Experimental Infection of Domestic Pigs () with Rift Valley Fever Virus.

Rift valley fever (RVF), caused by the RVF virus (RVFV), is a vector-borne zoonotic disease that primarily affects domestic ruminants. Abortion storms and neonatal deaths characterise the disease in animals. Humans develop flu-like symptoms, which can progress to severe disease.

Evaluation of Potency and Duration of Immunity Elicited by a Multivalent FMD Vaccine for Use in South Africa.

South Africa (SA) experiences sporadic foot and mouth disease (FMD) outbreaks irrespective of routine prophylactic vaccinations of cattle using imported commercial vaccines. The problem could be mitigated by preparation of vaccines from local virus strains related to those circulating in the endemically infected buffalo populations in the Kruger National Park (KNP). This study demonstrates the individual number of protective doses (PD) of five vaccine candidate strains after homologous virus challenge, as well as the vaccines safety and onset of humoral immunity in naïve cattle.

The Development of Dual Vaccines against Lumpy Skin Disease (LSD) and Bovine Ephemeral Fever (BEF).

Dual vaccines ( = 6) against both lumpy skin disease (LSD) and bovine ephemeral fever (BEF) were constructed, based on the BEFV glycoprotein (G) gene, with or without the BEFV matrix (M) protein gene, inserted into one of two different LSDV backbones, nLSDV∆SOD-UCT or nLSDVSODis-UCT. The inserted gene cassettes were confirmed by PCR; and BEFV protein was shown to be expressed by immunofluorescence. The candidate dual vaccines were initially tested in a rabbit model; neutralization assays using the South African BEFV vaccine (B-Phemeral) strain showed an African consensus G protein gene (Gb) to give superior neutralization compared to the Australian (Ga) gene.

Influence of the Viral Superoxide Dismutase (SOD) Homologue on Lumpy Skin Disease Virus (LSDV) Growth, Histopathology and Pathogenicity.

Lumpy skin disease is an important economic disease of cattle that is controlled by vaccination. This paper presents an investigation into the role of the lumpy skin disease virus (LSDV) superoxide dismutase (SOD) homologue on growth and histopathology of the virus both in vitro and in vivo. SOD homologue knock-out and knock-in recombinants (nLSDV∆SOD-UCT and nLSDVSODis-UCT, respectively) were constructed and compared to the Neethling vaccine (nLSDV) for growth in a permissive bovine cell line as well as on fertilized chick chorioallantoic membranes (CAMs).

Refined experimental design may increase the value of murine models for estimation of bluetongue virus virulence.

Bluetongue is a serious non-contagious vector-borne viral disease in ruminants, causing poor animal welfare and economic consequences globally. Concern has been raised about the development of novel bluetongue virus (BTV) strains and their possibly altered virulence through the process of viral reassortment. Virulence is traditionally estimated in lethal dose 50 (LD) studies in murine models, but agreement with both and virulence in ruminants is questionable, and a refined experimental design is needed.

Efficacy of a foot-and-mouth disease vaccine against a heterologous SAT1 virus challenge in goats.

Goats are susceptible to infection with foot-and-mouth disease virus (FMDV), but their role in the epidemiology of the disease and response to vaccination is poorly understood. In southern Africa, FMDV serotypes Southern African Territories (SAT) 1, 2 and 3 are known to be endemic. In this study, we evaluated the efficacy of a pentavalent FMD vaccine in goats against heterologous challenge with a pool of field SAT1 FMDV.

Pathogenesis, biophysical stability and phenotypic variance of SAT2 foot-and-mouth disease virus.

Foot-and-mouth disease (FMD) is a highly contagious vesicular disease of cloven-hoofed animals, which severely decreases livestock productivity. FMD virus (FMDV), the causative agent, initiates infection by interaction with integrin cellular receptors on pharyngeal epithelium cells, causing clinical signs one to four days after transmission to a susceptible host. However, some Southern African Territories (SAT) viruses have been reported to cause mild or subclinical infections that may go undiagnosed in field conditions and are likely to be more common than previously expected.

A novel method for performing antigenic vaccine matching for foot-and-mouth disease in absence of the homologous virus.

Foot-and-mouth-disease (FMD) is a highly contagious transboundary animal disease that has negative consequences on regional and international trade. Vaccination is an important approach for FMD control and an essential consideration is the degree of cross-protection conferred by the vaccine against currently circulating field viruses. The objective of this study was to evaluate a new vaccine matching technique that does not require knowledge concerning the homologous vaccine virus.

Intra-serotype SAT2 chimeric foot-and-mouth disease vaccine protects cattle against FMDV challenge.

The genetic diversity of the three Southern African Territories (SAT) types of foot-and-mouth disease virus (FMDV) reflects high antigenic variation, and indications are that vaccines targeting each SAT-specific topotype may be needed. This has serious implications for control of FMD using vaccines as well as the choice of strains to include in regional antigen banks. Here, we investigated an intra-serotype chimeric virus, vSAT2(ZIM14)-SAT2, which was engineered by replacing the surface-exposed capsid-coding region (1B-1D/2A) of a SAT2 genome-length clone, pSAT2, with that of the field isolate, SAT2/ZIM/14/90.

Vaccine Potential of Two Previously Uncharacterized African Swine Fever Virus Isolates from Southern Africa and Heterologous Cross Protection of an Avirulent European Isolate.

African swine fever (ASF) is a mostly fatal viral infection of domestic pigs for which there is no vaccine available. The disease is endemic to most of sub-Saharan Africa, causes severe losses and threatens food security in large parts of the continent. Naturally occurring attenuated ASF viruses have been tested as vaccine candidates, but protection was variable depending on the challenge virus.

Transplacental infection in goats experimentally infected with a European strain of bluetongue virus serotype 8.

The capability of the recently emerged European strain of bluetongue virus serotype 8 (BTV-8) to cross the ruminant placenta has been established in experimental and field studies in both sheep and cattle. Seroprevalence rates in goats in North-Western Europe were high during the recent outbreak of BTV-8; however the capability of the virus to infect goats through the transplacental route has not been established. In the present study, four Saanen goats were inoculated with the European strain of BTV-8 at 62 days of gestation; this resulted in mild clinical signs, however gross lesions observed post mortem were more severe.

Foot-and-mouth disease marker vaccine: cattle protection with a partial VP1 G-H loop deleted virus antigen.

Contrary to the dogma that the VP1 G-H loop is essential for FMD vaccine efficacy, it has been previously shown that foot-and-mouth disease 146s antigen containing heterologous VP1 G-H loops confers complete protection in pigs and cattle. Moreover, serological evaluation of cattle vaccinated with an antigen lacking a large proportion of the VP1 G-H loop indicated that these animals should be protected against infection with FMD. Absence of this loop provides opportunity for the development of an FMD negative marker vaccine, allowing infection to be detected by antibodies against this missing region.