Molecular detection of avian coronavirus (Infectious bronchitis virus) associated with poultry enteritis

Abstract

Poultry enteritis is an important multifactorial disease. Avian coronavirus (ACV) is one of many viruses related to enteric diseases and infectious bronchitis. Aim of this study was to find out the occurrence of ACV in enteritis affected broiler, molecular detection, phylogenetic analysis of avian corona virus and to examine intestine and liver for gross and microscopic lesions. Dead poultry birds (N=604) affected with enteritis were examined for presence of ACV. Intestinal samples of four birds were pooled to make one biological sample enteric ACV as the causative agent of enteritis in commercial poultry sector in and around four major districts of Rajasthan by RT-PCR. Molecular characterization was carried out by partial gene sequencing. Liver and intestine were examined grossly during post-mortem and by histopathology. Out of 151 pooled samples tested 51 (35.10%) were found positive for ACV. Prevalence of enteric ACV was highest in Ajmer (45.94%) and lowest in Dungarpur (23.07%) districts. 0-1 weeks age chicken flocks were found more susceptible for enteric ACV with 33.80% prevalence. Comparison of ACV sequence of this study revealed nucleotide (nt) identities from 99.44% among themselves, 99.44% with ACV from abroad. The amino acid (aa) identities of ACV of this study among themselves and with abroad sequences was 47.06 to 100%. Further severe congestion in intestine and necrotic patches on liver were recorded. Histopathology showed severe villous atrophy, congestion and cystic glands in sub-mucosa in intestine and severe congestion and haemorrhages along with infiltration of inflammatory cells in liver parenchyma.