Ten-year experiences of the tuberculosis control programme in the southern region of Ethiopia.

SETTINGS: The tuberculosis control programme, southern region of Ethiopia. OBJECTIVE: To assess the impact of the expansion of the DOTS strategy on tuberculosis (TB) case finding and treatment outcome. DESIGN: Reports of TB patients treated since the introduction of DOTS in the region were reviewed. Patients were diagnosed and treated according to World Health Organization (WHO) recommendations. Case notification and treatment outcome reports were compiled quarterly at district level and submitted to the regional programme. RESULTS: Of 136,572 cases registered between 1995 and 2004, 47% were smear-positive, 25% were smear-negative and 28% had extra-pulmonary tuberculosis (EPTB). In 2004, 94% of the health institutions were covered by DOTS. Between 1995 and 2004, the smear-positive case notification rate increased from 45 to 143 per 100,000 population, the case detection rate from 22% to 45%, and the treatment success rate from 53% to 85%. The default and failure rates decreased from 26% to 6% and from 7% to 1%, respectively. DISCUSSION: There was a steady increase in the treatment success rate with the decentralisation of DOTS. Although 94% coverage was achieved after 10 years, the stepwise scale-up was important in securing resources and dealing with challenges. The programme achieved 85% treatment success; however, with the current low case detection rate (45%), the 70% WHO target seems unachievable in the absence of alternative case-finding mechanisms.     

Rapid decline in prevalence of pulmonary tuberculosis after DOTS implementation in a rural area of South India

SETTING: Tiruvallur District in Tamilnadu, South India, where the World Health Organization-recommended DOTS strategy was implemented as a tuberculosis (TB) control measure in 1999. OBJECTIVE: To assess the epidemiological impact of the DOTS strategy on the prevalence of pulmonary tuberculosis (PTB). DESIGN: Surveys of PTB were undertaken on representative population samples aged > or =15 years (n = 83000-90000), before and at 2.5 and 5 years after the implementation of the DOTS strategy. The prevalence of PTB (smear-positive/culture-positive) was estimated. RESULTS: TB prevalence declined by about 50% in 5 years, from 609 to 311 per 100000 population for culture-positive TB and from 326 to 169/100000 for smear-positive TB. The annual rate of decline was 12.6% (95%CI 11.2-14.0) for culture-positive TB and 12.3% (95%CI 8.6-15.8) for smear-positive TB. The decline was similar at all ages and for both sexes. CONCLUSION: With an efficient case detection programme and the DOTS strategy, it is feasible to bring about a substantial reduction in the burden of TB in the community.     

Human immunodeficiency virus and the prevalence of undiagnosed tuberculosis in African gold miners

We hypothesized that rapid presentation may be a general feature of tuberculosis (TB) associated with human immunodeficiency virus (HIV) that limits the impact of HIV on the point prevalence of TB. To investigate this, we performed a cross-sectional HIV and TB disease survey with retrospective and prospective follow-up. HIV prevalence among 1,773 systematically recruited miners was 27%. TB incidence was much more strongly HIV associated (incidence rate ratio, 5.5; 95% confidence interval [CI], 3.5-8.6) than the point prevalence of undiagnosed TB disease (odds ratio, 1.7; 95% CI, 0.9-3.3). For smear-positive TB, 7 of 9 (78%) prevalent cases were HIV negative, and point prevalence was nonsignificantly lower in miners who were HIV positive (odds ratio, 0.8; 95% CI, 0.1-4.2). The calculated mean duration of smear positivity before diagnosis (point prevalence/incidence) was substantially shorter for HIV-positive than HIV-negative TB patients (0.17 and 1.15 years, respectively; ratio, 0.15; 95% CI, 0.00-0.73). HIV has considerably less impact on the point prevalence of TB disease than on TB incidence, probably because rapid disease progression increases presentation and case-finding rates. The difference in mean duration of smear positivity was particularly marked and, if generalizable, will have major implications for TB control prospects in high HIV prevalence areas.     

