Figure 5. Photomicrographs showing histopathologic features and immunolocalization of Balamuthia mandrillaris antigens in central nervous system tissue from a donor with B. mandrillaris infection. A) Typical amebic trophozoites with prominent karyosomes in central nervous system. Hematoxylin and eosin staining. Original magnification, ×158. B) B. mandrillaris antigens in amebic trophozoites. Immunoalkaline phosphate staining, naphthol fast red substrate with light hematoxylin counterstain. Original magnification, ×100.