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H L Rieder

Publications and source records attributed to H L Rieder.

At least 37 records · Page 2Linked to original sources
PubMed2000

Trends in the prevalence of infection with mycobacterium tuberculosis in Korea from 1965 to 1995: an analysis of seven surveys by mixture models.

SETTING: Korea. OBJECTIVE: Estimation of the prevalence of tuberculous infection from tuberculin skin test surveys can be difficult if cross-reactions resulting from infection with environmental mycobacteria outweigh reactions resulting from tuberculous infection. Mixture analysis was thus chosen as a novel approach for estimating the prevalence of tuberculous infection in Korea. DESIGN: Seven tuberculin skin test surveys conducted between 1965 and 1995 were analyzed by mixture models, a statistical methodology used either to estimate a prevalence or to classify individuals into predefined homogeneous sub-populations. A Bayesian approach including prior information on component distributions was taken. The final model was selected based on the fit to observed values, and the analysis was therefore stratified by sex and year of survey and included age as a covariate. RESULTS: The results showed a large decrease in tuberculous infection in the population below 30 years of age: among 10- to 14-year-old boys (girls), infection prevalence decreased from 74.5% (67.9%) in 1965 to 16.5% (16.9%) in 1995. Additionally, the mean induration for individuals with tuberculous infection decreased by 2mm between 1965 and 1995, indicating a changing sensitivity of tuberculin over time. CONCLUSIONS: Mixture analysis is a promising approach for determining the prevalence of tuberculous infection in the presence of substantial interference from infection with environmental mycobacteria and changing tuberculin reaction sizes over time.

Adolescent↗
PubMed2000

Standardization of antituberculosis drug resistance surveillance in Europe. Recommendations of a World Health Organization (WHO) and International Union Against Tuberculosis and Lung Disease (IUATLD) Working Group.

Surveillance of antituberculosis drug resistance is an essential tool for evaluating the quality of tuberculosis control programmes. Consensus-based recommendations on uniform reporting of antituberculosis drug resistance surveillance data in Europe have been developed by a Working Group of the World Health Organization (WHO) and the International Union Against Tuberculosis and Lung Disease (IUATLD). Laboratories should use standardized methods for testing drug susceptibility with a quality assurance programme including national and international proficiency testing. The proportion of drug resistance, particularly resistance to isoniazid, rifampicin or both (multidrug resistance) among all definite, i.e. culture-positive, tuberculosis cases at the start of treatment is the major indicator of interest. It should be calculated separately among patients treated previously and among those who have never been treated with > or = 1 month of combined antituberculosis drugs. The Working Group recommends that, in countries in which resources allow, laboratories report drug susceptibility test results on all isolates of the Mycobacterium tuberculosis complex. Test results of the specimen at the start of treatment and clinical data from the notification should be linked using a suitable identifier. Results should be presented by calendar year and analysed by age, sex, place of birth, site of disease and sputum smear results. In countries in which a routine system cannot be organized, representative surveys or sentinel systems are possible alternatives. In some countries, the annual prevalence of multidrug-resistant tuberculosis may be estimated through a national laboratory reporting system.

Antitubercular Agents↗
PubMed1999

A comparison of fluorescence microscopy with the Ziehl-Neelsen technique in the examination of sputum for acid-fast bacilli.

SETTING: National Tuberculosis Reference Laboratory in Dakar, Senegal. OBJECTIVES: Comparison of results with fluorescence and bright-field microscopy for acid-fast bacilli. METHODOLOGY: Two smears from 2,630 consecutive sputum specimens between January 1996 and June 1998 were prepared for blinded examination of one smear each by the Ziehl-Neelsen technique and fluorescence microscopy at 1,000x magnification. The time required to declare a slide as negative was determined for both techniques in a sample of 68 slides. RESULTS: Concordancewas 96.9% and 92.3% for diagnostic and follow-up examinations, respectively. The yield was similar with both techniques for specimens with at least 10 bacilli per 100 fields, but higher with fluorescence microscopy in those with fewer than 10 bacilli per 100 fields. The mean time required by fluorescence microscopy before declaring a slide as negative with the same magnification was 3 minutes 34 seconds, compared to 7 minutes 44 seconds with the Ziehl-Neelsen technique. CONCLUSIONS: The results obtained with one technique are highly reproducible by the other. Fluorescence microscopy appears to be more likely to detect bacilli in paucibacillary cases than bright-field microscopy, and it more than halves the required examination time.

Humans↗
PubMed1999

Tuberculosis chemotherapy and sputum conversion among HIV-seropositive and HIV-seronegative patients in south-eastern Uganda.

