Zoonotic Diseases in Dogs
Dr. Douglas Brum
Whether you own a dog or a cat, a bird or a reptile, a rabbit or fish, you should be aware that your pet can have an effect on your health by infecting you with certain diseases. These are called zoonotic diseases, which are animal diseases that can be transmitted to humans. Cat scratch disease – a bacterial disease caused by bacteria carried in cat saliva. The bacteria can be passed from a cat to a human through biting or scratching.
You may already know about some of the more common zoonotic diseases: Lyme disease is a bacterial disease transmitted by tick bites; malaria is transmitted by the Anopheles mosquito, and bubonic plague is transmitted by rats, or rather by fleas that become infected by biting the rats. However, you should also be aware of several common zoonotic diseases that can be transmitted by your pet. Most common are:
Psittacosis – a bacterial disease you can get by inhaling dust from dried bird droppings.
Rabies – a viral infection caused by a virus found in the saliva of infected animals and is transmitted to pets and humans by bites. Infected bats, raccoons, foxes, skunks, dogs or cats provide the greatest risk to humans.
Toxoplasmosis – a parasitic disease you can acquire from soil or other contaminated surfaces by putting your hands to your mouth after gardening, cleaning a cat's litter box, or by touching anything that has come into contact with cat feces.
Ringworm – the most common zoonotic disease transferred from animals to humans. It is a contagious fungal infection that can affect the scalp, the body (particularly the groin), the feet and the nails. Despite its name, it has nothing to do with worms. The name comes from the characteristic red ring that can appear on an infected person's skin.
All animals can acquire zoonotic diseases, but animals at increased risk include: outdoor pets, unvaccinated animals, pets that are immunocompromised (a suppressed immune system), poorly groomed animals and animals that are housed in unsanitary conditions. People with immune disorders, on chemotherapy or immunosuppressive therapy may be at increased risk of infection.
Animals with zoonotic diseases may exhibit a variety of clinical signs depending on the type of disease. The signs can vary from mild to severe. As a pet owner you should know your animal and be aware of any changes in behavior and appearance.
What to Watch For
Bruising under the skin
Your veterinarian will need a good history, including an accurate travel history, and complete physical examination in order to make an accurate diagnosis. Since there are so many different kinds of zoonotic diseases, your veterinarian will also do various diagnostic tests. Some of these may include blood tests, cultures, x-rays and ultrasounds.
Treatment depends on the specific diagnosis and may include antibiotics, anti-parasitic drugs or anti-fungal drugs; intravenous fluids; symptomatic care for associated conditions (e.g. vomiting or diarrhea); and analgesic (pain) medication.
Not all animals with zoonotic diseases are serious risks to people, but good hygiene practices should always be observed. Proper education, a good understanding of the disease and its method of transmission are a vital part of home and preventative care. Use proper hygiene and sanitation when handling pets and their excretions and maintain a good program of veterinary care.