Animal fever likely after heavy rain

Rain is always welcomed by farmers but floods could have a devastating consequences, especially for animals.

Scientists from North-West University have warned livestock farmers to be on the lookout for a possible outbreak of mosquito-borne Rift Valley fever (RVF) due to the recent rain in many parts of the country.

While the virus mainly affects animals – wild and domestic – South Africa has recorded a number of human deaths due to the fever – especially those who work closely with animals.

“Worst of all, RVF is zoonotic, meaning people can become infected, mainly by handling sick or dead animals, drinking raw milk from infected animals and/ or eating raw or undercooked meat,” said the scientists in a joint statement.

“We have suffered the loss of a state veterinarian to this disease in recent times and, over the years, other persons who worked with infected animals.”

RVF thrives under conditions that include flooding and where water pans formed and is carried by Aedes mosquitos which breed and multiplies in such conditions. It is transmitted from the infected female mosquito to its eggs and thus to future generations of these insects.

NWU professors Paul Lubout and Mulunda Mwanza said while sheep were the main sufferers, goats and cattle may be affected. Wild animals prone to it include buffalo, sable antelope, springbok, impala and blesbok.

It causes many abortions in livestock – 80% to 100% in sheep, and somewhat less in cattle, goats and wild animals – as well as deaths among young animals, particularly lambs. But infections are frequently subclinical or mild in older animals and the severity varies from species to species.

According to the scientists, RVF is a notifiable disease by law. A few localised outbreaks were reported – one in Jacobsdal, Free State, in May 2018 and others occurred at irregular intervals in different areas.

The last major outbreak was in 2010-11. “The only way to prevent the disease spreading is by vaccinating livestock and controlling the vector, the mosquito, using products registered for the control of mosquitos [usually dips, sprays and topical applications containing deltamethrin],” said Lubout and Mwanza.

Only way to prevent spread is by vaccinating livestock and controlling mosquitos with registered products.

Animal health professors North-West University