What Animal Started TB?
Cattle are the primary source of Mycobacterium bovis (M. bovis), the bacteria causing bovine tuberculosis (TB), which is a zoonotic disease meaning it can spread from animals to humans. While the origin of tuberculosis in humans is a complex topic, with studies pointing to a human origin 70,000 years ago, cattle serve as a significant reservoir for M. bovis, representing the main source of human infection. Other animals, such as sheep, goats, bison, elk, deer, and even badgers can also be infected and contribute to the spread, particularly in specific regions. The name "tuberculosis" itself stems from the tubercles (nodules) forming in the lymph nodes and tissues of affected animals.
- Major Reservoir: Cattle are the largest known reservoir for M. bovis. This means they harbor the bacteria and facilitate its spread.
- Primary Source of Human Infection: Humans primarily contract M. bovis through contact with infected cattle. This occurs most often through consumption of unpasteurized dairy products or close contact with infected animals.
- Zoonotic Disease: Bovine TB is a zoonotic disease, meaning it can transmit between animals and humans.
Other Animals Involved in Tuberculosis Transmission
While cattle are the main culprits, other animals contribute to the spread of bovine TB:
- Sheep and Goats: These animals are also susceptible to M. bovis infection and can serve as reservoirs.
- Bison, Elk, and Deer: These wild animals can carry and spread the bacteria, particularly in areas where they interact with cattle.
- Badgers: In certain regions (like the west of England and parts of Wales), badgers play a significant role in spreading M. bovis to cattle and vice versa.
The Importance of Bovine Tuberculosis Control
Controlling bovine TB is crucial for both animal and human health. Measures like testing and culling infected animals are used to minimize the spread of the disease. Maintaining good biosecurity practices in cattle farms is also essential.
