Cutaneous and diphtheritic avipoxvirus infection confirmed by PCR in a great horned owl ( Bubo virginianus ) in Mexico

Abstract A juvenile female great horned owl ( Bubo virginianus ) from Nuevo León, Mexico, presented with proliferative eyelid, beak, and pedal lesions, and yellow nodules on the hard palate. Histopathology revealed epidermal hyperplasia, ballooning degeneration and numerous eosinophilic intracytoplasmic inclusion bodies (Bollinger bodies), which are pathognomonic for Avipoxvirus infection. PCR amplification of the P4b core protein gene (fpv167 locus) with validated primers yielded the expected 576‐bp amplicon, providing complementary molecular confirmation. Sequencing was unsuccessful due to formalin‐induced DNA fragmentation. To our knowledge, this is the first PCR‐confirmed description of Avipoxvirus in B. virginianus worldwide, the first report in a Mexican raptor, and the first documented description of diphtheritic (oral) lesions in any strigiform bird. This case demonstrates that a definitive diagnosis can be achieved through integrated histopathology and PCR, even when sequencing fails, underscoring the need for avian pox surveillance in Mexican raptor populations.