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Feedback: Watch out for this sheep disease

Friday April 6 2018

Sheep grazing in a farm.

Sheep graze in a farm. A human host can carry the prion disease which affects sheep and goats for many years without showing any symptoms. FILE PHOTO | NMG 

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I am trying to find an answer on a very serious disease that is attacking goats and sheep mainly on their head. It makes the animal look like its mad.

On the early stages, the animal stops eating, raising its head high with ears erected and tail twisted many times. On full occurrence of the disease the animal makes sounds, stops eating, runs around, sometimes it looks like the back and the legs also get affected since it’s unable to move, and eventually dies.

The only thing we found when we slaughter the animal is a lot of fluid in the brain. We have gone to many vets and tried many medicines but still no cure for this disease. 

Daniel Mamai, Kajiado County

What you are describing has every symptom of prion disease, also called Transmissible Spongiform Encephalopathy, Scrapie, and/or Creuzfeldt Jacob’s Disease. It was first diagnosed in sheep in 1730.


The affected sheep scratched themselves on fences hence the name scrapie. This disease is very serious because it can be transmitted to humans and 100 per cent of the cases are fatal – for human and animal victims.

A human host can carry it for many years without showing any symptoms. However, when the symptoms begin to manifest, no intervention can save the victim. The disease has no cure.

Cause and transmission

Prion disease is complex. It can be transmitted through contact with an infected tissue/contaminated material, can occur spontaneously, and can also be inherited from a carrier parent.

It is caused by a prion protein, which is an abnormal protein in the brain tissue. Post mortem examination of the brain tissue reveals a spongiform matter, that is the brain looks like a mattress.

Eliminating it is not easy because the protein can withstand very high temperatures. For this reason, some countries like the UK requires by law that all animals older than 30 months destined for human consumption must be tested for prion disease.

Symptoms of prion disease

Symptoms usually begin by hyper-excitability where the victim may run around. This is followed by itching – the victim may scratch its body on fences.

The victim then starts to lose coordinated movement (becomes ataxic) followed by paralysis. Eventually, the victim succumbs. I’m using the term victim because it affects both humans and animals.

Control measures

First, resist any form of temptation to open the carcass of the dead animal because the disease is highly transmissible. You have correctly described that it spreads like bush fire.

Opening the carcass, especially the brain tissue exposes you to the risk of getting the disease.

Prion disease has very long incubation period, so, you may not know if you already have it. You only know that you have it when the symptoms begin to manifest, at which point it will be too late to do anything.

To be safe, ensure the following:

1. Eliminate all risk materials from the animal feed and human food chain. Ensure the healthy animals do not graze on contaminated pastures (could be on hay at the barn or out in the field where the post mortem was carried out).

2. Do not eat the meat recovered from the vertebral column of the victim because the prion protein is not destroyed through cooking temperatures.

3. Cull all the sick animals. Contact your vet to advice on the best elimination method.

4. All the devices used in the post mortem operations must be sterilised to avoid cross contamination. Post-mortem must be done by a qualified vet.

Kevine Otieno, Department of Dairy, Food Science & Technology,

Egerton University


I am Justine Ayub. I would like to grow sunflower and Canola. Help me to know if there is available market and how much per kilo? I come from Nyamira County but I would like to do my farming in either Nyamira or Nandi County.

You cannot lack market for canola and sunflower seeds. The price of sunflower seed is Sh30 per kilogramme.

An extension official explains a point on canola.

An extension official explains a point on canola. There is a huge market for canola and sunflower. FILE PHOTO | NMG

You can try Kieni Canola oil firm and for sunlower Ndeka virgin sunflower business or other oil manufacturing companies in Kenya.

Carol Mutua,
Department of Crops, Horticulture and Soils, Egerton University



I would like to grow garlic in Nyeri. When can I plant garlic and where can I buy seeds?

Mukami McCrum

The production of garlic is similar to that of onions, the only difference is that a top dress of nitrogen is needed when bulbing starts.

Make sure that harvesting coincides with the dry season. You can get garlic seedlings from Garlic and Pepino Farm contact them through 0723713642.

Carol Mutua, Department of Crops, Horticulture and Soils, Egerton University



Does the bone meal from the donkeys used in making animal feeds have the same protein percentage as fish meal like omena?

Bin Uweid Luqman, Mombasa

Meat and Bone Meal (MBM) is a product of the animal carcass rendering process. Calcium is 7 to 10 per cent and phosphorus 4.5 to 6 per cent thus a good mineral source. Protein is 50 per cent minimum compared to 50-60 per cent protein in omena.

Dennis Kigiri,
Department of Animal Sciences, Egerton University.



What causes black dairy cows to start changing colour to brownish?

Isaac Kimani, Murang’a

De-pigmentation of cattle occurs as grey/brown discolouration of the hair coat and is commonly classically associated with deficiency of copper.

The condition is most common in animals on pastures or home-grown feeds established on soils with deficient minerals.

Induced deficiency of copper can also be caused by ingestion of excessive molybdenum and sulphur in pasture or feed supplements.

Calves in a farm.

Calves in a farm. De-pigmentation of cattle occurs as grey/brown discolouration of the hair coat and is commonly classically associated with deficiency of copper. FILE PHOTO | NMG

In calves, poor growth rates, scouring and bone fractures are manifested while in cows, signs of weight loss, scouring, reduced milk yields and reproductive problems are most commonly seen during copper deficiency.

In general, supplementation is beneficial. Commercially available dietary trace mineral supplements can be added to feeds so that your cattle meet their required daily intake of copper diets.

Felix Akatch Opinya,
Department of Animal Sciences, Egerton University.


I live in Ongata Rongai. I am jobless and have been given a piece of land for farming, would you advice what type of fast moving crops to farm.

Elizabeth Kariuki, Nairobi

Thank you for your interest in farming. You can try red, yellow and green capsicums, onions, tomatoes, leaf amaranth, black nightshade, spider plant, beans, garlic, chia and herbs like rosemary, mint, coriander, parsley, dill.

Carol Mutua,
Department of Crops, Horticulture and Soils, Egerton University