在押犯人中肺结核病人发现方式和治疗效果研究

目的　对2004—2006年天津市监狱系统在押犯人中肺结核病人的发现方式和治疗效果进行评价。方法 采用结核病普查、因症就诊和入监体检3种方式发现在押犯人中肺结核病人。对确诊的全部肺结核病人执行统一的化疗方案,并实施直接面视下短程化疗(DOTS)。疗程结束时对病人治疗管理效果进行评价。结果 3年间结核病普查、因症就诊和入监体检3种方式发现的肺结核病人分别为269、111和113例,其中通过入监体检方式发现的病例数呈逐年上升趋势。初、复治涂阳治愈率分别为78.8%、72.7%。涂阳病例中因治疗失败而未治愈的占60%;涂阴病例中因刑满释放而未完成疗程的占62.7%。结论 通过以上3种发现方式和督导化疗管理工作,提高了在押犯人中肺结核病人的发现和管理水平,有效地控制了传染源,降低了结核病在监狱内的传播。     

全国初治涂阴肺结核病例登记现状分析

目的分析全国各省初治涂阴肺结核病例登记现状,为评价初治涂阴肺结核病例诊断质量提供依据。方法根据2004—2005年全国结核病防治规划报表中初治涂阴和初治涂阳肺结核病例登记资料,分析各省2年初治涂阴肺结核病例登记率变化和增长幅度;统计各省及不同地区初治涂阴与初治涂阳肺结核病例登记率;对各省初治涂阴与初治涂阳肺结核病例登记率进行直线回归分析。结果2005年全国登记初治涂阴肺结核病例316 405例,登记率为24.27/10万,各省登记率在6.01/10万72.17/10万;2005年登记初治涂阴病例数比2004年增加了19.9%,其中2个省登记数呈负增长,其余各省登记数增长了0.5%62.3%;2005年全国初治涂阳病例登记率是涂阴病例登记率的1.5倍,其中23个省初治涂阳病例登记率高于涂阴病例登记率,8个省相反;初治涂阴病例占初治涂阳病人登记率的比例,京津沪地区为149.28%,非项目地区为83.6%,项目地区为50.3%;对涂阳和涂阴病例登记率进行直线回归分析,回归方程y=22.342+0.563 6x。结论对初治涂阴肺结核患者实行免费政策后,全国涂阴肺结核病例登记率提高。但各省初治涂阴病例登记率和增长幅度以及涂阴病例登记率与涂阳病例登记率的比例悬殊。由于涂阴病例诊断困难,对于涂阴病例登记率高或增长幅度大的地区,特别在DOTS执行时间短和人力资源有限的地区,应对涂阴病例诊断质量予以进一步检查和评价。     

A preliminary study of the influence of HIV infection in the transmission of tuberculosis

The human immunodeficiency virus (HIV) epidemic has had a profound influence on the epidemiology of tuberculosis (TB). The potential for HIV-associated TB cases to transmit M. tuberculosis and to produce a secondary increase in TB morbidity is unknown. A cross-sectional study was carried out to compare the prevalence of M. tuberculosis infection among the household contacts of HIV-positive and HIV-negative pulmonary tuberculosis (PTB) patients. Records of tuberculin (Mantoux) tests administered during routine contact investigations at the Chest Clinic, Hospital Kota Bharu, from 1999 to 2000 were reviewed. The HIV status of the patients was based on the results of ELISA tests while information on household contacts was gathered during visits to their houses. Ninety-four contacts of 39 HIV-negative patients and 44 contacts of 17 cases of HIV-positive patients were included in this preliminary study. 30% (12/40) of the contacts of HIV-positive PTB had a positive tuberculin compared with 52.8% (47/ 94) of the contacts of HIV-negative patients [OR = 0.41, 95% Confidence interval (CI) 0.17 - 0.97; p = 0.016]. The difference was still significant after performing multivariate logistic regression analysis to adjust for variables associated with infectiousness of TB (adjusted OR = 0.24, 95% CI 0.07 - 0.87; p = 0.03). This study has shown that HIV-infected PTB patients are less infectious to their contacts than HIV-negative patients. The presence of MV in the community may not necessitate a change of the current policy of the management of contacts.     

