Tuberculosis in HIV infection.

Persons with AIDS (PWAs) are 100 times more likely to develop tuberculosis (TB) than the general population. The TB incidence rates in PWAs in the US range from 4-21%, especially among intravenous drug users and Haitians. In Florida, 60% of Haitian AIDS patients also had TB compared to 2.7% of non-Haitian AIDS patients. At a hospital in London, England, 25% of PWAs also had TB and 42% of all AIDS patients at this hospital were members of racial groups with a high prevalence of TB. In developed countries, reactivation of a latent TB infection is generally what occurs in AIDS patients. The absolute number of AIDS patients with TB in these countries is low and unlikely that it will spread to non-HIV seropositive patients. On the other hand, 30-60% of adults have been infected with Mycobacterium tuberculosis in central Africa and HIV seroprevalence is also high. So many AIDS patients here can develop TB through reactivation or exogenous primary infection. This situation significantly increases the risk of TB for HIV seronegative persons. In fact, TB is 1 of the most frequent opportunistic infections in PWAs in developing countries, such as central Africa. In patients at an early stage of HIV infection, TB manifests itself classically. The clinical presentation in patients in the late stages includes fever, weight loss, malaise, productive cough accompanied with labored breathing, an atypical chest radiograph, and extrapulmonary TB. This atypical pattern often results in delays of diagnosis and treatment. Many sputum samples do not test positive for M. tuberculosis therefore if a physician suspects TB, treatment should begin immediately. Some studies demonstrate that isoniazid prophylaxis substantially decreases the incidence of TB in HIV seropositive patients in Zambia. There is no conclusive evidence of the harm or effectiveness of the BCG vaccine in HIV children and adults.     

The benefits of isoniazid chemoprophylaxis and risk factors for tuberculosis among Oglala Sioux Indians.

In a case-control study of 92 Indian patients, 46 with active tuberculosis (cases) and 46 tuberculin reactors without the disease (control subjects), significantly more control subjects than patients had prior adequate isoniazid chemoprophylaxis. While the Indian Health Service recommends treating all tuberculin reactors with isoniazid prophylaxis, most (75%) of our tuberculosis (TB) cases could have been prevented if the guidelines of the American Thoracic Society had been followed. Diabetes, alcohol abuse, and chronic renal failure were risk factors for active TB. Despite marked reductions in TB morbidity and mortality rates among American Indians and Alaska Natives over the past 30 years, their TB rates are still two to three times higher than overall United States and white rates. Enhanced TB control programs with an emphasis on preventive therapy for patients at risk for developing active disease, especially those with diabetes and chronic renal failure, could decrease the incidence and eventually eliminate TB among American Indians and Alaska Natives.     

Latent tuberculosis infection: recommendations for preventive therapy in adults in Germany

The immunologic mechanisms of latent tuberculosis (TB) infection are complex and hitherto not completely understood. The lifelong risk of an immunocompetent individual of developing active TB after infection with M. tuberculosis is 5-10 % and highest during the first two years after infection. Various factors may considerably increase the risk of developing active TB, e. g., immunosuppressive disease or immunosuppressive medication. However, the development of active TB may be avoided by preventive chemotherapy, the therapy of choice being isoniazid over a 9-month period. Alternative treatment regimens may be indicated in special cases, but it must be borne in mind that the efficacy of these regimens has not been studied sufficiently while they seem to be less well tolerated than isoniazid monotherapy. The tuberculin skin test is still the only sufficiently documented method to detect latent infection with M. tuberculosis which is also suitable for routine application. This test today should be performed exclusively as described by Mendel and Mantoux. Its sensitivity and specificity depend on the prevalence of tuberculosis infection. It should therefore be restricted to individuals at increased risk of latent TB infection. When interpreting the tuberculin skin test, it is necessary to know whether an individual belongs to one of the defined risk groups or has an elevated risk of developing active TB. Among the risk groups are individuals who may have been infected recently with M. tuberculosis (contacts of contagious TB patients) or in whom other factors increase their risk of developing active TB. The indication for chemotherapy for latent TB infection must be based on a careful individual risk-benefit analysis and, besides patient compliance, requires full information of the patient and careful monitoring during therapy. Before initiating treatment, active TB must always be excluded by the proven methods.     

