Trachoma is one of oldest infectious diseases known to humans. It is caused by the bacteria Chlamydia trachomatis, which is transmitted through contact with eye secretions of infected people (shared use of towels and handkerchiefs, contact with fingers, etc.), as well by flies that help spread it.

Repeated eye infections from Chlamydia trachomatis over many years causes scarring on the inside of the upper eyelid, which causes the eyelid to retract and the eyelashes to turn inwards (a sign known as trachomatous trichiasis) and rub against the eyeball, causing pain, discomfort, and permanent damage to the cornea.

A damaged cornea impairs vision, and if not treated, leads to irreversible corneal opacity and blindness. The age at which this disability occurs depends on several factors, including the intensity of local transmission. In communities where the disease is highly endemic, it may happen in childhood, although it is more common among 30- to 40-year-olds.

The infection affects people that live in extreme poverty more than others. The main factors that can contribute to transmission of the disease are poor hygiene, crowded housing, water shortages, and insufficient access to latrines and sanitation services. Women are four times more likely to develop blindness from this disease than men, probably because they have more frequent contact with infected children.

This disease can be prevented through access to clean water and proper sanitation. Facial hygiene that does not remove eye secretions contaminated with the bacteria, as well as the shared use of towels by children, increase the persistence of the infection in a community.

Key facts
  • Globally, trachoma is considered to be a public health problem in 42 countries, and it was estimated that 2.5 million people were affected by trachomatous trichiasis in 2019.
  • Trachoma is one of the leading infectious causes of preventable blindness and is endemic in many of the rural, poor, and remote areas of countries in Africa, Asia, Australia, Central and South America, and the Middle East.
  • In the Region of the Americas, there is evidence of trachoma as a public health problem in Brazil, Colombia, Guatemala, and Peru, and it is estimated that up to 5 million people live in areas that warranted interventions for the elimination of trachoma.
  • In 2017, Mexico received validation from WHO for having eliminated trachoma as a public health problem, becoming the first country in the Region to reach this goal.
PAHO Response
  • PAHO/WHO helps countries to implement the SAFE strategy (Surgery, Antibiotics, Facial Cleanliness and Environmental Improvement), which consists of surgery to treat advanced trachoma (trichiasis), antibiotics (azithromycin) to clear the C. trachomatis infection, facial hygiene, and environmental improvements to reduce transmission from one person to another.
  • PAHO supports a regional forum that includes the participation of five countries of the Americas that have had communities affected by trachoma (Brazil, Colombia, Guatemala, Peru, and Mexico), as well as other countries where mapping is needed. In this forum, these countries, along with experts from other organizations, analyze the situation in the Region and make technical recommendations for achieving trachoma elimination.
  • In 2016, the PAHO/WHO Directing Council adopted Resolution CD55.R9 aimed at implementing a plan for the elimination of neglected infectious diseases, including trachoma.