Common household pets can transmit infection to people with weakened immune systems, as well as children, pregnant women and seniors, according to a new review.

According to the review published in the Canadian Medical Association Journal on Monday, while owning a pet can bring health and social benefits, it also carries specific risks.

A total of 332 studies were included in the review, including case reports, cross-sectional studies, cohort studies and case-control studies.

"Pet ownership can have health, emotional and social benefits; however, pets can serve as a source of zoonotic pathogens," the review authors write. Zoonotic pathogens are pathogens that can be transmitted from animals to people.

The review examines different infections that can be acquired from pets, and discusses various steps pet owners can take to prevent infection.

Infection transmission

While the risk for pet-attributable disease is low for healthy individuals, patients with weak immune systems remain at risk.

Dogs, cats, rodents, reptiles and various amphibians can pass on Salmonella, drug-resistant bacteria and Campylobacter jejuni – a type of bacteria found in animal feces. They can also pass on various parasites including hookworm, roundworm and Toxoplasma, the review said.

Infections are typically acquired from bites, scratches, or contact with animal saliva, urine, secretions and feces. Diseases can also be transmitted indirectly through contaminated surfaces.

Through these various mechanisms, the review notes that pets are a potential source of more than 70 human diseases.

While patient surveys and epidemiological studies suggest that the occurrence of pet-associated diseases is low overall, the proportion is unknown and likely underreported, according to the review.

One study included in the review found that reptiles and amphibians were responsible for about 11 per cent of all sporadic Salmonella infections in patients younger than 21.

Another study also found that 31 per cent of reptile-associated salmonella poisoning cases occurred in children younger than five, and 17 per cent occurred in children aged one year or younger.

Salmonella poisoning can cause diarrhea, fever and abdominal cramps. In people with weakened immune systems, it can result in meningitis and bone disease.

Steps to reduce risk

The authors of the review suggest pet owners take the following precautions to reduce their risk:

- regularly clean and disinfect animal cages, feeding areas and pet bedding

- wear gloves to clean aquariums and cages while removing pet feces

- use proper handwashing techniques after coming into contact with pets

- discourage pets from licking family members' faces

- cover playground boxes when they are not being used

- place litter boxes away from household eating and food preparation areas

- avoid coming into contact with exotic animals

- regularly schedule veterinary visits for your pets

Lead author Dr. Jason Stull said taking the right precautions can help prevent infection.

"Patients at high risk and their households should have increased vigilance of their pets' health and take precautions to reduce pathogen transmission," he said in a statement.

The review also suggests that doctors ask vulnerable patients about any pets and pet behaviour.

Veterinarians can act as a resource for doctors who need more information about pet-attributable infection, the authors say.