Molecular Detection of Newcastle, Infectious Bronchitis, and Influenza (H9) viruses in Respiratory Complex Samples in Broiler Flocks of Goles-tan Province, 2019-2020

The expansion of the poultry industry and the intensive breeding of birds indoors have led to respiratory infections of several different infectious agents, especially avian influenza (AI), Newcastle disease (ND) and infectious bronchitis. Evidence suggest that these agents act synergistically with each other in affected flocks.  Twenty broiler flocks with respiratory infection in Golestan province were selected. Trachea and kidney samples were transferred to the laboratory, and PCR was carried out to detect ND, IB, and H9 influenza viruses. According to the results, Flocks were more involved with IB infection (20%), and then ND (15%) and H9 influenza (10%) were more prevalent, respectively. Also, among these respiratory complex infections, the coinfection of IB with ND (20%) and AI (20%) viruses was the more common. According to the conclusions of this study, infectious bronchitis virus played the most crucial role in the development of respiratory complexes, and co-infection with Newcastle disease virus and Influenza H9 also causes severe symptoms and mortality in the Flocks. It is recommended that accurate epidemiological studies be conducted each year to determine the prevalence of risk factors of this disease and vaccines' efficiency in Flocks. This is the first comprehensive study on the respiratory complex of broiler herds in Golestan province, one of the centers of chicken meat production in the country.