African swine fever control and prevention: an update on vaccine development

Abstract

African swine fever (ASF) is a lethal and highly contagious viral disease of domestic and wild pigs, listed as a notifiable disease reported to the World Organization for Animal Health (OIE). Despite its limited host range and absent zoonotic potential, the socio-economic and environmental impact of ASF is very high, representing a serious threat to the global swine industry and the many stakeholders involved. Currently, only control and eradication measures based mainly on early detection and strict stamping-out policies are available, however, the rapid spread of the disease in new countries, and in new regions in countries already affected, show these strategies to be lacking. In this review, we discuss approaches to ASF vaccinology, with emphasis on the advances made over the last decade, including the development of virulence-associated gene deleted strains such as the very promising ASFV-G-ΔI177L/ΔLVR, that replicates efficiently in a stable porcine epithelial cell line, and the cross-protecting BA71ΔCD2 capable of stably growing in the commercial COS-1 cell line, or the naturally attenuated Lv17/WB/Rie1 which shows solid protection in wild boar. We also consider the key constraints involved in the scale-up and commercialization of promising live attenuated and virus-vectored vaccine candidates, namely cross-protection, safety, lack of suitable animal models, compatibility with wildlife immunization, availability of established and licensed cell lines, and differentiating infected from vaccinated animals (DIVA) strategy.

Identification and analysis of the interaction network of African swine fever virus D1133L with host proteins

“…ASF caused great economic losses to the global pig industry posing a serious threat to pork safety and supply. Despite researchers' efforts, there are no safe and efficient ASF vaccines or treatments available, and ASF prevention only relies on the rapid culling of susceptible animals and strict epidemic control measures (Urbano and Ferreira, 2022).…”

Identification and characterization of nanobodies specifically against African swine fever virus major capsid protein p72

“…Nowadays, continual outbreaks and spread of ASF are taking place in Europe and Asia. More recently, the disease was reintroduced into the Dominican Republic in July 2021 and later Haiti after its initial emergence in the Western hemisphere over 40 years ( Gonzales et al, 2021 ; Urbano and Ferreira, 2022 ). In the last decade, great efforts and notable advances have been made on the vaccine development of ASF, especially for the live attenuated vaccines (LAVs) ( Urbano and Ferreira, 2022 ).…”

“…More recently, the disease was reintroduced into the Dominican Republic in July 2021 and later Haiti after its initial emergence in the Western hemisphere over 40 years ( Gonzales et al, 2021 ; Urbano and Ferreira, 2022 ). In the last decade, great efforts and notable advances have been made on the vaccine development of ASF, especially for the live attenuated vaccines (LAVs) ( Urbano and Ferreira, 2022 ). Previous attempts on the inactivated vaccines against ASFV have failed to induce protection ( Dixon et al, 2020 ).…”

“…Previous attempts on the inactivated vaccines against ASFV have failed to induce protection ( Dixon et al, 2020 ). Some viral antigens of ASFV have been evaluated and applied in the development of subunit, DNA and virus-vectored vaccines, which provide a variable degree of protection against challenge with ASFV ( Urbano and Ferreira, 2022 ). Currently, several LAVs containing one or more deletion of virulence-associated genes in the genome have been reported and showed to confer fully protection during challenge, such as ASFV-G-Δ9GL/ΔUK, HLj/18-7GD and ASFV-G-ΔI177L ( O’Donnell et al, 2017 ; Borca et al, 2020 ; Chen et al, 2020 ).…”

“…Currently, several LAVs containing one or more deletion of virulence-associated genes in the genome have been reported and showed to confer fully protection during challenge, such as ASFV-G-Δ9GL/ΔUK, HLj/18-7GD and ASFV-G-ΔI177L ( O’Donnell et al, 2017 ; Borca et al, 2020 ; Chen et al, 2020 ). Although LAVs seem to be the promising vaccine candidates against ASFV so far ( Urbano and Ferreira, 2022 ); their safety, genetic stability and side effects in animals should be fully considered and evaluated prior to large-scale field application.…”