Household pets can transmit infections to people, especially those with weak immune systems

Posted on Monday, April 20, 2015

Household pets can transmit infections to people, especially people with weak immune systems, young children, pregnant women and seniors, according to an article in CMAJ (Canadian Medical Association Journal). Health care providers and pet owners should be aware of this to prevent illness in vulnerable people.

“Surveys suggest that the general public and people at high risk for pet-associated disease are not aware of the risks associated with pet contact or recommendations to reduce them. For example, 77% of households that obtained a new pet following a cancer diagnosis acquired a high-risk pet, such as a young dog or cat, rodent, reptile or amphibian,” says Dr. Jason Stull, assistant professor, Department of Veterinary Preventive Medicine, Ohio State University, Columbus, Ohio.

The article discusses how infections are transmitted from pets, the types of infections, prevention and the role of health care providers.

“Studies suggest physicians do not regularly ask about pet contact, nor do they discuss the risks of zoonotic diseases with patients, regardless of the patient's immune status,” writes Dr. Jason Brophy, assistant professor at the University of Ottawa's Faculty of Medicine and the Children's Hospital of Eastern Ontario (CHEO).

All pets can transmit diseases to people.  For instance, dogs, cats, rodents, reptiles and amphibians can transmit diseases such as Salmonella, multi-drug resistant bacteria, Clostridium difficile, Campylobacter jejuni and other diseases. Parasites such as hookworm, roundworm and Toxoplasma can also be transmitted. Infection can be contracted from bites, scratches, saliva and contact with feces. Reptiles and amphibians can transmit disease indirectly, such as via contaminated surfaces.

“Reptiles and amphibians are estimated to be responsible for 11% of all sporadic Salmonella infections among patients less than 21 years of age, and direct contact with such animals is not required for zoonotic transmission,” write the authors. “In one study, 31% of reptile-associated salmonellosis cases occurred in children less than 5 years of age and 17% occurred in children aged 1 year or younger; these findings highlight the heightened risk in children and the potential for reptile-associated Salmonella to be transmitted without direct contact with the animal or its enclosure.”

For healthy people, the risk of pet-associated disease is low, but vulnerable people are at risk, including children with leukemia and adults with cancer, newborns and others.

“Given the health benefits of animal ownership and the reluctance of patients to give up their pets, resources highlight the importance of following specific precautions,” says Stull. “Patients at high risk and their households should show increased vigilance concerning their pets' health and take precautions to reduce pathogen transmission.”  Simple steps can dramatically reduce the disease risks from pets.

Recommendations for reducing infection transmission include:

  • Wearing protective gloves to clean aquariums and cages and remove feces
  • Properly washing hands after pet contact
  • Discouraging face licking of immunocompromised children and adults
  • Covering playground boxes when not in use
  • Avoiding contact with exotic pets and non-human primates
  • Cleaning and disinfecting animal cages, feeding areas and bedding regularly
  • Locating litter boxes away from the kitchen and areas where eating and food preparation occur
  • Waiting until immune status has improved before acquiring a new pet
  • Making regular veterinary visits for all pets

In light of illness in vulnerable people, physicians and other health care providers should enquire about pets and repeat questions as well as seek advice on the risks of pet ownership and how to reduce risks of disease.

The authors also note that veterinarians can be a resource for physicians seeking more information on zoonotic infections, unusual pets and associated diseases.

Media inquiries

Kina Leclair (for Dr. Jason Brophy — French requests)
Media Relations Officer
University of Ottawa
Office: 613-562-5800 ext. 2529
Cell: 613-762-2908

Adrienne Vienneau
Director of Communications
CHEO Research Institute
Office: 613-737-7600 ext. 4144

Melissa L. Weber (for Dr. Jason Stull)
Director of Communications and Marketing
Ohio State University College of Veterinary Medicine
Office: 614-292-3752
Cell: 614-327-6024

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