Introduction
African swine fever (ASF) is a highly contagious, fatal, economically important, transboundary, viral disease of pigs caused by a DNA virus belonging to the genus Asfavirus and in the family Asfaviridae (Murphyet al ., 1999; FAO, 2013; Igbokwe and Maduka, 2018). The first ASF outbreak in Nigeria was reported in 1998 at a farm located in Lagos (FAO, 1998; Odemuyiwa et al ., 2000). The disease has spread widely within the country and has become endemic resulting in huge economic losses in the pig industry (Majiyagbe, 1999; Luther, 2001; Costard et al ., 2009; Fadiga et al ., 2013; Igbokwe and Maduka, 2018). It is a very fatal disease that can cause up to 100% mortality in a naïve pig population (Costard et al ., 2009). Poor biosecurity, bad abattoir practices and extensive or free range pig farming systems led to extensive spread of the disease in the country (Owolodun et al ., 2010). African swine fever was previously thought to exist only within domestic pig population with humans and other formites potentiating its spread, however, Luther et al . (2007a,b) reported the existence of ASF virus in the bush pig (Potamochoerus porcus ) and warthog (Phacochoerus aethiopicus ). It is therefore now a known fact that both domestic and wild pigs are susceptible to ASFV but the suids are hitherto said to be asymptomatic. The soft tick (Ornithodoros moubata) has been established as the primary reservoir of the virus (Luka et al ., 2016; Lukaet al ., 2017a). Areas with high pig-related activities such as marketing, consumption, and farming, have higher prevalence compared with areas with less pig-related activities. Farm-gate buyers, marketing systems and transport of untested pigs within the country has greatly aided the circulation of the virus in the country (Fasina et al ., 2010) The disease is characterized by a febrile syndrome, erythema and cyanosis of the skin, anorexia, bloody diarrhea, abortion in pregnant sows, meningitis, interstitial pneumonia, high morbidity and mortality (Fasina et al. 2010; Igbokwe and Maduka, 2018). Diagnosis of ASF is based on history, clinical signs, lesions and laboratory confirmation by viral isolation, and molecular characterization. The report represents the investigation of an acute ASF outbreak (July-August, 2019) in pig farms in Jos, Nigeria.