Mammalian Tuberculosis: What Meat Professionals Should Know
Mammalian TB is a slow-spreading but serious disease in livestock that affects animal health, human safety, and meat trade.
What Is Mammalian TB?
Mammalian tuberculosis (TB) is a chronic bacterial disease caused mainly by Mycobacterium bovis. It affects cattle and can also infect other livestock, wildlife, and humans.
This disease harms animal health, causes productivity losses, and can block market access due to strict regulations.
More Than Just a Cattle Disease
TB doesn’t stop at cows. It also infects:
Pigs, goats, sheep, horses, dogs, cats
Wild animals like deer, boars, badgers, and possums
Predators such as lions and tigers
Humans, especially through contaminated animal products or close contact
How the Disease Spreads
TB spreads slowly and quietly:
Inhalation: coughing animals release bacteria into the air
Ingestion: calves can get it from milk; humans from raw milk or undercooked meat
Contact: direct exposure to infected body fluids or tissues
Infected animals often show no signs while spreading the disease.
Recognising the Signs
The disease progresses over months or even years. Symptoms may include:
Weight loss
Chronic cough
Weakness
Swollen lymph nodes
On-and-off fever
Diarrhoea
Some animals may never show symptoms but still spread the bacteria.
Diagnosis: What Works
Skin test (tuberculin): standard for live animals
Blood tests: detect immune response
Post-mortem inspection: finds visible lesions
Lab culture: confirms the diagnosis (takes weeks)
Meat inspection plays a key role in identifying undetected cases.
Public Health Risk
Mycobacterium bovis can infect people. It poses a serious risk through:
Drinking raw milk
Eating contaminated meat
Handling infected animals or carcasses
Some countries report up to 10% of human TB cases caused by this strain. It is also harder to treat due to drug resistance.
Where It Exists
Widespread in Africa and Asia
Present in parts of Europe and the Americas
Often controlled in cattle but remains in wildlife reservoirs
Even countries with strong control programs face re-infection risks from wildlife.
Preventing and Controlling TB
Effective programs rely on several actions:
Testing and culling infected animals
Traceability and movement control
Meat inspection at slaughter
Pasteurising milk
Educating farmers and workers
Enforcing local animal health laws
Test-and-slaughter works best but is not always practical. Some countries begin with test-and-segregate.
What Meat Professionals Should Do
Source livestock from tested herds
Inspect meat and milk properly
Train workers in safe handling and hygiene
Follow animal movement and identification rules
Report suspected cases to authorities
Vaccination in animals is not yet widely used because it interferes with testing. Research is ongoing.
In Summary
Mammalian TB is a long-lasting threat to livestock production, public health, and trade. It requires consistent testing, strict hygiene, and cooperation between farmers, vets, and meat professionals to keep it under control.
Source: https://www.woah.org/en/disease/mammalian-tuberculosis/