National immunisation days and vitamin A distribution in Mali: has the vitamin A status of pre-school children improved?

OBJECTIVES: The impact on vitamin A status of the distribution of vitamin A during national immunisation days (NIDs) has not been well established despite strong promotion by international agencies and donors. Using a pre-post design, the change in prevalence of vitamin A deficiency was examined in pre-school children in Mali. DESIGN: Two cross-sectional surveys were conducted in Mopti region, the first in March 1997 before this strategy was adopted and the second in March 1999, four-and-a-half months after a mass distribution of vitamin A during NIDs. SUBJECTS AND SETTING: We compared the vitamin A status of children aged 12 to 66 months targeted in 1999 by NIDs with the status of children in the same age group in 1997. Infectious events of the previous two weeks were concurrently recorded. Within the 1999 sample, the status of recipient and non-recipient children was also compared. RESULTS: In 1997, the prevalence of xerophthalmia (defined by the presence of night blindness and/or Bitot spots) was 6.9% (95% confidence interval (CI) 5.1-9.2) and the modified retinol dose response (MRDR) test proved abnormal in 77.8% of 12-66-month-old children (95% CI 68.27-85.17). In 1999 this picture had improved significantly, both for xerophthalmia prevalence, 3.3% (95% CI 2.1-5.2), and abnormal MRDR test response, 63.1% (95% CI 54.25-71.23). The infectious morbidity rates between 1997 and 1999 tended to decrease. No significant improvement was found among children older than those targeted by NIDs. In 1999, children who received vitamin A had a lower risk for xerophthalmia (3.0% for recipients vs. 8.7% for non-recipients) and experienced fewer infectious events. CONCLUSIONS: The clinical and biological vitamin A status of pre-school children improved between 1997 and 1999. Mass distribution of vitamin A appears to reduce the occurrence of xerophthalmia and would seem to be associated with a decrease in other related illnesses. Vitamin A supplementation during NIDs should be given a high priority when vitamin A deficiency remains a public health problem.

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.

[Onchocerciasis and epilepsy. Epidemiological survey in Mali]. / Onchocercose et épilepsie. Enquête épidémiologique au Mali.

A door-to-door survey was conducted in 18 villages in Mali with a total of 5,243 inhabitants classified according to the endemicity of onchocerciasis. Each epileptic was matched with two controls. The survey protocol included the following steps in cases and controls: census taking, socioeconomic data, screening for epilepsy, clinical examination, laboratory testing to detect parasites in stools and urine, and snip-test. The crude prevalence of epilepsy was 13.35 per 1,000 (n = 70). Epidemiological study provided a number of valuable demographic insights concerning age at onset, type of seizure activity during seizure and personal and family medical history. A transverse study showed that the prevalence of epilepsy was not significantly higher (p = 9.09) in zones of high endemicity of onchocerciasis (16.1 per 1000) than in zones of low endemicity (10.8 per 1000). Case-control findings showed evidence of onchocerciasis in 22.4 p. 100 of epileptics and 21.7 p. 100 of controls (odds ratio = 1.02 IC 95 p. 100: 0.4-2.19, not significant). Various risk factors including genetic factors and low socio-economic status could explain the trend toward a higher incidence of epilepsy as well as higher morbidity rates in zones of high endemicity of onchocerciasis.

[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.

[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.