Treatment of latent tuberculosis infection: renewed opportunity for tuberculosis control.

New recommendations for targeted tuberculin testing and treatment of latent tuberculosis (TB) infection have recently been published. Changes in nomenclature from screening to targeted tuberculin testing and from preventive therapy to treatment of latent TB infection (LTBI) are intended to promote more widespread implementation by programs and health care providers. Targeted tuberculin testing is designed to identify persons at high risk for TB and is discouraged for persons at low risk. New recommendations for treatment of LTBI in both human immunodeficiency virus (HIV)-infected and HIV-uninfected patients include isoniazid for 9 months as the preferred regimen: isoniazid for 6 months based on local program conditions, rifampin and pyrazinamide for 2 months, and rifampin for 4 months. Treatment monitoring now places greater emphasis on clinical, rather than routine, laboratory monitoring. More widespread implementation of targeted tuberculin testing and treatment of LTBI is an important control strategy that will enhance efforts to eliminate TB in the United States.     

Management of tuberculosis and latent tuberculosis infection in human immunodeficiency virus‐infected persons

The syndemic of human immunodeficiency virus (HIV)/tuberculosis (TB) co‐infection has grown as a result of the considerable sociogeographic overlaps between the two epidemics. The situation is particularly worrisome in countries with high or intermediate TB burden against the background of a variable HIV epidemic state. Early diagnosis of TB disease in an HIV‐infected person is paramount but suffers from lack of sensitive and specific diagnostic tools. Enhanced symptom screening is currently advocated, and the wide application of affordable molecular diagnostics is urgently needed. Treatment of TB/HIV co‐infection involves the concurrent use of standard antiretrovirals and antimycobacterials during which harmful drug interaction may occur. The pharmacokinetic interaction between rifamycin and antiretrovirals is a case in point, requiring dosage adjustment and preferential use of rifabutin, if available. Early initiation of antiretroviral therapy is indicated, preferably at 2 weeks after starting TB treatment for patients with a CD4 of <50 cells/μL. Development of TB‐immune reconstitution inflammatory syndrome (TB‐IRIS) is however more frequent with early antiretroviral therapy. The diagnosis of TB‐IRIS is another clinical challenge, and cautious use of corticosteroids is suggested to improve clinical outcome. As a preventive measure against active TB disease, the screening for latent TB infection should be widely practiced, followed by at least 6–9 months of isoniazid treatment. To date tuberculin skin test remains the only diagnostic tool in high TB burden countries. The role of alternative tests, for example, interferon‐γ release assay, would need to be better defined for clinical application.     

Tuberculosis and human immunodeficiency virus infection

Because of the abnormalities of host defenses caused by the human immunodeficiency virus (HIV), persons with HIV infection are vulnerable to tuberculosis. Inferential data from several parts of the country indicate increases in tuberculosis case rates, probably occurring in patients with HIV infection. In a person infected with both HIV and Mycobacterium tuberculosis, attack rates of tuberculosis seem to be very high. In general, the disease tends to occur earlier in the course of HIV infection than other opportunistic processes that serve to define the acquired immunodeficiency syndrome (AIDS), presumably because M tuberculosis is more pathogenic than Pneumocystis carinii or Mycobacterium avium complex, for example. The clinical features of tuberculosis in this patient population seem to vary depending on the stage of the HIV infection. Late in the process, tuberculosis usually has atypical features with chest films showing diffuse infiltration, no cavities, and intrathoracic adenopathy. Tuberculin skin tests commonly are negative. At earlier stages of HIV infection, the clinical findings are similar to those in HIV-seronegative persons. Response to treatment is generally good; however, it is recommended that the standard duration be at least 9 months, using isoniazid and rifampin usually supplemented by pyrazinamide in the first 2 months. The use of isoniazid for preventive therapy is recommended for all HIV-seropositive persons who have tuberculin skin test reactions greater than or equal to 5 minutes. Those implementing infection-control measures for HIV-infected patients who have pulmonary findings should take tuberculosis into account until the disease is excluded. Medical personnel providing care for patients with tuberculosis should use universal blood and body substance precautions because of the possibility of undetected HIV infection in patients with tuberculosis.     

