Kiderlen AF, Laube U, Radam E, Tata PS (2007): Oral infection of immunocompetent and immunodeficient mice with Balamuthia mandrillaris amebae
Parasitol. Res. 100 (4): 775-782 [Epub 2006 Nov 17].

Balamuthia mandrillaris is an opportunistic agent of lethal granulomatous amebic encephalitis (GAE). In mice, we have shown that intranasally instilled B. mandrillaris amebae infect the brain via the olfactory nerve pathway. In this study, we raised the question, whether this ameba might also reach the brain after an oral gastrointestinal infection. Immunocompetent (WT) and immunodeficient (RAG) mice received B. mandrillaris amebae by gavage into the esophagus. Mice of both groups became ill and some died (WT 20%, RAG 40%) within 42 days. All mice infected orally revealed B. mandrillaris amebae in the central nervous system. Apparently intact amebae and/or specific antigen were found widely distributed in various organs and the stool. The data indicate that oral infection with B. mandrillaris leading to GAE is possible. Exit from the gastrointestinal tract and dissemination remain unresolved. Though stool cultures were negative, transmission of this highly pathogenic ameba via stool cannot be ruled out.