Clinical features of infected birds show multiple skin lesions varying from papules to nodules. Gross lesions in both the cutaneous and the diphtheritic forms, seen on birds and during necropsy, are usually sufficient to suspect APV infection [60] . However, these signs are sometimes not sufficient for definitive diagnoses of APV infection as other agents, such as papilloma virus, scaly leg mites [72] and mycotoxins may produce similar lesions in the skin [60] , and conditions like candidiasis, capillariasis and trichomoniasis may give lesions in the oral cavity similar to the diphtheritic form of APV infection [73] . It is therefore crucial to secure samples and confirm the viral etiology of the condition.