Vet on call: You want to be a vet? Know about this risk - Daily Nation

Vet on call: You want to be a vet? Know about this risk

Saturday November 10 2018

Community animal health officials in Turkana County help vaccinate livestock in a cross-border exercise targeting 30,000 cattle, sheep and goats.

Community animal health officials in Turkana County help vaccinate livestock in a cross-border exercise targeting 30,000 cattle, sheep and goats. It is documented that about 60 per cent of infectious diseases affecting humans emanated from animals. PHOTO | PETER WARUTUMO | NMG 

By DR JOSEPH MUGACHIA
More by this Author

Sometime back, I was injured by the incisor tooth of a calf that I was giving some medicine by mouth. It twisted the head and cut my finger.

The sharp tooth went right through my latex glove like a razor and made a fairly deep cut across all the layers of my skin.

You see, latex gloves are only meant to protect against disease-causing micro-organisms but not physical force.

I cleaned the wound thoroughly with iodine and surgical spirit and later visited my doctor. I was treated with antibiotics and the wound was cleaned again with antiseptics and bandaged.

Good healing occurred uneventfully but four weeks after the wound closure, the scar became itchy and later developed a hard tissue, the size of a pigeon pea. I could tell something was growing inside the swelling and, therefore, I visited my doctor again.

Dr John examined the swelling and then asked me, “Doc, what do you think the calf planted in your hand?” He further asked we should work on the issue together because animals are the source of many human diseases, some of which human doctors rarely encounter.

Actually, I had spent sleepless nights dreading what could have been happening to my hand. From the appearance and texture of the swelling, I suspected the calf could have inoculated me with one of the tenacious bacteria that cause either wooden tongue or lumpy jaw in cattle.

The bacteria reside in the soil and mouths of ruminants without causing any problem. However, once they get into the tissues through an injury, they cause debilitating diseases called wooden tongue and lumpy jaw, which are very difficult to treat.

In lumpy jaw, the bacteria infect the tissues and bones of the jaws and cause them to become very big with a hard lump at the infection epicentre.

PATHOLOGICAL ANALYSIS

Smaller lumps may develop away from the initial infection site. Wooden tongue, on the other hand, causes the animal’s tongue to become very hard like a piece of wood and the animal is unable to eat. In most cases, such animals are destroyed or slaughtered.

Now you can understand my dilemma as I faced the doctor with the itchy lump on my hand. He proposed to take a small tissue called a biopsy from the swelling for laboratory examination by a specialist called a pathologist.

These are the doctors who specialise in studying disease processes, their causes and impacts on tissues. The results would have been out in about one week.

In the meantime, John suggested he puts me on antibiotics and anti-inflammatories awaiting directions from the lab on the treatment they would recommend from their specialist diagnosis.

That suggestion only enhanced my anxiety. The biopsy collection procedure could open healthier cells to the disease organisms and thereby spread the infection. I could imagine having a hard swollen hand similar to what I had seen in infected cattle tongues and jaws.

“Sorry Doc, I don’t like what I’m seeing on my hand and the itchy feeling in the lump,” I started. I informed him I knew of only two bacteria that could cause the kind of reaction I had.

Then I proposed the doctor to surgically remove the whole lump at a distance and depth far enough from the lump margins to ensure all particles of the agent causing the growth had been removed.

The lump could then be taken to the lab for pathological analysis and I would be at peace knowing that nothing was growing in my hand.

He readily concurred. He removed the lump, stitched up the wound and gave me antibiotic and anti-inflammatory shots.

For the next seven days, my work was limited to office duties but the wound healed very well. In the second week, Dr John called me to his office. I could see from his face he had confirmatory results from the pathologist.

EMERGING DISEASES

“Doc, you may have a look at the microscope,” he told me as he pointed to the equipment mounted with a slide ready for viewing. I sighed with relief when I saw the thin slice of my hand tissue contained short pink rods among the body cells.

The calf had for sure inoculated me with bacteria of the group actinobacillus. One of these organisms, Actinobacillus lignieresii is the cause of wooden tongue in cattle, sheep and goats.

The pathologist’s report said correctly the bacteria could only be classified by family as actinobacillus, but the laboratory work needed to culture the organisms and identify the specific species was not possible due to the small size of the sample.

Actinobacillus species are mainly pathogenic or disease-causing bacteria of herbivorous animals but in favourable circumstances may affect humans.

The main method of entry into human tissues is through open injuries to the skin — as happened in my case.

To date, I still carry the surgical scar for the operation that saved me from a possible full blown infection by actinobacillus from a calf.

It is a reminder of the great care that veterinary doctors must always take in the line of duty to prevent diseases jumping species from animals to humans.

It is documented that about 60 per cent of infectious diseases affecting humans emanated from animals. In addition, 75 per cent of new diseases that affect humans emanate from animals.

They are called emerging diseases. Avian influenza and swine fever are recent examples of such diseases.

In some cases, some bacteria become more lethal to humans by developing resistant to common antibiotics after being exposed to small doses of the drugs in animals.

In other situations, the microorganisms get adapted to thrive in humans due to regular close contact of humans and and animals.

Advertisement