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Lutte contre le trachome en Afrique subsaharienne

 | 
Anne-Marie Moulin
, 
Jeanne Orfila
, 
Doulaye Sacko
, 
et al.

Part One. Synopsis and recommendations. English Version

The lessons of history

Texte intégral

1Trachoma disappeared from many European countries about the time of the Second World War. What are the social, cultural and medical determinants explaining this disappearance and persistence in other countries?

2Are there cases where blinding trachoma has disappeared in regions with endemic disease, but without significant improvements in socio-economic levels?

3Trachoma is an infection historically recognized at least since the time of the Pharaohs. Over the years, we have acquired abundant though mixed documentation. Historians have great difficulty in sorting out the history of trachoma within the current meaning of the word, which is infection of the conjunctiva due only to Chlamydia, and not ocular ophthalmia or infection in general. However, they can easily follow the history of trichiasis, and blindness due to corneal opacity.

TRACHOMA, AN INTERNATIONAL INFECTION

  • 1 In the nineteenth century meaning, which was a configuration of etiological factors.

4It has never been demonstrated that a group or population is particularly sensitive. Today, genetic factors of individual susceptibility are suspected, but knowledge of them is still rather feeble. Historically, trachoma has affected all sorts of people. It was rife in cold and hot countries, from Finland to Senegal, on plains and in valleys, on the coast and far from the shore. Nineteenth century doctors were unable to identify the niche1 of trachoma. At most, they noted a certain prevalence in the hot, dry regions, where dust storms chronically irritate the conjunctiva. Sahelian Africa, for example, appeared more affected than central Africa. Being able to take on epidemic form in rapidly mixing populations, trachoma appeared above all favored by poverty, promiscuity and lack of water for the basic needs of life.

5A microbial etiology was envisaged at the very start of the bacteriological era, after identification of the bacilli of tuberculosis, leprosy and cholera in the 1880s. However, in spite of persistent effort, with several periods of false hopes, the pathogenic agent was not discovered by bacteriologists until they finally succeeded in cultivating it in laboratory in the 1950s.

6This long time taken over “modernizing” the infection undoubtedly encouraged a great deal of deep thought on the natural and social, climatic and behavioral factors, potentially implicated in the outbreak and evolution of trachoma. Today, epidemiology still examines the many factors statistically associated with the risk of trachoma, without however succeeding in accurately quantifying their respective action.

TRACHOMA, AN AFFLICTION IN EUROPE FOR HALF OF THE TWENTIETH CENTURY

7At the end of the nineteenth century, trachoma was considered by hygienists to be a real affliction in countries becoming industrialized: England, France, Germany and Russia. Nevertheless, up to the First World War, without the intervention of any wonder drug, trachoma had very clearly decreased. It appeared again during the hostilities. With the return of peace, the hygiene organization of the League of Nations set about recording the first statistics on a worldwide scale, obviously with very unequal reliability (Tunisia and the United States declared the same number of cases in 1923!).

8In 1939, therefore before antibiotics, trachoma was no longer a real health problem for the principal countries of Western Europe. What happened, and what action had been taken?

9The infection being especially manifest within certain communities, it is within these communities that the national effort took place, namely the army and schools (with the extension of schooling) and to a lesser degree in the place of work. In this latter case, the role of work-related illnesses (for stonemasons, polishers, builders) was admitted, resulting in a whole range of laws and procedures to be used at the workstation.

10Screening has been combined with treatment by various eye lotions, over the years, using salts of copper or silver, then the sulfonamides after 1930. Surgery was developed to treat trichiasis and prevent blindness. To avert contagion, the isolation of patients was proposed, and in certain cases, regiments and schools for those afflicted with trachoma were even created.

11Internationally, an examination of travelers and especially immigrants was instituted. The United States notably set up draconian checks, which pushed applicants for immigration to be screened and treated before their departure, especially in English hospitals.

  • 2 A debate illustrated by the best-seller of Ivan Illich, Némésis médicale, Seuil, Paris, 1984.

