Carsten column: The sneezing cat
Integrative Pet Vet
Upper respiratory infections (URI) are common in cats worldwide with an average of 25-35 percent of cats being affected in some shelter studies. Owned cats have a lower incidence than shelter cats. URI in cats can be caused by a variety of viruses and bacteria. Signs of infection include eye discharge, nasal discharge, sneezing, oral ulcers and eye ulcers. Many cats can effectively clear the infection, while others become carriers or have latent infections.
Younger cats and older cats are thought to be at higher risk for developing URI because their immune systems cannot effectively prevent the infection. Older cats with health concerns or increased stress levels may have further impairment of their immune system. Vaccination history can have an impact on preventing infection, but vaccines are not available for all organisms.
URI in cats is complex because multiple organisms can be involved. These organisms include feline herpesvirus-1 (FHV), feline calicivirus (FCV), Chlamydophila felis (C. felis), Bordetella bronchiseptica (B. bronchiseptica), and Mycoplasma felis (M. felis). While some authorities estimate that 90 percent of infections are caused by FHV or FCV, one organism or a combination of organisms at the same time can cause URI. This complexity can create challenges for initial treatment and long-term management, especially because each of the infectious organisms has unique disease patterns in the cat and susceptibility to environment conditions.
FHV and FCV are viruses. C. felis and B. bronchiseptica are bacteria, while M. felis is an unusual type of bacteria. Cats infected with any of these organisms will typically have sneezing and nasal discharge as a sign of infection. Some infections with FHV and FCV can result in ulcers in the mouth and eyes. B. bronchiseptica can cause coughing. Interestingly, infections with FCV and M. felis can result in lameness from joint pain and osteoarthritis.
Diagnosis is based on the signs, but there are tests that can be performed to confirm the diagnosis. In severely affected cats additional tests like blood counts and X-rays may be necessary for full patient evaluation.
Generally, the infections run their course in 7-21 days but this can be complicated by secondary bacterial infections and the ability of the immune system to respond adequately. Viruses like FCV have multiple strains. Some strains are very aggressive at causing disease and can be so severe that they can cause death. Other organisms like FHV infection can lead to latent infections, and C. felis can have a chronic carrier state. These infections can re-emerge following stress or other events that can suppress the immune response.
Infections are spread through sneezing and direct contact with infected cats or organisms in the environment. The organisms can survive in the environment for variable times. For example, FHV and C. felis do not live long in the environment, while FCV can survive over a month.
Treatment depends on the organism(s) causing the URI and the severity of the infections. Antibiotics may be needed for organisms like C. felis and B. bronchiseptica or for secondary bacterial infections. Use of anti-viral drugs is becoming more common for FHV and FCV infections. Severely affected cats may have to be hospitalized for treatment to help maintain hydration and assist with eating. Many cats stop eating because of the mouth ulcers and nasal discharge. Supportive care for the lining of the respiratory tract and immune system using vitamins like A and C can be important. Probiotics have been shown to increase immune activity. Mushrooms and certain herbs may be beneficial for boosting the immune system. The amino acid lysine has been advocated for helping to manage the viral infections.
If you have questions about your sneezing cat, contact your veterinarian. Keep in mind that not all sneezing is caused by a respiratory infection. There are other causes.
Ron Carsten, DVM, PhD, CVA, CCRT was one of the first veterinarians in Colorado to use the integrative approach, has lectured widely to veterinarians, and has been a pioneer in the therapeutic use of food concentrates to manage clinical problems. In addition to his Doctor of Veterinary Medicine, he holds a PhD in Cell and Molecular Biology and is a Certified Veterinary Acupuncturist and Certified Canine Rehabilitation Therapist. He practices integrative veterinary medicine in Glenwood Springs.