Longitudinal evaluation of three azithromycin distribution strategies for treatment of trachoma in a sub-Saharan African country, Mali

OBJECTIVES

Trachoma, caused by repeated ocular infections with Chlamydia trachomatis is an important cause of blindness. Mass azithromycin distribution is part of current recommended strategies for controlling trachoma. In order to ascertain an efficient strategy model at an acceptable cost, an intervention study was conducted in Mali between May 2000 and February 2002.

METHODS

Three azithromycin administration strategies were evaluated: mass community-based treatment of all residents (strategy I), treatment of all children under 11 years of age and of women between 15 and 50 (strategy II), and treatment targeted to inhabitants of households where at least one child had clinically active trachoma diagnosed (strategy III). In a particular Malian area in which trachoma was known to be mesoendemic, three villages were selected for each of the three strategies. According to the strategy allocation, adults were eventually given a single dose of 1g azithromycin, and children a unique dose of 20 mg/kg. Moreover, cleanliness and washing of children's faces were assessed, and additional questions were addressed about education, environmental and socio-economic conditions for each household at baseline. Ophthalmic examination was performed at baseline and 1, 6 and 12 months after inclusion. The outcome variable was clinically active trachoma frequency 12 months after intervention among children under 11 years of age. A descriptive analysis was performed, and then logistic regression models were built to test the efficiency of the three strategies.

RESULTS

Among children under 11 years of age, the active trachoma prevalence fell dramatically in each strategy, from 23.7% to 6.4% in strategy I, from 20.8% to 6.8% in strategy II, and from 20.2% to 8.5% in strategy III. After adjustment on age (adjusted odds ratio [AOR] = 0.81; 95% confidence interval [95% CI]: 0.75-0.87) and on active trachoma occurrence at baseline (AOR = 3.81; [95% CI]: 2.70-5.39), the multiple logistic regression model showed that both strategies I and II gave similar results, while strategy III appeared significantly less effective (AOR = 1.56; [95% CI]: 1.00-2.43).

CONCLUSION

In mesoendemic trachoma areas, targeted treatment to all children under 11 years of age and women between 15 and 50 (strategy II) was as effective as indiscriminate mass distribution (strategy I) and more effective than treatment targeted to inhabitants of households where at least one child had active trachoma diagnosed (strategy III). Strategy II could therefore reduce the prevalence and intensity of trachoma infection at a lower cost than mass community-based treatment of all residents (strategy I).

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.

Trachoma, flies and environmental factors in Burkina Faso

The presence of flies is one of the earliest risk factors for trachoma and it has been suggested that flies could act as vectors for transmission of chlamydiae. A national trachoma survey was conducted in 1997 in Burkina Faso to (i) study the relationship between trachoma occurrence, flies, dirty faces and some environmental factors, and (ii) investigate the role of flies in the presence of trachoma. The country was stratified into eight groups of provinces and a random sample of 30 clusters was selected in each group. All children aged < 10 years were examined for the diagnosis of active trachoma (trachomatous inflammation which was follicular and/or intense) and the dirtiness of the face and the presence of flies on the face were recorded. The children's carers were questioned about the number of baths given and daily face-washing. Household heads were asked about ownership of cattle and small ruminants. The presence of latrines, a stable, and garbage collection inside the yard was noted. Among 16,514 children examined, 27.0% had active trachoma and 3.3% intense inflammatory trachoma. Flies were present on 11.2% of children's faces and 82.4% and 19.7% of these children had active and intense inflammatory trachoma, respectively. Among the 30.2% of children with dirty faces, 70.2% had active and 10.2% intense inflammatory trachoma. In multivariate analysis, at least one daily bath showed a protective effect on both active and intense inflammatory trachoma. Face-washing twice daily was found to be significantly protective for active trachoma in some regions. A strong association was demonstrated between the presence of flies and dirty faces (odds ratio = 334, 95% confidence interval 202-546). The presence of flies on children's faces, dirty faces and trachoma appeared to be strongly associated. Although the presence of flies may be a marker of socio-economic status and is probably linked with other trachoma risk factors, our data indicated that interventions targeting fly control should be an important issue in controlling trachoma.

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.

Traditional couching is not an effective alternative procedure for cataract surgery in Mali

INTRODUCTION

In Mali, more cataract patients receive sight-restoring surgery using a traditional "couching" procedure (the lens inside the vitreous body) than by modern cataract surgery. In order to evaluate the relative effectiveness and other outcomes of the traditional procedure compared to the modern surgical intervention, we conducted a population-based survey in a rural district of Mali in 1996.

