(A) Focal interstitial inflammation, acute tubular necrosis, and fibrinous casts in a human kidney. Hematoxylin-eosin staining. Original magnification, ×100. (B) Positive staining of Rift Vallye fever (RVF) viral antigens in renal tubules of a human kidney. Immunoalkaline phosphate staining, naphthol fast red substrate with light hematoxylin counterstain. Original magnification, ×100. (C) Intra-erythrocytic parasites (arrow) in the blood vessel of a human muscle. Hematoxylin-eosin staining. Original magnification, ×630. (D) Positive staining of Plasmodium falciparum antigen in red blood cell (arrow) of a human muscle. Immunoalkaline phosphate staining, naphthol fast red substrate with light hematoxylin counterstain. Original magnification, ×630.