Diagnostic and management challenges for childhood tuberculosis in the era of HIV

The diagnosis and management of childhood tuberculosis (TB) pose substantial challenges in the era of the human immunodeficiency virus (HIV) epidemic. The highest TB incidences and HIV infection prevalences are recorded in sub-Saharan Africa, and, as a consequence, children in this region bear the greatest burden of TB/HIV infection. The tuberculin skin test (TST), which is the standard marker of Mycobacterium tuberculosis infection in immunocompetent children, has poor sensitivity when used in HIV-infected children. Novel T cell assays may offer higher sensitivity and specificity than the TST, but these tests still fail to make the crucial distinction between latent M. tuberculosis infection and active disease and are limited by cost considerations. Symptom-based diagnostic approaches are less helpful in HIV-infected children, because of the difficulty of differentiating TB-related symptoms from those caused by other HIV-associated conditions. Knowing the HIV infection status of all children with suspected TB is helpful because it improves clinical management. HIV-infected children are at increased risk of developing active disease after TB exposure/infection, which justifies the use of isoniazid preventive therapy once active TB has been excluded. The higher mortality and relapse rates noted among HIV-infected children with active TB who are receiving standard TB treatment highlight the need for further research to define optimal treatment regimens. HIV-infected children should also receive appropriate supportive care, including cotrimoxazole prophylaxis, and antiretroviral therapy, if indicated. Despite the difficulties experienced in resource-limited countries, the management of children with TB/HIV infection could be vastly improved by better implementation of readily available interventions.     

Effectiveness of isoniazid chemoprophylaxis for HIV-infected drug users at high risk for active tuberculosis.

OBJECTIVE: To define the effectiveness of chemoprophylaxis, outside of a clinical trial setting, in preventing tuberculosis among tuberculin-reactive and anergic HIV-infected drug users at high risk of developing active tuberculosis. DESIGN: An observational cohort study. SETTING: Methadone maintenance treatment program with on-site primary care. PARTICIPANTS: Current or former drug users enrolled in methadone treatment. INTERVENTIONS: Annual skin testing for tuberculosis infection and anergy was performed, and eligible patients were offered daily isoniazid for 12 months and followed prospectively. MAIN OUTCOME MEASURE: The development of active tuberculosis. RESULTS: A total of 155 persons commenced chemoprophylaxis. Among tuberculin reactors, tuberculosis rates were 0.51 and 2.07/100 person-years in those completing 12 months versus those not taking prophylaxis [rate ratio 0.25, 95% confidence interval (CI) 0.06-1.01]. Among anergic individuals, comparable rates were 0 and 1.44/100 person-years. Lower tuberculosis rates among completers were not attributable to differences in immune status between the treated and untreated groups. CONCLUSION: The completion of isoniazid chemoprophylaxis was associated with a marked reduction in tuberculosis risk among tuberculin reactors and anergic persons in this high-risk population. These data support aggressive efforts to provide a complete course of preventative therapy to HIV-infected tuberculin reactors, and lend weight to the findings of others that isoniazid can reduce the rate of tuberculosis in high-risk anergic HIV-infected persons.     

Factors associated with tuberculin skin test reactivity among HIV-infected people in Bangkok