METHOD

A total of 99,800 persons from 160 villages were eligible to be included in the sample. All individuals operated for cataract by a modern procedure were checked for visual acuity and questioned regarding their clinical history, the cost of the surgery and their satisfaction with the surgery immediately following the operation and presently. Each patient was paired with one person operated by a traditional cataract surgical procedure.

RESULTS

From a total population of 99,800 we found 85 individuals (0.085%) who had been operated by intracapsular extraction (ICCE) without lens implantation and we paired these with 82 individuals operated by the traditional method and by a local healer. In both groups, males were predominant (74.4% in the modern group and 61.3% in the traditional) and the median age was 65 and 68 years, respectively. Men with a higher social status (defined as administrative or religious authority) were slightly more common among those operated by ICCE (18.9%) than among those operated by the traditional healer (4.4%). Nearly half (47.6%) of the patients operated by couching did not know that a modern alternative existed. The mean cost to the patient of the two procedures was similar; with traditional couching costing on average US$ 42.10 and modern surgery (including transport and drugs) costing US$ 52.40. The traditional healer was often paid partially in kind and the price paid varied according to the patient's ability to pay. The clinical results differed greatly between the two methods. After aphakic correction of eyes operated by ICCE, 5.3% had good vision (33/18), 76.8% had low vision (33/60 and <3/18) and 17.9% were still blind (<3/60). Of eyes operated by traditional couching, none had good vision, 29.1% had low vision and 70.9% were blind. The level of satisfaction was high (89.7%) among persons operated in an ophthalmic center by the modern method, and relatively low (22.6%) among persons operated traditionally.

DISCUSSION

In Mali, two types of providers offer two different interventions to treat cataract-blind persons. This study suggests that the couching method used by traditional healers is relatively expensive and ineffective. It is also potentially dangerous although this study did not address this question specifically. It is important that health policy makers and medical authorities do what they can to prevent traditional healers from performing the couching procedure, as well as informing the population about the existence of a more-effective and safer alternative. However, while more effective and safer, the results obtained by ICCE are not excellent either. Further, it is important to improve the quality of ophthalmic services in order to provide cataract patients with the best, most accessible and least expensive services possible.

[Rapid trachoma assessment method (TRA): comparison with an exhaustive prevalence survey in a region of endemic trachoma in 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.

[Research at the African Institute of Tropical Ophthalmology]

Research is one of the four main activities of AITO. It is vital for the determination of health care priorities, and for the design, implementation, and evaluation of programs and projects in OCCCMED countries. Most of the research is surgical and focused on the diseases which cause blindness. Cataracts are the principal cause of blindness and have been the focus of many studies aimed at making surgery more accessible in terms of both geographical availability and cost. Trachoma is a major public health priority in the countries of the Sahel and a survey of its prevalence is underway in several countries. This study should lead to the development of preventive and curative treatments aimed at controlling blindness caused by trachoma by the year, 2020. Vitamin A deficiency, the cause of xerophthalmia and high mortality rates in infants, has been surveyed in several countries. A survey of glaucoma, another major cause of blindness which is often not recognized or treated, will be carried out in Bamako. Other studies focus on leprosy, malaria and the effects of visual disability on the quality of everyday life. It will be a major challenge over the next five years to develop the capacity within local populations to identify, design and implement research programs in community health aspects of ophthalmology that will take into account the needs and constraints of sub-Saharan Africa.

[Training at the African Institute of Tropical Ophthalmology in Bamako]

The African Institute of Tropical Ophthalmology (AITO) is an OCCCMED institute, founded in Bamako in 1953. The OCCCMED itself is based at Bobo Dioulasso (Burkina Faso). AITO is a WHO collaborating center for the prevention of blindness. Training is one of the main activities of the institute, along with eye care, research and assessment. The prevalence of blindness in sub-Saharan countries is about 1.2%, with blindness mostly caused by cataracts, trachoma, glaucoma and onchocercosis. The demand for eye care is high but there are currently too few trained personnel to satisfy that demand. Therefore, AITO's role in training eye-care professionals is particularly important. The institute trains ophthalmologists, specialist nurses, eye surgeons (who remove cataracts) and spectacle manufacturers. Training is carried out within the framework of the community and apprenticeship in the workplace. The student must attain specific targets, listed in a "competency passport" issued at the start of training. Clinical and surgical ophthalmology and general eye care are taught. Training costs and grants are mostly paid by the Lions Club International Sight First Program or by the French Overseas Development Ministry. Since 1991, AITO has trained to graduation: 18 ophthalmologists; 24 eye surgeons; 83 specialist nurses; 16 spectacle manufacturers.

