This archive report was first published on 10 July 2020.
July 10, 2020
As a veterinarian, I have seen my fair share of tick-borne diseases in cattle. But a recent visit to a farm in Kiambu left me with a sense of unease and a warning to all farmers: ignore tick control at your own peril.
Dr. Kamau, a fellow professional and farmer, called me two weeks ago to seek my help with a lumpy skin disease (LSD) outbreak on his farm. He had vaccinated his 50 dairy cattle for the year, but despite the vaccination, some of the animals were still showing symptoms of the disease.
What struck me as unusual was that the affected cows were all pregnant heifers, and none had aborted. The anti-inflammatories given to the animals had worked well to maintain their temperature, but the nodules on their skin were small-sized to moderate and did not overlap.
However, as I examined the animals further, I noticed that they were all producing pelleted droppings, a sign that they had a blood parasite called anaplasma that causes anaplasmosis. The disease lowers intestinal and stomach movement, causing hardening and pelleting of the dung.
Further examination revealed that the sickliest heifer had a temperature of 40.6 degrees centigrade, was very dull, and had not been eating for the past two days. Its eyes were beginning to sink into their orbit, and the rumen was stagnant. The heart had a loud pounding beat, and breathing was laboured and shallow.
After taking a blood sample smear, I diagnosed possible complication of LSD with diseases spread by ticks. Back in the office, I found that the two cows I had examined first had east coast fever (ECF) in the early stages. Their red blood cells had small blue dots that signify the parasites.
The sickliest cow had both ECF and anaplasma parasites. The anaplasma parasites were responsible for thinning of the blood, and to defend itself, the body destroys red blood cells that contain the parasites. As the disease progresses and more cells are destroyed, the blood becomes watery and the mucous membranes become pale due to low blood supply.
I informed Dr. Kamau of the findings and advised him to treat all the animals for the combination of tick-borne infections I call “the three musketeers”. They are ECF, anaplasmosis, and babesiosis. They can quickly exterminate your cattle especially when they come in combination.
Dr. Kamau regretted having stopped washing his animals weekly against ticks. It is the best way of controlling the three musketeers. He had argued that his cows were safe since they were fully zero-grazed, but I warned him that tick control is essential, regardless of grazing practices.
