Table 2: IBV isolates with their tissue tropism (according to the presence of IBV by diagnostic N gene RT-PCR) and clinical history.

Isolate Tropism Clinical findings Vaccine used Chicken/age JOA4 Trachea, ovary Drop in egg production H120 Watery cysts in ovaries M41 Layer, 24 weeks Short and enlarged oviducts 4/91 JOA2 Trachea, kidney, ovary Drop in egg production H120, M41, 4/91 Layer, 22 weeks Saudi-1 Trachea Respiratory signs H120, 4/91 Broiler, 22 days Saudi-2 Trachea Respiratory signs H120, 4/91 Broiler, 24 days Iraqi IBV Trachea, kidney Respiratory signs, nephritis, and drop in egg production H120, M41, 4/91 Breeder, 25 weeks