Introduction
Humans can transmit a number of viral and bacterial infections to cats. Some of the most common and concerning viruses that can be passed from humans to cats include feline panleukopenia virus, feline herpesvirus, feline calicivirus, feline immunodeficiency virus, and rabies. Bacterial infections like salmonella and ringworm are also risks. Many of these diseases produce flu-like symptoms in cats but can become serious if left untreated. Kittens, senior cats, and cats with compromised immune systems are most at risk. While it is impossible to completely eliminate risks, there are ways humans can reduce transmission by being aware of common pathogens, limiting contact with unfamiliar cats, practicing good hygiene, and keeping cats up-to-date on vaccines.
Feline Panleukopenia
Feline panleukopenia, also known as feline distemper, is caused by the feline parvovirus and is highly contagious and often fatal in cats (AVMA, 2022). The virus attacks and kills white blood cells, leaving cats vulnerable to potentially deadly secondary infections. It spreads through direct contact with infected bodily fluids as well as indirectly through objects like food bowls, shoes, and clothing (PetMD, 2022).
Feline panleukopenia mainly affects unvaccinated kittens under 5 months old, with mortality rates up to 90% if untreated. Symptoms include fever, diarrhea, vomiting, loss of appetite, and lethargy. There is no specific treatment beyond supportive care like IV fluids, antivirals may help. Strict hygiene measures are crucial to avoid transmission. Vaccination starting at 6-8 weeks of age can prevent infection (AVMA, 2022).
While humans cannot directly catch feline panleukopenia, they can easily transmit it between cats on hands or clothing. Thorough handwashing and changing clothes/shoes after contact with infected cats can help break the chain of transmission (PetMD, 2022).
Feline Herpesvirus
Feline herpesvirus (FHV) is a highly contagious upper respiratory infection in cats (Source 1). It is estimated that over 50% of the cat population has been exposed to FHV. The virus causes rhinitis, conjunctivitis, and respiratory disease in cats (Source 2).
FHV is spread through direct contact with infected secretions, such as nasal discharge, oral fluids, or eye fluids. The incubation period ranges from 2-10 days. Most kittens are exposed to FHV early in life from their mother. The symptoms generally involve the upper respiratory tract and eyes. Common signs include sneezing, nasal discharge, conjunctivitis, and eye ulcers or corneal ulcers.
There is no cure for FHV, but supportive care and medications can help relieve symptoms. The virus remains dormant in the nerves of infected cats. Stress or illness can reactivate the virus, leading to recurrent infections. Keeping cats in low stress environments and separated from infected cats can help reduce outbreaks.
Feline Calicivirus
Feline calicivirus is a highly contagious respiratory virus that causes oral ulcers and flu-like symptoms in cats [1]. The virus spreads through direct contact with infected cats’ saliva, nasal mucus, eye discharge, and aerosol droplets [2]. Common symptoms include ulcers on the tongue, hard palate, gums, lips, and nose, as well as sneezing, nasal discharge, congestion, fever, and lethargy. In some cases, severe pneumonia, lameness, or chronic stomatitis can occur. There is no cure for feline calicivirus, so treatment focuses on supportive care and managing symptoms. Vaccines can help prevent infection but may not fully protect against all strains. Feline calicivirus poses no known risk to human health.
Feline Immunodeficiency Virus
Feline immunodeficiency virus (FIV) is a lentivirus that weakens a cat’s immune system leading to secondary infections [1]. FIV is sometimes referred to as feline AIDS because it has a similar effect on cats as HIV does in humans. However, FIV cannot be transmitted to humans [2].
FIV attacks and disables a cat’s immune system by targeting CD4+ T cells which help coordinate the immune response. As the disease progresses, the cat’s ability to fight off other infections becomes severely impaired leading to chronic secondary infections. Common secondary infections include upper respiratory infections, stomatitis, cancer, and kidney disease.
FIV is transmitted through deep bite wounds, where the virus present in the infected cat’s saliva enters the bloodstream of another cat. Casual contact such as sharing food bowls or grooming does not transmit FIV [3]. FIV cannot survive long outside of the cat’s body and is not easily transmitted.
Rabies
Rabies is a viral disease that is almost 100% fatal if contracted by a cat and not treated properly. It attacks the central nervous system, with the most common transmission method happening through the saliva from an infected animal via a bite wound.[1] Rabies can be spread from an infected wild animal like a raccoon, skunk, bat or fox to a cat. Household pets like cats and dogs can contract rabies, but cases of transmission from cats to humans are extremely rare in the United States.[2]
Rabies causes neurological symptoms and aggression in cats as the virus makes its way to the brain via the nerves. A rabid cat may act restless, aggressive, disoriented, paralyzed, or may suffer from seizures. Death usually occurs within 10 days from when signs start.[3] If a human gets bitten or scratched by a cat suspected to have rabies, immediate medical attention is required as rabies is fatal if left untreated.
