Molecular survey of avian respiratory pathogens in commercial broiler chicken flocks with respiratory diseases in Jordan.

Acute respiratory tract infections are of paramount importance in the poultry industry. Avian influenza virus (AIV), infectious bronchitis virus (IBV), Newcastle disease virus (NDV), avian pneumovirus (APV), and Mycoplasma gallisepticum (MG) have been recognized as the most important pathogens in poultry. In this study, trachea swabs from 115 commercial broiler chicken flocks that suffered from respiratory disease were tested for AIV subtype H9N2, IBV, NDV, and APV by using reverse transcription PCR and for MG by using PCR. The PCR and reverse transcription PCR results showed that 13 and 14.8% of these flocks were infected with NDV and IBV, respectively, whereas 5.2, 6.0, 9.6, 10.4, 11.3, and 15.7% of these flocks were infected with both NDV and MG; MG and APV; IBV and NDV; IBV and MG; NDV and AIV; and IBV and AIV, respectively. Furthermore, 2.6% of these flocks were infected with IBV, NDV, and APV at the same time. On the other hand, 11.3% of these flocks were negative for the above-mentioned respiratory diseases. Our data showed that the above-mentioned respiratory pathogens were the most important causes of respiratory disease in broiler chickens in Jordan. Further studies are necessary to assess circulating strains, economic losses caused by infections and coinfections of these pathogens, and the costs and benefits of countermeasures. Furthermore, farmers need to be educated about the signs and importance of these pathogens.