Risk factors for trachoma in Mali.

OBJECTIVES: Prior to commencing a campaign to eliminate blinding trachoma in Mali, a national disease prevalence survey was conducted from March 1996 to June 1997. The prevalence of trachoma was estimated and potential risk factors were studied. METHODS: In each of Mali's seven regions (excluding the capital Bamako), a sample of 30 clusters was taken from the general population, in accordance with the principle of probability proportional to the size of the community. All children under 10 years of age were examined. The simplified clinical coding system proposed by the World Health Organization was used. The position of each village was established and subsequently related to the nearest meteorological station. Socioeconomic and environmental information was collected at both village and household level. The mother or caretaker of each child was questioned about availability and use of water for washing the child. At the time of examination, facial cleanliness and the presence of flies on the face were noted. RESULTS: A total of 15,187 children under 10 years of age were examined. The prevalence of active trachoma (follicular [TF] or intense trachoma [TI]) was 34.9% (95% CI : 32.3-37.6) and the prevalence of TI was 4.2% (95% CI : 3.5-5.0). Aridity/environmental dryness appears to be a risk factor influencing the current geographical distribution of trachoma. Small villages had considerably higher trachoma prevalence than their larger neighbours. The proximity of a medical centre and the existence of social organizations such as a women's association were associated with lower levels of trachoma. Crowded living conditions increased the risk. Using a monetary marker of wealth, we observed a linear inverse relation between wealth and trachoma prevalence. The presence of a dirty face was strongly associated with trachoma (odds ratio [OR] = 3.67) as was the presence of flies on the child's face (OR = 3.62). Trachoma prevalence increased with distance to a water source. Disease prevalence decreased with a higher frequency of both face washing and bathing. CONCLUSIONS: Of all the risk factors examined, facial cleanliness had the strongest association with the prevalence of trachoma. This was followed by the presence of flies on the child's face. Both face washing and bathing showed beneficial effects. Socioeconomic factors such as wealth were significantly explanatory. It is likely that hygiene education and fly control by environmental improvement could have a very significant impact on the prevalence of trachoma in Mali.

Trachoma and vitamin A deficiency.

Both vitamin A deficiency and trachoma are important causes of preventable ocular diseases. We examined 10 559 children in Mali for clinical signs of trachoma and of xerophthalmia. In five regions, the mean prevalence of trachoma was 39.3% (95% CI: 37.4-41.2). Clinical xerophthalmia was present among 1.89% of children (1.59-2.25). The diagnosis of xerophthalmia appeared to be associated with active trachoma (OR=2.04 [1.52-2.74]). This association remained after controlling for socio-economic status.

[Rapid trachoma assessment method (TRA): comparison with an exhaustive prevalence survey in a region of endemic trachoma in Mali]. / Une méthode d'appréciation rapide du trachome, l'"ART". Comparaison avec une enquête épidémiologique exhaustive dans une zone d'endémie du Mali.

In 1997, the World Health Organization (WHO) endorsed a new strategy aimed at controlling blinding trachoma by 2020. The WHO developed a rapid assessment method for trachoma (TRA) for identifying communities affected by blinding trachoma and for ranking villages with endemic trachoma in order of priority for intervention. We applied this method to communities in Mali in which trachoma was prevalent, and compared the results with those of a classical prevalence survey. Seven villages from the Dogon region were first investigated using the rapid method. Members of the local community were asked to identify individuals with suspected trichiasis, using a diagram to help them with recognition. The individuals thus identified were then examined by an ophthalmic nurse for confirmation of the diagnosis. Fifty children aged less than ten years from poorer households were then selected. These children underwent ophthalmic examination, using a magnification of 2.5, and trachoma status was established. The next day, the villages were visited by an ophthalmologist who examined all of the inhabitants. The rapid assessment method identified 18 of the 52 patients requiring surgery. This method had a sensitivity of 34.6% and a specificity of 98%. The prevalence of active trachoma among children was 29.0% in the exhaustive survey and 29.9% for the rapid assessment method. Overall sensitivity was 54.6% and overall specificity 79.6%, as the two methods did not identify the same individuals. The Kappa coefficient, estimating agreement between observers, was 0.34. The ranking of the villages in order of priority differed slightly for the two methods. With the rapid assessment method, five of the seven villages were classified as having a prevalence of over 20% whereas, with the exhaustive survey, six of the seven villages fell into this category. TRA was not designed to replace epidemiological survey and the prevalence of trachoma should not be inferred from this method. However, it is a useful tool for determining the order of priority for intervention of communities at risk.

[Cataracts, a way into the national health system of Mali?]. / La cataracte, une entrée dans le système de santé national malien?

