How is Bovine TB transmitted?

How was the buffalo in South Africa infected?

Exactly how do the lions contract TB?

Shocking Facts

How is Bovine TB transmitted? Tubercle bacilli are transmitted through sputum, mainly in airborne droplets, or by dust particles of dried sputum. The most common means is by airborne transmission. Infected animals exhale bacteria through breathing, coughing and sneezing. Animals are more likely to infect each other when they share a common watering and feeding place. This is a debilitating disease, affecting the lung cavity of the animal and other organs can also be affected. The animal gradually becomes weaker and may easily be infected with other diseases

How was the buffalo in South Africa infected? A team of 30 scientists and assistants killed 19 Cape buffalo in the Kruger National Park and performed autopsies in the field to study the prevalence of bovine TB in the herd. At least one animal with gross lesions was found. Tuberculosis is not a natural disease for the herd. The buffalo contracted it by mingling with infected cattle herds prior to fencing of the park's southern boundary in the 1950`s. The disease progresses slowly in buffalo, but is more rapidly progressive in feline park predators for instance lions and leopards.

Exactly how do the lions contract TB?

Buffalo are the reservoir host of the bacteria, and lions eat as much buffalo as they can catch. The pink membrane of a buffalo's lungs contains white tubercular lumps. If a lion eats this he will get a massive dose of TB. Because the disease is ingested, the lion's intestines are the first to be affected. The lion will develop intestinal lesions before the disease spreads to the lymph nodes and other organs. Unlike buffalo, which get TB from breathing the germs, the lion's lungs are not immediately affected.

When the lions are feeding or resting they are often in close proximity to each other. An infected lion may cough; this action produces minute aerosol droplets. These may drift through the air for a few meters, and be inhaled by another lion. Should the lion have a poor immune status then the chances are quite good for it to contract the disease. Once a member of the cat family has the bacteria, it seems to spread through the animal's body very rapidly, where buffalo can be carriers without actually developing the disease. When a lion is visibly sick, they are probably only days away from death.

Shocking Facts

The lions in the Kruger National Park, one of the world's largest game reserves, have picked up the fatal disease after feeding on the infected buffalo, their natural prey. Of the total of 33 lions tested for TB, 32 are positive. That means that 90% of the lions tested in the south have TB and it's believed that the lions in the far north are not infected.

It is suspected of cutting the number of adult lions in one study area from 25 to12 in less than 2 and 1/2 years. The picture above is an example of lions in close proximity where transmission by aerosol droplets occurs.