Emergence of African Swine Fever in China, 2018

Summary African swine fever virus (ASFV) is one of the most threatening infectious diseases of pigs. There are not sufficient data to indicate the importance of the sylvatic cycle in the spread and maintenance of the disease locally and potentially, globally. To assess the capacity to maintain ASF in the environment, we investigated the presence of soft tickreservoirs of ASFV in Gorongosa National Park (GNP) and its surrounding villages. A total of 1,658 soft ticks were recovered from warthog burrows and pig pens at the wildlife/livestock interface of the GNP and viral DNA was confirmed by nested PCR in 19% of Ornithodoros porcinus porcinus and 15% of O. p. domesticus. However, isolation of ASFV was only achieved in approximately 50% of the PCR‐positive samples with nineteen haemadsorbing virus isolates recovered. These were genotyped using a combination of partial sequencing of the B646L gene (p72) and analysis of the central variable region (CVR) of the B602L gene. Eleven isolates were classified as belonging to genotype II and homologous to contemporary isolates from southern Africa, the Indian Ocean and eastern Europe. Three isolates grouped within genotype V and were similar to previous isolates from Mozambique and Malawi. The remaining five isolates constituted a new, previously unidentified genotype, designated genotype XXIV. This work confirms for the first time that the virus currently circulating in eastern Europe is likely to have a wildlife origin, and that the large diversity of ASFV maintained in wildlife areas can act as a permanent sources of different strains for the domestic pig value chain in Mozambique and beyond its boundaries. Their genetic similarity to ASFV strains currently spreading across Europe justifies the need to continue studying the sylvatic cycle in this African country and other parts of southern Africa in order to identify potential hot spots of ASF emergence and target surveillance and control efforts.

The rapid and reliable detection of African swine fever virus (ASFV) is essential both for timely implementation of control measures to prevent the spread of disease, and to differentiate African swine fever (ASF) from other pig disease with similar clinical presentations. Many virological tests are currently available for the detection of ASFV (live virus), antigen and genome, including virus isolation, ELISA, fluorescent antibody, polymerase chain reaction (PCR) and isothermal assays. In recent years real-time PCR (rPCR) has become one of the most widely used formats for virological diagnosis providing sensitive, specific and swift detection and quantification of ASFV DNA. The ability to integrate rPCR into automated platforms increases sample throughput and decreases the potential for cross-contamination. In more recent years isothermal assays, which are a lower-cost alternative to PCR more suitable for use in non-specialised or mobile laboratories, have been developed for the detection of ASFV, however these assays have not been fully validated for routine use in the field. The performance of all virological detection assays in ASF diagnostics, as well as prospects for improving diagnostic strategies in the future, are discussed and reviewed in this chapter. Copyright © 2012 Elsevier B.V. All rights reserved.

African swine fever (ASF) is arguably the most dangerous and emerging swine disease worldwide. ASF is a serious problem for the swine industry. The first case of ASF in Russia was reported in 2007. We report an outbreak of ASF in Siberia, Russia, in 2017.