- Feline chlamydiosis is contagious among cats and tends to be spread through direct contact with infected cats.
- Vaccinating cats against feline chlamydiosis reduces the severity of clinical signs in infected cats.
- Separating sick cats from healthy ones and keeping the environment clean are good methods for preventing disease spread.
What Is Feline Chlamydiosis?
Feline chlamydiosis (also called feline pneumonitis) is caused by the bacterial organism Chlamydophila felis (C. felis). The C. felis organism does not live for very long in the environment, so infection is generally spread through direct or close contact with a sick cat. Because infected cats sometimes sneeze, contact with these droplets can also spread the infection.
Signs of Feline Chlamydiosis
The primary clinical sign associated with feline chlamydiosis infection is conjunctivitis (inflammation of the inner eyelids and associated tissues). When conjunctivitis occurs, the eyes can become bloodshot and often develop a discharge. The discharge may be watery or thicker, resembling mucus. One or both eyes may be affected. Sometimes an infected cat may squint or rub its eyes. The severity of infection can vary, so other clinical signs, such as fever and sneezing, may also be observed.
Because feline chlamydiosis can occur along with other organisms that cause a feline respiratory infection (commonly called a feline cold), clinical signs associated with the other organisms can also be observed. These can include a runny nose, lethargy (tiredness), coughing, and a more severe respiratory infection that can progress to pneumonia.
Diagnosis and Treatment
Diagnosis of feline chlamydiosis is generally made based on clinical signs and a history of exposure to the organism. When a definite diagnosis is required, the organism can be identified through bacterial culture testing of discharge from the eyes.
Treatment generally consists of administering antibiotics, which may be given by mouth or injection, applied as ointment or drops to the eyes, or given in a combination of these treatment methods. Depending on the severity of infection, many cats begin to improve within the first few days of treatment.
Following recovery, some cats can become chronically infected with the disease. For these cats, the clinical signs may return later in life and may require additional treatment.
Vaccination and Prevention
Several feline chlamydiosis vaccines are available, all of which have been tested and found to be safe and effective when administered as directed.
Kittens are generally vaccinated around 8 to 9 weeks of age according to the vaccine label directions. A booster vaccination is given 3 to 4 weeks later, followed by yearly boosters. Vaccination reduces the severity of clinical signs in an infected cat but does not prevent infection or shedding of the organism into the environment.
The feline chlamydiosis vaccine is not a required vaccine for all cats. Vaccination should be based on risk for exposure to the C. felis organism. Cats that go outside, live with other cats, or visit grooming or boarding facilities are at greater risk for exposure than cats that stay indoors and have limited contact with other cats. Ask your veterinarian if the feline chlamydiosis vaccination is recommended for your cat.
Feline chlamydiosis is contagious to other cats, but it is not generally considered contagious to humans. However, people who may have a compromised (weakened) immune system should notify their physician if their cat is diagnosed with feline chlamydiosis.
Routine household disinfectants and detergents kill the C. felis organism, so keeping the environment clean is a good way to reduce the risk of disease spread. Also, keeping sick cats separated from healthy cats can reduce the likelihood of transmission. Any new kitten or cat being introduced into the home should be examined by a veterinarian as soon as possible and separated from all other household pets for a quarantine period of at least a few weeks. During that time, the new cat should be monitored closely for any signs of illness. Any problems should be reported to your veterinarian before introducing the new cat to your other pets.