Tuberculosis in Asia

1. Philippines: The development, expansion and maintenance of pilot area activities: Cristina B. Giango (Technical Division, Cebu Provincial Health Office, the Philippines) In 1994, the Department of Health developed the new NTP policies based on WHO recommendations and started a pilot project in Cebu Province in collaboration with the Japan International Cooperation Agency. To test its feasibility and effectiveness, the new NTP policies were pre-tested in one city and one Rural Health Unit. The test showed a high rate of three sputum collection (90%), high positive rate (10%), and high cure rate (80%). Before the new guidelines were introduced, the new policy was briefed, a baseline survey of the facility was conducted, equipment was provided, and intensive training was given. Recording/Reporting forms and procedures were also developed to ensure accurate reporting. Supervision, an important activity to ensure effective performance, was institutionalized. Laboratory services were strengthened, and a quality-control system was introduced in 1995 to ensure the quality of the laboratory services. With the implementation of DOTS strategy, barangay health workers were trained as treatment partners. In partnership with the private sector, the TB Diagnostic Committee was organized to deliberate and assess sputum negative but X-ray positive cases. The implementation of the new NTP guidelines in Cebe Province has reached a satisfactory level, the cure rate and positive rate have increased, and laboratory services have improved. Because of its successful implementation, the new NTP guidelines are now being used nationwide. 2. Nepal: The DOTS Strategy in the area with hard geographic situation: Dirgh Singh Bam (National Tuberculosis Center, Nepal) Three groups of factors characterize the population of Nepal: 1) Socio-cultural factors, e.g. migration, poverty, language; 2) Environmental factors, e.g. geography and climate; and 3) Political factors, prisoners and refugee populations. These factors pose particular problems for implementing DOTS in various ways. Socio-cultural and environmental factors are particularly important in Nepal, and several measures have been developed to overcome these difficulties. One is active community participation through the DOTS committee. The committee consists of a group of motivated people, including social workers, political leaders, health services providers, journalists, teachers, students, representatives of local organizations, medical schools and colleges, industries, private practitioners, and TB patients. One DOTS committee is formed in every treatment center. A key role of the DOTS committee is to identify local problems and their solutions. It increases public awareness about TB and DOTS; supports people with TB in the community by providing treatment observers and tracing late patients; and encourages cooperation among health institutions, health workers, NGOs, and political leaders. The case finding rate is now 69%, and nearly 95% of diagnosed TB cases are being treated under DOTS. The treatment success rate of new smear-positive cases is nearly 90%. Thus, DOTS increases the case finding and treatment success. 3. Cambodia: HIV/TB and the health sector reform: Tan Eang Mao (National Center for Tuberculosis and Leprosy Control, Cambodia) Cambodia is one of the 23 high burden countries of tuberculosis in the world. Moreover, HIV/AIDS has been spreading rapidly since 1990s, which is worsening the tuberculosis epidemics. To cope with the burden, Cambodia has started implementation of DOTS in 1994 and has expanded it to most of public hospitals across the country by 1998. NTP of Cambodia is now enjoying high cure rate of more than 90%. However, due to the constraints such as weak infrastructure and the poverty, it is proved that many of TB sufferers do not have access to the TB services, resulting in still low case detection rate. It is for this reason that the NTP has decided to expand DOTS to health center and community level based on the new health system. Its pilot program that has been carried out in collaboration with JICA and WHO since 1999 has achieved promising results with high detection and cure rates. All of the over 900 health centers across the country will be involved in DOTS strategy by 2005. In the fight against TB/HIV, National Center for TB Control is providing free TB screening for PLWH (people living with HIV/AIDS), and it is developing a comprehensive plan of TB/HIV care including home delivery DOT services. 4. China: The World Bank Project and the Prevalence Survey in China: Hong Jin DuanMu (National Tuberculosis Control Center, China) Since 1992, China has utilized a World Bank loan to implement TB control projects among 560 million people in 13 provinces. Free diagnosis and treatment services have been provided to all patients, and a fully supervised standard short-course chemotherapy was applied to all diagnosed tuberculosis patients. In 1999, more than 190,000 smear-positive cases, ten times the number in 1992, were detected, and the registration rate of new cases reached 30 per 100,000 population. From 1992 to 1999, a total of 1.40 million smear-positive TB patients were discovered. The cure rate of smear-positive TB patients has been improved to an overall cure rate of 93.6%. The cure rates for the new cases and re-treatment patients were 95.1% and 89.6%, respectively. The fourth nationwide random survey for the epidemiology of tuberculosis was conducted in 2000. The prevalence of active tuberculosis was 367/100,000, the prevalence of infectious tuberculosis was 160/100,000, and the prevalence of smear-positive tuberculosis was 122/100,000. The tuberculosis mortality was 9.8/100,000. 5. Vietnam: The road to reaching the Global Target: Le Ba Tung (Pham Ngoc Thach Tuberculosis and Lung Disease Center, Vietnam) TB control activities started in 1957 and were reorganized in 1986 with the technical assistance of IUATLD, KNCV and material assistance of Medical Committee Netherlands Vietnam (MCNV). The New National TB Control Program follows the main directives of WHO and IUATLD's procedures of case-finding, chemotherapy and management. Passive case-findings are based on sputum smear. Chemotherapy with priority for smear positive cases is 3SHZ/6S2H2 for new cases and 3HRE/6H2R2E2 for retreated cases, which is undertaken with directly observed therapy (DOT strategy) mainly at commune health posts. Since 1989, DOTS strategy with 2SHRZ/6HE for new cases and 2SHRZE/1HRZE/5H3R3E3 for retreated cases has gradually been introduced in districts and communes of every province. In 1995, the government established the National and Provincial TB Control Steering Committees and has provided incentives for detected smear positive cases and cured smear positive cases. The government has also started strengthening the program of managerial and supervisory capacity for TB staff and has promoted the cooperation of all associated organizations of TB control. The WHO global surveillance and monitoring project reports that in 2000 Vietnam reached the global target, i.e., 99.8% population covered by DOTS with 80% of expected new smear positive cases being detected and a high cure rate ranging from 85.3% in 1989 to 90.3% in 1999. A distinguishing aspect of TB control in Vietnam is the effective international partnerships combined with high political commitment of the government nationally and provincially as well as active participation of all organizations in the community.     

