Molecular subtype of infectious bronchitis virus in broiler flocks in Jordan.

Infectious bronchitis virus (IBV) causes respiratory disease in chickens all over the world. Infectious bronchitis virus has many serotypes that do not confer cross protection against each other. The current study was designed to know which IBV types were circulating in Jordanian broiler chickens. Tracheal swabs from 175 broiler flocks at the acute phase of respiratory disease were collected. The swabs were subjected to RNA extraction and tested by reverse transcription PCR (RT-PCR). Specific-nested PCR were performed on RT-PCR products to detect and differentiate strains of Massachusetts, 4/91, and D274 types. The nucleic acid of IBV was detected in 105 out 174 (60%) broiler flocks by RT-PCR. Specific-nested PCR revealed that 35.2, 31.4, and 8.6% of these flocks had Massachusetts, 4/91, and D274, respectively, alone. In 24.8% of tested flocks, 2 types of IBV were detected. However, because the primers used in this study were designed specifically for 3 types of IBV, other types might have been present but not detected. Future work should include the isolation and molecular characterization of IBV in the region to adopt a suitable vaccination program using the common field serotypes as vaccines to protect against IBV-caused disease.