Common Sheep Diseases in South Africa: Signs, Prevention and Control

Sheep diseases cost South African farmers more than most of them realise. A few deaths from pulpy kidney after a move to green lands, a bad wireworm season that leaves the lambs pale and stunted, an outbreak of bluetongue after good rains: each one eats into a year’s profit, and most of them can be prevented with a sound vaccination programme, good parasite control and a sharp eye in the camps.

This guide covers the most common sheep diseases in South Africa: what causes them, the signs to look for, and how to prevent them. It is written to help you recognise problems early and plan your health programme, not to replace your vet. Every farm is different, so work out your vaccination and dosing programme with a veterinarian who knows your area.

Common Sheep Diseases at a Glance

1. Wireworm: The Biggest Parasite Problem

Wireworm (Haemonchus contortus) is one of the most damaging sheep diseases in the summer-rainfall areas of South Africa. According to Farmer’s Weekly, the worm uses a small tooth to cut the wall of the sheep’s fourth stomach and feeds on the blood that is released. Heavy infections cause anaemia, poor growth and death.

Signs: pale gums and eyelids, weakness, lagging behind the flock, and “bottle jaw”, a soft swelling under the jaw. Lambs and ewes around lambing are most at risk, especially in warm, wet months.

Prevention and control: resistance to dewormers is a serious and growing problem, so dosing the whole flock on a fixed calendar is no longer a good idea. The FAMACHA system, developed by South African scientists Francois Malan, Gareth Bath and Jan van Wyk, uses a colour card to check the inner eyelid for anaemia, so that you only treat the sheep that need it. This keeps worms that have not been exposed to the drug in the flock, which slows down resistance. Farmer’s Weekly notes that a trained team can check up to 500 sheep an hour.

Rotate camps where you can, avoid overgrazing, and ask your vet for faecal egg counts to check whether your dewormers still work.

2. Pulpy Kidney and Other Clostridial Diseases

Pulpy kidney, also called overeating disease, is caused by a toxin produced by Clostridium perfringens type D, a bacterium that normally lives in the sheep’s gut. According to a veterinary article on AgriOrbit, it is usually triggered when sheep move suddenly from poor grazing to rich feed such as lucerne, green wheat or oats, or onto a high-protein ration. The bacteria multiply rapidly and release a toxin that can kill within hours. Our guide to feeding sheep explains how to change rations safely.

Signs: often there are none: the first sign is a dead lamb, usually one of the best in the flock. Some animals show depression, teeth grinding, staggering or mild diarrhoea before they die. Lambs from about three weeks to three months old, and young sheep of six to twelve months, are most at risk.

Pulpy kidney is one of a group of clostridial sheep diseases, including lamb dysentery, blackleg, tetanus, malignant oedema and black disease. The bacteria form spores that survive in the soil for years, and almost all cases are fatal once signs appear.

Prevention: vaccination is the answer. A guide on clostridial diseases published by the Meatmaster Sheep Breeders’ Society recommends:

• two doses about six weeks apart for lambs and unvaccinated adults, with immunity developing about 14 days after the second dose;
• a booster for ewes two to six weeks before lambing, so that lambs are protected through the colostrum for their first weeks;
• an annual booster, as protection lasts about a year.

Change diets gradually, especially when moving sheep onto planted pastures or feedlot rations.

3. Bluetongue

Bluetongue is one of the most important viral sheep diseases in South Africa. It is spread by tiny Culicoides midges, which breed in warm, moist conditions. In South Africa it mainly affects sheep and is most common in late summer and autumn, especially after good rains.

Signs: according to Farmer’s Weekly, affected sheep develop a fever, lose their appetite and become lethargic. The lips, mouth and tongue swell and may turn red, blue or purple, and sore feet can make sheep reluctant to walk or graze. Some sheep hold their necks twisted.

Prevention: vaccinate before the midge season. Farmer’s Weekly advises that ewes should be vaccinated at least three weeks before the mating season or straight after winter lambing, and rams two months before or after mating. Our sheep breeding guide includes a full checklist for preparing ewes and rams. Lambs get some protection from colostrum and are ideally vaccinated from about six months. Follow the vaccine instructions and your vet’s advice carefully, especially for pregnant ewes. During outbreaks, move sick sheep to shade with water and soft green feed, and handle them as little as possible.

4. Heartwater

Heartwater is a tick-borne disease spread by the bont tick (Amblyomma hebraeum), which is found mainly in the bushveld and eastern parts of the country. It affects sheep, goats and cattle and is often fatal. For how it shows in other livestock, see our guides to goat diseases in South Africa and cattle diseases in South Africa.

Signs: a high fever of 40°C or more, followed by nervous signs such as high stepping, walking into fences, circling, chewing movements, and finally convulsions with paddling legs, according to Farmer’s Weekly, citing the ARC-Onderstepoort Veterinary Institute. The name comes from the fluid often found around the heart at post-mortem.

Treatment and prevention: speed is everything. Sheep treated early with an oxytetracycline product have a much better chance of recovery. In areas where heartwater is established, vaccination combined with sensible tick control is usually the best long-term approach. Ask your vet what works in your district.

5. Footrot

Footrot is caused by the bacterium Dichelobacter nodosus, working together with other bacteria, and thrives in wet, muddy conditions. It is a particular problem after heavy rain, on irrigated pastures and in poorly drained pens.

