Export protocols may soon change

SOUTH Africa is a step closer to breaking the shackles governing the direct export of horses from this country.

There have been three significant developments in African Horse Sickness (AHS) research that will assist in the development of protocols for direct exports of horses from South Africa.

A recent study by the Equine Research Centre (ERC),where samples collected between 2004 and 2014 were analysed, has revealed that AHS outbreaks in the AHS Controlled Area of the Western Cape Province were caused by transmission of AHS vaccine derived viruses.

Vaccination period

These findings led to a restricted vaccination period in the AHS Controlled Area and the strong recommendation that horse owners vaccinate their horses between 1 June and 31 October each year in the rest of the country.

There have also been advances in diagnostics using the RT-PCR test that means that cases of AHS can be confirmed within four hours of samples being submitted.

Previously confirmation took at least two weeks.

The World Organisation for Animal Health (OIE) and the European Union (EU) have incorporated this test into documentation which has been proposed for ratification, a process that is currently underway.

Risk management

Finally an AusVet Risk Assessment confirmed the likelihood of undetected AHS infection in horses exported from South Africa can be reduced to miniscule by appropriate risk management measures, giving confidence to trading partners to re-examine quarantine procedures, which should boost the export market.

The next goal is to raise around six million Euro towards the trials and commercial development of a new generation AHS vaccine.

It is anticipated that with the latest scientific information and the validation of diagnostic testing in-hand, South African horses can be safely exported all around the world while fundraising takes place for the longer term goal of developing a new AHS vaccine.

Infected equines

It had long been believed that illegal movement of infected equines into the AHS Controlled Area was the most probable source for the repeated outbreaks of AHS in the area, but a study has proven that this is not the case. Data from this study shows that use of polyvalent (many types included) AHSV-LAV (AHS virus -live attenuated vaccine) can result in emergence and spread of virulent viruses to resident susceptible horses.

These findings are consistent for other modified live virus vaccines and this has major implications for strategies to control AHS.

This does not mean that the vaccine is harmful.

The vaccine provides excellent protection if used correctly and should be administered to horses older than six months from 1 June to 31 October each year.

Mortality rate

Without vaccination, the mortality rate due to African horse sickness infection can rise to 90%. Without the current AHS vaccine, South Africa would not have a horse industry and there would be no possibility at all of export.

According to Professor Alan Guthrie of the ERC, based at the Faculty of Veterinary Science, Onderstepoort, University of Pretoria, “The concept that horses cannot be worked at all through the vaccination period is pure fallacy. Horses that are having their first vaccinations (such as young stock or imported horses) need to be monitored and not overly-stressed through this period. But the standard practise of leaving horses, or even working them lightly, is not necessary in veterans of the vaccine.”

According to Professor Guthrie, “The OIE (World Organisation for Animal Health) is in the process of adopting the ERC RT-PCR test to its protocol for RT-PCR testing, and it is scheduled to be adopted by the European Union on its list of approved tests.” This is an incredible achievement from a local research facility with minimal financial support.