Study of Ecology and Epidemiology of Avian Influenza Viruses Type A by molecular methods

Wild birds are considered as a very important link in the epidemiological chain of avian influenza virus. After emergence of highly pathogenic avian influenza viruses (HPAIV) subtypes H5N6 in 2013 and H5N8 in 2014, a surveillance study using molecular epidemiology approaches was carried out during 2014 – 2019 in Iran to find a potential introduction of HPAIV into the wild birds’ population or any outbreak of HPAIV in wild birds. All sick and dead wild birds found in nature, or in cases of an outbreak, a collection of representative samples, were tested using the specific molecular methods for HPAIV H5 subtypes. Additionally, wild bird species in wetlands, several zoos, zoological garden or rehabilitation centers were tested for HPAIV. During the active surveillance plan, several individual and outbreak cases of HPAIV and orthoavulaviruses were identified. In general, more than 900 faecal materials, cloacal and oropharyngeal swabs, and/or tissue samples were collected from apparently healthy live birds representing several different species and families. In addition, tissue and swab samples were collected and investigated from any reported wild birds’ mortality cases in different parts of Iran in the framework of this study. No positive bird was found among apparently healthy live birds, however highly pathogenic influenza viruses of H5N1,H5N2, H5N6 and H5N8 were found in individual dead birds or mass die-off cases.
Keywords: highly pathogenic avian influenza viruses (HPAIV), surveillance, wild birds, outbreak, Iran