12The progressive improvement in public and private health, the low price of soap, and the arrival of running water have surely played a role in the disappearance of trachoma as other infectious diseases. From this point of view, trachoma is a disease like any other. The debate on trachoma leads to a wider debate2 on the factors of the decline in infectious patients in Europe during the twentieth century. Apart from special cases, the action of medicine on this decline appears relatively modest compared with improvements in nutrition, habitat and working conditions.

13As regards trachoma, specific measures of isolation, screening and treatment by pharmaceutical remedies have surely contributed to limiting the spread of the disease. The surveillance of frontiers, in any case in Europe, has probably only played a minor role since it has not really been applied. On the other hand, the epidemic outbursts of trachoma during major wars provide proof of the aggravating role of the massive displacement of populations and the brutal deterioration in living and hygiene conditions.

14History does not suggest any clear model. To understand the disappearance of trachoma in the countries concerned, it is necessary to analyze the resources deployed against the disease over the last fifty years, and the political, economic and social transformations. It is nevertheless difficult to identify the part played by improvements in the socio-economic standard of living and the individual measures adopted.

THE DIFFERENT HISTORICAL MODELS FOR ELIMINATING TRACHOMA

15Is it possible to benefit from the experience of countries that have now rid themselves of blinding trachoma, and identify the crucial factors in the disappearance of the disease?

16Among the possible historical models, the oldest is that of the countries of Western Europe: France, England, then later Italy, Spain, Portugal and Ireland, where trachoma disappeared before the arrival of antibiotics. Screening and more or less effective treatment were practiced within closed communities (armies, hospitals, schools), while standards of living and hygiene improved gradually in the populations.

17More recently, the countries of Central Europe, like Poland and Yugoslavia knew a similar evolution. A distinct upsurge in the infection during the Second World War gradually died out over the years of rebuilding these countries. An undeniable rise in the standard of living and an overall improvement in hygiene in this case also contributed to the demographic transition of the twentieth century and the decline in blindness of infectious origin.

18It was similar in the ex-Soviet Union (including Central Asia where nineteenth century travelers reported the great number of blind people around the mosques in Bukhara and Samarkand). The number of cases of blinding trachoma fell following intensive schooling and a good public health system after the Second World War.

19Antibiotic therapy has played a role in other countries where trachoma has been more recently eliminated.

20Tunisia offers a particularly well documented example. Thanks to a continuous series of monographs, running from Cuénot and Nataf to Dawson and Daghfous, it is possible to reconstitute the history of the infection in the country. As from the beginning of the twentieth century, unsuccessful attempts at vaccination were made; microbiological and experimental research around Charles Nicolle; and epidemiological investigations led by the local hygiene authorities. At first, trachoma was rife over the whole land. Between the two wars, a gradient took shape between north and south, and east and west, reflecting the economically active part of the country, the north and the Sahel, and the poor and rural regions with a semi-desert climate, where trachoma was very strong. In 1958, prevalence exceeded 30% more or less everywhere, but more seriously and frequently in the south, from Sfax to the desert.

21Twenty years later, all stages together including trichiasis, the prevalence of trachoma collapsed. Only the great South remained very much affected with total rates of trachoma higher than 30%. During these twenty years, which coincided with the first years of independence, trachoma was attacked in several ways and the effects of this began to accumulate. There were mass treatment campaigns in the schools, using ointment with 1% aureomycin, often administered by the teacher himself and in the dispensaries. But, the local grocer also had ointment with aureomycin at low cost; a conscious encouragement to self-administration of medicines that witnesses today remember because the ointment “stung the eyes”. Trichiasis was screened by mobile teams, together with interventions in dispensaries and hospitals.

22During this period, electrification began to arrive in the country. Schooling, which was rudimentary under the protectorate, was briskly instituted for boys and girls, reaching levels higher than 70% and covering almost the whole country. Per capita income increased moderately, but the development of the building trades made it possible to build larger and more hygienic housing, while water supplies facilitated access to the towns and villages of the north and the Sahel.

