Bulletin of the International Union against Tuberculosis and Lung Disease最新文献

During the last 5 years, a worldwide resurgence of tuberculosis has been convincingly documented. Increased numbers of cases have been reported from several industrialized countries and there has been a veritable explosion of tuberculosis in the developing countries of sub-Saharan Africa. The fact that most of this increase is attributable to coexisting infection with the human immunodeficiency virus (HIV) should come as no surprise, because of the role played by cell-mediated immunity in protecting against tuberculosis and the depletion of this immunity by HIV infection. The World Health Organization estimates that there are more than 3 million persons in the world dually infected with HIV and tubercle bacilli. To combat this problem, there needs to be an expansion of programmes designed to identify and treat all patients with tuberculosis, whether HIV infected or not. In addition, the prospects for further advances in basic research, clinical research, epidemiological research and operations research, which have broad application to clinical medicine, are great, and these results will help combat the dual scourges of HIV infection and tuberculosis.

The Mutual Assistance Programme of the IUATLD is aimed at trying to compensate for the neglect into which tuberculosis had fallen from the part of governments, teaching institutions and international agencies, and represents an innovative approach to promote solidarity between governments and voluntary organizations of low tuberculosis prevalence countries and those of high prevalence countries. The main objective has been to develop a system of delivery of treatment and diagnosis of tuberculosis that would be efficacious even under the difficult conditions of high prevalence of tuberculosis, low resources and/or socio-political disturbances. The system turned out not only to be efficacious in terms of cure rates and epidemiological impact but also to be efficient in terms of cost/benefit. The National Tuberculosis Programme's approach includes the application of short-course chemotherapy, the regular provision of drugs and products, a system of registers, forms and periodic reports, the assessment of the yield of case-finding and, most important of all, the analysis of the therapeutic results in successive cohorts of patients. Cure rates repeatedly reach around 85% in new cases and approximately 80% in retreatment cases, nationwide, in the countries where such programmes have been successively implemented. Each national programme has an important role of training and of capacity building. While serving the populations, the national programmes also provide the framework for relatively inexpensive operational research and, finally, the careful collection of data represents a basis--unique of its kind in the world--for the study of the clinical and epidemiological relationships between tuberculosis and HIV. The method has been endorsed by the WHO and has the support of the World Bank, the United Nations Development Plan and the main government Agencies for Development Cooperation. It is part of the new Global Strategy against Tuberculosis which is presently being developed under the WHO TB Unit. The other aspects of Mutual Assistance concern courses, consultation to programmes not directly sponsored by the IUATLD and publications.

The structure, manpower and tasks of the Tuberculosis Programme (ELAT) in Mozambique are explained. The activities are organised on three levels (ministerial, provincial and district). From 1985 to 1990 (1st half) 59,339 cases were detected. Of them, 32,978 were new smear-positive, 17,772 new smear-negative, 5,664 relapses and 2,425 extra-pulmonary cases. Results achieved by 3 regimens used by the Programme varied on average from 55% for the standard, 77% for the short-course and 72% for the retreatment regimen. The Programme is run by paramedical staff and no specific personnel exists in the districts. To upgrade the few personnel involved in the ELAT, supervision and training are considered as backbones of the Programme. The country suffers from a devastating war, which has aggravated the poor transport network, reduced accessibility to remote areas, hampered regular supervision and makes distribution of supplies irregular and very expensive, since drugs, reagents, forms and spare parts have to be sent by air or sea. In spite of all these terrible misfortunes, results achieved show that it is possible to diagnose and treat cases under such condition.

A research study was in progress in a Czech district (100,000 inhabitants) in the years 1961-1972 with the aim to analyze the epidemiological situation of tuberculosis and the impact and effectiveness of control measures. Most of the conclusions are still valid and have their role in present tuberculosis programmes in Czechoslovakia or in other countries, too. There were recommended sensitive epidemiological indices and methods by which the actual situation should be characterized, changed or monitored: direct smear-positive cases and their importance, reevaluation of BCG vaccination and revaccination, as well as of case-finding and economic aspects of chemotherapy. The study built up fundamental prerequisites of a modern approach to tuberculosis control.

This Symposium honours the achievements of Dr Karel Styblo. In this presentation, specific epidemiologic insights are reviewed. Studies of the epidemiology of tuberculosis in Eskimos showed a picture of tuberculosis at the height of the epidemic. Very high incidence was observed in young people who experienced a high fatality rate. Application of specific control measures were accompanied by rapid decline in rates, greater than observed in any other human population, demonstrating that tuberculosis could be brought under control by specific intervention. Studies of the natural trend of tuberculosis in South India showed that, even in the absence of intervention, a decline was observed in the rates of this disease. In the absence of chemotherapy, 50 per cent of cases die within 5 years, 30 per cent recover spontaneously and 20 per cent remain sputum positive. Studies of the efficacy of BCG in Madras, enabled to study the impact of efficient case-finding associated with poor treatment results showing that such a situation multiplies the number of surviving, infectious cases in the community and, thus, actually deteriorates the epidemiological situation. These various basic studies have shown both how to create success and how to create failure in tuberculosis programmes.

In developed countries, the risk of tuberculosis infection is often less than 0.05%, and the majority of diseases is caused by remote infections, so that the ratio of incidence to risk of infection is now becoming bigger than that in developing countries. Surveillance on the trend of incidence, surveillance of tuberculosis group infections and surveillance of diagnostic and treatment measures, especially that of delay in case-finding, are considered as important functions of tuberculosis surveillance in developed countries.

Social, economic and operational research has already contributed to the growing global awareness of the neglected burden of tuberculosis on individuals, families and communities. These studies have also illustrated that short-course chemotherapy for smear-positive pulmonary tuberculosis is a highly cost-effective tool for combatting tuberculosis. In the present work, the author examines the costs and effectiveness of the national tuberculosis programmes in Malawi, Mozambique and Tanzania. Chemotherapy for smear-positive tuberculosis is found to be among the most cost-effective health interventions known, costing 1-4 US dollars per year of life saved. In all situations, short-course chemotherapy is found to be more cost-effective than standard 12-month chemotherapy. General conclusions about the role of hospitalization are difficult to make; its cost-effectiveness depends on local patterns of compliance and the cost of hospitalization. Because more than three-quarters of the benefits of chemotherapy for smear-positive tuberculosis are due to transmission reduction, treating HIV sero-positives, smear-positives is probably cost-effective.

The success of IUATLD-assisted National Tuberculosis Programme developed by Dr. Karel Styblo is dependent on a number of important principles. The most important step is the organization of the basic components of the National Tuberculosis Programme. This first step requires 1) a political commitment on the part of the Government, 2) a secure supply of drugs and materials, including a reserve stock, 3) a network of microscopy centres with a system of quality control and 4) proper recording and reporting of cases. These conditions can result in significant improvement in case-finding and treatment results but rarely results in a cure rate of smear-positive cases in excess of 55 per cent. To obtain the levels of cure necessary to achieve an epidemiologic impact, it is necessary to employ short-course chemotherapy. Additional conditions must be met for this to be successful: 1) adequate supervision of drug-taking in the initial intensive phase, 2) proper training of staff prior to commencement of the treatment and 3) step-wise introduction throughout the country. Several factors may adversely affect the outcome of treatment programmes. These are drug resistance, a high rate of relapse and HIV infection. To date, the IUATLD-assisted programmes have shown sustained success.