Fig. 2. Purulent conjunctivitis and chemosis in a cat with Chlamydia felis infection. Courtesy of Eric Déan Diagnosis Direct detection methods Nakanishi H, Furuya M, Soma T, Hayashiuchi Y, Yoshiuchi R, Matsubayashi M, Tani H, Sasai K (2019): Prevalence of microorganisms associated with feline gingivostomatitis. J Feline Med Surg 21(2), 103-108. Lubrithal Eye Gel is sterile, and contains cetrimide & disodium EDTA as the preservative/stabilizer. 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.

Lang GH (1992): Ontario. Prevalence of antibodies of Coxiella and Chlamydia spp. in cats in Ontario. Can Vet J 33(2), 134. Wons J, Meiller R, Bergua A, Bogdan C, Geissdorfer W (2017): Follicular Conjunctivitis due to Chlamydia felis-Case Report, Review of the Literature and Improved Molecular Diagnostics. Front Med (Lausanne) 4105.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. Streeten BW, Streeten EA (1985): “Blue-body” epithelial cell inclusions in conjunctivitis. Ophthalmology 92(4), 575-579. 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. Segarra S, Papasouliotis K, Helps C (2011): The in vitro effects of proxymetacaine, fluorescein, and fusidic acid on real-time PCR assays used for the diagnosis of Feline herpesvirus 1 and Chlamydophila felis infections. Vet Ophthalmol 14 Suppl 15-8. 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.

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 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.

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 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. Sturgess CP, Gruffydd-Jones TJ, Harbour DA, Jones RL (2001): Controlled study of the efficacy of clavulanic acid-potentiated amoxycillin in the treatment of Chlamydia psittaci in cats. Vet Rec 149, 73-76.

Wills JM, Howard PE, Gruffydd-Jones TJ, Wathes CM (1988): Chlamydia psittaci in different cat populations in Britain. J Small Anim Pract 29337-339. Dechra Academy launches interactive CPD modules for unintended feline weight loss keyboard_arrow_down 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 Harley R, Herring A, Egan K, Howard P, Gruffydd-Jones T, Azuma Y, Shirai M, Helps C (2007): Molecular characterisation of 12 Chlamydophila felis polymorphic membrane protein genes. Vet Microbiol 124(3-4), 230-238. Graham EM, Taylor DJ (2012): Bacterial reproductive pathogens of cats and dogs. Vet Clin North Am Small Anim Pract 42(3), 561-582, vii.

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.