Deletion of an African swine fever ATP-dependent RNA hel-icase QP509L from the highly virulent Georgia 2010 strain does not affect replication or virulence

Authors: Ramirez-Medina, Elizabeth; VUONO, ELIZABETH - US Department Of Agriculture (USDA); PRUITT, SARAH - US Department Of Agriculture (USDA); RAI, AYUSHI - Oak Ridge Institute For Science And Education (ORISE); Espinoza, Nallely; Spinard Iii, Edward; VALADARES, ALYSSA - Oak Ridge Institute For Science And Education (ORISE); Silva, Ediane; Velazquez, Lauro; Borca, Manuel; Gladue, Douglas

Submitted to: Viruses
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/8/2022
Publication Date: 11/17/2022
Citation: Ramirez Medina, E., Vuono, E., Pruitt, S., Rai, A., Espinoza, N.N., Spinard III, E.J., Valadares, A., Silva, E.B., Velazquez Salinas, L., Borca, M.V., Gladue, D.P. 2022. Deletion of an African swine fever ATP-dependent RNA hel-icase QP509L from the highly virulent Georgia 2010 strain does not affect replication or virulence. Viruses. 14(11). https://doi.org/10.3390/v14112548.
DOI: https://doi.org/10.3390/v14112548

Interpretive Summary: African swine fever virus (ASFV) causes a devastating disease in swine, called African swine fever (ASF), that is currently spreading across Europe, Asia and recently appeared in the Americas. Sequencing ASFV is a difficult task that has only recently been efficiently accomplished by using new sequencing technologies, here we present for the first time the full genome sequence of the ASFV strain that was causing outbreaks in 1980.

Technical Abstract: African swine fever virus (ASFV) produces a lethal disease (ASF) in domestic pigs, currently causing a pandemic deteriorating pig production across Eurasia. ASFV is a large and structurally complex virus with a large genome harboring more than 150 genes. ASFV gene QP509L has been shown to encode for an ATP dependent RNA helicase, which appears to be important for efficient virus replication. Here we report the development of a recombinant virus, ASFV-G-'QP509L, having deleted the QP509L gene in the highly virulent field isolate ASFV Georgia 2010 (ASFV-G). It is shown that ASFV-G-'QP509L replicates in primary swine macrophages cultures as efficiently as the parental virus ASFV-G. In addition, the experimental inoculation of pigs with 102 HAD50 by the intramuscular route produced a slightly protracted, but lethal clinical disease when compared to that of animals inoculated with virulent parental ASFV-G. Viremia titers in animals infected with ASFV-G-'QP509L had also a slightly protracted kinetics of presentation. Therefore, ASFV gene QP509L is not critical for the processes of virus replication in swine macrophages, nor is it clearly involved in virus replication and virulence in domestic pigs.