Keeping Pets When You're Diagnosed With Cancer

Infection risks can run high during cancer therapy

Pets can be a source of comfort and companionship any time, but especially during cancer treatment. Research has shown that pet therapy can be beneficial during chemotherapy, if appropriate safety precautions are taken. A pet can decrease feelings of loneliness, promote a sense of well-being, and even reduce the need for pain medications.

Knowing more about pet-related infections or illnesses and taking safety precautions can help reduce your risk for pet-related diseases. Read on to find out more.

Cancer patient cuddles with dog
KatarzynaBialasiewicz / iStock / Getty Images


Diseases can be spread from pets to humans in a variety of ways, including:

  • Scratches
  • Flea bites
  • Fecal and urinary transmission
  • Licking of an open wound
  • Bites
  • Tick-borne illnesses
  • Contact with infected tissues

Understanding Zoonotic Diseases

We don't often think of catching diseases from pets, but the simple fact is that as many as 60% of known infectious diseases can be passed from animals to humans. Called zoonotic infections, these are the types of diseases that are spread through bites, scratches, and contact with the saliva or feces of pets and other animals.

People undergoing chemotherapy are more prone to these infections due to the immune suppressive nature of the drugs, which lower the number of white blood cells needed to fight disease.

There are around 30 to 40 infectious organisms that can be spread from animals to humans, the vast majority of which are rare. The more common types are around us every day and tend to only cause disease when our immune system is severely compromised.

Cat-Borne Infections

The most serious cat-related infection is toxoplasmosis caused by a parasite called Toxoplasma gondii. The disease is considered widespread with upwards of 30% of the population having evidence of a prior infection. While symptoms are most often mild to non-existent in healthy individuals, cat-borne infections can be serious in those with compromised immune systems, leading to seizures, blindness, and encephalitis (swelling of the brain).

Another common cat-related infection is bartonellosis (cat scratch fever) caused by the bacterium Bartonella henselae. After getting scratched by an infected cat, people can experience symptoms similar to that of mononucleosis (mono), including a sore throat, fatigue, and swollen glands in the neck and/or armpits. Kittens are more likely to spread the disease than adult cats.

Dog-Borne Infections

As with cats, your dog can inadvertently spread infection when you are scratched, bitten, or come to contact with their feces. Exposure to eggs of the dog's tapeworm (echinococcosis) is known to cause severe liver disease. While rare in the U.S., experts believe that over a million people have been infected worldwide.

Other infections can be spread by flea bites from your pet, including bartonellosis, allergic dermatitis, Yersinia pestis (plague), and epidemic typhus is seen occasionally in rural parts of the U.S.

Bird-Borne Infections

The most common disease transmitted by birds is psittacosis, an infection caused by the bacteria Chlamydia psittaci. Symptoms in humans include fever, muscle pain, headache, diarrhea, fatigue, dry cough, and vomiting.

Birds with psittacosis often appear sickly with rash, eye discharge, diarrhea, and a general lackluster appearance. The bacteria is typically spread by contact with either a sick bird or its droppings.

Infections Caused by Reptiles, Amphibians, and Fish

While careful handling can prevent many pet-borne infections, reptiles and amphibians appear to be the exception. Some oncologists, in fact, recommend that pets such as iguanas, snakes, lizards, frogs, and salamanders be completely avoided during chemotherapy. Reptiles and amphibians are known to harbor bacteria such as salmonella and campylobacter, all of which can easily be transmitted by touch.

For their part, aquarium fish can sometimes carry Mycobacterium marinum, a bacterial disease commonly identified by nodules on the fish's skin. Contact with either the fish or the inside of the aquarium can pass the infection to those with compromised immune systems. Symptoms include the formation of skin lesions called granulomas. In rare cases, the bacteria can spread through the bloodstream to infect other organs.


