Field samples and clinical finding
The study was administered from April 2013 to May 2020, including 46 broiler farms from different Sulaymaniyah governorate areas, Kurdistan of Iraq. Clinically, the birds showed a sudden onset of high mortality, lethargy, ruffled feathers, and inappetence. At necropsy, the livers were the primarily affected organs, appearing as enlarged, pale yellow with necrotic foci and multiple petechial hemorrhages, enlargement of kidney, and hemorrhage in skeletal muscles. Tissue samples of liver, kidneys, and testicles were fixed in 10% neutral-buffered formalin solution for histopathology. For virus detection by RT-PCR also pool issue samples were collected from livers, kidneys, and spleens.