Infectious bronchitis virus in Jordanian chickens: seroprevalence and detection

Infectious bronchitis (IB) is one of the most important viral diseases of poultry; it causes major economic losses to the poultry industry. This study was conducted to investigate the prevalence of infectious bronchitis virus (IBV) in commercial chicken flocks in Jordan. Serum samples from 70 commercial chicken flocks (40 broilers, 18 layers, and 12 broiler breeders) free from respiratory disease were collected and screened for the presence of Massachusetts-41 (M-41), D274, and 4/91 strain antigens of IBV by using the hemagglutination inhibition (HI) test. In addition, 51 commercial chicken flocks (25 broilers, 15 layers, and 11 broiler breeders) suffering from respiratory disease were tested for the presence of IBV, using the reverse-transcription polymerase chain reaction. Overall, 92.9% of the flocks free from respiratory disease were seropositive for antibodies to the M-41 strain, whereas 90% and 61.4% of the flocks were seropositive for antibodies to the 4/91 and D274 strains, respectively. Infectious bronchitis virus nucleic acid was detected in 16 broiler (64%), 8 layer (53%), and 6 broiler breeder (54.54%) flocks affected with respiratory disease. This study clearly demonstrates that several strains of IBV are present in poultry flocks in Jordan. Future work should include the isolation and serotyping of IBV in the region, so that a suitable vaccination program, using the common field serotypes as vaccines, can be adopted to protect against IBV-caused disease. Furthermore, farmers need to be educated about the clinical signs of IB and the importance of IBV.