Since Chlamydophila felis has ability is unable to survive outside the host, transmission requires close contact between cats and transfer of ocular secretions is probably the most important method of infection. Chlamydophila felis infection is most common in multicat environments, particularly breeding catteries, and therefore the prevalence of infection may be more common among pedigree cats [Wills et al, 1987]. The majority of cases occur in young cats, particularly under one year of age. Chlamydophila felis is the infectious organism most frequently associated with conjunctivitis in cats and is isolated from up to 30% of affected cats, particularly in those with chronic conjunctivitis [Wills et al, 1988]. Serological surveys have shown that 10% or more of unvaccinated household pets have antibodies against Chlamydophila [Gunn-Moore et al, 1995, Lang, 1992].
Prevalence studies by PCR in cats with ocular or URTD signs have resulted in 12 to 20%. Prevalence in normal cats is low, by PCR some studies show less than 2-3% in cats without clinical signs [Di Francesco et al, 2004].
There is some evidence for zoonotic potential but there is no epidemiological evidence that C felis represents a significant zoonotic risk. Conjunctivitis caused by C felis was reported in an HIV-infected patient [Hartley 2001].