Acanthamoeba species and B mandrillaris are distributed worldwide

in freshwater and soil, and can cause GAE year-round.25 The portal of entry for these opportunistic pathogens is through the respiratory tract or ulcerating skin wounds with hematogenous spread to the CNS and, less commonly, with dissemination to other organs in the severely immunocompromised.26 To date, at least 250 cases of Acanthamoeba GAE and 150 cases of Balamuthia GAE have been reported, with acanthamoebiasis still confined mostly to the immunocompromised and balamuthiasis affecting both immunocompromised and immunocompetent individuals.27–30 Besides immunocompromise, other potential http://www.selleckchem.com/products/MDV3100.html risk factors for balamuthiasis may include contact with stagnant freshwater or with contaminated soil, often through agricultural work, desert motorcycling, dirt-biking, or even gardening.30 http://www.selleckchem.com/products/Everolimus(RAD001).html The risk factors for balamuthiasis are analyzed in Table 4. The incubation period for Acanthamoeba GAE could extend for weeks or months after primary inoculation in the skin, sinuses, or lungs, with subsequent draining ulcers, chronic sinusitis, or pneumonia.30 Although primary inoculation with B mandrillaris is also via the skin or lungs, the incubation period is shorter than in Acanthamoeba GAE with a mean of 8.5 days and a range of 1 to 30 days.26

The clinical presentation of GAE from either causative pathogen is the same with early behavioral and personality changes, fever, depressed mental status, seizures, photophobia, visual loss, and nonspecific cranial nerve dysfunction, followed by signs of increased ICP, including headache, nausea, vomiting, and loss of consciousness.31,32 The laboratory diagnosis of GAE from either causative pathogen is also similar with cysts and trophozoites rarely identified in the CSF, but more often identified in fixed and stained skin ulcer Tacrolimus (FK506) biopsies, brain biopsies, and post-mortem brain tissue.

Recently, immunodiagnostic tests, such as indirect immunofluorescent ultraviolet microscopy and indirect immunofluorescent antibody ultraviolet microscopy with specific antipathogen antibodies, and new PCR assays for identification of pathogen DNA have been developed for diagnostic specimens.33 In 2006, Qvarnstrom and colleagues at the CDC described a new multiplex real-time PCR assay for the simultaneous detection of Acanthamoeba spp, B mandrillaris, and N fowleri, which will permit rapid and specific detection of a single free-living ameba in clinical specimens within 5 hours.33 Neuroimaging studies by axial CT and/or MRI in GAE are nonspecific and often include single to multiple space-occupying lesions in the brain from the frontal cortex to the cerebellum with ring enhancing and other focal effects slightly more common in balamuthiasis than in acanthamoebiasis.