Do you have to give up your pet?

The short version

What the guidelines say, animal by animal

This is the position of the CDC, a 2015 review in the Canadian Medical Association Journal (CMAJ), the American Society of Transplantation, the US HIV guidelines and the European parasite council ESCCAP, condensed. Your medical team can narrow it down to your situation.

• Adult dog or cat already at home

  Can usually stay. The guidance is about hygiene, regular veterinary care and parasite control, not rehoming.

• Puppy, kitten or stray

  The CMAJ review advises avoiding dogs and cats under 6 months old and strays. The CDC says people with weakened immune systems should avoid owning cats under a year old.

• Any animal with diarrhoea

  Keep your distance until a vet has seen it. ESCCAP says immunocompromised people should not be in close contact with sick cats and dogs.

• Reptiles and amphibians

  Not recommended by the CDC for households with people with weakened immune systems. The CMAJ review says they should be kept out of such homes.

• Rodents

  On the CDC’s list of riskier animals. The CMAJ review keeps them out of high-risk households too.

• Backyard poultry, chicks and ducklings

  On the same CDC list. The CMAJ review singles out baby poultry.

• Pet birds

  Someone else should clean the cage where possible. Transplant guidance asks recipients not to handle cages or feeders, with gloves and a mask if droppings can’t be avoided.

• Aquarium fish

  The CMAJ review advises gloves, and keeping tank water out of kitchen sinks. Transplant guidance asks recipients to leave tank cleaning to someone else.

• Exotic pets

  The CDC names monkeys and other wild animals as riskier, and the CMAJ review advises avoiding contact with exotic pets.

• Farm animals and petting zoos

  The CMAJ review advises avoiding young farm animals, and the HIV guidelines advise limiting or avoiding direct contact with calves and lambs.

Two things can change this list for you: how weakened your immune system is right now, and the health and history of the animal in question.

Who this is about

“Immunocompromised” covers more people than you might think

The CDC says a weakened immune system can come from “a genetic condition, an illness such as HIV/AIDS, cancer, or kidney disease, or a treatment such as an organ transplant or radiation therapy”, and from medicines including steroids, chemotherapy and drugs for autoimmune diseases like rheumatoid arthritis or psoriasis. ESCCAP lists the elderly, diabetics, people with HIV, and those undergoing chemotherapy, organ transplantation or treatment for autoimmune diseases. Living without a spleen carries a specific risk of its own, covered below under bites.

The CMAJ review groups them with young children under 5, adults aged 65 and over and pregnant women, who are also at increased risk of zoonotic disease and of more severe illness. For everyone else, it says “the risk of pet-associated disease is small.”

It doesn’t have to be the owner, either. The advice applies to the whole household: a child on chemotherapy or a parent after a transplant changes what makes sense for the family’s dog. And the risk moves over time. Transplant guidance singles out the first 6–12 months after a transplant and the period after treatment for rejection.

The gap

Most people are never told

A survey of 265 adults with blood cancers, haemoglobin disorders or HIV found that 52% owned an animal and that only 16% of those owners could recall being told how to behave safely around animals. Eighty percent did something that could expose them to infection. Among owners, 37% let an animal sleep in the same bed and 28% let it lick their face. Across all the patients, 30% had been bitten or scratched by an animal.

This isn’t carelessness. The CMAJ review notes that pet ownership and animal contact among high-risk people look much the same as in the general public, and that doctors don’t regularly ask about pets. One result: 77% of households that got a new pet after a cancer diagnosis chose a high-risk one.

Cats

Toxoplasmosis: a worse reputation than the evidence supports

Toxoplasmosis is the usual reason people are told to give up a cat, and the disease itself is serious. ESCCAP says immunocompromised people “can suffer from severe, or even fatal” infection, in the eyes, the brain or throughout the body. What the evidence questions is how much of that risk comes from the cat.

A European study in six large cities compared pregnant women with a recent infection against uninfected women. Undercooked or cured meat accounted for 30–63% of infections, depending on the centre, and soil contact for 6–17%. “Contact with cats was not a risk factor.” These were pregnant women, not immunocompromised people, but the HIV guidelines list the same routes, and their paediatric edition notes that “most studies have failed to show a correlation between cat ownership and Toxoplasma infection in humans.”

