Transmission of African swine fever virus to the wild boars of Northeast India

Abstract

Background: India recorded the first outbreak of African swine fever (ASF) in North-eastern region (NER) in the year 2020. Aim: The current study was undertaken to investigate the transmission of African swine fever virus (ASFV) in the wild boars of Northeast India, particularly of Assam. Material and Methods: ASF suspected mortal tissue remains and blood samples of wild boars collected from different locations of Assam were screened for molecular detection of swine viruses which includes Classical swine fever virus, Porcine Circovirus 2, Porcine reproductive and respiratory syndrome virus and ASFV. Results: One sample each from Manas and Nameri National Parks was detected positive for ASFV. Besides this, one of the samples was positive for CSFV and one of the ASFV positive samples was also positive for PCV2. Several striking gross and microscopic alterations were noticed in different organs of ASFV infected animals. Sequencing and phylogenetic analysis of B646L gene confirmed the presence of ASFV genotype-II in wild boars. Circulation of similar genotype in domestic pigs of NER in the contemporary period as well as locations near to the aforementioned national parks indicates the transmission of ASFV from domestic to wild boars. Clinical Relevance: The detection of ASFV in the wild boars of Assam is alarming as it is an impending threat to pig population and other endangered species (particularly Pygmy hog), making it increasingly daunting to control the disease. Conclusion: Chances are high for ASFV to become endemic in Assam region if stringent measures are not taken at proper time.