The emergence of porcine circovirus 2 infections in the Northeastern part of India: A retrospective study from 2011 to 2017.

Porcine circovirus (PCV) infection has emerged as an alarming threat to the pig population of India, especially in the Northeastern region (NER) over the last 10 years. The present study is a comprehensive report of the seroepidemiology of PCV2 and its incidences in the pig population from organized and unorganized farms of the entire NER of India from 2011 to 2017. A total of 5697 serum samples were screened by ELISA and the mean positivity of PCV2 antibodies in suspected sera was 31.27%. A total of 22 confirmed cases of PCV2 infection were recorded during the years 2014-2017. Seroprevalence of PCV2 infection in sows causing reproductive disorders in NER suggested its higher incidence in organized farms (65.7%) as compared to unorganized farms (17.6%). A detailed pathological and histopathological examination of the tissue samples collected from the affected animals indicated the presence of PCV2. Molecular characterization and phylogenetic analysis of four PCV2 isolates depicted the circulation of PCV2d genotype in the states of Meghalaya and Assam.