Timing explains much of it. A cat usually sheds the parasite only after its first infection, for up to 20 days, and afterwards sheds few or no oocysts, even if reinfected. Those oocysts aren’t infective when they’re passed: they need at least 24 hours in the environment, and usually 2–5 days. A litter box emptied every day is cleaned before they’re ready. ESCCAP concludes that, compared with food, water and soil, the risk directly from a litter box “seems minor if it is cleaned daily”, while garden soil or sand where cats bury their faeces “may represent a greater infection risk”.

What the guidelines advise. ESCCAP says daily litter cleaning should not be done by “pregnant women or other persons at risk”. The HIV guidelines are more specific: for people with a CD4 count below 200 whose blood tests show no past infection, someone else (not pregnant, without HIV) should change the litter every day, and anyone who has to do it themselves should wear gloves and wash their hands thoroughly afterwards. Cats should stay indoors and eat only commercial or well-cooked food, and strays shouldn’t be adopted or handled.

The kitchen matters as much as the litter box. ESCCAP advises high-risk people to eat meat only after thorough cooking or freezing (−20 °C for at least two days), to wash fruit and vegetables thoroughly, and to wear gloves when gardening.

Cats

Cat scratch disease: it starts with fleas

The bacterium Bartonella henselae passes between cats through flea bites, and reaches people when a scratch is contaminated with flea droppings. The CDC says studies have found it in the blood of up to 1 in 3 healthy cats, particularly kittens, and that people with weakened immune systems are at higher risk of severe disease. In the HIV guidelines, the highest concern is for people with a CD4 count below 100.

So prevention is mostly about fleas and scratches: ongoing flea control supervised by a vet, no rough play, and washing any cat wound promptly with soap and water. The guidelines don’t advise declawing, and they find no benefit in testing a healthy cat for Bartonella or in treating a healthy cat that tests positive. The CDC’s bottom line: “You can still own a cat even if you are living with HIV, are being treated for cancer, or have another condition that might suppress your immune system.”

Dogs and cats

Why a bite is a different event for you

The CDC is careful to say that “Most dog or cat bites do not lead to a Capnocytophaga infection or any illness.” Even so, that bacterium is the reason bites are handled differently for some people. Capnocytophaga canimorsus lives in the saliva of healthy dogs and cats. Serious infection is rare, but it can move fast.

A review of an estimated 484 laboratory-confirmed cases put the case-fatality rate at about 26%. That figure describes cases serious enough to be confirmed and published, not the odds after a bite. Dog bites came before the illness in 60% of patients, and scratches, licking or other contact with dogs or cats in a further 27%. Prior removal of the spleen was recorded in 59 patients and alcoholism in 58.

The CDC’s higher-risk conditions are a weakened immune system from conditions like cancer, diabetes or HIV, medicines such as chemotherapy, having no spleen, and alcohol use disorders. People without a spleen stand out: the CDC’s clinical overview gives them a 30–60 times greater risk of death from this infection, with organ failure and death possible within 24–72 hours of onset.

That’s why the Infectious Diseases Society of America recommends early antibiotics for 3–5 days after a dog or cat bite for people who are immunocompromised, have no spleen or have advanced liver disease, without waiting for an infection to appear. It adds that rabies post-exposure treatment may be indicated, in consultation with local health officials. Transplant guidance tells recipients to contact their team immediately if they’re scratched or bitten by an animal, “including your own pet”.

Licks. The CMAJ review says pets shouldn’t lick open wounds, cuts or medical devices such as intravascular catheters, and may be discouraged from licking the faces of immunocompromised people. Transplant guidance simply says not to kiss pets.

The common thread

The animal to keep away from is the one with diarrhoea

Several infections take the same route, from faeces to hands to mouth. With Campylobacter, the CMAJ review says “recent acquisition of a puppy or kitten is associated with the highest risk of transmission.” Salmonella can come from any species and is especially common in reptiles, amphibians, rodents and young poultry. Cryptosporidium spreads through contact with infected people or animals, particularly those with diarrhoea, and ESCCAP says infections with the dog and cat species are “usually, but not always, restricted to immunocompromised individuals”.

