IMMUNOPEROXIDASE DETECTION OF OPHIDIAN PARAMYXOVIRUS IN SNAKE LUNG USING A POLYCLONAL ANTIBODY

In a retrospective study of proliferative interstitial pneumonia in vi perid and nonviperid snakes, formalin-fixed, paraffin-embedded lungs f rom 52 snakes were screened for immunohistochemical reactivity to ophi dian paramyxovirus. All snakes were from zoological collections that e xperienced mortalities attributed to paramyxovirus infection. Of the 5 2 snakes, 47 had pulmonary lesions compatible with ophidian paramyxovi rus infection. Histologic changes in affected lungs included hyperplas ia and hypertrophy of septal and faveolar epithelial cells, loss of ci liated cells, mixed leukocytic interstitial infiltrates, fibrinonecrot ic exudate in the lumen of proximal and distal faveolar compartments, and occasional epithelial syncytial cell formation or intraepithelial eosinophilic intracytoplasmic inclusions. Lungs were immunohistochemic ally stained for paramyxovirus antigens by utilizing rabbit polyclonal antibodies against a paramyxovirus isolate from a black mamba (Dendro aspis polyepis polyepis). Virus infection in 6 snakes was confirmed by virus isolation from frozen lung tissue. Of the 6 lungs from which pa ramyxovirus was isolated, 5 lungs stained positively for viral antigen s utilizing antisera to the black mamba isolate. Altogether, 36 lungs stained positively for paramyxovirus antigens. There was multifocal to diffuse linear staining of the lumenal surface of faveolar epithelium , and there were multiple foci of granular cytoplasmic staining. Immun ohistochemical staining of formalin-fixed lungs from snakes with proli ferative interstitial pneumonia was helpful as a routine diagnostic te st for substantiating a diagnosis of ophidian paramyxovirus infection.