INH preventive therapy (IPT) has been shown in several randomized controlled trials to reduce the risk of developing active TB in tuberculin skin test (TST) or purified protein derivative (PPD) positive HIV infected individuals. Detection of latent tuberculosis by TST and determination of factors associated with the PPD positivity in HIV-infected persons are important for the targeting of chemoprophylaxis. Six hundred asymptomatic and early symptomatic HIV-infected subjects attending the AIDS Clinic of the Chulalongkorn University Hospital, Bangkok, Thailand were enrolled in two randomized clinical trials of chemoprophylaxis against TB from December 1994 to December 1996. The availability of baseline characteristics, including TST reactivity, among these participants enabled a cross-sectional analysis of factors associated with PPD positivity. The results showed that 117 (19.5%) were PPD positive and 483 (80.5%) were PPD negative with ages 18-65 years (median 29 years). HIV exposure category was 46.2%, 34.5%, and 6.7% for heterosexual contact, commercial sex work, and homosexual and bisexual male contact respectively. The median CD4 cell count was 315/mm3 (range, 5-1,074/mm3). HIV exposure category and CD4 cell count were significantly associated with PPD status. Homosexual/bisexual contact had 3 times higher risk of PPD positivity than heterosexual contact (adjusted OR=2.9; 95% CI, 1.4-6.1) and risk of PPD positivity was higher among patients with CD4 cell counts of 200-500/ mm3 (adjusted OR=1.8; 95% CI, 1.0-3.1) and above 500/mm3 (adjusted OR=3.4; 95% CI, 1.7-6.7) when compared to patients with CD4 cell counts of less than 200/mm3. The HIV-infected persons in Bangkok with homosexual/bisexual contact are at higher risk for latent TB. Population-based tuberculin screening without accompanying HIV testing cannot be used to estimate the prevalence of actual latent TB in a population where HIV infection is widespread, such as in Thailand.     

人类免疫缺陷病毒合并结核感染患者外周血Vγ2Vδ2+T淋巴细胞的数量与功能变化

目的 探讨外周血Vγ2Vδ2+T淋巴细胞数与功能变化对HIV合并结核感染状态的影响.方法 将76例HIV/AIDS合并结核感染患者分为活动性结核感染组(HIV+TB组)和潜伏结核感染组(HIV+LTB组).流式细胞仪测定外周血淋巴细胞分类情况.酶联斑点免疫法(ELISPOT)和胞内细胞因子染色(ICS)方法 检测在PPD和磷酸化抗原(HMBPP)的刺激下T淋巴细胞亚群分泌IFN-γ功能的情况.统计学处理采用t检验.结果 HIV+TB组CD3+T淋巴细胞绝对计数(t=-3.67,P<0.01)和Vγ2Vδ2+T淋巴细胞所占CD3+T淋巴细胞比例(t=-2.06,P<0.05)均显著低于HIV+LTB组.PPD刺激时,HIV+LTB组分泌特异性IFN-γ的T淋巴细胞和参与分泌IFN-γ的CD4+T淋巴细胞所占CD3+T淋巴细胞比例,与HIV+TB组比较差异均无统计学意义.HMBPP刺激时,HIV+LTB组与HIV+TB组比较,分泌IFN-γ的特异性T淋巴细胞计数(t=2.71,P<0.01)和产生IFN-7的特异性Vy2'T淋巴细胞比例(t=3.003,P<0.01)均显著增加.结论 Vγ2Vδ2+T淋巴细胞在HIV/AIDS合并活动性结核患者中的数量和功能都有受损,提示该类细胞在CD4+T淋巴细胞受到抑制的情况下可能是人体内抵御结核感染的重要免疫细胞.     

Tuberculous Cystitis

Tuberculosis (TB) has claimed its victims throughout human history. It is becoming a major world heath problem once again, with nearly one third of the world’s population being infected with Mycobacterium tuberculosis. With the advent of HIV infection, TB is the most common opportunistic infection among AIDS patients. Genitourinary tuberculosis (GUTB) is the second most common form of extrapulmonary TB, with more than 90% of cases occurring in developing countries. The kidneys are the most common site of infection in GUTB and are infected through hematogenous spread of the bacilli. Bladder lesions are without exception secondary to renal TB. The diagnosis is based on culture studies by isolation of the causative organism, but biopsy occasionally may be required. Multidrug treatment is the first-line therapy in GUTB and is effective in most patients, though surgery in the form of ablation or reconstruction may be necessary.     

Management of tuberculosis in children in low-income countries.