Prevalence of pulmonary tuberculosis among HIV-infected persons in a home care program in Phnom Penh, Cambodia.

SETTING: Phnom Penh, Cambodia. OBJECTIVE: To determine the burden of active pulmonary tuberculosis among an HIV-infected cohort and the proportion of drug-resistant strains, using active case-finding adapted to a home care setting. DESIGN: Cross-sectional study. Measures include the prevalence of culture-confirmed Mycobacterium tuberculosis, utilizing a single spot sputum specimen; the proportion of pulmonary TB, detected and undetected; proportion of cases resistant to isoniazid, rifampicin, ethambutol, streptomycin; and the diagnostic value of symptoms. RESULTS: Of 441 persons surveyed, 41 (9%) had active pulmonary TB by culture; 29 were smear-positive (71%), and only one case was on treatment. The total burden of pulmonary TB was 12% (54/441), with a ratio of undetected to detected cases of 3:1. Primary isoniazid resistance was detected in six new cases (15%); no MDR-TB was identified. Symptoms were not predictive of active pulmonary disease. Mortality was high among those not surveyed (20%) and those found to have TB (49%). CONCLUSIONS: Tuberculosis is epidemic in this HIV-infected population. Active case-finding yielded three times the number of cases already detected and should be considered where resources allow. However, effective passive case detection and improved coordination of TB and HIV care programs are required to address HIV-associated TB morbidity and mortality.     

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.     

