Pets and the immunocompromised person

“Immunocompromised” means that part of your immune system is not working at full strength. This may happen because of a health condition or a treatment such as chemotherapy, transplant medicines, corticosteroids like prednisone or hydrocortisone, or certain biologic medicines.

The degree and type of immune suppression matter. For example, a low neutrophil count reduces protection from some bacteria and fungi. Neutrophils are white blood cells that respond quickly to infection. Other conditions or treatments affect different parts of the immune system.

Pets can provide companionship, routine, exercise, and emotional support. Having a weakened immune system does not automatically mean that you must give up a pet. In many cases, an established, healthy pet can remain at home with sensible precautions.

The main concern is exposure to zoonotic infections—infections that can pass between animals and people. Your specialist team can help you judge risk based on your treatment, blood test results, pet species, and how you interact with the animal.

Animals may carry germs without appearing ill. Germs can spread through bites, scratches, saliva, feces, urine, skin, feathers, tank water, bedding, or contaminated pet food.

Risk is shaped by three things: how strongly your immune system is suppressed, the animal involved, and the type of contact. Cleaning a litter tray creates a different exposure from stroking a healthy indoor cat. Caring for a reptile, a sick animal, or a young animal with diarrhea may carry additional risk.

Raw pet food can also expose both pets and people to bacteria such as Salmonella and Listeria. The germ may spread through food bowls, preparation surfaces, the animal’s mouth, or its feces.

Regular veterinary care helps identify illness, parasites, and skin problems in a pet. However, there is no test that can certify an animal as free of every infection that could affect an immunocompromised person.

Many animal-related infections cause limited illness in people with healthy immune systems. The same infections can sometimes become more severe, last longer, or spread beyond their usual location when immune protection is reduced.

Your level of risk may change over time. It may be higher during intensive chemotherapy, after a transplant, while taking stronger immune-suppressing medicines, or when certain white blood cell counts are low. A precaution that is important during one phase of treatment may not be necessary later.

This topic also affects practical decisions, such as whether to adopt a new animal, who cleans cages or litter trays, whether a pet should eat raw food, and when an animal exposure needs medical attention.

Pregnancy has its own animal-related precautions, especially around cat feces and toxoplasmosis. If you are both pregnant and immunocompromised, ask your maternity and specialist teams to consider both sets of risks.

The possible problems are infections and injuries linked to animal contact—not a condition called “pets and immunocompromise.”

Examples include:

• Toxoplasmosis, linked to cat feces, contaminated soil, and undercooked meat
• Salmonellosis, linked particularly to reptiles, amphibians, backyard poultry, rodents, and raw pet food
• Campylobacter infection, which can spread from animals with diarrhea
• Cryptosporidiosis, a diarrheal infection linked to infected animals or contaminated water
• Cat-scratch disease, caused by Bartonella henselae after some cat scratches or bites
• Ringworm, a fungal skin infection carried by several animal species
• Psittacosis, a bacterial infection associated with parrots and some other birds
• Wound infections after bites or scratches, including infections caused by Pasteurella or Capnocytophaga bacteria

Reptiles and amphibians commonly carry Salmonella, even when healthy. Young animals, strays, animals with diarrhea, and exotic species can also present particular concerns. Fish tanks may expose broken skin to waterborne bacteria.

Bites can damage tendons, joints, nerves, or blood vessels as well as introduce infection. Contact with a bat or a possibly rabid mammal needs prompt assessment because rabies treatment must begin before illness develops.

Ask your specialist team a specific question: “Does my condition or treatment require any pet restrictions right now?” Mention the animal’s species, age, health, diet, and whether you clean its waste or enclosure. If you are considering a new pet, ask before bringing it home.

Keep a current list of your medicines and recent relevant blood results, if your team provides them. A single result does not define your full risk, but information such as a neutrophil count may affect advice during treatment.

Arrange routine veterinary care. Tell the veterinarian that someone in the household is immunocompromised. Seek veterinary advice if the pet develops diarrhea, vomiting, coughing, unexplained skin changes, or unusual behavior. Do not handle a sick animal’s waste without protection.

Useful everyday precautions include:

• Wash your hands after touching animals, waste, cages, tanks, bowls, or pet food
• Keep pets away from open wounds, medical devices, and your face
• Do not allow pets to lick cuts, surgical sites, or catheter areas
• Feed commercially prepared or thoroughly cooked food rather than raw pet food
• Keep cats indoors when practical and discourage hunting or scavenging
• Have someone else clean litter trays, cages, and animal waste when possible
• If you must clean, use disposable gloves and wash your hands afterward
• Avoid direct contact with animal diarrhea and contaminated bedding
• Use gloves when cleaning an aquarium if you have cuts on your hands
• Avoid adopting stray or visibly ill animals without medical and veterinary advice

You may be advised to avoid direct contact with reptiles, amphibians, backyard poultry, or certain exotic animals during periods of significant immune suppression. This is not the same for everyone, so ask about your particular treatment.

After a bite or scratch, wash the area thoroughly with soap and running water. Contact your healthcare service promptly about puncture wounds, wounds to the hand or face, worsening redness, swelling, drainage, or pain. Ask whether your tetanus protection is current.

A bat exposure, contact with a possibly rabid mammal, or saliva from such an animal entering broken skin, eyes, nose, or mouth needs urgent medical or public health assessment. Do not wait for the animal or wound to look abnormal.

Seek urgent care for fever, persistent diarrhea, bloody diarrhea, or signs of dehydration after animal exposure. Call emergency services for uncontrolled bleeding, trouble breathing, confusion, fainting, or rapidly worsening illness.

For routine follow-up, mention changes in your immune-suppressing treatment, plans to adopt an animal, or repeated animal exposures at your next planned appointment.

Do I need to give away my pet?

Usually, no automatic decision is required. An established, healthy pet may often remain in the home. The answer should account for your immune suppression, the animal species, its health, and who performs higher-risk tasks such as waste cleaning.

Is a dog safer than a cat?

Neither species is completely risk-free, and both can usually be managed safely. Their risks differ. Cats are relevant to toxoplasmosis and cat-scratch disease, while dog and cat bites can both become infected. Individual behavior, health, age, and diet also matter.

Can my pet be tested to prove it is safe?

No single test can do this. A veterinarian can examine the animal and order tests for specific illnesses when there is a reason. Routine screening of a healthy pet for every possible zoonotic infection is not available.

Can I clean a litter tray?

If someone else can do it, that may reduce your exposure. If you must do it, use disposable gloves, avoid touching your face, and wash your hands well afterward. Ask your specialist team whether your current immune status calls for stricter precautions.

Are pet allergies the same as being immunocompromised?

No. An allergy is an immune reaction to substances such as dander or saliva. Immunocompromise means that parts of the immune response are weakened. A person can have either or both.

What about therapy animals or visiting pets?

Ask whether the hospital, clinic, or care service has an animal-visitation policy. Avoid animals that are ill, very young, poorly controlled, or fed raw food. Clean your hands after contact and keep the animal away from wounds and medical equipment.