Detection of African swine fever virus genotype II in domestic pigs during a hemorrhagic fever outbreak in Ogun State, Nigeria

African swine fever outbreaks are ongoing in Europe and other parts of the world. In Nigeria, genotype I has been previously described, while genotype II was only reported recently. This study investigated a major disease outbreak in one of the largest pig farms in Nigeria, detected the etiology and determined the evolutionary history of African swine fever virus. Viral DNA was extracted and used to confirm the circulation of the African swine fever virus (ASFV) by Polymerase Chain Reaction, followed by the sequencing of the amplified products by Sanger’s method. Phylogenetic analysis showed that all the ASFV detected in this study belong to genotype II and clustered with reference strains from the Euro-Asian region and Tanzania in East Africa. This being the second report of ASFV genotype II in quick succession from Nigeria, suggests there may have been an unrecognized indigenous circulation or re-emergence of previously contained, or introduction of ASFV genotype II into the country. This reinforces the need for active surveillance and biosecurity measures to prevent and control transmission.