Disease Overview

Although disease caused by Chlamydophila felis in cats has been referred to as feline pneumonitis, Chlamydophila rarely causes pneumonia in cats.

Feline Chlamydophila is regarded as a primary conjunctival pathogen and infection always involves the eye, resulting in conjunctivitis and occasionally also causing signs of rhinitis, with sneezing and nasal discharge.

FELINE CHLAMYDOPHILA FAST FACTS

Transmission of Chlamydophila between cats occurs through direct contact with other cats or infected animals.³²

Kittens may become infected by their mothers during birth.³²

TRANSMISSION

Transmission occurs as a result of direct, close contact between cats, because the organism survives poorly in the environment.

Infected cats also shed Chlamydophila from their rectum and vagina, although whether venereal transmission may occur has not been confirmed.

CLINICAL SIGNS

• Watery or yellowish discharge from one or both eyes
• Swelling and reddening of the conjunctiva
• Mild sneezing and nasal discharge
• Mild fever (occasionally)
• Lethargy (occasionally)

CATS AT RISK

Cats exposed to others:

• Boards often or comes from a shelter environment
• Shares food and water bowls, or litter areas
• Lives in a multiple cat household

Young Cats with Chlamydophila conjunctivitis are generally <1 yr old, and cats 2–6 months old are at higher risk of infection.

MORBIDITY THREATS

The signs are most severe 9–13 days after onset and then become mild over a 2-3 week period.

In some cats, clinical signs can last for weeks despite treatment, and recurrence of signs is not uncommon.

SPREADING DISEASE

The incubation period after exposure to an infected cat ranges from 3 to 10 days.

Untreated cats may harbor the organism for months after infection.

DIAGNOSIS

Chlamydophila conjunctivitis in cats should be differentiated from conjunctivitis caused by feline herpesvirus 1 and feline calicivirus.

Diagnosis can be confirmed by demonstration of intracytoplasmic inclusions in exfoliative cytologic preparations, by isolation of the Chlamydophila organism in cell culture, or by PCR for DNA on conjunctival swabs.