Cowpox is a pox virus infection that cats pick up from small rodents, not from cows. The name is a leftover from history. [1] Today cats are among the animals in which it turns up most often, which is why it is sometimes called catpox, and more than 400 cases in pet cats have been described. [4][5]
Where cowpox is found
Cowpox viruses belong to Europe and Asia (Eurasia) and are found mainly in Europe. [5][7] Cases in cats are reported from Northern and Western Europe, including the United Kingdom. [2][4]
How cats catch it
Small wild rodents, especially voles and some mice, carry the virus. In experiments, infected bank voles showed no signs of illness. [5] Cats usually get the virus through the skin when a rodent bites them, typically while hunting; infection through the nose or mouth is rare. [2] That is why the first sore usually sits where a hunting cat gets bitten.
In a German study of 46 cats with cowpox, most were outdoor cats from rural areas, and signs showed up in late summer or autumn. [3]
Cat-to-cat spread seems uncommon. In the same study, about half the cats shared their home with other pets, yet only one other cat in those homes showed typical signs. [3]
Signs
- A first sore at the bite site. The infection usually starts as a single local sore where the virus got in through broken skin or a bite wound. [5]
- Several ulcerated, crusted sores. Typical lesions are crusty, ulcerated patches of skin, found mostly on the head, neck, front legs and paws, and sometimes in the mouth. [1][2][4][6]
- Eye signs. Some cats get conjunctivitis or a pus-like discharge from the eyes. [4]
- Mild illness. Some cats are mildly unwell along with the skin sores. [6]
The severe form
Severe, body-wide illness is uncommon. It mostly affects kittens and cats with a weakened immune system, and it can be fatal. [1][6] When the virus spreads inside the body, cats can have fever, poor appetite, low energy and pneumonia. [2][4] Lung involvement, other infections at the same time and immune problems are the factors linked to this systemic form. [4]
What one study found
Researchers in Germany collected cat cowpox cases from 2004 to 2010 through pathology laboratories and sent questionnaires to the vets and owners involved. They evaluated 46 cases. [3]
- Most cats lived outdoors in the countryside and fell ill in late summer or autumn.
- Every cat had skin sores, mostly on the front half of the body, and 61% had other signs as well.
- About half lived with other pets, but typical signs turned up in another household cat only once.
- The authors thought the cat passed the virus to a person in two cases.
The team also tested 92 healthy-looking outdoor cats from areas with earlier cases. 16 of them (17%) carried antibodies to orthopoxviruses, a figure the authors said may be high because the cats came from areas where cases were already known. [3]
How vets diagnose cowpox
History matters. A cat that goes outside and hunts rodents and turns up with skin sores, cough or fever should make a vet think of cowpox. [2] The diagnosis is confirmed with laboratory tests on samples such as scabs from the sores, for example PCR testing, electron microscopy or virus culture. Blood tests for antibodies can help too, though a rising level is needed to show an active infection. [2]
Other skin problems can look similar, so your vet may need tests to tell them apart. See itchy cat and overgrooming, eosinophilic granuloma complex in cats and ringworm in dogs and cats.
Treatment
An early diagnosis matters. The authors of a case report on cat cowpox stress that vets should recognise the signs and test early, so the cat is treated appropriately and the right precautions are taken. [2] Because severe disease is tied to a weakened immune system, [1][6] tell your vet if your cat hunts before any skin treatment is chosen.
Care is mostly supportive. Antibiotics may be used to control bacterial infection of the sores. [2] Your vet will decide what your cat needs.
Can people catch cowpox from a cat?
Yes. Cowpox can infect people, and cats are now a common route: more than half of human cowpox cases in the United Kingdom are thought to be linked to contact with cats. [4] The earliest recorded case of a cat passing it to a person dates from 1985, in the Netherlands. [7] In people the infection usually causes local skin sores on the arms, legs or face. [4]
Human cases are still rare and usually stay local, but people with a weakened immune system can become seriously ill. [4][5] Cat owners should be told about this risk. [1] If your cat has been diagnosed with cowpox, ask your vet what precautions to take at home, and see your doctor about any sore of your own.