OBJECTIVE: To investigate if there is a difference in response to tuberculosis treatment between HIV seronegative and HIV seropositive patients following two months of intensive phase tuberculosis treatment. DESIGN: Prospective cohort study. SETTING: St. Francis Leprosy Centre, south-east Uganda. SUBJECTS: Four hundred fifty seven patients with never previously treated sputum smear-positive tuberculosis admitted during a two-year period in 1991/1993. INTERVENTION: Intensive phase treatment with streptomycin, isoniazid, rifampicin and pyrazinamide. MAIN OUTCOME MEASURES: Sputum conversion from a positive to a negative smear at eight weeks of treatment. RESULTS: HIV seropositivity prevalence was 28%. Among HIV seronegative patients, conversion to a negative smear status occurred in 76% persons compared to 78% in HIV seropositive patients. This difference was not statistically significant (OR = 0.9; 95% CI, 0.6-1.5). HIV seropositive patients, however, were more likely to die (p = 0.017). A high prevalence of resistance to isoniazid and streptomycin was found. Isoniazid resistance was more likely in HIV seronegative patients with M. tuberculosis strains compared to HIV seropositive persons (p < 0.005). Initial resistance to antituberculosis drugs did not have a significant effect on smear conversion. CONCLUSION: This study demonstrates that HIV-seropositive status is not a principal factor in delaying sputum conversion among patients receiving intensive phase tuberculosis treatment.

AIDS-Related Opportunistic Infections↗
PubMed1998

Global surveillance for antituberculosis-drug resistance, 1994-1997. World Health Organization-International Union against Tuberculosis and Lung Disease Working Group on Anti-Tuberculosis Drug Resistance Surveillance.

BACKGROUND: Drug-resistant tuberculosis threatens efforts to control the disease. This report describes the prevalence of resistance to four first-line drugs in 35 countries participating in the World Health Organization-International Union against Tuberculosis and Lung Disease Global Project on Anti-Tuberculosis Drug Resistance Surveillance between 1994 and 1997. METHODS: The data are from cross-sectional surveys and surveillance reports. Participating countries followed guidelines to ensure the use of representative samples, accurate histories of treatment, standardized laboratory methods, and common definitions. A network of reference laboratories provided quality assurance. The median number of patients studied in each country or region was 555 (range, 59 to 14,344). RESULTS: Among patients with no prior treatment, a median of 9.9 percent of Mycobacterium tuberculosis strains were resistant to at least one drug (range, 2 to 41 percent); resistance to isoniazid (7.3 percent) or streptomycin (6.5 percent) was more common than resistance to rifampin (1.8 percent) or ethambutol (1.0 percent). The prevalence of primary multidrug resistance was 1.4 percent (range, 0 to 14.4 percent). Among patients with histories of treatment for one month or more [corrected], the prevalence of resistance to any of the four drugs was 36.0 percent (range, 5.3 to 100 percent), and the prevalence of multidrug resistance was 13 percent (range, 0 to 54 percent). The overall prevalences were 12.6 percent for resistance to any of the four drugs [corrected] (range, 2.3 to 42.4 percent) and 2.2 percent for multidrug resistance (range, 0 to 22.1 percent). Particularly high prevalences of multidrug resistance were found in the former Soviet Union, Asia, the Dominican Republic, and Argentina. CONCLUSIONS: Resistance to antituberculosis drugs was found in all 35 countries and regions surveyed, suggesting that it is a global problem.

Antitubercular Agents↗
PubMed1998

Mortality from respiratory tuberculosis in Switzerland.

Since 1901, the Swiss Federal Office of Statistics has published at least each decade detailed mortality statistics from tuberculosis. These cross-sectional data on deaths from respiratory tuberculosis from 1901 to 1991 were utilized to analyse retrospectively tuberculosis death experience within each birth cohort. The cross-sectional data indicate that tuberculosis mortality increases with age in each successive decade. Nevertheless, the cohort-contour approach indicates that this phenomenon is the result of a much higher mortality that each cohort experienced in their early adulthood, and that mortality form respiratory tuberculosis in Switzerland always preferentially affected the young. The data also indicate that tuberculosis mortality in Switzerland has been decreasing for at least 160 years, and perhaps peaked as early as in the eighteenth century.

Adolescent↗
PubMed1998

Standardized tuberculosis treatment outcome monitoring in Europe. Recommendations of a Working Group of the World Health Organization (WHO) and the European Region of the International Union Against Tuberculosis and Lung Disease (IUATLD) for uniform reporting by cohort analysis of treatment outcome in tuberculosis patients.

