I told the farm manager that while disposing of the carcass, everybody should avoid direct contact with any fluids from the animal. As I finished the discussion, the cow went into a frenzy, clawing the ground with its front legs and breathed its last.
I provided all the farm staff with gloves. They dragged the animal to a burial site in the maize field where I cut off the head and packed it in a watertight plastic material.
I instructed the manager to keep the package safely on the farm and take it to the laboratory early the next morning together with the case notes I had written.
The lab confirmed receiving the sample and would communicate the results in 48 hours. I advised the paravet to get rabies post-exposure shots, just in case the results turned out positive.You see, rabies is a disease that no one should take chances with.
The blood sample I took showed indications of a blood parasite or viral infection. Microscopic examination is limited in such a situation where the rabies virus is suspected and the animal had already been treated for red water.
The red water parasites, medically called babesia, can also cause a blood cell reaction that mimics a viral infection.
However, the parasites would not be seen because they would already have been destroyed by the treatment given.
The laboratory called after 72 hours and said the sample had tested negative for rabies. This was highly welcome news but the question remained, “What was the killer disease that resisted treatment and evaded clinical detection?”
The suspicion of rabies had precluded my carrying out a post-mortem examination on the farm. The cow went into the grave with the secret in her body.
There are a number of diseases that cause nervous signs in cattle such as what David’s cow exhibited. They include the brain form of red water, heart water, a bacterial infection called listeriosis, mad cow disease and a tapeworm that affects the brain.
I had ruled out the diseases because the differentiating signs for each of them were missing in this case. Rabies had also been doubtful because the mucous membranes of the eyes were a healthy pink as opposed to being red and engorged as it happens with rabies infection.
However, we always say diseases do not read books to show all the documented signs. In addition, the set of disease signs documented for any ailment do not necessarily have to all occur in one case at the same time.
I shared with David the laboratory findings, and like myself, the mysterious disease is still confounding.
For now, the case is rested because no further investigations are possible without the carcass. However, if another animal shows similar signs, I will refer it to the University Veterinary School at Kabete for higher level pathological laboratory diagnoses on both the live and dead animal.