Seroprevalence Investigation of Newcastle Disease in Rural Poultries of the Northern Provinces (Golestan, Gilan, and Mazandaran) of Iran.

Rural poultry farming is common in the Northern provinces. Similar to commercial poultry, rural poultry is susceptible to most infectious diseases. In addition, by increasing the density of poultry farming, the probability of disease incidences has been increased. Newcastle disease is the most highly infectious disease which is endemic in Iran and causes outbreaks among commercial and rural poultry every year. The present study aimed to investigate the prevalence and virus circulation of Newcastle disease among rural poultry in Northern provinces of Iran. In the current study, 70 villages in 3 provinces (20, 30, and 20 villages in Mazandaran, Golestan, and Gilan, respectively) and a total of 1,374 birds (600, 400, and 374 birds in Mazandaran, Golestan, and Gilan, respectively) were sampled. Each village was regarded as an epidemiological unit. In the present study, birds of 67 (96%) villages were positive (presence of antibodies against Newcastle disease virus), including 28 (93.3%), 19 (95%), and 20 (100%) villages in Golestan, Mazandaran, and Gilan, respectively. Moreover, out of 1,374 birds, 616 (45%) of them were seropositive against Newcastle disease virus with 242 (41%), 159 (39.8%), and 211 (56%) samples in Mazandaran, Golestan, and Gilan, respectively. According to the results of the current study, the seroprevalence rate was reported to be high in both villages and birds. Such a high seroprevalence rate was indicative of the continuous exposure of the rural poultry to Newcastle virus and high virus circulation rate in the mentioned provinces which could result in the dissemination of the disease to commercial farms. Consequently, the implementation of proper control and care programs (e.g., vaccination of native poultry) can facilitate the reduction of Newcastle disease prevalence.