Besides rising feed costs, the disease challenge poses a menacing threat to livestock farming. An example of such a disease is East Coast Fever (ECF), a cattle tick-borne disease that has left a trail of destruction and losses at the farm. This tide is however changing as a vaccine has been found against this killer disease.
According to Dr Monica Maichomo, a Senior Research Scientist and Director at the Veterinary Research Institute at Kenya Agriculture and Livestock Research Organization (KALRO) in Muguga, ECF ranks among the most devastating diseases of livestock. When left untreated, the disease causes high mortality in naive cattle, especially calves.
What is East Coat Fever?
The brown ear tick (Rhipicephalus species) is responsible for transferring ECF in cattle. The tick prefers areas around the ears and under the tail.
She noted that ECF is caused by a protozoal parasite called Theileria parva parva, which invades the lymph nodes.
Mode of spread
“East Coast Fever is transmitted from cattle to cattle by the Brown Ear Tick.
Incubation varies between 9 to 18 days, most commonly 14 to 16 days after exposure to infective ticks,” added Dr Moses Olum, a Research Scientist at the Veterinary Research Institute.
Common signs of East Coast Fever
Dr Olum highlighted that, following exposure to infected ticks, the lymph nodes below the ear become enlarged 12 to 18 days after attachment of the tick, and a fever develops a few days later which can be up to 41 – 420 Celsius. There is a significant decrease in milk yields, appetite decreases and then body condition declines.
There is fluid in the lungs and pneumonia occurs. The animal breathes increasingly rapidly and with increasing distress. It starts to cough, especially if made to move and nasal discharge develops.
Moreover, the eyes often appear milky or blue and there may be shedding of tears, often there is diarrhoea which can be blood-stained.
Finally, muscle wasting develops and the animal collapses and dies, usually about 20 to 28 days after the tick attaches to the cow.
About the vaccine
According to Dr Olum, KALRO has come up with a live vaccine for ECF which uses the infection and treatment method of immunization to administer. The antibiotic used is a long-acting Oxytetracycline. This inhibits the development of the parasite when given at the onset of infection.
That the vaccine is live means that when the vaccine is not handled properly, the animals can come down with this disease.
It is for this reason that KALRO has partnered with county governments to train veterinary surgeons and animal health assistants as vaccinators on how to do the job right. So far 10 counties have benefited from this training. More than 600 animal service providers have been trained and over 3 million heads of cattle vaccinated.
Benefits of the vaccine
According to Dr Maichomo, the vaccine confers protection against ECF for a lifetime. Calves under one month and pregnant cows in the first trimester are not to be vaccinated. Additionally, the cost of vaccinating a calf is about Sh600 while that of an adult cow is about Sh1,500. In contrast, available curative drugs are very expensive and the cost of treatment for ECF is between Ksh 4,000 and 6,000.
[The writer is a Veterinary Surgeon and the Resident Vet at Farmkenya]