This is where the litter-box logic stops working. Toxoplasma needs a day or more to become infective, but Giardia and Cryptosporidium are, in ESCCAP’s words, “immediately infective in fresh faeces”. The HIV guidelines advise avoiding direct contact with pets’ diarrhoea or stool, wearing gloves when cleaning up, and limiting or avoiding direct contact with calves and lambs. ESCCAP adds that immunocompromised people “should not be in close contact with sick cats and/or dogs”, and calls strict hygiene the only way to prevent transmission of the zoonotic types.

Giardia deserves a calmer note. Dogs and cats mostly carry animal-adapted types, so ESCCAP calls transmission from pets to people “very rare”; when animal types do turn up in people, it’s usually in the context of immunosuppression. It doesn’t generally advise treating a healthy pet that tests positive, but it makes an exception where there are immunocompromised people at home, which is one more reason to tell your vet.

Worms and ringworm

Why the deworming schedule changes

ESCCAP’s worm guideline treats your household as a risk factor in its own right. For dogs and cats sharing a home with small children, immunocompromised or elderly people, it sets out, depending on the risk assessment, planned deworming once a month or a monthly faecal test with treatment according to the findings. The concerns include Toxocara roundworms, whose larvae can lodge in the eye, nerves or brain, and Echinococcus tapeworms. Frequencies and side effects are covered in Is deworming safe?

Much of the exposure happens outdoors. The CMAJ review notes that Toxocara larvae need two to three weeks after being passed to become infective, so the highest risk is soil contaminated by untreated or stray animals, in sandboxes, gardens and playing fields. ESCCAP’s list is short: clean up faeces regularly, wear gloves when gardening, keep sandboxes covered, and wash hands after handling pets and before eating.

Ringworm is a fungal skin infection, not a worm, and cats are the usual source. ESCCAP calls for minimising exposure, “especially of children or immunocompromised people”, to infected animals and contaminated environments. Patchy hair loss on a pet is a reason to call the vet, though infected animals don’t always show obvious signs.

Other animals

Reptiles, birds and fish: the risks you can’t see

Reptiles and amphibians. They top every list because a healthy animal can’t be made safe. The CDC says even healthy ones can carry Salmonella, which reaches people through the animal, its environment or its tank water, and it is blunt about what a check-up can do: “A veterinarian will not be able to prevent your reptile or amphibian from shedding Salmonella because these bacteria are normally found in healthy reptiles and amphibians.” It adds that people with weakened immune systems shouldn’t handle feeder rodents. If such an animal is already at home, the CDC mentions having someone else in the household care for it.

Birds. Psittacosis comes from infected birds, and you don’t have to touch one to catch it. The World Health Organization says people are infected mainly by breathing in airborne particles from respiratory secretions, dried droppings or feather dust, and that “Direct contact with birds is not required for infection to occur.” In February 2024, Austria, Denmark, Germany, Sweden and the Netherlands reported a rise in cases, with five deaths, though WHO assessed the overall risk as low. Hence the advice to let someone else clean the cage.

Fish and rodents. The CMAJ review links aquarium fish with Mycobacterium marinum, and rodents, particularly mice and hamsters, with lymphocytic choriomeningitis. The CDC lists people with weakened immune systems among those more likely to become severely ill from the germs small mammals carry.

Rescue dogs

Brucella canis: rare, but worth a question

This dog infection reaches people through contact with infected secretions, with the greatest risk around birth or miscarriage in infected dogs. A 2023 UK risk assessment rated the probability of infection as very low for the general population and low for people such as breeders, kennel staff and owners of infected dogs. It also said “Immunocompromised individuals are likely to be at higher risk of severe infection.” By July 2023 the UK had identified two laboratory-confirmed human cases, one of them an immunocompromised person who needed hospital treatment.

Most UK cases in dogs involved animals imported from Eastern Europe, the great majority young dogs from Romania. If you’re adopting a dog of unknown background, it’s reasonable to ask your vet whether testing makes sense. If a dog is diagnosed, the assessment says owners with underlying conditions should tell their health professionals about the possible exposure.

