Graham EM, Taylor DJ (2012): Bacterial reproductive pathogens of cats and dogs. Vet Clin North Am Small Anim Pract 42(3), 561-582, vii.

Lubrithal Eye Gel is sterile, and contains cetrimide & disodium EDTA as the preservative/stabilizer. The genome of C. felis has been sequenced (Azuma et al., 2006). There is extensive nucleotide sequence homology between the genomes of various Chlamydia species. The membrane contains important families of proteins: the major outer membrane proteins (MOMPs) and polymorphic outer membrane proteins (POMPs). The organism attaches to sialic acid receptors of cells. It has a unique pattern of replication within cells, involving reticulate bodies and elementary bodies. The latter represent the infectious forms of the micro-organism that are released following cell lysis. Some C. felis isolates appear to contain plasmids, and this may be related to their pathogenic ability (Everson et al., 2003). Epidemiology Halanova M, Petrova L, Halan M, Trbolova A, Babinska I, Weissova T (2019): Impact of way of life and environment on the prevalence of Chlamydia felis in cats as potentional sources of infection for humans. Ann Agric Environ Med 26(2), 222-226. Longbottom D, Livingstone M (2006): Vaccination against chlamydial infections of man and animals. Veterinary Journal 171(2), 263-275. Dean R, Harley R, Helps C, Caney S, Gruffydd-Jones T (2005): Use of quantitative real-time PCR to monitor the response of Chlamydophila felis infection to doxycycline treatment. J Clin Microbiol 43(4), 1858-1864.Sanderson H, Vasquez M, Killion H, Vance M, Sondgeroth K, Fox J (2021): Fatal Chlamydia psittaci infection in a domestic kitten. J Vet Diagn Invest 33(1), 101-103. Sparkes AH, Caney SM, Sturgess CP, Gruffydd-Jones TJ (1999): The clinical efficacy of topical and systemic therapy for the treatment of feline ocular chlamydiosis. J Feline Med Surg 1(1), 31-35. Fig. 4. Indirect immunofluorescence test to titrate antibody directed against Chlamydia felis; infected cell culture serves as the antigen substrate. Courtesy of The Feline Centre, Langford Vets, University of Bristol, UK Treatment O’Dair HA, Hopper CD, Gruffydd-Jones TJ, Harbour DA, Waters L (1994): Clinical aspects of Chlamydia psittaci infection in cats infected with feline immunodeficiency virus. Vet Rec 134(15), 365-368. Lipman NS, Yan LL, Murphy JC (1994): Probable transmission of Chlamydia psittaci from a macaw to a cat. J Am Vet Med Assoc 204(9), 1479-1480.

Vaccination should be considered for cats at risk of exposure to infection, particularly in multicat environments, and if there has been a previous history of Chlamydia infection. In most cats, conjunctival shedding ceases at around 60 days after infection, although some may continue to become persistently infected (O’Dair et al., 1994). C. felis has been isolated from the conjunctiva of untreated cats for up to 215 days after experimental infection (Wills, 1986). Immunity Passive immunity Streeten BW, Streeten EA (1985): “Blue-body” epithelial cell inclusions in conjunctivitis. Ophthalmology 92(4), 575-579. Fernandez M, Manzanilla EG, Lloret A, Leon M, Thibault JC (2017): Prevalence of feline herpesvirus-1, feline calicivirus, Chlamydophila felis and Mycoplasma felis DNA and associated risk factors in cats in Spain with upper respiratory tract disease, conjunctivitis and/or gingivostomatitis. J Feline Med Surg 19(4), 461-469.Infected cats develop antibodies and kittens appear to be protected initially for the first one or two months of life by maternally derived antibodies (Wills, 1986). Active immunity Chlamydia infection in cats can be treated very effectively with antibiotics. Systemic antibiotics are more effective than local topical treatment (Sparkes et al., 1999). Tetracyclines are generally regarded as the antibiotics of choice for chlamydial infections (Dean et al., 2005). Doxycycline has the advantage of requiring only a single daily dose and is most frequently used at a daily dosage of 10 mg/kg orally, although 5 mg/kg orally twice daily can be used if vomiting occurs with single day dosing. Administration of the hyclate preparation of doxycycline should always be followed by food or water because of the possibility of it inducing oesophagitis in cats with incomplete swallowing. Studies have shown that treatment must be maintained for 4 weeks to ensure elimination of the organism (Dean et al., 2005). In some cats, recrudescence may be noted some time after discontinuation of therapy. Continuation of treatment for two weeks after resolution of clinical signs is recommended. Tetracyclines have potential side effects in young cats although these appear to be less common with doxycycline than oxytetracycline. Alternative antibiotics may be considered if this is a concern. Both enrofloxacin and pradofloxacin have shown some efficacy against Chlamydia spp. (Gerhardt et al., 2006; Hartmann et al., 2008), although pradofloxacin would be preferred over enrofloxacin in view of the diffuse retinal degeneration and acute blindness that has been reported following enrofloxacin treatment in cats, albeit very rarely. A 4-week course of therapy with clavulanic acid potentiated amoxicillin may represent the safest choice of alternative to doxycycline in young kittens (Sturgess et al., 2001). Vaccination Chlamydia felis vaccines are non-core. Both inactivated and modified live (attenuated) vaccines, based on whole Chlamydia organisms, are available, but only as components of multivalent vaccine preparations. Vaccines are effective in protecting against clinical manifestation of the disease, however, not against occurrence of infection (Wills et al., 1987). No reliable data are available to compare the efficacy of inactivated versus modified live vaccines. Di Francesco A, Piva S, Baldelli R (2004): Prevalence of Chlamydophila felis by PCR among healthy pet cats in Italy. New Microbiol 27(2), 199-201.

Sibitz C, Rudnay EC, Wabnegger L, Spergser J, Apfalter P, Nell B (2011): Detection of Chlamydophila pneumoniae in cats with conjunctivitis. Vet Ophthalmol 14 Suppl 167-74. Dechra Academy launches interactive CPD modules for unintended feline weight loss keyboard_arrow_down Gunn-Moore DA, Werrett G, Harbour DA, Feilden H, Gruffydd-Jones TJ (1995): Prevalence of Chlamydia psittaci antibodies in healthy pet cats in Britain. Vet Rec 136(14), 366-367. Consult your vet prior to use if your pet is on any other eye medication or if they are showing any of the following signs: pain or irritation, red or inflamed eyes, excessive tear production, opaque discharge or if your pet is scratching or rubbing at its eyes. Wills JM, Gruffydd-Jones TJ, Richmond SJ, Gaskell RM, Bourne FJ (1987): Effect of vaccination on feline Chlamydia psittaci infection. Infect Immun 55(11), 2653-2657.ABCD follows a recent nomenclature proposal to classify all 11 currently recognized Chlamydiaceae species in a single genus, the genus Chlamydia (Sachse et al., 2015); these species include Chlamydia felis, Chlamydia pneumoniae and Chlamydia psittaci. C. felis is the species typically seen infecting cats.