Amebic Meningoencephalitis Caused byBalamuthia mandrillaris: Case Report and Review

Abstract

Balamuthia mandrillaris, formerly referred to as a leptomyxid ameba, is a free-living ameba that has recently been identified as a cause of meningoencephalitis. Previously, only two genera, Naegleria and Acanthamoeba, were recognized as causes of central nervous system (CNS) infections in humans. In contrast to Naegleria, Balamuthia causes a subacute-to-chronic infection of the CNS. Distinct from Acanthamoeba, which appears to favor the immunocompromised host, Balamuthia is capable of infecting both healthy and immunosuppressed hosts. Retrospective analyses as well as an accumulation of newly identified cases have demonstrated that this ameba is an increasingly important pathogen to recognize. We report the isolation, histopathologic features, and confirmation by indirect immunofluorescence of B. mandrillaris in a case of fatal amebic meningoencephalitis.

GENOTYPING OF BALAMUTHIA MANDRILLARIS BASED ON NUCLEAR 18S AND MITOCHONDRIAL 16S rRNA GENES

“…A review of the literature suggests that cases involving males are more prevalent. [3][4][5][6][7][8][9][10][11][12][13][14][15] Characteristic symptoms of GAE include fever, headaches, nausea, seizures, and other focal neurologic indicators, such as brain lesions. B. mandrillaris usually is found within localized areas of the brain and clustered around blood vessels.…”

Amebic Meningoencephalitis Caused by Balamuthia Mandrillaris (Leptomyxid Ameba) in a Horse

“…1,2,5,6,8,[10][11][12][13][14][15][16] The ameba has two stages in its life cycle: a feeding trophic stage and a thick-walled cyst stage. 15 Balamuthia mandrillaris can be successfully cryopreserved and cultured on a variety of mammalian cell cultures.…”

“…Balamuthia mandrillaris, the only known species of Balamuthia, has been isolated only from human and animal tissue, never from the environment. 4,5,9,16 Several species of Acanthamoeba (A. castellani, A. culbertsoni, A. healyi, A. rhysodes, A. polyphaga) and B. mandrillaris cause an insidious and chronic GAE. Only 1 species of Naegleria (N. fowleri) causes an acute, fulminating infection, primary amebic meningoencaphalitis.…”

“…11 They can have mature (well-differentiated) or immature histologic components. 5 They belong to the family of germ-cell tumors, which also includes germinoma, embryonal carcinoma, endodermal sinus tumor, and choriocarcinoma, each of which represents the malignant transformation of an embryonic tissue stage. 5,7 Teratomas and germcell tumors in general are mostly found in the gonads but sometimes occur in the neck or along the midline of the brain, generally involving the suprasellar, thalamic, or pineal regions.…”

Histopathologic spectrum and immunohistochemical diagnosis of amebic meningoencephalitis

“…1,7,8 Previous histopathologic reports describe single cases or small series of patients infected by one amebic genus. [9][10][11][12][13][14][15][16][17][18][19][20] Side-by-side histopathologic comparison of cases caused by different ameba is not available. To better characterize the central nervous system pathology caused by the three different genera of free-living ameba, we evaluated the histopathologic and immunohistochemical features of patients infected with Acanthamoeba, Balamuthia, and Naegleria.…”