When to see your vet
- Crusty, ulcerated sores on the head, neck, front legs or paws of a cat that hunts, especially in late summer or autumn. [1][3]
- Your cat is unwell with skin sores: fever, low appetite or low energy. [2]
- Coughing or breathing problems in a cat with skin sores. [2]
- A kitten, or a cat with a weakened immune system, that develops new crusty sores. [1]
- Before any skin treatment for sores in a hunting cat, mention that your cat hunts. [2]
FAQ
Is cowpox in cats found in the United States?
Cowpox viruses are found in Eurasia, mainly in Europe, [5][7] and cat cases are reported from Northern and Western Europe. [2][4] Ask your vet about what is common where you live.
Can my cat give cowpox to my other cats?
It seems uncommon. In the German study, about half the cats lived with other pets, but typical signs showed up in another cat in the home only once. [3]
How serious is catpox?
In most cats the disease stays in the skin, sometimes with mild illness. [6] Severe, sometimes fatal disease mainly affects kittens and cats with a weakened immune system. [1]
Can I catch it from my cat?
Yes, cats are a common source of human cowpox. [4] Ask your vet about precautions and see your doctor about any sore of your own.
The bottom line
Cowpox (catpox) is a pox virus that cats catch from wild rodents, usually while hunting. It is found in Eurasia, mainly Europe. Most cats get crusty, ulcerated sores on the head, neck, front legs or paws, often in late summer or autumn, and severe disease is mostly seen in kittens and cats with a weakened immune system. Tell your vet if your cat hunts, because early testing helps the cat get the right care, and the virus can also infect people. [1][2][3][4]
This article is for general information and is not a substitute for a veterinary exam. If you are worried about your cat’s skin, see your veterinarian.
Sources
- Möstl K, Addie D, Belák S, et al. Cowpox virus infection in cats: ABCD guidelines on prevention and management. J Feline Med Surg. 2013;15(7):557-559. PMID 23813814 (abstract). https://pubmed.ncbi.nlm.nih.gov/23813814/
- Breheny CR, Fox V, Tamborini A, et al. Novel characteristics identified in two cases of feline cowpox virus infection. JFMS Open Rep. 2017;3(2):2055116917717191. CC BY-NC 4.0. https://pmc.ncbi.nlm.nih.gov/articles/PMC5528940/
- Appl C, von Bomhard W, Hanczaruk M, Meyer H, Bettenay S, Mueller R. Feline cowpoxvirus infections in Germany: clinical and epidemiological aspects. Berl Munch Tierarztl Wochenschr. 2013;126(1-2):55-61. PMID 23367669. https://pubmed.ncbi.nlm.nih.gov/23367669/
- Chomel BB. Emerging and re-emerging zoonoses of dogs and cats. Animals (Basel). 2014;4(3):434-445. CC BY 3.0. https://pmc.ncbi.nlm.nih.gov/articles/PMC4494318/
- Bruneau RC, Tazi L, Rothenburg S. Cowpox viruses: a zoo full of viral diversity and lurking threats. Biomolecules. 2023;13(2):325. CC BY 4.0. https://pmc.ncbi.nlm.nih.gov/articles/PMC9953750/
- Godfrey DR, Blundell CJ, Essbauer S, et al. Unusual presentations of cowpox infection in cats. J Small Anim Pract. 2004;45(4):202-205. PMID 15116889 (abstract). https://pubmed.ncbi.nlm.nih.gov/15116889/
- Diaz-Cánova D, Mavian C, Brinkmann A, Nitsche A, Moens U, Okeke MI. Genomic sequencing and phylogenomics of cowpox virus. Viruses. 2022;14(10):2134. CC BY 4.0. https://pmc.ncbi.nlm.nih.gov/articles/PMC9611595/