An outbreak of adenoviral infection in inland bearded dragons (Pogona vitticeps) coinfected with dependovirus and coccidial protozoa (Isospora sp.)

Thirty of 200 (15%) hatchling inland bearded dragons were found dead after a short period (48 hours) of weakness and lethargy. The most common clinical signs were head tilt and circling. Six bearded dragons with neurological signs were euthanized, and postmortem examination revealed no gross abnormalities. Microscopically, severe, randomly distributed hepatocellular necrosis with large basophilic intranuclear inclu- sion bodies in numerous hepatocytes was noted. Small-intestinal enterocytes contained intracytoplasmic coc- cidial protozoa (Isospora sp.) and occasional enterocytes had basophilic intranuclear inclusion bodies. Trans- mission electron microscopy revealed both 80- and 20-nm-diameter viral particles, which were consistent with adenoviruses and dependoviruses, respectively. Adenoviral outbreaks in groups of animals are uncommon. An adverse synergistic effect of the coccidiosis with the adenoviral infection may have played a critical role in the high morbidity and mortality in this case. Adenoviruses (Family Adenoviridae) are well-known pathogens in several mammalian and avian species. Ade- noviruses are double-stranded DNA viruses, 70-90 nm in diameter, and have a characteristic nonenveloped, icosahe- dral structure. Generally, adenoviruses are host specific and are transmitted by the fecal-oral route or direct contact via oronasal secretions. Often, mammalian infections are sub- clinical, except for infectious canine hepatitis. Adenoviral disease generally occurs in immunocompromised or young animals. Outbreaks in groups of animals are uncommon. Re- cently, adenoviral infections also have been reported in sev- eral reptilian species, including crocodiles, snakes, and liz- ards.