DEVELOP AN INACTIVATED AFRICAN SWINE FEVER VACCINE

Since African Swine Fever (ASF) was first reported 83 years ago in Africa and subsequently spread to several countries in Europe, Asia, and the Americas, no adequate vaccine has been developed to control the disease. This study aims to investigate the pathogenesis of the African Swine Fever Virus (ASFV) and the inactivation of ASFV for vaccine preparation. Spleen samples were collected from field cases with ASF symptoms in Bali and Nusa Tenggara. Spleens that tested positive via Quantitative-Polymerase Chain Reaction (q-PCR) were processed into a suspension and inactivated using a combination of Triton-X100 and formaldehyde containing antibiotics (Inactivated ASFV). This suspension was then injected into three piglets aged 2.5 months. Another suspension, untreated with formaldehyde (Non-Inactivated ASFV), served as a control and was injected into three other piglets of the same age. Pigs infected with the Non-Inactivated ASFV exhibited typical ASFV clinical symptoms and died on the twelfth day post-infection. In vitro confirmation showed that these pigs were q-PCR positive and exhibited histological changes characteristic of ASFV infection. In contrast, pigs infected with Inactivated ASFV remained healthy up to two months post-infection, indicating that the virus did not replicate in vivo. The inactivated ASFV suspension was emulsified with ISA 50 oil to create an inactivated vaccine, which was administered to three piglets aged 2.5 months. As a control, two piglets of the same age received a placebo. Blood samples were collected before vaccination and at one and two months post-vaccination for serological testing. Three months after vaccination, all five pigs were challenge-tested with a 15% spleen suspension (LD50). All unvaccinated pigs succumbed to ASF symptoms, while one out of three vaccinated pigs also died with clinical ASF symptoms. No specific ASF antibody responses were detected via ELISA. It was concluded that ASFV in this study was successfully inactivated using formaldehyde and Triton-X100, while non-inactivated ASFV effectively demonstrated pathogenicity through Koch's Postulates. Two of the three vaccinated pigs (67%) survived up to one month post-challenge, indicating partial vaccine success despite the absence of a humoral antibody response. This phenomenon suggests the presence of cellular immunity contributing to recovery. Further research is needed to optimize this vaccine using higher spleen concentrations (100%) and booster does.