Cutaneous fowlpox occurring in vaccinated layer hens was investigated pathologically and microbiologically. Anorexia, decrease in egg production, increased mortality, yellow scabs on their faces, and alopecia of the feathered skins with yellow scabs were observed in affected hens. Histologically, proliferative and necrotic dermatitis with eosinophilic ring-shaped cytoplasmic inclusions (Bollinger bodies) and clumps of gram-positive cocci (Staphylococcus hyicus ) were noted in the affected birds. Fowlpox lesions were observed primarily on the feathered skins. Proliferation of feather follicular epidermal cells with cytoplasmic inclusions and degeneration of the feather and bacterial clumps in the feather follicles were noted on the affected skins. Ultrastructurally, characteristic fowlpox viral particles were observed in the cytoplasmic inclusions of hyperplastic epidermal cells. Amyloid depositions were observed in Disse’s space of the liver, the splenic sinus, and the lamina propria of the bronchiolar, bronchial and tracheal areas. Amyloidosis could be one factor inducing the fowlpox infection in vaccinated chickens.
(Research Team for Viral Diseases, TEL +81-29-838-7843)
Reference:
Nakamura et al. (2006) Avian Dis. 50 : 152-156.
