African Horse Sickness Fever in Vaccinated Horses: Short Communication.

The research article discusses an investigation into the effectiveness of existing vaccinations for African horse sickness (AHS) in protecting horses from the disease. The study found that while the vaccination protected against AHS, a mild form of the disease known as African horse sickness fever (AHSF) still developed in around 10% of vaccinated horses.

Investigating the Efficacy of Multiple Vaccinations

• The researchers examined the impacts of multiple vaccinations with inactivated African horse sickness vaccines in horses.
• The vaccines contained all nine serotypes of the disease and were produced at the Central Veterinary Research Laboratory in Dubai, UAE.
• The main aim of the study was to determine the level of protection these vaccines offer against AHS.

Results of Vaccination

• The study found that despite vaccination, around 10% of the horses still developed AHSF. This suggests that the vaccines were not completely successful in eliminating all forms of the disease.
• In tests conducted on the horses that developed AHSF, no virus was found in the EDTA blood drawn during the acute phase of infection.

Neutralizing Antibodies and Virus Detection

• Despite the presence of high levels of neutralizing antibodies, the serotype 9 virus was still detected by polymerase chain reaction (PCR) in four of the six horses that developed AHSF.
• This suggests that although the vaccines were able to stimulate the production of antibodies, they were not entirely effective in preventing infection.

Recovery from AHSF

• The study reports that all six horses recovered from AHSF within 72 hours of mild clinical signs of AHS being detected.
• This indicates that AHSF, while not completely preventable by existing vaccinations, is a less severe form of AHS and can be overcome by the horses’ immune systems relatively quickly.