Trachoma: global magnitude of a preventable cause of blindness.

OBJECTIVES: Trachoma is the leading cause of infectious blindness worldwide. It is known to be highly correlated with poverty, limited access to healthcare services and water. In 2003, the WHO estimated that 84 million people were suffering from active trachoma, and 7.6 million were severely visually impaired or blind as a result of trachoma: this study provides an updated estimate of the global prevalence of trachoma based on the most recent information available. METHODS: A literature search of recent published and unpublished surveys in the 57 endemic countries was carried out: the result of surveys that used the WHO trachoma grading system and additional information from regional and country experts served as a basis to determine the prevalence of trachoma in each country. RESULTS: Population-based surveys provided recent information for 42 out of 57 endemic countries. 40.6 million people are estimated to be suffering from active trachoma, and 8.2 million are estimated to have trichiasis. CONCLUSIONS: The current estimate of prevalence of trachoma is lower than the previous WHO estimates: this can be explained by the success in implementing control strategy, by more accurate data, as well as by socio-economic development in endemic countries.

2002 global update of available data on visual impairment: a compilation of population-based prevalence studies.

PURPOSE: For the past 25 years, the WHO Programme for the Prevention of Blindness and Deafness has maintained a Global Data Bank on visual impairment with the purpose of storing the available epidemiological data on blindness and low vision. The Data Bank has now been updated to include studies conducted since the last update in 1994. METHODS: An extensive literature search was conducted in international and national scientific and medical journals to identify epidemiological studies that fulfilled basic criteria for inclusion in the Data Bank, namely a clearly stated definition of blindness and low vision, and prevalence rates derived from population-based surveys. Sources such as National Prevention of Blindness Programmes, academic institutions or WHO country or regional reports were also investigated. RESULTS: Two-hundred-and-eight population-based studies on visual impairment for 68 countries are reported in detail, providing an up-to-date, comprehensive compilation of the available information on visual impairment and its causes globally.

Preventing trachoma through environmental sanitation: a review of the evidence base.

A review of the available evidence for the associations between environmental sanitation and transmission of trachoma was undertaken with a view to identifying preventive interventions. The WHO Global Alliance for the Elimination of Trachoma by the Year 2020 (GET2020) has adopted the "SAFE" strategy, consisting of four components: Surgery, Antibiotic treatment, promotion of Facial cleanliness and initiation of Environmental changes. This review of 19 studies selected from the 39 conducted in different parts of the world shows that there is clear evidence to support the recommendation of facial cleanliness and environmental improvements (i.e. the F and E components of the SAFE strategy) to prevent trachoma. Person-to-person contact and flies appear to constitute the major transmission pathways. Improvement of personal and community hygiene has great potential for a sustainable reduction in trachoma transmission. Controlled clinical trials are needed to estimate the relative contribution of various elements to the risk of transmission of trachoma and the effectiveness of different interventions. These could show the relative attributable risks and effectiveness of interventions to achieve improvement of personal hygiene and fly control by environmental improvements, alone or in combination, and with or without antibiotic treatment.

[World Health Organization alliance for the elimination of trachoma]. / L'alliance de l'Organisation Mondiale de la Santé pour l'élimination du trachome.

Although trachoma has either decreased or disappeared in many Third World countries through socio economic development during the past forty years, it remains a major problem among the poorest communities, which is often ignored by decision-makers when setting priorities. Fortunately, recent developments will allow to overcome many of the past obstacles and to offer new opportunities for trachoma control programmes. WHO aware of this new favourable context for trachoma control has taken the leadership in mobilizing and coordinating trachoma control efforts through the creation of a WHO Alliance for the Global Elimination of Trachoma. The aim of this Alliance is to assist Member States where trachoma is endemic achieve the goal of (global) elimination of trachoma by the year 2020. This is indeed possible through the combination of various interventions such as those proposed by the SAFE strategy (Surgery for trichiasis, Antibiotics, Face washing and Environmental changes) recommended by WHO. The prevention of trachoma and its treatment will rely largely on the efforts made by the endemic countries concerned with this problem. Therefore, new and or existing trachoma control programmes should be either implemented or strengthened at community-based level within the framework of the available primary health care systems based on the application of the SAFE strategy and on the assistance of the Alliance partners.