The food bowl

Raw diets are the easiest risk to remove

When researchers in the Netherlands tested 35 commercial frozen raw diets, they found E. coli O157:H7 in 23%, Listeria monocytogenes in 54%, Salmonella in 20% and ESBL-producing, antibiotic-resistant E. coli in 80%. Freezing works far better against parasites than against many bacteria. A 2019 review concluded: “On a precautionary basis, the advice against raw feeding issued by various professional bodies appears justified, especially in the case of the many households that include individuals especially vulnerable to infectious disease.”

The guidance is unusually consistent here. Transplant guidance says not to feed pets raw diets. The CMAJ review recommends canned or dry commercial food or well-cooked home-prepared food, and notes that raw treats such as pig’s ears are commonly contaminated with Salmonella. (If you’re rethinking the bowl, start with Dog Nutrition Decoded.)

In practice

What the guidance adds up to

Most of the advice from the CMAJ review, the CDC, ESCCAP and transplant guidance comes down to this list:

1. Wash your hands with soap and water after touching animals or their things, and before eating.
2. Hand over the dirty jobs. Litter, cages, tanks and droppings go to someone else where possible. If not, wear gloves, and a mask too if you’ve had a transplant.
3. Clean the litter box every day and keep it away from where food is prepared or eaten.
4. Keep parasite control up to date, including fleas, on the schedule your vet sets for your household.
5. Feed commercial or well-cooked food, and skip raw meat, raw eggs and raw treats.
6. Keep licks away from your face, cuts and any medical device.
7. Avoid scratches. Keep nails short and avoid rough play. Declawing isn’t recommended.
8. Limit what your pet picks up. Cats indoors, dogs on a lead, and no drinking from toilets or surface water.
9. Clean what they use. Wash bedding regularly, for example weekly, and disinfect cages and feeding areas.
10. See the vet early. Regular check-ups, and a visit at the first sign of illness.

A new animal

If you’re thinking of getting a pet

This is the moment to ask first. Transplant guidance says to talk to your team before getting a new pet, and warns they may ask you not to in the first 6–12 months after a transplant or after treatment for rejection. The CMAJ review suggests that when immunosuppression is temporary or variable you consider waiting until it’s stable, and that “mature animals from established vendors pose a lower risk than other types of animals”. For cats, the HIV guidelines add: older than a year, in good health, from a known environment, with a documented health history and no fleas.

Your doctor and your vet

Two people who rarely speak to each other

Your doctor knows your immune system and may know nothing about your animal. Your vet knows the animal but, as the CMAJ review points out, “may not be aware of the immune status of a pet owner”. A 1999 survey in Wisconsin found “a nearly complete lack of communication” between the two professions on zoonoses, and in 2015 the CMAJ review was still reporting that most don’t regularly discuss these risks with patients, clients or each other.

So the message has to travel with you. Tell your doctor which animals you live with, and mention them again whenever you fall ill: the CMAJ review says an animal contact history helps doctors think of the right diagnoses. Tell your vet that someone at home is immunocompromised. You don’t have to share the diagnosis, and ESCCAP says this information should be available “without the need for a medical history of the client”. That one sentence can change the deworming schedule, how a positive Giardia test is handled and the advice you get about a new animal.

The limits

What the guidelines can’t tell you

Much of this advice is careful reasoning, not measured risk. The 2019 American Society of Transplantation guideline says many of its recommendations rest on “good infection prevention standards, extrapolation from other immunocompromised hosts, and risks found from cases series in transplant patients”. The CMAJ review says the information available to help people weigh the risks and benefits of pet contact “is limited”. Some of the most specific advice here was written for people with HIV and low CD4 counts, and may not transfer directly to other conditions. Nobody can give you a personal percentage.

The benefits count too. The same review says pet ownership “can have health, emotional and social benefits”, and that is why the guidance leans towards precautions, not removal. If a conversation about rehoming does come up, it deserves to be specific: which animal, which infection, for how long. Your medical team can answer that, with your vet filling in the animal’s side.

