RESUMEN
African swine fever virus causes a lethal hemorrhagic disease in domestic swine and wild boar for which currently licensed commercial vaccines are only available in Vietnam. Development of subunit vaccines is complicated by the lack of information on protective antigens as well as suitable delivery systems. Our previous work showed that a pool of eight African swine fever virus genes vectored using an adenovirus prime and modified vaccinia virus boost could prevent fatal disease after challenge with a virulent genotype I isolate of the virus. Here, we identify antigens within this pool of eight that are essential for the observed protection and demonstrate that adenovirus-prime followed by adenovirus-boost can also induce protective immune responses against genotype I African swine fever virus. Immunization with a pool of adenoviruses expressing individual African swine fever virus genes partially tailored to genotype II virus did not protect against challenge with genotype II Georgia 2007/1 strain, suggesting that different antigens may be required to induce cross-protection for genetically distinct viruses. IMPORTANCE: African swine fever virus causes a lethal hemorrhagic disease in domestic pigs and has killed millions of animals across Europe and Asia since 2007. Development of safe and effective subunit vaccines against African swine fever has been problematic due to the complexity of the virus and a poor understanding of protective immunity. In a previous study, we demonstrated that a complex combination of eight different virus genes delivered using two different viral vector vaccine platforms protected domestic pigs from fatal disease. In this study, we show that three of the eight genes are required for protection and that one viral vector is sufficient, significantly reducing the complexity of the vaccine. Unfortunately, this combination did not protect against the current outbreak strain of African swine fever virus, suggesting that more work to identify immunogenic and protective viral proteins is required to develop a truly effective African swine fever vaccine.
Asunto(s)
Adenoviridae , Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Vectores Genéticos , Genotipo , Vacunas Virales , Animales , Virus de la Fiebre Porcina Africana/genética , Virus de la Fiebre Porcina Africana/inmunología , Fiebre Porcina Africana/prevención & control , Fiebre Porcina Africana/virología , Fiebre Porcina Africana/inmunología , Porcinos , Vacunas Virales/inmunología , Vacunas Virales/genética , Vacunas Virales/administración & dosificación , Vectores Genéticos/genética , Adenoviridae/genética , Adenoviridae/inmunología , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Vacunas de Subunidad/inmunología , Vacunas de Subunidad/genética , Antígenos Virales/inmunología , Antígenos Virales/genéticaRESUMEN
African swine fever (ASF) is a devastating disease of domestic pigs that has spread across the globe since its introduction into Georgia in 2007. The etiological agent is a large double-stranded DNA virus with a genome of 170 to 180 kb in length depending on the isolate. Much of the differences in genome length between isolates are due to variations in the copy number of five different multigene families that are encoded in repetitive regions that are towards the termini of the covalently closed ends of the genome. Molecular epidemiology of African swine fever virus (ASFV) is primarily based on Sanger sequencing of a few conserved and variable regions, but due to the stability of the dsDNA genome changes in the variable regions occur relatively slowly. Observations in Europe and Asia have shown that changes in other genetic loci can occur and that this could be useful in molecular tracking. ASFV has been circulating in Western Africa for at least forty years. It is therefore reasonable to assume that changes may have accumulated in regions of the genome other than the standard targets over the years. At present only one full genome sequence is available for an isolate from Western Africa, that of a highly virulent isolate collected from Benin during an outbreak in 1997. In Cameroon, ASFV was first reported in 1981 and outbreaks have been reported to the present day and is considered endemic. Here we report three full genome sequences from Cameroon isolates of 1982, 1994 and 2018 outbreaks and identify novel single nucleotide polymorphisms and insertion-deletions that may prove useful for molecular epidemiology studies in Western Africa and beyond.
Asunto(s)
Virus de la Fiebre Porcina Africana , Fiebre Porcina Africana , Porcinos , Animales , Fiebre Porcina Africana/epidemiología , Camerún/epidemiología , Sus scrofa/genética , Análisis de Secuencia , Análisis de Secuencia de ADNRESUMEN
The 2023 International African Swine Fever Workshop (IASFW) took place in Beijing, China, on 18-20 September 2023. It was jointly organized by the U.S.-China Center for Animal Health (USCCAH) at Kansas State University (KSU) and the Chinese Veterinary Drug Association (CVDA) and sponsored by the United States Department of Agriculture Foreign Agricultural Service (USDA-FAS), Harbin Veterinary Research Institute, and Zoetis Inc. The objective of this workshop was to provide a platform for ASF researchers around the world to unite and share their knowledge and expertise on ASF control and prevention. A total of 24 outstanding ASF research scientists and experts from 10 countries attended this meeting. The workshop included presentations on current ASF research, opportunities for scientific collaboration, and discussions of lessons and experiences learned from China/Asia, Africa, and Europe. This article summarizes the meeting highlights and presents some critical issues that need to be addressed for ASF control and prevention in the future.