New study suggests ways to avoid catching diseases from pets

As new medical diagnostics become available, researchers are increasingly discovering situations in which pets can transmit diseases to humans--especially when an owner's immune system is compromised.

At The Ohio State University and partner institutions, researchers have compiled the latest information from more than 500 studies worldwide to make recommendations on how families can minimize the risk of disease transmission by choosing the right type of pet, or by making small changes in how they enjoy the pets they already have.

The review was published in the April 20 issue of CMAJ, The Canadian Medical Association Journal.

Salmonella, E. coli and roundworms are among the nearly 20 different diseases that people most commonly acquire from pets, explained Jason Stull, assistant professor of veterinary preventative medicine at Ohio State. Infants, the elderly, pregnant women, and people with limited immune function are most at risk for animal-borne, or zoonotic, diseases.

Since different species of pets--dogs, cats, rodents, birds, fish, reptiles and amphibians--carry different types of diseases and at different stages of life, Stull and his colleagues suggest that families talk to both their doctor and veterinarian about what pet is the safest choice for their family.

"It's all about safe pet ownership," Stull said. "There are very few situations in which a person couldn't or shouldn't have some type of pet if they wish. It's about matching the right species with the right person and taking the appropriate precautions."

And there is need for more communication about pets among health professionals and the people they serve.

"Surveys suggest that most veterinarians and physicians do not regularly discuss zoonotic disease risks with clients, patients or each other," Stull said. "That needs to change if we are going to effectively reduce pet-associated diseases."

He suggests physicians could reach out to veterinarians for information about the health risks of owning particular pets, especially when they have a patient whose immune system is compromised.

Pets naturally shed disease causing organisms in their feces, saliva, or from skin, he explained. For example, reptiles and amphibians--pets such as turtles, snakes, frogs and salamanders--naturally carry salmonella in their digestive tract. After touching these pets, handwashing is important for everyone, but especially for people who are more vulnerable to infections.

Stull also offered the example of families in which a child has been diagnosed with cancer and is undergoing treatment that compromises the immune system.

"We've worked with families whose kids are spending a lot of time in physicians' offices, and for numerous reasons miss out on typical activities with other kids," he said. "Parents may decide to get a puppy or kitten to help replace some of that lost social interaction. But puppies and kittens shed some organisms that adult animals don't, so an adult animal would probably be a better choice in that situation."

General recommendations for reducing transmission of infection in vulnerable groups include:

• wearing protective gloves to clean aquariums and cages and remove feces
• proper handwashing after pet contact
• discouraging pets from face licking
• covering playground boxes when not in use
• avoiding contact with higher risk animals such as reptiles, amphibians, and exotic animals
• regular cleaning and disinfection of animal cages, feeding areas and bedding
• locating litter boxes away from areas where eating and food prep occur
• waiting to acquire a new pet until immune status has improved
• regularly scheduling veterinary visits for all pets.
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Some pets can become infected with disease causing organisms such as methicillin-resistant Staphylococcus aureus (MRSA) or Clostridium difficile, Stull said. Researchers believe that such infections come from people, but that pets can then become sick and pass along the disease to other people. Owners who have been diagnosed with these diseases should speak to their healthcare provider and veterinarian and take precautions to safeguard their pets.

Stull said that the topic of zoonotic diseases is one that he and his colleagues are particularly passionate about.

"Pets do so much good for people in terms of mental, physical, and emotional health. But at the same time, they can transmit diseases to us. Physicians, veterinarians, and the public have to work together to make sure the benefits outweigh the risks."