Children become infected when they are exposed to infectious adults with smear-positive tuberculosis (TB). Most children become infected, but few progress to disease (TB). Children at greatest risk of developing disease are those younger than 5 years of age, HIV-infected and severely malnourished. TB is diagnosed in a child when the child has been exposed to an infectious case, has symptoms and a radiological picture suggestive of TB. Children are treated by the DOTS strategy, and can be treated with 6- or 8-month regimens. HIV-infected children are treated with the same regimens. Children under 5 years of age exposed to an infectious case or infected with TB (tuberculin skin test positive) who are asymptomatic must receive preventive chemotherapy (isoniazid for 6 months). Babies born to mothers with active TB must be managed carefully, as they could have congenital TB, and if they do not have TB they will need preventive chemotherapy for 6 months. BCG is indicated in all children soon after birth, except for those with symptomatic HIV infection. The main aim of any TB programme is to prevent the spread of TB, and also the spread to children, which is best achieved by early detection and treatment of adults with smear-positive TB.     

Outbreak of multidrug-resistant tuberculosis at a methadone treatment program.

SETTING: An out-patient methadone treatment program MTP). OBJECTIVE: To investigate transmission of multidrug-resistant tuberculosis (MDR-TB) in the MTP. DESIGN: Cases were defined as MTP clients or staff who developed TB between 1 January 1994 and 1 January 1996, with at least one positive culture for Mycobacterium tuberculosis resistant to isoniazid and rifampin. Contacts were identified, located and evaluated. RESULTS: Thirteen cases of MDR-TB occurred among 462 clients and staff. One fifth (6/30) of the members of a counseling group for human immunodeficiency virus (HIV) infected clients developed MDR-TB. Individuals known to be HIV positive were at greater risk for TB than those who were HIV negative (RR 5.2, 95%CI 1.2-22.7). Of 449 clients and staff identified as contacts, 393 (87.5%) were located and screened. Among those with a negative baseline tuberculin skin test, 18.5% (56/303) were skin test converters. Attendance at the MTP during a period when the index case was infectious was associated with an increased risk of conversion (RR 2.5, 95%CI 1.1-6.0). CONCLUSION: Extensive transmission of MDR-TB occurred at an out-patient MTP serving numerous clients with HIV infection. This outbreak underscores the importance of developing effective strategies to prevent TB transmission in this setting.     

Tuberculosis

Tuberculosis (TB) is a disease of antiquity, caused by Mycobacterium tuberculosis, which principally affects the lungs. It is a major public-health problem, with around 9 million new cases and 2 million deaths estimated to occur each year. Patients with pulmonary TB whose sputum is smear-positive for M. tuberculosis form the main source of infection in communities. About 5%-10% of infected individuals are likely to develop symptomatic TB during their lives but the risk of developing the clinical manifestations of the disease is greatly increased by HIV co-infection. The strong association between HIV and TB in sub-Saharan Africa is responsible for the massive increase in the incidence of TB observed in that region in the last 20 years. Diagnosis of TB in resource-poor countries is largely based on sputum-smear microscopy and chest radiography, although these methods lack sensitivity or specificity, especially when used on HIV-infected patients. Effective treatment has existed for 40 years but TB-attributable mortality remains high among HIV-infected patients in Africa, who are also particularly likely to develop TB again after receiving drug treatment for the disease. In Eastern Europe it is drug resistance in the local M. tuberculosis that makes the treatment of TB relatively ineffective. The approach to TB control that is now internationally recommended is the DOTS ('directly-observed treatment, short-course') strategy, which aims to prevent the transmission of M. tuberculosis, and the related illness and death, by using combinations of anti-TB drugs to treat patients with the active disease. Unfortunately, countries in sub-Saharan Africa are falling short of the World Health Organization's targets for case detection and treatment. This failure is, in turn, making the achievement of the Millennium Development Goals for TB--to ensure that the incidence of TB is falling by 2015 and to halve the prevalence of TB and the annual number of TB-attributable deaths between 1990 and 2015--less likely. To improve the performance and impact of TB-control programmes, in the face of HIV co-infection and other constraints on DOTS, the World Health Organization has launched the revised 'Stop TB Strategy'. The new strategy, to be implemented via the Global Plan to Stop TB (2006-2015), includes intensified TB-case finding, treatment of latent TB infection with isoniazid, prevention of HIV infection, cotrimoxazole preventive therapy, and antiretroviral therapy.     

