State veterinary services, private veterinarians and the department of forestry fisheries and the environment were involved in field investigations. Postmortems were performed and samples were collected to confirm the cause of the deaths. Diagnostic tests were performed at the Onderstepoort Veterinary Research Laboratory and the reason was confirmed as RHD.
RHD is a disease caused by a virus (Calicivirus) and this is the first detection of the disease in South Africa. The disease results in a high number of deaths in rabbits and hares and animals die suddenly with bleeding in the organs such as the liver, kidney and spleen.
At this stage, it is still unclear how the disease could have entered the country since the importation of rabbits and hares is not allowed.
Investigations are underway to determine whether illegal importation could be the source.
Control of RHD in rabbitries relies mainly on vaccination, but the vaccine is not available in South Africa. This increases the importance of biosecurity measures in rabbitries and anywhere where rabbits or hares are kept. Rabbit owners are advised to ensure that their rabbits are secured and must prevent any contact with other rabbits or hares, either directly or indirectly through people or equipment.
Biosecurity measures are difficult to implement in wild populations. The occurrence of RHD in the Karoo is therefore of great concern, as South Africa's indigenous Red Rock rabbit, endangered Riverine rabbit and hare species are highly susceptible to this disease.
Carcasses of RHD-infected rabbits may be a significant source for viral spreading, since the virus seems to be highly resistant and stable, even when exposed to harsh environmental conditions.
Members of the public are encouraged to report any dead or dying rabbits or hares to the nearest state veterinarian for investigation.