Evaluation of novel inactivated vaccines for the SAT 1, SAT 2 and SAT 3 serotypes of foot-and-mouth disease in pigs

Abstract

BackgroundThe foot-and-mouth disease (FMD) virus is classified into seven serotypes, of which the South African types have South African Territories (SAT)1, SAT2, and SAT3 that are prevalent in Africa. Especially SAT2 have spread to Arabian Peninsula and the Palestinian Autonomous Territories. Of these viruses, the incidence of SAT2 is the highest. It is important to prepare for the spread of the virus to other continents, even though most FMD viruses are bovine-derived. In particular, due to the high breeding density of pigs in Asia, more attention is usually paid to the immunity and protection of pigs than cattle. For this reason, this study investigated the immunity and protection of pigs against the SAT viruses.MethodsSpecific vaccines were developed for SAT1, SAT2, and SAT3 serotypes. These vaccine viruses were designed to be distinguished from the wild-type strain. An immunogenicity test was conducted using these vaccines in both cattle (n = 5/group) and pigs (n = 20/group).ResultsHigh virus-neutralizing titer of antibodies (> 1:100) was induced in only 2 weeks after the immunization of cattle with the individual vaccine for SAT1, SAT2 or SAT3, and a clear immune response was induced after the second immunization in pigs. When the vaccinated pigs (n = 4–5/group) were challenged by the homologous wild-type virus strain 4 weeks after immunization, all the pigs were protected from the challenge.ConclusionsThis study confirmed that these vaccines can be used against SAT1, SAT2, and SAT3 viruses in cattle and pigs. The vaccine strains developed in this study are expected to be used as vaccines that can protect against FMD in the event of a future FMD outbreak in pigs in consideration of the situation in Asia.

Calcium Chloride Treatment Enhances Antigen Production in Foot-and-Mouth Disease Vaccines for Serotypes SAT1 and SAT3

“…SAT1 BOT and SAT3 ZIM, which were used in this study, have been previously shown to provide viral defense in pigs, in addition to immunotypic performance in pigs and cattle [ 9 ]. In addition to the results showing that calcium treatment improved the stability of the physically unstable type O FMDV, we also have data showing that the immunogenicity in pigs of the calcium-treated and untreated experimental groups for type O FMDV was the same, indicating that the calcium treatment did not exert any negative effect on the vaccine-induced immunogenicity in pigs.…”

“…Calcium chloride was purchased from Sigma-Aldrich (St. Louis, MO, USA), dissolved in distilled water, and used after preparing a 300 mM stock. FMDV SAT1 BOT and SAT3 ZIM were isolated from the infectious clones, as previously described [ 9 ]. FMDV infection and culture were performed at APQA’s biosafety level 3 facility.…”

“…Effective FMD vaccines should elicit potent immune and antigenic responses similar to those with locally circulating FMDV [ 5 ]. Several affected countries, including South Korea, are developing region-specific FMD vaccine strains to address local contexts [ 6 , 7 , 8 , 9 , 10 , 11 ]. FMD vaccine strain research has explored virus strains in cattle, buffalo, goats, and pigs capable of mass production in baby hamster kidney (BHK-21) cells [ 12 ].…”

Chimeric Porcine Parvovirus VP2 Virus-like Particles with Epitopes of South African Serotype 2 Foot-and-Mouth Disease Virus Elicits Specific Humoral and Cellular Responses in Mice

“…The reports of the World Organization for Animal Health/ Food and Agriculture Organization of the United Nations (WOAH/FAO) Foot-and-Mouth Disease Reference Laboratory Network noted the presence of FMD in North Yemen (1990), Saudi Arabia (2000), KwaZulu-Natal, South Africa (2001), Libya (2003), Bahrain, and Egypt (2012), and more recently in Mauritania, Botswana, Zimbabwe, Nigeria, Kenya, and Ethiopia (2015–2017) [ 4 ]. SAT2 FMDV has spread to Arabian Peninsula and the Palestinian Autonomous Territories [ 5 ]. There have been outbreaks in the Middle East and Africa in the last two years, including SAT 2 outbreaks in provinces of KwaZulu-Natal and Free State [ 6 ]; the most recent outbreak occurred in Zarqa of Jordan or in Iraq in 2023 [ 7 ].…”