfavourable Outcomes in Transplant Recipients

“…Free-living amoebas (FLA) are environmental protozoan parasites that can cause fatal diseases during immunosuppressive treatment. FLA are isolated from soil, sand, ponds, streams, tap water, sea water, physiotherapy pools, and other environmental sources [ 51 , 52 ]. There are three clinical presentations of amoebiasis: granulomatous amoebic encephalitis (GAE), disseminated amoebic disease and amoebic keratitis.…”

“…Initial symptoms involve the skin, sinuses or lungs. Multiple recurrent panniculitis-like subcutaneous nodules with eosinophilia, chronic rhinitis and chronic sinusitis are observed [ 51 , 52 ]. The disease becomes rapidly fatal when protozoa cross the blood–brain barrier.…”

“…GAE was observed mainly after BMTx, but also after SOTx and in HIV-infected patients [ 51 ]. Risk factors of GAE are IS, a history of nasal drainage, nasal congestion, exposure to contaminated water or garden soil, and road accidents that result in skin lesions [ 51 , 52 ]. Radiological studies show subarachnoid bleedings, hydrocephalus, ring-enhancing lesions, cortical and periventricular hypodense lesions and oedema.…”

Denouement

“…The CSF findings of B. mandrillaris infection in the CNS resemble those of Acanthamoeba infections and include pleocytosis with lymphocytic predominance, elevated protein count and moderate hypoglycorrachia; although a normal CSF profile has also been reported. [6][7][8] Cysts and trophozoites may be visible in CSF and can confirm the diagnosis. In a microscopic examination of fresh, non-centrifuged CSF, actively moving trophozoites may be present.…”

“…However, a serologic survey following a fatal case of B. mandrillaris infection in a previously healthy landscaper found that exposure to the organism seems to be far more common than the development of granulomatous amebic encephalitis. 6 It is therefore possible that other factors play an important role in disease pathogenesis such as amoeba virulence, frequency of exposure to contaminated soil, organism load, climatic conditions, soil biochemical characteristics or even host genetic factors.…”