Studies on some respiratory viral infections and the value of histopathology as a mean of diagnosis in chickens

One hundred chickens of 4 days age were used in this work. These chickens were divided into 5 equalgroups (1, 2, 3, 4 and 5). Chickens in grou.ps 1” 2 and3 we.r e given an intranasal Lnecul.um of 0.1 ml, , Ve Logend c , Mesogenic and Lent ogerd,c strains of the Newcastle vi.rua- respectively. Each chick in group 4 was inoculatedintranasally with 0.1 ml of Adenovirus (CELO). Each chick in group 5 was inoculated intranasally with 0.1 mls t e.r Ll.Lz ed distilled water (control group). Five chickensfrom each group were sacrificed 4, 8, 16 and 32 days following infection.The most common clinical signs of chickens in group 1 were sever e respiratory and nervous manifestations, while those in group 2 wer e only moderate .r e spf.r at or’y manifesta-tions. Chickens in group 3 did not show any clinical signs. ,The most predomi~ant lesions in the first 3 groups were cat ar.rha’L tracheitis , bronchitis and broncho- .pneumonia. Lymphocytic meningoencephalitis, encephalo-malcia and demyelination were seen in the b.rain. Inter- muscular lymphocytic aggregations, edema and hyalinedegenel’ation of the cardiac muscle were noticed. The lymphoid organs (spleen and bursa of Fabricius) showedcoagulative necrosis 01” the lymphocytes. Catarrhal and