[Strategies to control trachoma]

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.

[Cataracts, a way into the national health system of Mali?]

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 vitamin A deficiency]

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.

[Strategies to control cataracts]

Cataracts, often associated with aging (80%), are a major cause of blindness (more than 50% of cases of blindness in Africa), and for this reason, up to 80% of cases could be predicted or prevented. The socio-economic costs (care and loss of productivity) are increased by morbidity (blindness, impaired vision, congenital, complicated or infected cataracts). The biological determinants of cataracts account for the difficulties in developing and implementing effective preventive action. These epidemiological determinants (prevalence, incidence, increase in life expectancy) account for the size of the public health problem. The surgical removal of cataracts in Africa currently only deals with about 1% of the prevalence rate or 10% of the incidence. Cataracts are, however, easy to cure, resulting in great benefits to public health. The waiting list for cataract operations is very short because of social and cultural barriers which limit the acceptability and accessibility of treatment. Rather than formalizing the dogmatic choices of surgical techniques and structures (fixed, mobile, advanced?), we should promote all phases of treatment from active screening and the selection of cases for surgery to the follow-up of interventions and their impact. We should also increase public awareness, develop a system for the transfer of information that is effective and improve the cost-effectiveness and capacity of the region to provide high quality services on a large scale. We must promote patient satisfaction at all stages of treatment: its quality, its delivery and its low cost.

[Future of ophthalmology nurses and physicians trained at the African Institute of Tropical Ophthalmology]

Six ophthalmologists and 24 specialist ophthalmology nurses from French-speaking African countries graduate from AITO each year. Their training focuses on the skills they will need to participate in the national programs to combat blindness. All the ophthalmologists (10) and specialist ophthalmology nurses (42) from Mali, Niger, Burkina Faso and Senegal, who graduated from AITO within the last ten years were interviewed. Eight of the ten ophthalmologists and all of the specialist nurses are currently working in national programs to combat blindness. The specialist nurses knew more about public eye health issues than about optics. The training given is appropriate for ophthalmology professionals working in these countries. The chief demand of both ophthalmologists and specialist nurses was that they should have continuous training and supervision.

[Activities of the African Institute of Tropical Ophthalmology, 1990-1997]

The African Institute of Tropical Ophthalmology (AITO) was founded in Bamako in 1953. It is part of a regional structure, The Organization for Cooperation and Coordination in the Control of Major Endemic Diseases (OCCCMED). AITO is a WHO collaborating center for the prevention of blindness and has four aims: the provision of eye care, training (ophthalmologists, cataract surgeons, specialist nurses, spectacle manufacturers), research (epidemiology, clinical and surgical) and assessment of public eye care as a function of the needs of the member states of OCCCMED. The European Regional Program for the Prevention of Blindness and an International Sight First Program Center are located at AITO. AITO is at the heart of a network dedicated to fighting blindness, and its activities extend beyond the borders of the OCCCMED.

[Synthesis of the blindness situation in the countries of the Organization for Cooperation and Coordination in the Control of Major Endemic Diseases]

The major causes of blindness in the OCCCMED states are cataracts, trachoma, glaucoma and oncocercosis. The prevalence of blindness is about 1.2% and there are about 880,000 blind individuals and 2,500,000 people with impaired vision. Cataracts were the cause of blindness in 440,000 people and the cause of visual impairment in 1,320,000 individuals. About 1,500,000 people were found to have oncocercosis, and about 24,000 were blind. The true rate of trachoma is unknown. Thirteen thousand cataracts are surgically removed in the region each year, the CSR (cataract surgery rate) being 210. In the last few years, national programs have been set up to combat blindness and equipment and training have been established. With a ratio of 1 ophthalmologist per 523,000 people, the WHO's objectives are becoming attainable.

[Cartography of trachoma in Mali: results of a national survey]

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.

Scanning electron microscopic study of an anterior chamber intraocular lens: latent endophthalmitis

Two years after intracapsular cataract extraction and intraocular lens implantation, an anterior chamber lens was removed. The lens was studied by scanning electron microscope which demonstrated the presence of colonies of cocci, a thin acellular membrane covering part of the lens and some modifications of the lens surface.