Further progress in the control of sleeping sickness in Nigeria

Three types of sleeping sickness are described as occurring in Nigeria— the mild type, the toxic and the nervous. The great majority of the cases found at sleeping sickness surveys belong to the first group. Patients suffer from occasional attacks of headache and fever and from some weakness, very little else. It is their increased susceptibility to intercurrent diseases which often caused the depopulation found in some of the more heavily infected areas. In the second group, which is much more rare, toxaemia is the salient feature. In the third, there are signs of progressive nervous involvement. The proportion of patients suffering from the three types varies. Even in the more virulent epidemics the mild form is common.In Northern Nigeria there is a striking correlation between the areas of infection and the lines of communication, railways, roads, and mining areas. The main zone is confined to the central part of the country. Peripheral areas, though heavily infested with tsetse-fly, are still practically free from infection.Nigerian policy is to establish convenient permanent treatment centres once a full survey of the whole population has been followed by mass treatment. The information obtained at the survey makes the planning of effective protective measures possible. The work of the sleeping sickness teams, dispensaries and the control of mines labour is described.From 1931 to 1943 a total of 3,148,069 people were examined in new areas and 306,322 cases found, an infection rate of 9·7 per cent. In the worst areas 913,718 people were re-examined and an infection rate of 2·2 per cent. found. During the first 5 years of this period the disease was still increasing. The average infection rate was 13·6 per cent. In the next 5 years the spread had been stopped though the infection rate was still high in the remaining new areas. From 1941 onwards the new areas discovered had a low infection rate. The rate for resurveys of what were formerly some of the worst areas was 2·5 per cent. Taking Northern Nigeria as a whole, it is doubtful if there is much more than a tenth of the old amount of infection.The sleeping sickness dispensary system has been expanded during the last few years. Some 80,704 cases of sleeping sickness have been treated. Practically all were voluntary attendances. The general medical and health work also has been improved.With the 43,674 cases treated at general medical stations, a total of 450,451 cases have been treated in the last 13 years. Of these about 400,000 were new cases, the remainder relapses. 'The control of the disease by communal clearing campaigns is described. So far about 240,400 people have been protected from any serious risk of contracting sleeping sickness.A brief account is also given of the Zaria sleeping sickness settlement scheme. So much attention has been paid to all aspects of rural planning and development in the settlement area that it has come to be regarded as a model of rural development.The changes in population figures, particularly in Zaria Emirate, give a striking indication of what has been accomplished. In the period 1923–1933, when the disease was increasing, the population fell by about 12 per cent. At the survey of the whole Emirate 78,000 cases were diagnosed and treated, an infection rate of 20 per cent. There was direct evidence of correlation between infection rates and mortality. With the decrease in sleeping sickness consequent on treatment and control, depopulation stopped. Since 1933 the total population has increased about 24 per cent. It is not claimed that results of treatment have been as valuable in the milder area where there was no sign of the disease causing immediate loss of population.The general position is much more satisfactory throughout the country though constant vigilance is necessary if this relative improvement is to be maintained.     

The pathogenesis of sleeping sickness

Although the clinical and pathological features of sleeping sickness have been well recognized since the beginning of the century, we still have very little idea about how these changes are brought about. A convincing role for a trypanosome-derived toxin has yet to be established and it is probable that most tissue damage results from an immunopathological reaction. An immediate type hypersensitivity reaction might account for the pruritus and urticaria sometimes encountered in patients with the infection. Autoantibodies are produced by patients with sleeping sickness but it has not been established that these can cause tissue damage. Similarly, although high levels of immune complexes are found in patients with sleeping sickness, it has yet to be clearly established that these damage the brain or heart. The dominant pathological event in sleeping sickness is B lymphocyte proliferation, first within the lymph nodes and then within the brain and meninges, and this response may lead to tissue damage in some way which has not yet been identified. B lymphocyte proliferation could result from the action of a trypanosome-derived mitogen or from interference with T lymphocyte control over B lymphocyte function.     

Rhodesian sleeping sickness in Eastern Uganda

The occurrence of an epidemic of sleeping sickness involving 2,500 persons in the Busoga and Samia districts of Uganda is described.Proof is given that the trypanosome responsible is T. rhodesiense.Epidemiological and experimental results point to G. pallidipes as the principal vector. The part played by G. palpalis is still uncertain.Experiments are described which prove that G. pallidipes can carry naturally a trypanosome of the brucei-rhodesiense group which is capable of causing sleeping sickness in man.It is probable that the infection was introduced by alien labourers from the west of Lake Victoria.     

睡眠障碍应用健康教育的探讨

目的 了解健康教育在睡眠障碍中应用的效果.方法 选择2002年1月-2002年6月在我院门诊就诊的睡眠障碍的病人,将其随机分为宣教组和对照组.结果 宣教组明显优于对照组,P＜0.01.结论 实施健康教育可明显改善病人的睡眠状况.     

New concepts in the epidemiology of Rhodesian sleeping sickness

The results from recent studies of a number of outbreaks of T. rhodesiense sleeping sickness have enabled workers in this field to reconsider the epidemiology of the disease.