While many farmers across the country remain focused on the devastating impact of foot-and-mouth disease (FMD), livestock producers are being urged not to lose sight of another serious and highly disruptive threat, Rift Valley Fever (RVF).

By Lebogang Mashala, editor at African Farming

The Beefmaster Group has issued a strong warning for farmers to take proactive measures against RVF, a preventable mosquito-borne viral disease that affects livestock and can also infect people. Left unmanaged, the disease can derail an entire breeding season and inflict significant financial losses.

The warning comes as heavy summer rains drive up mosquito populations across parts of South Africa. Adding to the concern, an outbreak of RVF was reported among livestock in the Northern Cape in late 2025, a reminder of how quickly the disease can resurface under favourable climatic conditions.

“RVF is a classic ‘after the rains’ disease,” said Thapelo Kgosi “King” Ramokala, Animal Health Specialist at Beefmaster Group. “Sheep are typically hit hardest, and young animals and pregnant females are most vulnerable. Farmers may see sudden deaths in lambs and calves, or a spike in abortions within a short window, red flags that demand immediate action.”

Also read: Rift Valley Fever: Outbreak prevention lies in cattle farmers’ hands

Know The Signs, Act Fast

Mosquitoes are the primary drivers of RVF transmission following wet spells, but infection can also occur through direct contact with infected blood or organs.

In adult livestock, symptoms may include fever, weakness, loss of appetite, nasal discharge and diarrhoea. Abortions in pregnant animals are a key warning sign. In young animals, the disease can cause sudden death, often with little or no prior indication of illness.

“Diagnosis cannot be made by sight alone,” Ramokala stressed. “If RVF is suspected, stop animal movements immediately and contact your veterinarian or state veterinary services. Laboratory testing of blood samples is required to confirm the disease.”

Also read: Rift Valley fever is deadly for humans and animals; vaccinate now

Human Health Risk

RVF is also a zoonotic disease, meaning it can infect people. However, Ramokala emphasised that it does not spread through casual contact with animals.

“Farmers and workers are most at risk when assisting births, slaughtering sick animals or handling carcasses without proper protection,” he explained.

In humans, most cases present with flu-like symptoms such as fever, headaches, muscle and joint pain, and fatigue. In rare instances, severe complications affecting the eyes, liver, or bleeding, and clotting systems may develop.

Prevention Starts Before The Rains

Vaccination remains the most effective tool for protecting livestock, but timing is critical.

“Where possible, vaccinate ahead of the rainy season and always under veterinary guidance, as some vaccines are not safe in early pregnancy,” Ramokala advised.

Mosquito control is equally important. Farmers are encouraged to reduce standing water, use approved insect control products, and limit grazing in wet or marshy areas during high-risk periods.

Also read: Biosecurity measures: You cannot be careful enough

Biosecurity Can Save Herds, And Livelihoods

Separating sick animals from healthy stock, restricting animal movements during outbreaks, and safely disposing of aborted material and carcasses are essential measures.

Ramokala advised:

Clean hands, clothing and equipment after handling animals.
Wear gloves and protective clothing when assisting with calvings or abortions.
Do not slaughter sick animals.
Cook meat thoroughly and avoid consuming raw milk during outbreaks.

The financial stakes are high. Deaths and abortions shrink herd numbers, milk and meat output decline, and movement or trade restrictions can further strain farm businesses.

“One outbreak can wipe out a breeding season,” Ramokala cautioned. “But RVF can be prevented and managed if we act early, by reporting suspect cases, vaccinating at the right time, controlling mosquitoes and educating workers and communities.”

As farmers navigate ongoing animal health challenges, vigilance against Rift Valley Fever may prove just as critical as the fight against FMD, especially in a season shaped by heavy rains and heightened risk.