A common infectious disease, trachoma is the major cause of blindness in the world.
Organism Chlamydia trachomatis, a microorganism that has features both of bacteria and viruses.
Clinical features Commencing as a kerato-conjunctivitis, the first sign is red eye. There may be irritation and discharge, but it is passed off as a self-limiting infection. A follicular infiltration of the conjunctiva then takes place particularly in the upper lid. Blood vessels grow into the periphery of the eye, forming pannus. Trachoma is often complicated by secondary infection. It is at the late stages of the disease, when it is non-infectious that scarring, particularly of the upper eyelid, turns the eyelashes inwards to rub on the eye, a condition called trichiasis. This constant rubbing of the eyeball, aided by the dryness of the conjunctiva, damages the cornea, leading to scarring and finally blindness.
Diagnosis is usually made on clinical grounds, but can be confirmed by finding the characteristic inclusion bodies in scrapings taken from the conjunctiva.
Transmission Trachoma is a disease of poor sanitary conditions where a combination of close contact and dirty conditions encourages transmission. Within the family unit, transmission is from child-to-child or by flies that are attracted to the discharges around the eyes. These are mainly Musca sorbens. Cycles of reinfection and recrudescence continue to damage the eye and lead to blindness at school age. The usual method of wiping away secretions with hands, towels or clothing, which is then used by the adult on other children or themselves, is a typical pattern of transmission.
Was this article helpful?