23After 1970, efforts were concentrated on the south, carried out by doctor ophthalmologists, with the assistance of nurses specializing in eye treatment, completing the work undertaken. On several occasions in recent years, trachoma specialists have visited Tunisia without finding a single case of active trachoma.

24In Algeria, trachoma was a massive problem at the beginning of the century, but regressed continuously as from the 1930s and after the Second World War and independence, following a trajectory similar to that in Tunisia. Trachoma was regarded as practically eliminated, but due to the troubles in recent years and the relaxation of vigilance as regards public health, prevalence has distinctly risen in the oases of the south.

25In Egypt, in spite of the hopes during the Nasser period to do away with “national ophthalmia“, the disease is far from having disappeared.

26From the Middle Ages to the nineteenth century, accounts of travelers agreed on the frequency of eye diseases and blindness in all villages.

27In 1904, under the English protectorate, the ophthalmologist MacCallan gave his name to a clinical classification of the lesions. He created the first mobile ophthalmology clinic, and in 1913 published Trachoma and its complications in Egypt, which has remained a reference work. The prevalence of trachoma then affected 90% of the villagers. One percent of the villagers were blind in both eyes, obviously without trachoma being the sole cause.

28Between the two world wars, Rowland Wilson, director of the Memorial Ophthalmic Research in Guizeh (founded in 1926 and still in existence), mainly accused malnutrition, poverty and defective hygiene; in short, the difficult life of the fellahs of Egypt. In the transmission of trachoma, he denounced the role of flies, which pullulate in the villages around excrement strewn on the ground in the absence of latrines, and lumps of fuel made from dried dung. He recommended measures combining the education of girls and the protection of babies from flies, the application of zinc sulfate in children’s eyes. Nevertheless, the Egyptian village has hardly improved because of lack of political will and finance.

29In 1948, a study of the Rockefeller Foundation reported the stagnation of the rate of infection in the Nile delta at around 90%. DDT gave birth to great hopes and the Foundation spread insecticide with profusion. However, two years later, the resistance of flies discouraged the continuation of the plans. Trachoma appeared unassailable in Egypt.

30In 1952, with the arrival of Nasser, trachoma was recognized officially as a health priority in the countryside, where the new regime multiplied health centers. At the start of the seventies, the government considered that trachoma was in the process of disappearing and no longer required any particular measures. Thus, in 1990, when the WHO envisaged eliminating trachoma, Egypt declined the invitation to be declared a country with an endemic disease. It was only in 2000, after alarming regional investigations, that trachoma regained its dimension as a national affliction; it concerned 30 to 60% of children in certain villages. The government from then on took part in the Alliance’s work to eliminate trachoma. Today, there is still no exhaustive national data. The number of schoolchildren affected in certain regions seems to be 30%.

31The example of Egypt illustrates the importance of vigilance as regards trachoma. If nobody at the dispensary or school takes trouble to turn over the eyelids of children, we pass over a simple way of tracking the disease. Moreover, it proves the need for continuity in the public health policy and awareness of the real dimensions of the affliction.

32Vietnam, in contrast, offers an example of centralized and sustained management of trachoma. In the 1950s, the government of North Vietnam assumed the combat against trachoma (reaching 90% of the population), with a defined “national line“, programs integrating hygiene in education, and using local traditional practitioners. The trachoma Institute in Hanoi dispatched mobile brigades into the villages, supported by a network of dispensaries for screening and treating trachoma. Trichiasis was treated by quickly trained community health workers.

33It is difficult to evaluate how the population adopted a teaching openly directed towards combating “bad habits” and changing mentalities. At all events, trachomatous endemic disease incontestably decreased in North Vietnam, then in the whole of the Vietnamese republic after the end of the war. The fight associated chemotherapy (mineral eye lotions then sulfonamides) tests with traditional medicines. Films, stickers illustrating the fight against trachoma on matchboxes and the covers of school notebooks disseminated the medical message; thereby enrolling the communities.

