Infectious Bronchitis Virus in Broiler Chickens: Seroprevalence and Associated Risk Factors

Infectious Bronchitis Virus (IBV) is one of the most important viral diseases  , causing considerable economic losses in the poultry industry worldwide. The present study was conducted in Algeria to investigate the seroprevalence, associated risk factors, clinical signs, and lesions of infectious bronchitis viral (IBV) disease in broiler chicken. The study was conducted in ۶۳ chicken farms  ,where three IBV vaccination protocols were used in the first protocol: a single H۱۲۰ dose was administered to the chicks at ۷ days of age, in the second protocol: H۱۲۰ at ۳ days with an MA۵ booster at ۱۴ days, and in the third protocol: H۱۲۰ at ۳ days with MA۵ and ۴/۹۱ boosters at ۱۴ and ۳۵ days, respectively. A total of ۲۱۴۲ sera were collected and analyzed using the ELISA test. IBV was detected in ۷۷.۷۷% of broiler farms.The most common clinical signs observed were wheezing, sneezing, coughing, nasal discharge in the respiratory form , aqueous diarrhea,and dehydration  in the nephropathogenic form. Lesions included  tracheitis, fibrin deposition in the respiratory form, hemorrhagic nephritis, uric acid deposition at the renal, visceral ,and articular level in the nephropathogenic form. Antibody titers were higher in winter compared with autumn and spring (p<۰.۰۱).  Antibody titers were also higher in chickens aged >۳۰ days, in farms with a high density, poor hygiene level, and under the first vaccination protocol , compared with chickens aged ≤۳۰ days (p<۰.۰۱), farms with a low density (p<۰.۰۰۱), farms with good hygiene level (p<۰.۰۱) and those  under the third vaccination protocol (p<۰.۰۱).These findings showed a high seroprevalence of IBV in Algeria and highlight the importance of continuous surveillance and molecular characterization of persistent strains to optimize vaccination strategies against emerging variants.

کلیدواژه ها:

Broiler chicken ، Infectious bronchitis virus ، risk factors ، Seroprevalence