In vivo pathogenicity of hydropericardium hepatitis syndrome (Angara disease)

Abstract

This study was conducted on 175 one day old broiler chicks in order to observe in vivo pathogenicity of hydropericardium hepatitis syndrome (Angara disease). Chicks were grouped into A (25 chicks; reared at the Poultry Research institute (PRI), Rawalpindi) and B groups (150 chicks; reared at National Veterinary Laboratories (NVL) Islamabad in poultry rearing units). Feed and water were provided adlibitum to all the birds in both groups. The LD₅₀ (lethal dose ₅₀) of the virus was determined at the age of 26 days of broiler chickens divided into sub-groups a, b, c, d and e (each having 5 birds). The LD₅₀ titre of the viral suspension (10%) was prepared from liver extract and determined as 10^-2.5 per ml. During the study, potency of the vaccines was determined by vaccinating 150 chicks of sub-group k, l, m, n and o (each having 30 birds) with a dose of 0.2 ml. The vaccinated and non-vaccinated chicks of sub-groups were challenged with viral dose of 2 ml at day 17 post-vaccination to know the protection potency of the vaccines. No chick showed clinical manifestation of disease up to five days post challenge. On the 6th day post challenge, all the chicks were slaughtered and subjected to postmortem. Some of the chicks showed the lesions of hydropericarium. Histopathological findings of liver of all sub-groups revealed different stages of necrosis, cloudy swelling, liquefactive necrosis, cytoplasmic blabing, fatty degeneration and intranuclear inclusion bodies of virus.

Key words: In vivo pathogenicity, hydropericardium hepatitis syndrome, Angara disease.