African swine fever virus: An emerging DNA arbovirus

Authors: GAUDREAULT, NATASHA - Kansas State University; MADDEN, DANIEL - Kansas State University; Wilson, William - Bill; TRUJILLO, JESSE - Kansas State University; RICHT, JUERGEN - Kansas State University

Submitted to: Frontiers in Veterinary Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/31/2020
Publication Date: 5/31/2020
Citation: Gaudreault, N.N., Madden, D., Wilson, W.C., Trujillo, J.D., Richt, J.A. 2020. African swine fever virus: An emerging DNA arbovirus. Frontiers in Veterinary Science. 7:215. https://doi.org/10.3389/fvets.2020.00215.
DOI: https://doi.org/10.3389/fvets.2020.00215

Interpretive Summary: The only known DNA arbovirus, African swine fever virus (ASFV) poses a significant threat to the US pork industry. Since its identification in Kenya in the 1920s, ASFV has remained endemic in Africa, maintained in a sylvatic cycle between Ornithodoros soft ticks and warthogs which do not develop clinical disease with ASFV infection. The virus has recently spread across Europe and into Asia causing devastating and economically significant disease of domestic and feral swine (Sus scrofa). There is no ASFV vaccine available, and current control measures consist of strict animal quarantine and culling procedures. Topics covered by this review include factors important for ASFV infection, replication, maintenance and transmission, with attention to the role of the soft tick vector and sylvatic cycle, current and future control strategies for ASFV, and gaps in knowledge regarding the virus, vector and host species.

Technical Abstract: African swine fever virus (ASFV) is the sole member of the family Asfarviridae, and the only known DNA arbovirus. Since its identification in Kenya in the 1920s, ASFV has remained endemic in Africa, maintained in a sylvatic cycle between Ornithodoros soft ticks and warthogs which do not develop clinical disease with ASFV infection. However, ASFV causes a devastating and economically significant disease of domestic and feral swine (Sus scrofa). There is no ASFV vaccine available, and current control measures consist of strict animal quarantine and culling procedures. The virus is highly stable and easily spread by infected swine, contaminated pork products and fomites, or transmission by the soft tick vector. Competent Ornithodoros vectors are known to exist not only in Africa, but also in parts of Europe and the Americas. Once ASFV is established in the soft tick vector, eradication can be difficult due to the long lifespan of Ornithodoros ticks and their proclivity to inhabit the burrows of feral swine. Establishment of ASFV in wild boar populations further complicates control of the disease. Between the late 1950s and early 1980s, ASFV emerged in Europe, Russia and South America, but was mostly resolved or eradicated by the mid-1990s. In 2007, a highly virulent ASFV strain emerged in the Caucasus region and subsequently spread into the Russian Federation and Europe, where it has continued to circulate and spread. Most recently, ASFV emerged in China and has now spread to neighboring countries in Southeast Asia. The high morbidity and mortality associated with ASFV, the lack of an efficacious vaccine, and the complex nature of ASFV and its lifecycle, make this pathogen a serious threat to the global swine industry. Topics covered by this review include factors important for ASFV infection, replication, maintenance and transmission, with attention to the role of the soft tick vector and sylvatic cycle, current and future control strategies for ASFV, and gaps in knowledge regarding the virus, vector and host species.