Rift Valley Fever has been confirmed at one farm in the Jacobsdal area in the Free State. So far, it is the only farm reported to be affected and further investigations are being carried out by the local veterinary services. Rift Valley Fever is caused by a virus carried by mosquitoes. It affects cattle, sheep and goats and causes abortions and deaths in especially young animals.
Humans can be infected with Rift Valley Fever if they come into contact with the blood and other body fluids of an infected animal or an aborted foetus. Care should be taken when handling possibly infected animals or carcasses of animals that have died of the disease.
Symptoms in humans are flu-like and some individuals can develop more serious complications. If a person suspects that they might have been infected with Rift Valley Fever, they must consult a doctor.
The reoccurrence of Rift Valley Fever is due to increased rainfall, which in turn causes an increase in mosquitoes. As this outbreak occurred in the beginning of the winter season, it will probably be an isolated incident as the cold weather will result in a decrease in the number of mosquitoes and therefore decrease the risk the disease spreading. It must be noted that the risk will increase at the start of the summer season.
This outbreak provides us with a useful warning that all cattle, sheep and goats have to be vaccinated to ensure that the level of immunity in the herds is high when the next summer season starts and the risk increases. Farmers are therefore advised to vaccinate their animals against Rift Valley Fever.
Live vaccines can only be used in non-pregnant animals as the live vaccine can cause abortions. Only dead (inactivated) vaccines must be used in pregnant animals. Please take care when vaccines are administered after outbreaks have been detected; Use a clean needle for each animal as the virus can be spread between animals if the animals are in the incubation period. Animals in the incubation period will have a virus infection but will not show symptoms of the disease yet.
Rift Valley Fever is a notifiable animal disease, but not a controlled animal disease, meaning that there are no prescribed control measures. The State Veterinary Services will give support and information to farmers in affected areas, but it is the responsibility of the animal owners to vaccinate their animals and prevent losses. Suspicion of disease must be immediately reported to the nearest State Veterinarian.
All livestock farmers in South Africa are advised to vaccinate all their cattle, sheep and goats yearly or at least once during weaning.
For more information, please contact your local State Veterinarian. The Gauteng Department of Agriculture State Veterinarian can be contacted on 011 240