There are a number of ways to avoid getting infections from your furry, scaled, or a feathered friend:

  • Make sure your pets' vaccinations are up to date and they get regular check-ups.
  • Avoid handling urine and feces.
  • Handle your pet more gently to avoid scratches or bites.
  • Keep your pets' nails short.
  • Keep your cat indoors.
  • Put a flea collar on your dog or cat and use flea powder or dip if the pet is scratching.
  • Wash your hand regularly, especially after your pet is outside, around other pets, or you've cleaned their living area (even if you used gloves).
  • Take your pet to the vet immediately if it has any sign of illness.
  • Keep pet areas clean.
  • Consider having a friend keep your pet while it is ill or board it with your vet.


Knowing more about how to protect yourself from pet-related illnesses can help you enjoy your pets even through cancer and its treatment. Make sure they have their shots, see their vet regularly, try to avoid handling urine and feces, and wash your hands regularly to help reduce your risk.

A Word From VeryWell

Pets can be such a comfort, especially when you're going through cancer treatment. Talk with your healthcare team about your pet, any safety risks you should be aware of, and what other things you can do to help further reduce your risk of any safety hazards. When you take your pet to the vet, ask them about safety precautions. They might know about things that human doctors might not be aware of.

Frequently Asked Questions

  • What animals should you stay away from if you have cancer?

    Exotic pets, reptiles, chickens, rodents, ducks, and pocket pets should be avoided. This is because they can have different diseases that would be bad for someone with a compromised immune system.

  • Can your chemotherapy affect your pet?

    No, they will be fine.

  • Can dogs smell cancer treatment?

    Dogs have smell receptors that are 10,000 times more sensitive than humans. Dogs can smell cancer, and multiple studies have found that dogs can identify blood samples with cancer. They are able to smell chemotherapy because of the chemical changes the drugs cause within the blood.

  • Can you get an emotional support animal for cancer?

    Yes, you can. Emotional support animals (ESAs) don't require any special training but need to behave appropriately. For an animal to be an ESA, you must have a mental health provider prescription. This is most often done for those with depression, anxiety, and panic attacks—all of which those with cancer experience.

17 Sources
Verywell Health uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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  2. Day MJ. Pet-related infections. Am Fam Physician. 2016;94(10):794-802.

  3. Centers for Disease Control and Prevention. Zoonotic diseases.

  4. Zwickey H. Chemotherapy-induced ImmunosuppressionNatural Medicine Journal. 2014;6(21).

  5. Washington State Department of Health. Animal transmitted diseases.

  6. Centers for Disease Control and Prevention. Parasites - Toxoplasmosis (Toxoplasma infection).

  7. Centers for Disease Control and Prevention. Bartonella infection (cat scratch disease, trench fever, and Carrión’s disease).

  8. Centers for Disease Control and Prevention. Parasites - Echinococcosis.

  9. World Health Organization. Echinococcosis fact sheet.

  10. Traversa D. Fleas infesting pets in the era of emerging extra-intestinal nematodes. Parasit Vectors. 2013;6:59. doi:10.1186/1756-3305-6-59

  11. New York State Department of Health. Psittacosis (ornithosis, parrot fever, chlamydiosis).

  12. Washington State Department of Health. Salmonella from reptiles and amphibians.

  13. Centers for Disease Control and Prevention. Invasive Mycobacterium marinum infections.

  14. Cancer Treatment Centers of America. What cancer patients need to know before getting a new pet.

  15. Jenkins EK, DeChant MT, Perry EB. When the nose doesn’t know: canine olfactory function associated with health, management, and potential links to microbiota. Front Vet Sci. 2018;5:56. doi:10.3389/fvets.2018.00056

  16. Pirrone F, Albertini M. Olfactory detection of cancer by trained sniffer dogs: a systematic review of the literature. J Vet Behav. 19:105-117. doi:10.1016/j.jveb.2017.03.004

  17. American Cancer Society. Pets, support, and service animals for people with cancer.

Additional Reading
  • Hemsworth, S., and Pizer, B. "Pet Ownership in Immunocompromised Children – A Review of the Literature and Survey of Existing Guidelines." European Journal of Oncology Nursing. 10(2):117-27.

  • Safdar, A. "Principles and Practice of Cancer Infectious Diseases." Humana Press; ISBN 9781617797460.

Originally written by Lisa Fayed