34In the sixties, ethnic minorities in the mountains were regarded as less at risk, perhaps because of overpopulation less obvious than in the delta. Alternatively, perhaps there was ignorance of the local situation. Today, trachoma is presented by the medical authorities of Vietnam as a disease of poor and underdeveloped minorities, which had not benefited from the measures of environmental sanitation and hygiene campaigns.

35Senegal has seen a reduction in trachomatous endemic disease in recent years. The prevalence of trichiasis, close to that of Mali, reflects the historical extent of endemic disease. However, the prevalence of active trachoma in children of the villages is three times less than in Mali, and this reduction suggests a tendency to a decrease in blinding trachoma. One of the hypotheses explaining this phenomenon could be a higher standard of living and a higher rate of schooling.

36During these last thirty years, other countries have shown a favorable evolution like Saudi Arabia, the Sultanate of Oman or Myanmar, which have instituted specific measures against trachoma. In the case of Saudi Arabia, the rise in the standard of living of the settled Bedouins is probably the principal factor, as all the reports testify. At the same time, the dispensaries have deployed an intense curative action. On the other hand, in Myanmar, the decrease in trachoma cannot be attributed to a spectacular rise in the standard of living, and the merit apparently is due to the mass campaigns of antibiotic therapy.

37In Morocco, in the fifties, trachoma was rife over the whole land. It gradually disappeared in a similar way to Tunisia, and for the same reasons, in most of the regions, except for the underprivileged provinces of the south east. Because of these residual areas, it was chosen as a pilot country with Gambia and Mali, during the first meeting of the Alliance in 1996, and probably now constitutes the best-documented example of application of the SAFE strategy.

38The Moroccan success, which is not yet a question of the elimination of trachoma, but of the interruption of the transmission of blinding trachoma, is explained by the convergence of several factors:

  • a political will to fight trachoma since 1994,
  • significant human resources, ophthalmologists guiding the nurses in the field,
  • an active campaign since 1997, associating the State and the NGOs; one of which is the ITI (International Trachoma Initiative).

39Morocco seized the opportunity of the SAFE strategy. To the antibiotic therapy facilitated by the gift from Pfizer, it combined information gathering and development, designed to consolidate the decline of the infection without need for prolonged administration of antibiotics.

CONCLUSIONS AND RECOMMENDATIONS

40If we compare countries where trachoma has disappeared or decreased significantly in a few decades, we see that the associated rise in the standard of living was unequal and that a moderate improvement in the case of Tunisia and the countries of Central Asia for example, can go hand in hand with the elimination of blinding trachoma, if certain conditions are fulfilled such as:

  • an awareness of trachomatous endemic disease among the populations, which either treat themselves spontaneously or go to health centers;
  • the achievement of spectacular campaigns, which tend to increase the social visibility of the infection;
  • the supportive role of public health action in the villages;
  • the availability of methods of treatment (eye ointment), relatively easy to apply and not very expensive.

41The rules of history are marked by the seal of contingency, which means that the same causes do not always produce the same effects, and that identical reproduction is impossible. Nevertheless, the SAFE strategy attempts to produce a united force identical to what appeared spontaneously effective in the past between social measures such as environmental sanitation and education, and the medical and surgical measures, without expecting everything from a radical modification in living standards. Several mutually-aiding factors should accelerate the historical trend of extinction of the disease.

42One of the lessons of history is not to expect everything from antibiotic therapy, which is neither absolutely essential nor indefinitely renewable, but to hope to trigger a virtuous circle of the reduction in trachoma and improvement in living conditions. This will complete an evolution that is perhaps partly “natural”.

Notes

1 In the nineteenth century meaning, which was a configuration of etiological factors.

2 A debate illustrated by the best-seller of Ivan Illich, Némésis médicale, Seuil, Paris, 1984.

© IRD Éditions, 2006

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