Rift Valley Fever on the rise

By Dr. Ananya Mandal, MDMar 29 2010

Rift Valley fever (RVF) is a viral infection transmitted by mosquitoes that mainly affects animals and livestock but may also infect humans. It can lead to high rates of death and disease. While mild forms of the disease can cause fever, muscle and joint pains, headaches, loss of appetite etc., the severe form can affect the eyes, cause meningitis, severe bleeding and even death.

There is a rising number of people in an around Western Cape affected by this virus. 63 South Africans have been reported to be affected as revealed by the Department of Health. Two deaths have also been reported from Free State. Nearly 50,000 livestock are already said to be infected. RVF episodes cropped up last month with the first human case reported on 13^th February. All cases in humans are believed to be due to contact with infected animals.

Farmers and have been since then concerned about the effects it will have on wool and meat production.

The provinces affected most till now include the borders of Western Cape namely the Northern Cape and Eastern Cape, and the Free State. Now, there is growing concern about the virus spreading to the Western Cape.

The provincial Department of Agriculture's deputy director for animal health, Pieter Koen, said that they only expected results within a few days because the national diagnostics lab was so busy. "They receive hundreds of requests every day," he said.

John Durr, chairman of the Red Meat Producers' Organization in the Western Cape, said that considering the impact the virus had had in other provinces, farmers were very worried that it would spread. "At this stage, there's nothing we can do; it's in the hand of the state," he said. "We understand that they're implementing a number of measures to prevent the spread, but it's definitely a concern for us in the near future."

Koen also expressed concern if the disease spread to the Western Cape. "The best we can do is try to vaccinate animals in advance to lessen the impact," he said. The department's chief director of veterinary services, Gininda Msiza, said they had already vaccinated 10 000 animals and expected 35 000 more doses to be issued soon. Both Koen and Mziza agree that the task of protecting all livestock in difficult since this disease is spread by mosquitoes that can travel far very rapidly. Areas like Karoo are considered high risk due to ideal RVF spread conditions like heavy rains, lower areas and more number of livestock. These areas are targets for vaccinations.

Agri SA president Johannes Möller however had reassuring words to say that, "the May frosts should help the virus die off".

Möller said that because the virus did not occur regularly in South Africa - the last major outbreak was between 1974 and 1976 - "it usually catches us unawares, because South Africa is normally too dry for the virus to survive". "Even though it is spreading, it is not a major national threat and we should be able to contain it within two or three weeks,". However, he said, the virus does "spread like wildfire once it starts", and because it's not a major threat in South Africa, the government-run Onderstepoort Veterinary Institute "won't have adequate vaccine reserves . So we will have to import vaccines, and that will take a while . .. but winter will save us. "

Dr Phemelo Kegakilwe, senior manager of veterinary services in the Northern Cape, said their department has ordered vaccines and that farmers will be able to borrow vaccines and replace the stocks when they are available.