Pets and the immunocompromised client
While pet ownership has many established health benefits, pets can also be a source of disease for pet owners. The disease risks associated with pet ownership are believed to be highest amongst young children, the elderly, pregnant women, and those who are immunocompromised. Estimates suggest the proportion of individuals with some degree of immunodeficiency is as high as 20% in the United States, explained Jason W. Stull, VMD, MPVM, DACVPM, speaking at the Ontario Association of Veterinary Technicians conference. Veterinary staff are in a key role to provide contact recommendations to high-risk clients and promote safe pet ownership practices.
Immunocompromising conditions
There is a degree to which people are immuno-compromised and this varies between and within conditions. Primary immunodeficiencies are those that result from genetic causes, while secondary immunodeficiencies result from non-genetic causes. Although both are important, secondary immunodeficiencies are much more common causes of immune dysfunction. Secondary immunodeficiencies may result from transplants, infectious diseases (e.g., HIV/ AIDS), metabolic diseases (e.g., diabetes), splenectomy, cancers, drugs (e.g., high doses of steroids, chemotherapeutics), and physiologic factors (e.g., malnutrition, extremes of age, and pregnancy). As a frame of reference, according to the Canadian Institute for Health Information, in 2008 there were over 26,000 people with HIV/AIDS and over 700,000 people with diabetes living in Ontario. In that same year 863 people in Ontario received a solid organ transplant and several hundred received a bone marrow transplant. Although limited information is available, studies suggest the numbers and types of animals owned by individuals who are immunocompromised are similar to the general public.
Health risks of animal ownership and guidelines to reduce health risks
As a general rule, immunocompromised people are at greater risk of getting sick than immunocompetent people, and are more likely to get seriously ill. For example, individuals infected with HIV are at 20-100 times greater risk of Salmonella bacteremia than those without HIV infection. Those with hematologic malignancies are twice as likely to be infected with Campylobacter bacteria as those without cancer, and illness is more likely to be severe and prolonged in these individuals.
The risk of disease transmission between pets and people is a function of pet and human-related factors. These factors include animal species, diet, age, opportunity for exposure (hospitalization, level of confinement), immunosuppression, and personal hygiene. Dr. Stull said that by targeting these factors, we can dramatically reduce the disease risks facing immunocompromised people.
While being immunocompromised is not a contraindication to having a pet, individuals who are immunocompromised, and households with such individuals, should be more cautious than other pet owners of ensuring their pets remain healthy and should follow precautions to reduce transmission of pathogens from pets. Pet contact guidelines can be categorized into 1) pet health and husbandry practices, 2) personal hygiene, and 3) types and ages of animals (see Table 1). These guidelines are general; clients that have questions about the risk to household members should be encouraged to consult with their physician.
Knowledge of client’s immune status: promoting and safeguarding client disclosure
Given the increased pet-associated disease risk for immunocompromised individuals, it is important for veterinary staff to be aware of these risks and provide targeted education and recommendations to those clients. However, most veterinarians are not aware of their clients’ immune status (only 66% in one study), making such targeted efforts difficult. Techniques that utilize passive (e.g., pamphlets, signs) and active (intake questionnaire) formats can be effective in encouraging clients to disclose the immune status of individuals in their household. Brochures and posters are available from a number of sources (e.g., the Centers for Disease Control and Prevention, Pets are Wonderful Support, Worms and Germs Blog – Ontario Veterinary College). Some advocate using intake questionnaires to obtain information on the client’s household, such as asking if there are any children less than five years of age, people with immune problems, or women who may be or are planning to become pregnant.
Veterinary clinic staff must recognize however, that such client personal health information may be considered confidential and protected under privacy laws. The greatest concerns focus on how this information is secured and provided to other individuals (e.g., clinic staff, other veterinary clinics). As such, veterinary clinics need to decide how such information is recorded, if at all. If information is recorded, it is best to ensure clients are aware why the information is requested, how the information will be used and, if included in the patient’s record, whether it may be transmitted to other veterinary clinics as part of the patient’s record. They should also be asked to sign a written consent, which should be reviewed with the client on a regular basis. CVT
Table 1: Pet contact guidelines for immunocompromised individuals
Personal hygiene
• Wash hands after handling animals or their environment; supervise hand-washing for children <5 years
• Avoid contact with pets’ feces and animal-derived pet treats
• Promptly wash bites and scratches from animals; do not allow pets to lick open wounds or cuts
• Have someone who is not immunocompromised clean cages/aquariums (if that is not possible wear gloves); do not dispose of aquarium water in sinks used for food preparation or bathtubs
Types and ages of animals
• Avoid contact with dogs and cats <6 months of age or strays; avoid acquiring a cat less than 1 year of age
• Avoid contact with animals with diarrhea
• Avoid contact with young farm animals (e.g., petting zoos)
• Avoid contact with reptiles, amphibians, rodents, ferrets, and baby poultry (chicks and ducklings) and anything that has been in contact with these animals; preferably these animals should be kept out of the households of immunocompromised individuals
• Reptiles, amphibians, rodents, and baby poultry should not be permitted to roam freely through a home or living area and should be kept out of kitchens and food-preparation areas
• Exercise caution when playing with cats to limit scratches; keep cats’ nails short
• When acquiring a new pet, seek larger, mature animals from established vendors
• Avoid contact with exotic pets and non-human primates
• When visiting other households with pets, take the same precautions with those pets
Pet health and husbandry
• Spay/neuter any pets
• Keep cats indoors; change litter boxes daily; keep cats away from kitchens or other areas where food preparation and eating occur
• Keep dogs confined when possible; walk on leash to prevent hunting and eating garbage or feces
• Feed only canned or dried commercial food or well-cooked home-prepared food; any dairy products should be pasteurized
• Prohibit access to non-potable water, such as surface water or toilet bowls
• Carry out routine preventative care, including steps to control and prevent ecto- and endoparasites (e.g., ticks, worms) as indicated by the area
• Clean bird cage linings daily; wear disposable gloves (+/- surgical mask) when handling
• Clean small rodent cages frequently
• Regularly (e.g., weekly) launder pet bedding
• Seek veterinary care at first sign of illness in an animal
