Educational Articles

Cats + Infectious Diseases

  • Chlamydial conjunctivitis in cats is an infection caused by a bacterial organism. The most common signs of chlamydia in cats involve the eyes or the upper respiratory tract (nose or throat), and only when infection is not treated does it spread to the lungs. In cats with conjunctivitis, the conjunctiva becomes swollen and red. Chlamydia is spread by close or direct contact with an infected cat, so all cats in the home can become infected. Chlamydia can be successfully treated with a course of oral and topical antibiotics.

  • When clinical signs of upper respiratory tract inflammation, such as sneezing or nasal and eye discharge, persist over weeks or months, or when they tend to recur at intervals of a few weeks, the condition is referred to as chronic upper respiratory tract disease. A runny or stuffed-up nose is the most common clinical sign in cats with chronic infections. There are many causes of this relatively common problem in cats. The treatment will be determined by the test results and diagnosis.

  • Coccidiosis is an intestinal tract infection caused by a one-celled organism or protozoa called coccidia. Coccidia are microscopic parasites that live within the cells that line the intestine. Many cats that are infected with coccidia do not have diarrhea or any other clinical signs. When the oocysts are found in the stool of a cat without diarrhea, they are generally considered a transient, insignificant finding. However, in kittens and debilitated adult cats, coccidiosis can cause severe, watery diarrhea, dehydration, abdominal distress, and vomiting. Kittens are commonly diagnosed with coccidiosis. The most common drug used to treat coccidiosis is a sulfa-class antibiotic, sulfadimethoxine. Cats are frequently reinfected from the environment, so disinfection is important.

  • Conjunctivitis is the medical term used to describe inflammation of the tissues surrounding the eye. Feline herpesvirus conjunctivitis a form of primary conjunctivitis caused by the highly infectious feline herpesvirus (FHV-1).

  • COVID-19 is a disease caused by the coronavirus, SARS-CoV-2. Current evidence suggests that person-to-person spread is the main source of infection. While there is evidence of transmission from humans to dogs and cats, it does not appear to be a common event at this time. If you suspect that you are ill with COVID-19, you should practice the same precautions with your pet as you would with people: wear a mask, keep your distance, wash your hands regularly, and avoid cuddling and other close contact. If your pet needs veterinary care while you are sick with COVID-19, do not take your pet to your veterinary clinic yourself.

  • Cytauxzoonosis is an often-fatal disease caused by a tick-borne protozoan parasite, typically found in bobcats. It is more commonly seen in the southern United States but is spreading with tick migration. It can cause anorexia, lethargy, respiratory difficulty, anemia, and jaundice. Diagnostic testing, treatment options, and preventives are described in this handout. This disease is not transmissible to dogs or humans.

  • Diarrhea is a symptom of an underlying problem that may be minor or very serious. Some cases may resolve on their own or with minimal treatment, while other cases require in-depth diagnostic testing and more aggressive treatment to address the underlying condition. The possible causes, diagnostic tests, and treatment protocols for diarrhea in cats are numerous and they are explained in this handout.

  • Echinococcus multilocularis is a tapeworm species that is found in the Northern Hemisphere. Dogs, cats, and humans are all susceptible to E. multilocularis infection, along with additional species. While the parasite typically produces no clinical sign in cats, it can have life-threatening effects in humans. E. multilocularis is impossible to distinguish from other tapeworm species without specialized testing, but it responds to the same dewormers that are used to treat other tapeworm species. Therefore, pets suspected of having tapeworms should be treated promptly and care should be taken to avoid direct contact with animal feces.

  • Famciclovir is given by mouth and is used off-label to control feline herpesvirus. Give as directed. Side effects may include vomiting, diarrhea, decreased appetite, and increased drinking and urination. Do not use it in pets that are allergic to it or penciclovir. If a negative reaction occurs, call your veterinary office.

  • Fechavirus is a chapparvovirus, which is a type of parvovirus. It is a newly discovered gastrointestinal virus identified in cats in 2018. The virus was discovered during an outbreak of vomiting and diarrhea among cats in three animal shelters in British Columbia, Canada. The significance of fechavirus in pet cats is unknown at this point. The most common signs associated with fechavirus are diarrhea and vomiting. If your veterinarian suspects fechavirus, your cat will receive supportive care in order to control clinical signs and prevent dehydration.