Swine tuberculosis is rare today, being the most common the Mycobacterium avium complex. It causes nodules in the lymph nodes of the neck resulting in the seizure of carcasses at the slaughterhouse.
Alternative names: TB, Mycobacterium tuberculosis, Mycobacterium avium, Mycobacterium bovis
Tuberculosis affects mammals, including humans, and birds. The causative organism, Mycobacterium tuberculosis, is subclassified into several types, human, bovine and avian. The avian type is called M. avium (or M. avium complex) which itself affects mainly birds but is also found in the environment. Pigs rarely become infected with the human types (M. tuberculosis) or bovine (M. bovis) but are often infected with M. avium complex.
The complex also causes not progressive sub-clinical illnesses in healthy people. The main concern is that it could cause serious illnesses in inmunodepressed people. In most countries, when in the slaughterhouse are seen lesions in the neck, the head is confiscated and, if lesions are found in the mesenteric lymph nodes that drain into the intestines, viscera are confiscated. If the disease is more widespread in the body, which is rare, the whole carcass will be confiscated. If small lesions are not detected during the inspection, normal cooking in the kitchen destroys the organism.
- It causes small lumps in the lymph nodes of the neck and those that drain into the small intestine.
- In the vast majority of cases the lesions are not progressive, they do not spread through the body, do not cause the pig to get sick and are not excreted.
- There are no clinical signs and no difference in production between infected and uninfected pigs.
Causes / Contributing Factors
- The disease is not transmitted between pigs and it should be considered an environmental infection. It is rarely diagnosed in live pigs.
- Fields that have been treated with chicken manure as a year before (or, in the case of bovine tuberculosis form, fields having infected cattle or badgers).
- The avian tuberculosis, as its name suggests, is found in wild birds. The organism is excreted in large quantities in their excrements and therefore food, cereal, water or bed contaminated by birds, are a potential source of disease.
- Water contaminated with M. avium is a common source of contamination.
- In live pigs the diagnosis is based on the tuberculin skin test, but usually the producer realizes that the disease is present in his farm when he receives the list of the percentage of seizures in the slaughterhouse.
- There is no treatment.
- Eliminate feed and contaminated bed.
- Eliminate access of birds to pigs’ areas.
- Use water chlorination.