Pet Diseases and People

By Lorie Huston, DVM on Dec. 24, 2012

There are many diseases that affect pets that can also be dangerous for people. These diseases even have a name. They are called zoonoses. Fortunately, many of these diseases are easily preventable. Let’s talk about some of the most serious diseases in question.

Rabies is probably one of the most dangerous of these diseases. Almost without exception, rabies is fatal once an animal or person becomes infected with it. People can be exposed to rabies through animal bites. Animals involved may be wild animals, stray or feral animals, or pets. Because of the public health concerns surrounding rabies, most communities require the vaccination of dogs, and often cats and ferrets as well.

Toxoplasmosis is a protozoan (one-celled) parasite that can infect a wide variety of animals, including cats and people. Toxoplasmosis is well-known for causing birth defects and abortion when expectant mothers become infected during their pregnancy. However, the organism has also been linked to symptoms such as brain cancer, schizophrenia, and increased risk of suicide. Pet cats often get blamed for the spread of this disease but, in actuality, people are more likely to become infected through eating uncooked meat or unwashed vegetables than from their cat, particularly if their cat is housed indoors.

Plague is another disease that has been in the news headlines recently. Plague is a contagious disease that can be passed from animals to people. Rodents and rabbits are most often involved in transmission of the disease but cats can become infected and can become a reservoir for the disease as well. The transmission of this disease also involves fleas, making flea control the best form of prevention for this disease.

Roundworms, also known as ascarids, are intestinal parasites that can infect dogs, cats, and many other mammals (including wild animals such as raccoons). This worm can also infect people, causing what is known as visceral and/or ocular larval migrans. This occurs when the larval form of the worm migrates through the body. It is particularly dangerous for children, potentially causing blindness, seizures, and other symptoms. Keeping pets free of parasites, picking up pet feces, and following good hygiene practices are the best defenses against this parasite.

Hookworms, like roundworms, are intestinal parasites. They are worms that live in the intestinal tract of dogs, cats, and other animals. These worms can infest sand and dirt, causing skin lesions for people who contact the parasite. Though usually not a life-threatening disease, the skin lesions can be quite itchy and uncomfortable. Picking up pet feces can help stop the spread.

Giardia is also an intestinal parasite. Unlike roundworms and hookworms, Giardia is a protozoan (or one celled) parasite. This disease can affect dogs, cats, and many other animals, as well as people. Infection usually occurs when a person eats or drinks contaminated food or water.

Salmonella, E. coli and other intestinal bacterial infections can affect many species of animals, including dogs and cats. These infections can be passed to people as well. There is some indication that pets eating raw food may be more likely to expose their owners to these diseases. In addition, people (particularly children) handling pet foods contaminated with Salmonella have been documented as being at risk. Proper hygiene and food handling techniques are the best way to prevent spread of these diseases.

Ringworm is a skin disease caused by a fungal infection. These infections are very contagious and easily passed from pets to people and also from people to pets. Ringworm should not be confused with roundworms. They are very different diseases. Animals with ringworm should be handled carefully, preferably wearing gloves when handling and washing hands frequently and thoroughly.

These are just a few of the diseases that can be spread from pets to people. The good news is that you can reduce your risk for these diseases by following some very simple rules. We’ll talk next week about steps to protect yourself and your family from these diseases.

Dr. Lorie Huston

Image: Kiss by scott feldstein / Flickr


Lorie Huston, DVM


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