Tuberculosis infection in HIV-infected Indian patients

Individuals with HIV infection are at increased risk for tuberculosis (TB). The altered CD4 T-cell homeostasis induced by HIV infection may play a key role in the development of tuberculosis in HIV-infected patients. In this retrospective analysis, lymphocyte profiles (CD4 and CD8 count) of subjects infected with HIV, with or without TB, were evaluated. The influence of tuberculosis treatment on the CD4 count in dually infected patients was analyzed in a subset of patients available for follow-up. Of 421 subjects with HIV infection studied, 105 (24.9%) were positive for TB (HIV+TB+). A statistically significant difference (p = 0.0001) was found in the median CD4+ counts between the HIV+TB- (297.5 per microliter) and HIV+TB+ (181 per microliter) groups. TB was found to be the indicator disease for HIV infection in 36 (34.2%). In 65.7% of HIV-infected patients, TB was the first AIDS-defining disease. Of 72 patients who were receiving TB treatment, 33 (45.9%) showed an increase in CD4 counts, but this was statistically not significant. None of these patients was undergoing antiretroviral therapy prior to TB treatment. We conclude from this retrospective study that TB, a common HIV-related opportunistic infection in Indian subjects, is associated with lower CD4+ counts. The influence of TB therapy on CD4 counts in the patients needs to be further investigated.     

Preferential recruitment of phagocytes into the lung of patients with advanced acquired immunodeficiency syndrome and tuberculosis

Limited data are available on the cellular and immunocytological characteristics of bronchoalveolar lavage (BAL) fluid in individuals infected with the human immunodeficiency virus (HIV) and pulmonary tuberculosis (TB). The immune host response against tuberculosis in early HIV-infection may differ from that in later stages of HIV disease, as is strongly suggested by different clinical and radiographic patterns. We studied the cellular elements in the lungs of 15 HIV-infected patients with advanced immunosuppression and pulmonary tuberculosis (TB/AIDS). The findings were compared with data from four other groups: 1) 15 HIV-seronegative patients with pulmonary TB; 2) 12 HIV-seropositive TB patients without previous AIDS-defining illnesses and with CD4+ >200 cells mm(-3); 3) five AIDS patients without pulmonary lesions; and 4) five healthy controls. BAL fluid and differential cell counts, as well as lymphocyte subsets, were determined. Despite a low CD4/CD8 ratio, the TB/AIDS group had a higher absolute number of CD8+ lymphocytes in the BAL fluid than the other groups. Alveolar macrophages and neutrophils were significantly increased in TB/AIDS patients compared to control groups. The number of eosinophils was increased in TB/HIV--patients but not in TB/AIDS patients. We conclude that tuberculosis in late stage HIV-infected patients has a distinct inflammatory cell profile, suggesting an enhanced compensatory mechanism that amplifies the unspecific inflammatory reaction.     

Chemotherapy and diagnosis of tuberculosis

Since after the first streptomycin 1944 trials, anti-tuberculous chemotherapy research has been focused upon establishing drug combination regimens capable of overcoming drug resistance and amenable to ambulatory treatment in resource strapped countries. The first milestone being the 1959 Madras trial comparing home and sanatorium treatment in South India. Subsequently, the MRC trials led Fox and Mitchison to indicate rifampicin, isoniazid and pyrazinamide as the first line drugs for short course, 6 month, regimens and the 1982 Hong Kong Chest Service trials established intermittent therapy as the ambulatory treatment standard for directly observed therapy (DOT). The rising of the HIV epidemic at the beginning of the 1980s has refuelled tuberculosis spread in Africa and Asia and contributed to the expansion of drug-resistant tuberculosis worldwide making the development of new drugs and drug regimens for ambulatory treatment a top priority. Led by biotechnological advances, molecular biology has been brought into TB laboratory diagnosis for the highly sensitive and specific rapid identification of Mycobacterium tuberculosis in biological samples. The field of immunological diagnosis of TB infection, dominated since the early 1900s by the intradermal tuberculin reaction has been put back in motion by the discovery of M. tuberculosis-specific proteins and peptides, now employed in blood tests of high sensitivity and specificity for the diagnosis of latent TB which may help with the identification of contacts at higher risk of active disease and the eradication of epidemic cases.     

