Severe or untreated protozoal infections can be fatal. Viruses and bacteria Viruses and bacteria are the culprits in the majority of infectious diseases that affect animals. Canine viruses include distemper, infectious hepatitis, parvovirus, rabies, Bordatella, adenovirus, and parainfluenza. Most state or local health codes require vaccination against rabies, a deadly disease that can be transmitted to people. Dogs can be protected against many other viruses through vaccines as well.
Bacteria are single-celled organisms that can be found throughout the environment.
Some bacteria cause disease. Bacterial diseases in dogs include leptospirosis, enteric campylobacteriosis, streptococcal and staphylococcal infections, brucellosis, tetanus, Lyme disease, erlichiosis, Rocky Mountain spotted fever, and infectious thrombocytopenia. Vaccines are available to protect against Lyme disease and leptospirosis. There are no vaccines to protect against fungal infections, but in some cases, owners can protect their pets by avoiding areas where fungal infestations can occur. For example, the fungus that causes blastomycosis tends to occur along sandy river banks, histoplasomosis is a problem where bird or bat feces have accumulated for years, and coccidioimycosis can be a problem in the Southwestern US, especially after a period of stormy weather.