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158 Chlamydiosis

felis with other Chlamydia spp or Bartonella • Transmission is by direct contact with care. In multi-cat households, all contact cats
spp respiratory secretions or ocular discharge; should be treated and good hygienic practices
VetBooks.ir humans with community-acquired pneumo- • Incubation period is 3-5 days, and infection Acute General Treatment
• C. pneumoniae is a pathogen associated in
aerosol, or contact with fomites.
followed.
may persist for months.
nia, atherosclerosis, and conjunctivitis and
has been identified in cats with conjunctivitis.
• Cat owners who are immunocompromised DIAGNOSIS • Due to the systemic nature of the disease,
systemic therapy has shown superior efficacy
should limit direct contact with infected cats, to topical therapy alone.
observe good hygienic practices, and obtain Diagnostic Overview • Treat all cats in the household simultaneously.
prompt treatment of affected cats. Diagnosis is suspected based on history and • Doxycycline 10 mg/kg PO q 24h or mino-
clinical findings from examination. Rule out cycline 5-12 mg/kg PO q 12h for at least 4
GEOGRAPHY AND SEASONALITY that the conjunctivitis is not secondary to weeks
Worldwide an intraocular disease process (e.g., uveitis, • Alternative is pradofloxacin 5 mg/kg PO q
glaucoma) (p. 199). 24h
ASSOCIATED DISORDERS • Azithromycin ineffective in clearing infection
Co-infections with feline herpesvirus 1 Differential Diagnosis compared to doxycycline
(FHV-1), feline calicivirus, and Mycoplasma felis Infectious causes: • A 4-week course of amoxicillin-clavulanic
are common and increase severity of clinical • FHV-1 acid (12.5 mg/kg PO q 12h) may also
disease. • Feline calicivirus eliminate C. felis.
• Bordetella bronchiseptica
Clinical Presentation • Mycoplasma spp Chronic Treatment
HISTORY, CHIEF COMPLAINT • Cryptococcus spp Ocular infections initially respond to topical
• Ocular discharge or redness • Aspergillus spp treatment, but recurrence has been documented
• Conjunctivitis: often unilateral initially and • Histoplasmosis spp without systemic therapy. Treatment should
later becomes bilateral Noninfectious causes: be continued for 2 weeks after resolution of
• Occasionally decreased appetite • Neoplasia (e.g., squamous cell carcinoma, clinical signs.
• Sneezing lymphoma)
• Nasal discharge • Nasopharyngeal polyps Possible Complications
• Dental disease • Risk of discoloration of the teeth in kittens
PHYSICAL EXAM FINDINGS • Congenital eyelid malformation if tetracyclines are used in the last 2-3 weeks
• Ocular discharge: serous or mucopurulent • Palate defects of pregnancy or for kittens in the first few
• Blepharospasm • Local irritants (e.g., chemical, contact allergy, months of life. Little evidence for this
• Conjunctival hyperemia topical eye preparations) complication with doxycycline
• Chemosis • Trauma • Esophagitis reported with the administra-
• Conjunctival hyperemia • Foreign body tion of doxycycline tablets. If tablets are
• Nasal discharge: serous, mucoid or • Immune-mediated/inflammatory (e.g., administered, they should be followed by a
mucopurulent eosinophilic keratoconjunctivitis) water bolus by syringe. Administration of
• Keratitis/corneal ulceration • Keratoconjunctivitis sicca doxycycline liquid oral suspension minimizes
○ Rare, often related to a co-infection (e.g., the risk of esophagitis; compounded suspen-
FHV-1) Initial Database sions may have a short shelf life.
○ Other chlamydial species: Parachlamydia • Conjunctival cytology to evaluate for intra- • Enrofloxacin can be effective but has been
acanthamoebae and N. hartmannellae cytoplasmic basophilic inclusions (reticulate associated with retinal toxicity and blindness
reported in cats with keratitis, corneal bodies) using Giemsa stain in cats and is not recommended.
ulceration, and conjunctivitis (clinical ○ Low sensitivity and specificity for early
relevance unclear, DNA also identified stages of infection PROGNOSIS & OUTCOME
in normal cats) ○ Topical eye preparations can create cyto-
• Transient fever plasmic inclusions resulting in misdiagnosis. • Excellent in households with low numbers
• Weight loss ○ Suppurative inflammation on conjunctival of cats
• Inappetence cytology is common with C. felis. • Fair in cattery situations; recurrence with
• Vaginal discharge large numbers of cats and poor compliance
Advanced or Confirmatory Testing • All cats in the household/cattery must be
Etiology and Pathophysiology • Polymerase chain reaction (PCR) and real- treated with the full course of antimicrobi-
• C. felis is an obligate intracellular bacterium time PCR: high sensitivity and specificity; als and proper hygiene and quarantine
that is similar in structure to gram-negative varies by laboratory. Assays specific for C. maintained.
bacteria. felis may miss other chlamydial species.
• Two forms: an infectious extracellular elemen- Conjunctival swabs recommended PEARLS & CONSIDERATIONS
tary body form that infects the epithelium • ELISA antigen test kits: sensitivity and
of ocular, respiratory, gastrointestinal, and specificity varies and is lower than other Comments
genitourinary systems; a noninfectious, intra- testing options available C. felis has been associated with lameness
cellular reticulate body form that replicates • Cell culture: requires special transport media and reproductive disorders in experimental
inside the cytoplasm of epithelial cells so primarily research tool, low sensitivity infections.
• Reticulate bodies divide within a cytoplasmic • Serology: not widely available or considered
vacuole (inclusions) and are released from useful Prevention
the host epithelial cell as elementary bodies. • Environmental hygiene in catteries and
• Systemic disease; organisms are shed from TREATMENT disinfection with a 1 : 32 solution of bleach
the conjunctiva, vagina, and rectum in tap water; detergent may be added. Other
• Appearance of conjunctivitis typically paral- Treatment Overview disinfectants (accelerated hydrogen peroxide
lels clinical shedding; shedding may continue The cornerstone of treatment is antibiotic and potassium peroxymonosulfate) also
after signs resolve. therapy (doxycycline) along with supportive effective
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