Zoonotic diseases are those that have the ability to spread between humans and animals, whether caused by bacteria, viruses, parasites or fungi. Tuberculosis, or TB, is a mycobacterial disease caused by a variety of different bacterial agents. Depending on the type of TB, transmission to dogs occurs through aerosol exposure or ingestion of contaminated substances. TB infection is not common in dogs, but reducing possible exposure risks reduces the chances of infection.
The three main types of TB infection come from different hosts. Human TB, caused by Mycobacterium tuberculosis, is airborne. Bovine TB, caused by Mycobacterium bovis, spreads to dogs through infected milk products or ingestion of animal feces or tissue, such as meat products or dead animals. Avian TB, caused by Mycobacterium avium, spreads through contact with infected bird tissue.
Clinical symptoms of TB, regardless of the type, are not always present in dogs. Outward symptoms depend on the method of disease contraction. For example, dogs contracting TB through inhalation may experience respiratory symptoms such as coughing or difficulty breathing. Contracting TB through ingestion of infected milk, tissue or feces can cause symptoms in the digestive tract, such as vomiting or diarrhea. Other general symptoms include fever, loss of appetite, weight loss, lethargy and increased salivation. Unfortunately, dogs do not respond well to traditional TB treatments and, because of the risk of TB transmission to humans, euthanasia is recommended for infected dogs.
- All Things Dog Blog: Ask the Vet with Dr. Mark: Tuberculosis and Dogs
- State of Michigan: Pet Issues
- Provet: Tuberculosis
- Centers for Disease Control and Prevention: Zoonotic Disease: When Humans and Animals Intersect
- The State of New Jersey: Animal Surveillance Case Definition Mycobacterium Tuberculosis [PDF]
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