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

Objective: To evaluate the need for the BCG revaccination programme of schoolchildren in Finland.

Design: Investigating tuberculin sensitivity using the standard WHO Mantoux test and developing a model to estimate the risk of discontinuation, assuming that the annual incidence of tuberculosis within ten years after revaccination will remain at its present level; that the revaccination rate will be 2, 6 or 20%; and that the degree of protection will be 10, 20, 40 or 80%.

Setting and participants: Urban and rural schoolchildren--3,346 vaccinated with Copenhagen and 655 with Glaxo BCG vaccine at birth.

Results of data analysis: The annual incidence of tuberculosis was 4.2 per 100,000 in the age-group 15-24 years. BCG revaccination was given formerly to 20% of the age cohort but nowadays only 6% or 2% meet the criteria after receiving either Copenhagen or Glaxo BCG at birth. After discontinuation the expected increase of tuberculosis in the age-group 15-24 years is predicted to fall within the limits of 0.1-24 cases per year. If 2% are left without revaccination the increase will be 0.1-2.4 cases.

Conclusions: Due to the low annual incidence of tuberculosis in adolescents and to the small risk of increase the BCG revaccination programme has been discontinued from 1990 onwards.

In rural Haiti we measured and compared the muscle protein and calorie reserves (anthropometrics) as well as the visceral protein reserves (serum albumin, tuberculin sensitivity) in 56 HIV (human immunodeficiency virus type-1) seropositive and 108 HIV seronegative pulmonary tuberculosis patients. Results in patients were also compared to the results of the same measurements made in 160 age, sex and residence matched HIV seronegative controls without tuberculosis. Tuberculosis patients, regardless of HIV status, had significantly reduced muscle protein and calorie reserves compared to controls. The serum albumin was significantly lower in HIV seropositive tuberculosis patients (21.0 g/l) compared to HIV seronegative tuberculosis patients (26.9 g/l) and the serum albumin in both tuberculosis groups was significantly lower than in controls (41.3 g/l). The lower the serum albumin in the tuberculosis patients the greater the likelihood of a negative tuberculin test. HIV seropositive tuberculosis patients were significantly more likely to be tuberculin negative than HIV seronegative tuberculosis patients. Tuberculosis is associated with significant malnutrition. Worse malnutrition in tuberculosis patients co-infected with HIV suggests that the effect of the two pathogens on nutrition is additive or, alternatively, that tuberculosis patients who are particularly malnourished are at increased risk for HIV.

Tuberculosis is one of the most widespread infections known in the world. WHO estimates that in 1990, 1.7 billion people, or one third of the world population, are or have been infected with the tubercle bacillus. Fortunately, few of those infected develop active forms of the disease but it is estimated that in 1990, there will be 8 million new cases and 2.9 million deaths from tuberculosis in the world. This already alarming situation of the tuberculosis problem is getting worse, mainly due to the AIDS epidemic. A basic understanding of tuberculosis/HIV epidemiology is necessary and priority actions are to be strongly recommended for application in government intervention programs. They are specified in the present article.

The impact of the new AIDS definition on tuberculosis in Barcelona is evaluated. In 1988 active epidemiological surveillance demonstrated a tuberculosis incidence rate of 58.31/100,000 and an AIDS incidence rate of 9.93/100,000 according to the old definition, and 14.16/100,000 according to the CDCs' new definition (42.5% increase). The majority of these new cases are HIV-positive drug abusers with extrapulmonary tuberculosis. Pulmonary or extra-pulmonary tuberculosis is also observed more frequently in drug abusers than in homosexuals (odds ratio = 7.4; CL 95%; 3.5-15.5). Up until 1986, 39% of AIDS cases were homosexuals and 36% drug abusers. In 1988, according to the old AIDS definition, 54.2% of AIDS cases were drug abusers and 31.9% were male homosexuals but with the new definition it is even more striking that the high risk group is still drug abusers. Today we must add to the old social problem of tuberculosis the problem of drug abusers, and all the difficulties of compliance with chemotherapy or antituberculous chemoprophylaxis. New strategies will have to be devised to deal with this new problem.

HIV is the strongest risk factor for tuberculous disease observed in the last 100 years in subjects infected with tubercle bacilli. Its impact upon tuberculosis incidence is so great that it has disrupted the balance between the tubercle bacillus and the community. The breakdown rate from tuberculous infection to active tuberculosis in persons infected dually is at least 30%. Although adequate chemoprophylaxis would prevent a considerable number of tuberculosis cases among these individuals, its application is not feasible in developing countries with a high prevalence of both tuberculous and HIV infections. Thus it seems that very little can be done against the increase in the incidence of tuberculosis caused by HIV. The only feasible measure to contain the transmission of tuberculous infection is to achieve a high cure rate and a high detection rate of smear-positive and other cases. This would enable us to contain-to an extent-the transmission of tuberculous infection. The results of IUATLD assisted National Tuberculosis Programmes in Tanzania and Malawi show that this can be achieved.

Among the many infectious complications of infection with human immunodeficiency virus (HIV), tuberculosis is now recognized as one of the most important. Coexisting HIV infection is believed responsible for the soaring incidence of tuberculosis in Africa, and for the increase in the number of reported cases in the United States. As HIV-induced immunosuppression worsens, tuberculosis may supervene by reactivation of remotely acquired infection or failure to defend against newly acquired Mycobacterium tuberculosis. Both mechanisms undoubtedly occur in Africa where the rate of exposure is high; the former prevails in the United States. The risk of tuberculous infection progressing to tuberculous disease is about six times higher in HIV seropositive than seronegative persons. Although not incontrovertibly established, tuberculosis probably also has a deleterious effect on coexisting HIV infection, either by accelerating the rate of destruction of CD4+ lymphocytes and/or promoting the release of new virions from HIV-infected macrophages. Tuberculosis, whether HIV-linked or not, can be controlled by the traditional means of case-finding and treatment, vaccination with BCG, and chemoprophylaxis. HIV infection can be controlled by eliminating high-risk behavior, and using uncontaminated blood and other medical supplies. An extensive campaign is needed to prevent further spread of these dual scourges that are overwhelming already meager health resources in many parts of the world.