2002—2007年安徽省肺结核病人发现及治疗转归分析

目的评价2002—2007全省肺结核病人发现及治疗效果。方法利用各结核病项目执行单位的月报表、季报表、网络专报督导及检查资料进行分析。结果2002—2007年全省发现活动性肺结核病人分别为9158、30279、41157、54869、50878、47628例,其中新发涂阳肺结核病人分别为2743、5846、12751、28329、28840、27836例,新涂阳登记率分别为10万人口中4.3、9.2、19.9、44.2、44.8和42.8,2002—2006年新发涂阳肺结核病人治愈百分率分别为82.8、82.8、89.3、91.4 和91.7。结论全面实施DOTS策略后,病人的发现率、治愈率都有了较大的提高。     

HIV-1 co-infection in children hospitalised with tuberculosis in South Africa.

SETTING: Hospitals associated with the Department of Paediatrics at the University of the Witwatersrand, Johannesburg, South Africa. OBJECTIVES: To define the prevalence of human immunodeficiency virus (HIV) co-infection and differences in clinical presentation between HIV-infected and non-infected hospitalised children with tuberculosis. DESIGN: Children were prospectively enrolled between August 1996 and January 1997. RESULTS: Of 161 children enrolled, 42% were HIV-infected, including 67/137 with pulmonary tuberculosis (PTB) and 1/24 with extra-pulmonary disease (EPTB). Positive microscopy or bacteriology did not differ by HIV status for children with either PTB or EPTB. Although age did not differ between HIV-infected and non-infected children with PTB, non-HIV-infected children with EPTB were significantly older than those with PTB only (median age 32 months vs 14.5 months, P = 0.004). Chronic weight loss, malnutrition and the absence of BCG scarring were more common in HIV-infected children with PTB. HIV-infected children were also more likely to show cavitation (P = 0.001) and miliary TB (P = 0.01) on chest X-ray. Reactivity to tuberculin (> or = 5 mm and > or = 10 mm in HIV-infected and non-infected children, respectively) was significantly lower in HIV-infected children, as were CD4+ lymphocyte levels. The mortality rate during the study was 13.4% in HIV-infected children compared with 1.5% in non-HIV-infected children (P = 0.03). CONCLUSIONS: There is a high prevalence of HIV co-infection in children with TB. Progressive PTB and death are more common in HIV-infected children. Tuberculin skin testing is of limited use in screening for TB in HIV-infected children even when using a cut-point of > or = 5 mm.     

The potential impact of enhanced diagnostic techniques for tuberculosis driven by HIV: a mathematical model

OBJECTIVE: To explore the potential impact of enhanced tuberculosis (TB) diagnostic techniques as a TB control strategy in an adult population with high HIV prevalence. DESIGN: A compartmental difference-equation model of TB/HIV was developed using parameter estimates from the literature. METHODS: The impact of five TB control interventions (rapid molecular testing, mycobacterial culture, community-wide and HIV-targeted active case finding, and highly active antiretroviral therapy) on TB incidence, prevalence, and mortality was modeled in a steady-state population with an HIV prevalence of 17% and annual TB incidence of 409 per 100 000. Sensitivity analyses assessed the influence of each model parameter on the interventions' mortality impact. RESULTS: Enhanced diagnostic techniques (rapid molecular testing or culture) are each projected to reduce TB prevalence and mortality by 20% or more, an impact similar to that of active case-finding in 33% of the general community and greater than the effect achievable by case-finding or antiretroviral treatment efforts in HIV-positive patients alone. The projected impact of enhanced diagnostics on TB incidence (< 10% reduction) is smaller. The impact of TB diagnostics is sensitive to the quality of existing diagnostic standards and the level of access to diagnostic services, but is robust across a wide range of population parameters including HIV and TB incidence. CONCLUSIONS: Enhanced TB diagnostic techniques may have substantial impact on TB morbidity and mortality in HIV-endemic regions. As TB rates continue to increase in these areas, enhanced diagnostic techniques merit further consideration as TB control strategies.     

Contact tracing using a new T-cell-based test: better correlation with tuberculosis exposure than the tuberculin skin test.

