Inclusion Body Disease in Boid Snakes

An inclusion body disease (IBD) in boid snakes (family Boidae) has been seen for over 20 yr in private and zoological collections of snakes in the United States, Africa, and Europe. In both a retrospective and prospective study, 70 members of the subfamily Boinae and 34 members of the subfamily Pythoninae were evaluated. Clinical signs in affected snakes included chronic regurgitation and neurologic disorders. Central nervous system disease was more apparent in members of the subfamily Pythoninae than in members of the Boinae and included the inability of animals to right themselves when placed in dorsal recumbency, head tremors, disorientation, incoordination, and paresis. Histologic examination of tissues demonstrated numerous eosinophilic intracytoplasmic inclusion bodies in epithelial cells of all major organs, including neurons in the brain and spinal cord. In all snakes with central nervous system disease, a nonsuppurative meningoencephalitis with neuron degeneration and perivascular cuffing was seen. Electron microscopic examination revealed viral particles in thin sections of the brain, pancreas, and kidney, as well as in primary kidney cells cultured from affected snakes. The enveloped particles were an average of 110 nm in diameter and morphologically resembled C-type particles of the family Retroviridae. Inoculation of young Burmese pythons (Python molurus bivittatus) with supernatant of primary cultured kidney cells from an infected boa constrictor (Boa constrictor) resulted in the development of clinical signs and microscopic lesions seen in IBD.