Signs: lameness, a strong rotten smell from the hoof, red and moist skin between the toes, a greyish discharge, and in severe cases sheep grazing on their knees.

Treatment and prevention: according to a veterinarian quoted by Farmer’s Weekly in May 2026:

• trim overgrown hooves, and disinfect your tools between sheep;
• use footbaths of 10% zinc sulphate or 5% formalin weekly, or at most every ten days, letting sheep stand in them for one to two minutes and then on dry concrete;
• treat severe cases with antibiotics prescribed by your vet;
• keep pens and walkways dry, and quarantine and inspect new sheep;
• cull sheep that are infected twice or more, as they are likely carriers.

6. Sheep Scab: A Controlled Disease

Sheep scab is caused by the Psoroptes ovis mite and has been controlled by law in South Africa for centuries. Under the Animal Diseases Act, it is a controlled disease with specific legal obligations for every sheep owner, as explained by AgriOrbit:

• you must report any suspected case to your state veterinarian, including any skin condition with itching, tangled wool or bare, scabby patches;
• infected and in-contact sheep must be treated twice with an effective remedy, between seven and ten days apart;
• newly bought sheep must be treated twice before they mix with the rest of the flock;
• sheep under quarantine may not be moved without the state vet’s permission.

Ignoring sheep scab is not only costly; it is against the law.

7. Rift Valley Fever and Other Sheep Diseases After Good Rains

Rift Valley fever is a mosquito-borne viral disease that flares up after heavy rains and flooding. It causes abortion storms in pregnant ewes and high deaths in young lambs, and it can also infect people who handle infected animals, blood or meat, so take care with sick animals and aborted foetuses.

Vets in South Africa stress timely vaccination against insect-borne diseases before the risk peaks. In a Farmer’s Weekly report, veterinarian Danie Odendaal pointed out that vaccinating already infected animals is of no use, recommended inactivated vaccines for pregnant animals to avoid abortions, and advised vaccinating all replacement animals when they arrive on the farm.

Depending on your area, your vet may also recommend vaccines against enzootic abortion and pasteurella pneumonia.

Preventing Sheep Diseases: A Simple Health Programme

The best way to avoid losses from sheep diseases is to plan ahead. A basic programme for most South African sheep farms includes:

• Clostridial vaccines for all sheep, with ewes boosted before lambing.
• Bluetongue and Rift Valley fever vaccines timed before the rainy season, following your vet’s advice on pregnant ewes.
• Selective deworming using regular FAMACHA checks during the high-risk season, and faecal egg counts to check that your remedies still work.
• Tick and external parasite control suited to your area, especially where heartwater occurs.
• Hoof care before and during the wet season.
• Quarantine for new sheep, including two scab treatments before they join the flock.
• Records of every vaccination, treatment and death, so you can spot patterns.

For breed-specific management, see our guides to Dorper sheep farming and Meatmaster sheep. Hardy breeds such as the Meatmaster and Dorper usually cope better with parasites and harsh conditions, but no breed is immune.

Keeping Sheep Diseases Off Your Farm When You Buy

Many disease problems arrive on a farm with newly bought sheep. Buy from flocks with a known health history, ask for vaccination and dosing records, check for lameness, skin problems and pale eyelids before you load, and keep new arrivals apart for a few weeks before they join your flock. Our guide to buying livestock in South Africa covers each step.

Frequently Asked Questions

What are the most common sheep diseases in South Africa?

Wireworm, pulpy kidney and other clostridial diseases, bluetongue, heartwater, footrot, sheep scab and Rift Valley fever are among the most important, depending on the region and season.

What causes sudden death in lambs?

Pulpy kidney is one of the most common causes of sudden death in well-fed lambs, often after a change to rich grazing or feed. Other clostridial diseases, heartwater and severe wireworm infections can also kill quickly. Ask your vet to do a post-mortem to confirm the cause.

How do I know if my sheep have wireworm?

Check the inner eyelids with a FAMACHA card. Pale or white eyelids, weakness and bottle jaw are signs of anaemia caused by wireworm. Treat the anaemic sheep and ask your vet about faecal egg counts.

When should I vaccinate my sheep against bluetongue?

Before the midge season in late summer. Farmer’s Weekly advises vaccinating ewes at least three weeks before mating or straight after winter lambing, and rams two months before or after mating. Check the vaccine instructions and your vet’s advice for pregnant ewes.

How do I prevent pulpy kidney?

Vaccinate all sheep against clostridial diseases, boost ewes two to six weeks before lambing, and change diets gradually when moving sheep onto rich pastures or rations.

Do I have to report sheep scab?

Yes. Sheep scab is a controlled disease under the Animal Diseases Act. You must report suspected cases to your state veterinarian and follow the official treatment and movement rules.

Can people catch diseases from sheep?

Some, yes. Rift Valley fever can infect people who handle infected animals, blood or meat. Wear gloves when handling aborted foetuses or sick animals, and contact a doctor if you develop flu-like symptoms after an outbreak.

Final Thoughts

Most sheep diseases are cheaper to prevent than to treat. A good vaccination programme, smart parasite control, dry pens, quarantine for new sheep and a vet who knows your area will save you far more than they cost. Start with healthy, well-adapted sheep and you are already halfway there. If you are building or expanding a flock, have a look at our Dorper sheep and Meatmaster sheep for sale, or send us your requirements and we will get back to you with a written quote, including delivery to your farm.