| Clinical Features |
Trachoma is a chronic follicular conjunctivitis that leads to scarring in the conjunctiva and cornea. Repeat active infections occur in children < 10 years of age. Subsequently, conjunctival scarring (cicatricial disease) and inversion of the eyelashes so they irritate the cornea (trichiasis) develops as a result of earlier infections. Trichiasis predisposes to corneal ulceration and corneal opacities resulting in decreased vision and blindness. |
| Etiologic Agent |
Chlamydia trachomatis, serovars A, B, Ba, and C. First description of disease in 16th-century BC in the Ebers Papyrus. Infectious potential demonstrated by experimental transmission of agent from a case-patient to an orangutan in 1907. |
| Incidence |
WHO estimates that approximately 6 million cases of blindness due to trachoma and 11 million cases of trichiasis occur yearly. Prevalence of active disease in children varies from 10-40% in some African countries to 3-10% in several Asian countries. The overall incidence is unknown. |
| Sequelae |
Repeat infections result in a chronic follicular conjunctivitis that leads to scarring in the conjunctiva and cornea. Ultimately, corneal opacification and blindness occurs. |
| Transmission |
Primary: person-to-person transmission by ocular and respiratory secretions. Secondary: insect vectors such as house flies. |
| Risk Groups |
Active infection occurs in children < 10 years, reinfection during childhood is common. Endemic disease is found in rural areas with limited economic means and poor sanitation and water supplies. |
| Surveillance |
No national or international surveillance exists. Blindness due to trachoma has been eliminated from the United States. The last cases were found among American Indian populations and in Appalachia. |
| Trends |
Major declines in some countries associated with multifaceted control program. |
| Challenges |
WHO has initiated a global campaign for the elimination of blindness due to trachoma, GET2020, that recommends a strategy including antibiotics, improved personal and community hygiene and sanitation, and surgery to correct trichiasis. Campaign challenges include: establishing surveillance for endemic trachoma, determining when mass treatment with antibiotics is necessary (i.e., retreatment), determining the effectiveness of improved hygiene and sanitation at preventing a resurgence of endemic disease, monitoring for adverse effects of mass treatment with antibiotics, and improving surgical outcomes. Additional challenges include: improving diagnosis of active disease, monitoring the emergence of antibiotic resistant C. trachomatis, and improving our understanding of the transmission and reservoirs of C. trachomatis. |
| Opportunities |
To develop laboratory methods to monitor antibiotic resistance in C. trachomatis, assist with the global campaign by supplying technical expertise, and design studies to improve our understanding of C. trachomatis transmission and reservoirs. |
