Molecular identification of agents causing respiratory infections in chickens from southern region of Pakistan from October 2007 to February 2008

Livestock and poultry contribute more than 49% of the agricultural GDP of Pakistan and play an important part in the alleviation of poverty and improvement in quality of life. Poultry industry is the second largest and organized industry of the country, progressing with an average rate of 8-10% yearly. However, viral and bacterial diseases are the major constraints in its growth. Respiratory infections are of paramount importance as high mortality may occur in poor management. Therefore, the etiology of respiratory disease is complex, often involving more than one pathogen at the same time. A wide variety of pathogens have been associated with respiratory infection in poultry, including Avian Pneumovirus (APV), Avian Influenza Virus (AIV), Infectious Bronchitis (IBV), Newcastle Disease Virus (NDV), Infectious Laryngotracheal virus (ILTV) and Mycoplasma gallisepticum (MG). As the Avian Influenza and Newcastle disease are endemic in the country, therefore, this study was planned to evaluate their status during the winter outbreaks. Tracheal samples were collected from poultry farms in southern region of Pakistan, experiencing heavy mortality of poultry flock. The samples were subjected to RNA extraction followed by RT-PCR. Out of 50 samples, 20 samples were positive for NDV, 28 for AIV and 2 were negative for both. Further, serotyping of 28 AIV isolates showed that, 6 were positive for H9, 20 for H5 and 2 for H7. Thus, it can be concluded that molecular techniques help in rapid identification of the agents causing infections. Further, the southern region of Pakistan had major infection resulting from AIV (H5) during October 2007 to February 2008.