Cataracts are common in Mali, where there are 60,000 people awaiting surgery for blindness caused by cataracts. This major cause of disability in adults could be used as an effective entry point into the national health system. The development of an effective referral system should increase the recruitment from districts and increase the standing of the highest level health centers. Surgery should be decentralized and carried out at the district level. A specialist surgical team, based at the regional hospital, would operate with portable equipment in the district health centers, with patients being referred by peripheral health centers. The success of this approach depends on the development of strong functional relationships between peripheral and district health centers and of interpersonal relationships between the staff members involved. This new approach should lead to a major reduction in the level of disability whilst strengthening and promoting the district health system as a whole.

[Strategies to control trachoma]. / Stratégies de lutte contre le trachome.

Epidemiological data for trachoma in Mali have suggested a number of ways in which blindness caused by trachoma could be prevented or cured: improvements in domestic and urban environments (e.g. sanitation), the provision of household water supplies, improvements in personal hygiene (through health education to promote the washing of children's faces), mass administration of local (tetracycline) or general (azithromycin) antibiotics and eyelid surgery using the method of Trabut. A cost-benefit analysis was performed for antibiotic distribution and eyelid surgery. Such a study is required to assess the value of environmental improvements and the provision of water supplies. Improvements in personal hygiene and environment are the only effective ways to reduce the incidence of trachoma, but eyelid surgery should be developed to prevent the blindness caused by trachoma.

[Strategies to control vitamin A deficiency]. / Stratégies de lutte contre les déficits en vitamine A.

Vitamin A deficiency is a major public health problem in the countries of the Sahel. It causes xerophthalmia and high rates of child mortality and it occurs mostly in underdeveloped regions. People of all ages may suffer from vitamin A deficiency but it is a particular problem in pre-school-age children. Each year, about 250,000 children throughout the world become blind due to vitamin A deficiency. Measles, pneumonia and diarrhea reduce the child's reserves of retinol and increase the dietary requirement for vitamin A. Improvement of social conditions is a radical approach to preventing vitamin A deficiency. Three strategies are currently in use: horticultural activities and health education; fortification of food products; distribution of high-dose vitamin A capsules.

[Cartography of trachoma in Mali: results of a national survey]. / Cartographie du trachome au Mali: résultats d'une enquête nationale.

Prior to a campaign to eliminate blinding trachoma, a survey of the prevalence of the disease was conducted in the seven administrative regions of Mali between March 1996 and June 1997. In each region (with the exception of Bamako District) a random sample of thirty clusters was taken from the general population, in accordance with the principle of probability proportionate to the size of the communities. All children under 10 years of age and all women over 14 years were examined. The simplified coding proposed by WHO was used for data gathering. A total of 15,310 children and 11,530 women were examined. The prevalence of active trachoma, follicular (TF) or intense (TI), was estimated to be 34.9% among children under 10 years of age (95% CI: 32.3-37.6). The prevalence of TI showing the intensity of trachoma was 4.2% (95% CI: 3.5-5.0) among the same children. The prevalence increased up to the age of 3 years, when it reached 49.2%. The prevalence of TF/TI was 35.7% among boys and 34.3% among girls. The prevalence of entropion trichiasis among women over 14 years of age was 2.5% (95% CI: 2.1-2.9), and 1% had central corneal opacity (95% CI: 0.8-1.3). These prevalences increased with age, such that 10% of women over 70 years of age had trichiasis. By region of the country, the prevalence ranged from 23.1% of active trachoma among children in Ségou, to 46.2% in Gao. The prevalence of entropion trichiasis was 0.65% in Gao region and 3.9% in Koulikoro region. This survey allows the trachoma treatment needs of Mali to be quantified. We estimate that 1.09 million children under 10 years are carriers of active trachoma and require local or general antibiotic treatment. If all the under-10-year-olds from all villages where TF/TI exceeded 20% were to be treated, a total of 2.436 million children would be involved. A total of 85,000 adults should have surgery to correct trichiasis and avoid the onset of blindness.

[Tolerance of ivermectin treatment of rural communities infected by savannah onchocerciasis in Mali]. / Tolérance d'un traitement de collectivités rurales atteintes d'onchocercose de savane par l'ivermectine au Mali.

In an open clinical trial in phase IV, 856 onchocerciasis infected subjects received 150 micrograms/kg of ivermectin in May 1987. While 607 were included as witness. This cohort was revisited 7 and 12 months after. In June 1988, the same treatment was administrated to the previously treated subjects, and the witnesses received their first ivermectin' dose. The clinical tolerance of the treatment appears good and, even improved during the second dose one year after. Among the subjects treated in May 1987, 15.2% of them showed secondary reactions mostly discrete or moderate, precocious and quickly reversible after a second dose. Only 8 of them were incommodated in their daily occupations. A second treatment of these same subjects one year later, caused reactions of feeble intensity 3.7% only. The research of intolerance risk factors, incriminated the high density of microfilaremia. This incite to be careful in mass treatment of hyperendemic area.