[1] https://www.merckvetmanual.com/cat-owners/brain,-spinal-cord,-and-nerve-disorders-of-cats/rabies-in-cats
[2] https://www.alleycat.org/cats-are-no-rabies-threat/
[3] https://www.webmd.com/pets/cats/rabies-cats
Toxoplasmosis
Toxoplasmosis is caused by a parasite called Toxoplasma gondii. Cats can become infected by eating infected rodents, birds, or other small animals. According to the CDC, cats only spread Toxoplasma in their feces for 1-3 weeks after initial infection[1]. Like humans, cats rarely show symptoms when infected. An indoor cat’s risk of infection is very low compared to outdoor cats that hunt[2].
Once infected, most cats will not become sick from toxoplasmosis. They can, however, pass the parasite on to humans through contact with their feces. Pregnant women are at the highest risk of health complications if infected.
Ringworm
Ringworm is a fungal skin infection that cats can transmit to humans. It causes distinctive circular rashes in both species. Ringworm is caused by dermatophyte fungi, which can live on cats’ skin, fur, and nails. The fungi are very contagious and spread through direct contact with infected skin, fur, or contaminated objects. Young kittens and cats with compromised immune systems are most susceptible.
On cats, ringworm causes patches of hair loss and scaly skin, often in circular lesions. The edges are usually red and raised. Ringworm is diagnosed through fungal culture, skin scraping, ultraviolet light examination, or biopsy. In humans, ringworm causes reddish, itchy, circular rashes on the skin. The rashes often have raised edges and thinner centers, giving them a ring-like appearance. Ringworm is diagnosed through physical examination and fungal culture.
To treat ringworm, antifungal medications are used on both cats and humans. Topical creams, oral medications, medicated shampoos, and lime-sulfur dips can be prescribed for cats. Environmental decontamination is also important. Humans are treated with topical antifungal creams, oral antifungals, or both. Ringworm is highly contagious between cats and humans through direct skin contact. To prevent transmission, avoid touching infected areas on a cat, wear gloves when applying medications, and disinfect the home environment.
Sources:
https://www.cdph.ca.gov/Programs/CID/DCDC/Pages/Ringworm.aspx
https://pvecvets.com/blog/does-my-cat-have-ringworm/
Prevention
There are several ways pet owners can help prevent the spread of viruses and diseases between cats and humans:
- Get cats vaccinated – Vaccines can protect cats from diseases like panleukopenia, herpesvirus, calicivirus, rabies, and feline leukemia. Kittens should receive a series of vaccinations starting around 6-8 weeks old. Adult cats need booster vaccines every 1-3 years depending on the disease.
- Practice good hygiene – Washing hands with soap and water after handling cats, cleaning the litter box, or touching any cat items can prevent spread of toxoplasmosis, ringworm, and other diseases. Keeping cat food preparation surfaces clean is also important.
- Limit outdoor access – Keeping cats indoors prevents them from contracting and spreading illnesses from other outdoor cats and wildlife. Cats allowed outdoors should be supervised.
- Control parasites – Routinely using flea/tick and heartworm prevention medications keeps parasites under control. Promptly treat cats if parasites are detected.
- Visit the vet regularly – Annual vet exams allow early detection and treatment of medical issues. Sick cats should be seen promptly by a vet.
Following these basic preventative measures greatly reduces the chances of disease transmission between cats and their human families.
Conclusion
Some of the most notable viruses that humans can pass on to cats include serious diseases like feline panleukopenia, feline herpesvirus, and feline immunodeficiency virus. Rabies is also a concern when it comes to transmission between humans and cats. In addition, humans can pass parasitic infections like toxoplasmosis and fungal infections like ringworm on to cats.
Fortunately, there are steps cat owners can take to protect the health of their feline companions. Getting cats vaccinated against panleukopenia, herpesvirus, calicivirus, and rabies is crucial. Regular veterinary checkups enable early detection and treatment of any illness. Practicing good hygiene, properly cleaning litter boxes, washing hands before and after contact with cats, and keeping cats indoors can also reduce the risk of disease transmission.
By understanding what viruses humans can give their cats and taking preventative measures, cat owners can keep their pets healthy and avoid the spread of contagious diseases.