SETTING: Residential institution for alcoholics in Switzerland. OBJECTIVE: To compare the results of the tuberculin skin test (TST) and the new T-cell-based test for tuberculosis infection (T-SPOT.TB) in subjects exposed to a case of smear-positive pulmonary TB (PTB). DESIGN: After the notification of smear-positive PTB in a resident of an institution for alcoholics, contacts underwent TST and determination of Mycobacterium tuberculosis specific T-cells in blood by T-SPOT.TB. Results were analysed according to age, history of BCG vaccination, and level of exposure to the index case. RESULTS: There was no correlation between the level of exposure and the TST results, but the T-SPOT.TB results were significantly correlated with the level of exposure (P = 0.029, OR 5.00, 95%CI 1.05-23.86). Contacts who had been previously BCG-vaccinated were significantly more likely to have a positive TST than unvaccinated contacts (52% vs. 0%, P = 0.0003), but there was no influence of prior BCG vaccination on T-SPOT.TB results. CONCLUSIONS: T-SPOT.TB test results correlated better than TST with level of exposure to M. tuberculosis and were not confounded by prior BCG vaccination. This test allows better selection of contacts who should receive treatment for latent TB infection.     

Identifying dynamic tuberculosis case-finding policies for HIV/TB coepidemics

The global tuberculosis (TB) control plan has historically emphasized passive case finding (PCF) as the most practical approach for identifying TB suspects in high burden settings. The success of this approach in controlling TB depends on infectious individuals recognizing their symptoms and voluntarily seeking diagnosis rapidly enough to reduce onward transmission. It now appears, at least in some settings, that more intensified case-finding (ICF) approaches may be needed to control TB transmission; these more aggressive approaches for detecting as-yet undiagnosed cases obviously require additional resources to implement. Given that TB control programs are resource constrained and that the incremental yield of ICF is expected to wane over time as the pool of undiagnosed cases is depleted, a tool that can help policymakers to identify when to implement or suspend an ICF intervention would be valuable. In this article, we propose dynamic case-finding policies that allow policymakers to use existing observations about the epidemic and resource availability to determine when to switch between PCF and ICF to efficiently use resources to optimize population health. Using mathematical models of TB/HIV coepidemics, we show that dynamic policies strictly dominate static policies that prespecify a frequency and duration of rounds of ICF. We also find that the use of a diagnostic tool with better sensitivity for detecting smear-negative cases (e.g., Xpert MTB/RIF) further improves the incremental benefit of these dynamic case-finding policies.     

Childhood tuberculosis in Malawi: nationwide case-finding and treatment outcomes.

SETTING: All 43 non-private hospitals (three central, 22 [corrected] district and 18 [corrected] mission) in Malawi that register and treat adult and paediatric TB cases. OBJECTIVE: To assess the rate, pattern and treatment outcome of childhood TB case notifications in Malawi in 1998. DESIGN: Retrospective data collection using TB registers, treatment cards and information from health centre registers. Information was collected on number of cases, types of TB and treatment outcomes using standardised definitions. RESULTS: There were 22,982 cases of TB registered in Malawi in 1998, of whom 2,739 (11.9%) were children. Children accounted for 1.3% of all case notifications with smear-positive pulmonary TB (PTB), 21.3% with smear-negative PTB and 15.9% with extra-pulmonary TB (EPTB). Estimated rates of TB in children were 78/ 100,000 in those aged less than one year, 83/100,000 in those aged 1-4 years and 33/100,000 in those aged 5-14 years. A significantly higher proportion of TB cases was diagnosed in central hospitals. Only 45% of children completed treatment. There were high rates of death (17%), default (13%) and unknown treatment outcomes (21%). Treatment outcomes were worse in younger children and in children with smear-negative PTB. Treatment completion was best (76%) and death rates lowest (11%) for the 127 children with smear-positive PTB. CONCLUSION: Childhood TB is common in Malawi and treatment outcomes are poor. Research should be directed towards improved diagnosis and follow-up of children with TB, and the National TB Programme should support appropriate management of childhood contacts of smear positive PTB cases.     

Excess mortality and tuberculosis among individuals with prolonged cough: a population-based study from Vietnam.

