Etiology

• Trachoma is a chronic conjunctivitis caused by C. trachomatis serovars A, B, Ba, and C. Transmission occurs through contact with ocular discharge from infected pts, which is sometimes transferred by flies.
• AIC is an acute eye infection occurring in adults exposed to infected genital secretions and in their newborns. This infection is caused by sexually transmitted C. trachomatis strains, usually serovars D-K.

Epidemiology

Trachoma is a leading cause of preventable infectious blindness, with ∼6 million pts having been affected. In the hyperendemic regions of northern and sub-Saharan Africa, the Middle East, and parts of Asia, the prevalence of trachoma is ∼100% by the third year of life. Reinfection and persistent infection are common.

Clinical Manifestations

Both trachoma and AIC present clinically as conjunctivitis characterized by small lymphoid follicles in the conjunctiva; trachoma usually starts insidiously before 2 years of age.

• With progression of trachoma, there is inflammatory leukocytic infiltration and superficial vascularization (pannus formation) of the cornea.
  • Scarring eventually distorts the eyelids, turning lashes inward and abrading the eyeball (trichiasis and entropion).
  • The corneal epithelium eventually ulcerates, with subsequent scarring and blindness.
  • Destruction of goblet cells, lacrimal ducts, and glands causes dry-eye syndrome (xerosis), with resultant corneal opacity and secondary bacterial corneal ulcers.
• AIC is an acute unilateral follicular conjunctivitis with preauricular lymphadenopathy and presents similarly to acute conjunctivitis due to adenovirus or HSV.
  • Corneal inflammation is evidenced by discrete opacities, punctate epithelial erosions, and superficial corneal vascularization.
  • Left untreated, the disease may persist for 6 weeks to 2 years.

Diagnosis

Clinical diagnosis of trachoma is based on the presence of two of the following signs: lymphoid follicles on the upper tarsal conjunctiva, typical conjunctival scarring, vascular pannus, or limbal follicles.

• Intracytoplasmic chlamydial inclusions are found in 10-60% of Giemsa-stained conjunctival smears from children with severe inflammation.
• Chlamydial nucleic acid amplification tests are more sensitive in detecting infection.