Viruslike Particles Associated with Pirhemocyton Inclusion Bodies in the Erythrocytes of a Water Snake, Nerodia erythrogaster flavigaster

Abstract

Viruslike particles were found associated with inclusion bodies in the erythrocytes of the Yellowbelly Water Snake (Nerodia erythrogasterflavigaster). Similar types of inclusions are still inter- preted by some workers as being protozoan in nature (Pirhemocyton sp.) despite recent evidence for a viral etiology. With light microscopy the intraerythrocytic inclusions are seen either as vacuoles, empty or containing a basophilic-staining substance, or as darkly staining granules. Electron microscopy revealed viruslike particles within small vacuoles quite unlike the icosahedral cytoplasmic deoxyribovirus (ICDV) particles previously observed in reptilian erythrocytes. The viruslike particles resembled the Type-A and Type-C virions of the oncornavirus group, both in morphology and size. Particles also were found budding off, or attaching to, the outer membrane of erythrocytes. It is suggested that the inclusions seen by light microscopy were formed as a result of the production of these viruslike particles because no eukaryotic structures were found associated with any inclusion bodies.