AbstractA method to identify concurrent viral respiratory infections in animals withPneumocystis Carinii(PC) has been developed by combining immunohistochemical and conventional special staining methods. In an effort to reduce both the number of slides to be screened microscopically and to demonstrate viral expression and PC cysts in the same paraffin section, a streptavidin immunohistochemistry protocol was combined with a rapid Grocott methenamine silver stain. This method is within the expertise and technical capabilities of most research and clinical laboratories. (The J Histotechnol17:349, 1994)