SETTING: A demographic surveillance site in north-west Vietnam. OBJECTIVES: To compare notification rates of sputum smear-positive tuberculosis (TB) and mortality rates between the general population and individuals with prolonged cough. DESIGN: A cohort study of 559 prolonged cough cases in a total population of 35,832, observed over 2.5 years. Outcome measures were sputum smear-positive TB and death. RESULTS: The age-standardised smear-positive TB notification rate among cough cases (553/100,000 person-years [py], 95%CI 268-1143) was significantly higher than in the general population (50/100,000 py, 95%CI 43-57), with a relative risk of 11.06 (95%CI 8.28-14.77). Among those who had a chest X-ray suggestive of TB but negative sputum smears prior to the study start, the rate was 6542/100,000 py (95%CI 2906-12,511). The cough cohort had a 2.61 (95%CI 2.38-2.87) times higher risk of dying than the general population. CONCLUSIONS: Individuals with prolonged cough in this study run a significantly increased risk of developing infectious TB and of dying. We recommend further evaluations of improved follow-up systems aimed at identifying and treating sputum smear-negative TB cases before they convert to an infectious stage.     

Low tuberculosis notification in mountainous Vietnam is not due to low case detection: a cross-sectional survey

Background  

Studies show that tuberculosis notification declines with increasing altitude. This can be due to declining incidence or declining case detection. In Vietnam notification rates of new smear-positive tuberculosis in the central mountainous provinces (26/100,000 population) are considerably lower than in Vietnam in general (69/100,000 population). In order to clarify whether this is explained by low incidence or low case detection, we aimed to assess the prevalence of new smear-positive tuberculosis among adults with prolonged cough in three mountainous provinces in central Vietnam.     

HIV and tuberculosis coinfection in the southern region of Ethiopia: a prospective epidemiological study

HIV has played a key role in TB, modifying its incidence and clinical presentation. This study describes the prevalence of HIV among TB patients attending health facilities in the southern region of Ethiopia. The HIV prevalence was 18% for female and 21% for male TB patients. 15% and 30%, respectively, of the rural and urban patients with TB were HIV positive (p<0.05). 19% (51/261) smear-positive PTB, 26% (36/137) smear-negative PTB and 11% (10/94) of the extrapulmonary TB patients were HIV positive. The proportion of patients with extra-PTB varied from 11% to 38% across the centres and was highest in the zones with the lowest HIV prevalence. In the light of limited diagnostic facilities, clinicians often make a clinical diagnosis of TB without laboratory confirmation. The increase in the number of TB cases could be due to HIV. However, the number of health facilities offering TB treatment in the area also increased (from 53 to 236) during the same period and the increase in TB is likely to be the result of a combination of factors, including improved detection and HIV. It is important to consider this multi-factorial phenomenon when interpreting the increase of TB in a geographical area.     

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.     

Passive versus active tuberculosis case finding and isoniazid preventive therapy among household contacts in a rural district of Malawi.

SETTING: Thyolo district, rural Malawi. OBJECTIVES: To compare passive with active case finding among household contacts of smear-positive pulmonary tuberculosis (TB) patients for 1) TB case detection and 2) the proportion of child contacts aged under 6 years who are placed on isoniazid (INH) preventive therapy. DESIGN: Cross-sectional study. METHODS: Passive and active case finding was conducted among household contacts, and the uptake of INH preventive therapy in children was assessed. RESULTS: There were 189 index TB cases and 985 household contacts. Human immunodeficiency virus (HIV) prevalence among index cases was 69%. Prevalence of TB by passive case finding among 524 household contacts was 0.19% (191/100000), which was significantly lower than with active finding among 461 contacts (1.74%, 1735/100000, P = 0.01). Of 126 children in the passive cohort, 22 (17%) received INH, while in the active cohort 25 (22%) of 113 children received the drug. Transport costs associated with chest X-ray (CXR) screening were the major reason for low INH uptake. CONCLUSIONS: Where the majority of TB patients are HIV-positive, active case finding among household contacts yields nine times more TB cases and is an opportunity for reducing TB morbidity and mortality. The need for a CXR is an obstacle to the uptake of INH prophylaxis.