Vet explains a deadly disease caused by ticks in goats and how it can be treated to save the animals
About two months ago, Isaac who rears goats in Kitengela came to my office in Nairobi with three goats in his covered pick-up truck. He found me at the reception just finishing off with another client.
Isaac looked disturbed and eager to have his case attended to. “My goats have been dying in the last two months and treatment does not appear to help,” he told me. He further wondered why he kept getting strange cases on his farm.
I recalled the last time Isaac had visited me he had some chicken that were unable to stand though they generally looked fine. I diagnosed them with severe roundworm infestation in the intestines and two of them died after treatment.
The worms were so many that they caused intestinal blockage, when they were killed by the medicine. However, the rest of the chicken recovered.
Isaac is still new to livestock farming and he has yet to learn a lot. I assured him the problem in the goats was unlikely to have anything to do with the worms in the chicken but I would thoroughly interrogate any possible linkage.
At his car, Isaac gave me the full history of the disease in his goats. He had 100 Small East African breed goats of various ages on his farm.
He had bought most of the animals from other areas of Kajiado County to ensure there was minimal change in the animals’ environmental conditions.
Around June this year, he bought five male Gala bucks from Isiolo aiming to improve the average body size of his goats. However, in July some of the goats started getting sick.
It started with two goats which showed poor appetite, weakness and getting startled by loud noise. One of the goats died soon after showing poor appetite while the other one started going round in circles before dying.
None of the goats from Isiolo was affected. The first two goats died without treatment and Isaac did not get a doctor to carry out post-mortem examination.
One of his friends, who also keeps goats, told him the animals sometimes die of strange illnesses but he could stay without losing another goat for a long time.
His friend’s advice did not hold and within two weeks, three other goats showed similar symptoms.
The goats were treated but they also died. One of the goats had stiff legs and would sometimes topple over and keep pedalling the legs as though riding an imaginary bicycle.
The three goats in the car started showing signs similar to the others two days before. Isaac decided to bring them for a second opinion. I examined the goats and confirmed the signs of disease as Isaac had described.
In addition, one of the goats had diarrhoea. All the goats had elevated body temperature or fever and higher than normal breathing rates. One goat had muffled heart sounds.
One of the goats lay on the side, kept pedalling and would get startled on being touched or when I tapped the floor of the car.
From the disease history Isaac gave and my clinical examination, I knew his chickens were innocent. “Isaac, this is a bacterial disease called heartwater or Ondiri disease,” I told him after concluding the examination.
I treated the goats with antibiotics both directly into the blood through the jugular vein and also into the muscles.
I cautioned Isaac that the goat that was unable to stand would most likely succumb.
It was nonetheless advisable to treat the animals as some cases could still recover at that stage.
Heartwater derives its name from the accumulation of fluid it causes in the pericardial sac surrounding the heart.
The fluid prevents a doctor from clearly hearing the heart beat sounds using a stethoscope.
The illness is also called Ondiri disease because the first case in Kenya was diagnosed around the Ondiri Swamp in Kikuyu.
The disease is spread by the Amblyoma species of ticks. It is caused by a bacterium known as Rickettsia ruminantium. Immature and adult ticks are infected with the bacteria when they feed on infected or carrier animals.
CAUSES SEVERE DAMAGE
They inject the germs into healthy animals when they attach on the skin to feed.
Heartwater is widely spread in Africa but the Amblyoma tick may be found in areas where the disease organisms are not present. Animals that recover naturally from the disease become carriers of the bacteria.
This may explain why Isaac’s goats from Isiolo were not affected by the disease. Animals from areas where the disease is present are also more resistant to the infection than those from clean areas. They may carry the bacteria in their bodies without developing the disease.
The disease affects cattle, sheep, goats and some wild ruminants such as deer and other antelopes.
In addition to the disease pattern seen on Isaac’s farm, animals may also die suddenly without exhibiting signs of heartwater. This happens when the infection causes severe damage to the heart.
Some animals may also show coughing, pressing of the head against objects due to swelling of the brain, bleeding in the gums and abortions.
To effectively control heartwater, farmers should treat their animals against ticks with chemicals once per week.
They should also promptly detect signs of illness and report to veterinary doctors for immediate treatment. Animals from infected areas should be given preventive antibiotic treatment before being mixed with others.
I gave all the goats on Isaac’s farm preventive antibiotic treatment since laboratory screening of the whole herd would be too expensive for him.
Isaac also started washing his goats once a week with acaricides. Two of the sick goats recovered but the one that was pedalling died. No other case of heartwater has appeared on the farm.