The source

“Is this safe for my household?”

Questions like this are easy to answer badly online, in both directions: “get rid of the cat” or “it’s fine”. Lares Pecoris is a reference tool for veterinarians. It answers from official documents, among them the ESCCAP guidelines cited here, and every answer comes with its source. It covers the animal’s side of the question; your own care stays with your medical team. When a question isn’t covered by the sources, Lares says so instead of guessing (more in how we build the corpus).

Questions

Frequently asked questions

Sources

1. US Centers for Disease Control and Prevention. Healthy Pets, Healthy People: risk factors, 30 January 2025; Reptiles and amphibians, 13 January 2026; Small mammals, 14 May 2026.
2. US Centers for Disease Control and Prevention. About cat scratch disease, updated 23 March 2026.
3. US Centers for Disease Control and Prevention. About Capnocytophaga and Clinical overview of Capnocytophaga, 26 August 2025.
4. Stull JW, Brophy J, Weese JS. Reducing the risk of pet-associated zoonotic infections. CMAJ 2015;187(10):736–743. doi:10.1503/cmaj.141020.
5. American Society of Transplantation. Interacting with animals after your transplant, patient handout, revised 1 March 2025.
6. Avery RK, Michaels MG, AST Infectious Diseases Community of Practice. Strategies for safe living following solid organ transplantation. Clinical Transplantation 2019;33(9):e13519. doi:10.1111/ctr.13519.
7. US National Institutes of Health. HIV Clinical Guidelines: Adult and Adolescent Opportunistic Infections. Toxoplasmosis, updated 9 September 2025; Bartonellosis, updated 14 November 2023; Cryptosporidiosis, updated 18 January 2023.
8. US National Institutes of Health. HIV Clinical Guidelines: Pediatric Opportunistic Infections. Toxoplasmosis.
9. ESCCAP Guideline 01: Worm Control in Dogs and Cats, 7th edition, June 2025.
10. ESCCAP Guideline 02: Superficial Mycoses in Dogs and Cats, 4th edition, February 2019.
11. ESCCAP Guideline 03: Control of Ectoparasites in Dogs and Cats, 7th edition, January 2022.
12. ESCCAP Guideline 06: Control of Intestinal Protozoa in Dogs and Cats, 3rd edition, March 2025.
13. Cook AJC, Gilbert RE, Buffolano W, et al. Sources of toxoplasma infection in pregnant women: European multicentre case-control study. BMJ 2000;321:142. Full text.
14. Butler T. Capnocytophaga canimorsus: an emerging cause of sepsis, meningitis, and post-splenectomy infection after dog bites. European Journal of Clinical Microbiology & Infectious Diseases 2015;34:1271–1280. PubMed.
15. Stevens DL, Bisno AL, Chambers HF, et al. Practice guidelines for the diagnosis and management of skin and soft tissue infections: 2014 update by the Infectious Diseases Society of America. Clinical Infectious Diseases 2014;59(2):e10–e52. doi:10.1093/cid/ciu444.
16. Gurry GA, Campion V, Premawardena C, et al. High rates of potentially infectious exposures between immunocompromised patients and their companion animals: an unmet need for education. Internal Medicine Journal 2017;47(3):333–335. Abstract.
17. Grant S, Olsen CW. Preventing zoonotic diseases in immunocompromised persons: the role of physicians and veterinarians. Emerging Infectious Diseases 1999;5(1):159–163. Full text.
18. van Bree FPJ, Bokken GCAM, Mineur R, et al. Zoonotic bacteria and parasites found in raw meat-based diets for cats and dogs. Veterinary Record 2018;182(2):50. PubMed.
19. Davies RH, Lawes JR, Wales AD. Raw diets for dogs and cats: a review, with particular reference to microbiological hazards. Journal of Small Animal Practice 2019;60(6):329–339. doi:10.1111/jsap.13000.
20. UK Health Security Agency, Human Animal Infections and Risk Surveillance group. HAIRS risk assessment: Brucella canis, August 2023.
21. World Health Organization. Psittacosis – European region, Disease Outbreak News, 5 March 2024.

All sources accessed 30 October 2026.