This is an ongoing project to determine the susceptibility of brown tree snakes (Boiga irregularis) to ophidian paramyxovirus infection and to study the pathogenesis of viral infections with this important group of snake pathogens. Two newly-isolated strains of ophidian paramyxovirus are currently being studied, in addition to further research with a previously isolated virus. Following inoculation with these viruses, brown tree snakes have become clinically ill and up to 50% have died in some inoculation trials. Paramyxoviruses have been isolated from infected snakes and propagated in cell culture and embryonated chicken eggs; the viruses have also been identified via transmission electron microscopy. Snake inoculation trials are continuing at the National Zoo.