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Trachoma

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Etiology


Trachoma is one of the principal causes of blindness. It affects populations in a state of poverty in rural areas where the access to water services and sanitation is limited. The disease is originated by the action of a bacterium called Chlamydia trachomatis, which is transmitted from one person’s eyes to another by means of flies, the fingers, or from the use of shared clothes or towels. 

Signs and symptoms


Repeated infection with Chlamydia trachomatis during many years produces scars in the internal part of the upper eyelid, which causes the eyelashes to go inwards and scratch the eyeball. The scars in the eyelid also affect the lacrimal secretion and produces dryness in the eye. These conditions increase the risk of ulcerations and scars in the cornea. The corneal scarring deteriorates the vision. If it is not treated, this condition damages corneal opacity irreversibly and lead to blindness. The active trachoma sequelae appear in the adult age and in medium age people. In hyperendemic areas active disease is common in pre-school age children in whom prevalence rates between 60 and 90% cab be found. It mainly affects the most vulnerable people such as women and children. As complication of trachoma, adult women have a greater risk than adult men to develop blindness, explained by the fact that women tend to devote a greater time with young children in close contact, whom are the principal reservoir of the infection. 

Distribution and magnitude of the disease


It is estimated that in the world it affects more than 84 million people, of which nearly 8 million have visual impairment. At the world level, it is currently responsible for more than 3% of blindness, although this figure changes due to the effect of the socioeconomic development and control programs of the disease. Despite this, trachoma continues to be hyperendemic in many remote and poor rural areas of Africa, Asia, Central and South America, Australia, and the Middle East. In the American Region, there exists evidence of trachoma in four countries and it is estimated that 50 million people live in areas at risk; there exists an active endemic foci in Brazil and Guatemala, clinical evidence of trachoma in indigenous communities of a department was published in 2010 for the first time in Colombia and there is no more active trachoma in Mexico, its only focus is in the State of Chiapas. 

Prevention and control


Principal risk factors for the occurrence of the disease are related to lack of access to water, the presence of flies, poor hygienic conditions and overcrowding. The prolonged exposure to infections from infancy and during youth seems to be necessary for producing complications that occur later in the course of life. A single episode of acute conjunctivitis by Chlamydia is not regarded as a threat to vision since virtually there is no risk of prolonged inflammation or complications for blindness. As a result, the principal interventions should aim at preventing the infection by trachoma including improvement of sanitation, reduction of fly breeding sites and to increase the activities of facial hygiene (with clean water) for children at risk of the disease. The scarring and the affectation of the vision by trachoma can be reversed through a simple surgical procedure that is carried out at local level in which the eyelashes that are rubbing the eyeball are inverted. 

Depending on the value of the prevalence of follicular trachomatous inflammation in children from 1 to 9 years at district level, the massive administration of antibiotics is recommended to all the residents of those communities once a year. WHO recommends two antibiotics for trachoma control: tetracycline to 1% in ophthalmic ointment and azithromycin. 

The Alliance for the Global elimination of trachoma for the year 2020 (GET 2020) and initiative of elimination in the `Region of the Americas`


The Alliance for the Global Elimination of Trachoma for the year 2020 GET 2020, was launched under the leadership of WHO in 1997. Through this initiative, there have been control activities implemented through primary health care, based on the SAFE strategy (Surgery, Antibiotic treatment, Facial cleanliness and Environmental changes). The strategy includes four basic components, directed to the pharmacological treatment of the infection, to the surgical treatment of inflammatory sequelae and to the implementation of sanitary, educational, and environmental measures aimed at preventing the appearance of new cases. 

At American Region level, the control and elimination of trachoma was ratified in Resolution CD49.R19, as priority from the Ministers of Health in order to eliminate new cases of blindness caused by trachoma by 2015 (reduction of the prevalence of trachomatous trichiasis to less than 1 case per every 1,000 people and reduction of the prevalence of follicular or inflammatory trachoma to less than 5% in children from 1-9 years old). 

In May 2011 the first regional reunion with trachoma program leaders in the American regions was formulated, in which the four countries progress toward elimination could be analyzed and where lines of action were designed for the achievement of goals by 2015.   Until 2010 Brazil has completed the national prevalence mapping and has formulated a national plan for the elimination; Colombia is implementing the mapping in the department of Vaupés in indigenous communities with diagnosed cases of trachoma; Guatemala completed mapping in 2011 and is completing  an action plan in order to target actions in the municipalities in accordance with their profile; Mexico initiated the documentation of a possible interruption of trachoma transmission in the Chiapas focus in 2011.

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Last Updated on Monday, 31 March 2014 18:49

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