Preventive medicine for HIV-infected patients

Objective:To analyze the policies of isoniazid prophylaxis for human immunodeficiency virus (HIV)-infected tuberculin reactors and for HIV-infected anergic patients with unknown tuberculin status. Methods:Transition-state model of clinical immune deterioration of HIV-infection over ten years, review of published data, and a survey of AIDS experts. Outcome measures are the numbers of tuberculosis cases and deaths prevented and isoniazid toxicity cases and deaths occurring with prophylaxis. Patients:Hypothetical cohorts of HIV-infected 40-year-olds. Results:Because the tuberculosis activation rate is so high in HIV-infected patients, the benefits of prophylaxis far outweigh the risks of isoniazid toxicity for tuberculin reactors with HIV infection at any stage of immune function: 1,469–2,868 tuberculosis cases and 170–274 deaths are prevented per 10,000 cohort over ten years, depending upon the cohort’s initial immune state. The benefits of prophylaxis outweigh the risks of isoniazid toxicity for anergic HIV-infected patients if they come from a community with a 2% to 3% or greater prevalence of Mycobacterium tuberculosisinfection. Conclusions:Isoniazid prophylaxis is a reasonable prevention measure for HIV-infected tuberculin reactors and for many HIV-infected anergic patients. Received from the Departments of Medicine, Community Medicine, and Biomathematical Sciences, the AIDS Center, and the Clinical Trials Unit, Mount Sinai School of Medicine, New York, New York. Presented in part at the 14th annual meeting of the Society of General Internal Medicine, Seattle, Washington, May 1–3, 1991. Supported in part by the following grants: 1/RO1 MH45686 from the National Institute of Mental Health, and UO1 AI27667 and UO1 AI27554 from the National Institute of Allergy and Infectious Diseases.     

HIV-associated tuberculosis in developing countries: epidemiology and strategies for prevention.

The association between tuberculosis and HIV presents an immediate and grave public health and socioeconomic threat, particularly in the developing world. In early 1992 WHO estimated that approximately 4 million people had been infected with both Mycobacterium tuberculosis and HIV since the beginning of the pandemic; 95% of them were in developing countries. The association between tuberculosis and HIV is evident from the high incidence of tuberculosis, estimated at 5-8% per year, among HIV-infected persons, the high HIV seroprevalence among patients with tuberculosis, the high occurrence of tuberculosis among AIDS patients, and the coincidence of increased tuberculosis notifications with the spreading of the HIV epidemic in several African countries. The impact of the two epidemics on resource-poor countries has ominous social and medical implications, and the already overstretched health services now have to face a tremendously increasing tuberculosis problem. HIV infection worsens the tuberculosis situation by increasing reactivation of latent tuberculosis infection in dually infected persons as well as by favouring rapid progression of new infections in the HIV-infected. This also results in an increase of the risk of infection and a subsequent increase of cases in the general population. In order to respond to this urgent problem, the highest priority must be given to strengthening tuberculosis control programmes in the countries where they are poorly developed and where the prevalence of HIV and tuberculosis infections is high. Besides improving the cure rate by early diagnosis and prompt treatment of patients with tuberculosis, two major strategies that need consideration include BCG vaccination and preventive chemotherapy among HIV-infected individuals. The latter strategy is considered as the most critical intervention that would help to limit the expected increase in clinical tuberculosis from the pool of HIV and tuberculosis coinfected individuals. However, a number of issues need to be addressed urgently and before such an intervention can be implemented in the developing countries.     

HIV／AIDS患者肺结核患病调查分析

目的了解HIV感染者和艾滋病病人合并肺结核状况,为HIV/TB双重感染防治工作提供基础资料。 方法对11个县、区能随访到的HIV感染者和艾滋病病人进行问卷调查,同时测CD4细胞计数、PPD试验、正位X线胸片、抗酸杆菌痰涂片显微镜检查。 结果622例被调查者的肺结核患病率为3.9%,双重感染病人的PPD阳性率为54.2%;HIV/AIDS患者的PPD阳性率为19.0%,随着CD4细胞计数的增加,PPD阳性率升高。 结论HIV/AIDS病人肺结核患病率高于普通人群,PPD阳性率低于普通人群。CD4细胞越少,PPD阳性率越低。