TRACHOMA AND OTHER INFECTIOUS DISEASES

Sheila West

By Sheila West, PhD

WHAT IS TRACHOMA?

Trachoma is a chronic conjunctivitis caused by repeated infections with the bacteria Chlamydia trachomatis. After years of repeated infection, scarring develops on the upper lid, leading to in-turned lashes (trichiasis). The destruction of normal eyelid tissue and the physical damage from rubbing on the cornea leads to vision loss. This process of infection and reinfection begins in early childhood and may continue to adulthood if the cycle is not broken. Those who live in impoverished communities, primarily in Africa, are most at risk. In hyperendemic communities, vision loss and blindness may occur in relatively young adults.

Women have two-to-three times the rate of scarring, trichiasis and vision loss compared to men, because as mothers, grandmothers and older sisters who care for children (the main source of infection), they are excessively and continually exposed to the bacteria. Crowded living conditions, lack of sufficient water and sanitation services to keep children’s faces clean are some of the many risk factors for trachoma. Trachoma is an indicator of public health and community health issues as well as a pathway to blindness for many individuals.

HOW IS TRACHOMA TRANSMITTED AND WHO IS AT RISK FOR TRACHOMA?

Trachoma is transmitted person-to-person through contact with infected ocular and nasal secretions. Children in trachoma endemic communities are the reservoir of infection and have signs of active trachoma. Young adults in these communities may present with scarring, which gets worse as the person ages. Older adults, and particularly women, are at risk of severe scarring and trichiasis. However, in highly endemic areas, children of both sexes, as young as nine or ten years of age, have been known to require trichiasis surgery. While trachoma has an ancient history and has existed as a problem in many parts of the world (including Europe and the USA), it is no longer only prevalent in countries located primarily in Africa, the Middle East, and parts of Asia.

WHAT ARE THE SIGNS OF TRACHOMA?

The World Health Organization and its advisors recommend use in the field of the simplified trachoma grading scheme. Often children have no symptoms when they have trachoma. In-turned eyelashes that rub on the cornea are painful and cause photophobia. To detect trachoma, the eyelid is flipped and the tarsal conjunctiva examined for trachomatous inflammation - follicular (TF), trachomatous inflammation – intense (TI), and trachomatous scarring (TS). The lid itself is examined for in-turning lashes (TT) or evidence of epilation. Finally, the cornea is examined for corneal opacity (CO); the following are the definitions used:

TF: Trachomatous Inflammation—Follicular. The presence of five (5) or more follicles (follicles are small, round, whitish swellings or dots) visible in the upper tarsal conjunctiva.

TI: Trachomatous Inflammation—Intense. Pronounced inflammatory thickening of the tarsal conjunctiva that obscures more than half the normal deep tarsal vessels.

TS: Trachomatous Scarring. The presence of scarring in the tarsal conjunctiva

TT: Trachomatous Trichiasis. At least one eyelash rubs on the eyeball or evidence of epilation.

CO: Corneal Opacity. Easily visible corneal opacity over the pupil.

The presence of these signs indicates active or chronic trachoma, or both.

WHAT CAN BE DONE TO PREVENT AND CONTROL TRACHOMA AND ELIMINATE IT AS A CAUSE OF BLINDNESS?

Trachoma is a disease of marginalized populations living in areas with limited resources and in need of a good water supply and sanitation near their home. As the education and economic welfare of a community rises, trachoma decreases. Meanwhile, the WHO, along with an alliance of interested parties, Alliance for Global Elimination of Trachoma by the year 2020 (GET 2020; World Health Organization's Prevention of Blindness and Deafness), has adopted the “SAFE” strategy to combat trachoma. The four components of the strategy include:

Surgery – to correct end-stage disease.

Antibiotic treatment – preferably azithromycin provided to entire districts whose prevalence of trachoma in 1-9 year olds exceeds 5 percent.

Facial cleanliness – behavior change that encourages children’s faces to be free of ocular and nasal secretions.

Environmental Improvement – improved water supply and sanitation facilities.

Women’s Eye Health

Partnerships