Consensus-based recommendations have been developed by a Working Group of the World Health Organisation (WHO) and the International Union Against Tuberculosis and Lung Disease (IUATLD) on uniform reporting of tuberculosis (TB) treatment outcome data in countries in Europe. The main purpose of treatment monitoring is to find out how many of the potential infectious TB patients notified were declared cured at the end of treatment. Following the uniform case definitions as defined in 1996, emphasis is placed on cohort analysis of definite cases of pulmonary TB. The Working Group recommends using a minimal set of six mutually exclusive categories of treatment outcome: cure, treatment completed, failure, death, treatment interrupted, and transfer out. More detailed subsets may be chosen. Treatment outcome is expressed as a percentage of the total number of cases notified. Analysis should be separate for new and retreatment cases. Treatment outcome data have to be collected at the local level and passed on to regional and national authorities on an ongoing basis. Evaluation of treatment results becomes, preferably, an inbuilt component of national monitoring of programme performance. Because of the long duration of treatment, it is recommended that analysis is carried out in the first quarter of the calendar year that follows a full year after the last patient was enrolled. Feedback is essential. Treatment outcome results should become an inseparable part of the annual report on tuberculosis.

Cohort Studies↗
PubMed1998

Tuberculosis control in refugee populations: a challenge to both relief agencies and national programs.

Today's worldwide tuberculosis epidemic and the movement of a growing number of refugees overlap geographically and have made tuberculosis control in refugee populations an issue of increasing importance. However, in developing countries, where both of these problems are concentrated, tuberculosis control in refugee populations remains a largely unmet need. Experience shows that despite difficult field conditions, tuberculosis control programs can be managed successfully in this setting. The range of outcome results reported for treatment completion and defaulting is, however, wide. Analyzing possible determinants for observed variation in treatment outcome results, this paper outlines prerequisites for establishing a tuberculosis control program in a refugee setting. An attempt is made to formulate a general strategy for the main policies which, if applied consistently, will reduce morbidity, mortality and transmission of tuberculosis among refugee populations living in camps. Criteria for the evaluation and monitoring of such a program are discussed.

Communicable Disease Control↗
PubMed1997

Evaluation of a standardized recording tool for sputum smear microscopy for acid-fast bacilli under routine conditions in low income countries.

SETTING: Laboratories performing sputum smear microscopy for tuberculosis in Benin, Malawi, Nicaragua and Senegal. METHODS: Analysis of computerized laboratory registers to ascertain workload, yield from serial smear examination, and demographic characteristics of examinees. RESULTS: Data from more than 60,000 examinees in 42 laboratories showed that the average number of smears examined per day ranged from 4 to 19 (mean 6) per country. To find one case of tuberculosis, on average 21 smears of suspects were examined (range 8 to 50). Of all cases with ultimately at least one positive result, 87% were already positive on the first examination. Demographic characteristics of cases differed considerably by country and gender. In 35 of 42 laboratories, males were more frequently found to be cases than females, and with increasing age an increasingly larger number of female than male suspects had to be examined to identify one case. CONCLUSIONS: This study demonstrates the usefulness of a standardized recording system for results of acid-fast microscopy in obtaining essential information for program management and on demographic characteristics of persons presenting for examination.

Adolescent↗
PubMed1997

Evaluation and planning in national tuberculosis control programmes: the usefulness of the standardised patient treatment card.

Through systematic evaluation of information contained in tuberculosis patients treatment cards, we present an example of a rapid operations evaluation method for identifying issues important to a national tuberculosis programme (NTP). Analysis of all 279 treatment cards of patients scheduled to attend one specific clinic day was made ((Kinondoni district in Dar es Salaam, Tanzania). Two hundred and twenty five patients (81%) were diagnosed as having pulmonary tuberculosis. Males accounted for 61% of cases. Ninety two per cent were cases without prior history of treatment. Of all patients, those under 15 years and those aged 25 to 54 years were more likely to be sputum smear-negative compared with other age groups. A chest radiograph was obtained as recommended to support the diagnosis in only 61 (38%) of 160 cases diagnosed as sputum smear-negative pulmonary tuberculosis. Initial drug dosing based on weight (mg/kg) revealed frequent dosing errors of isoniazid (97%) and pyrazinamide (65%), almost exclusively overdosing, in sputum smear-positive patients. Systematic examination of patient treatment cards provided usefull information and raises issues important to NTP planning and operations. Weaknesses in the execution of the national programme in Dar es Salaam were identified: the under-utilisation of chest radiography to diagnose sputum smear-negative tuberculosis and overdosing of certain drugs.

Adolescent↗
PubMed1996

Sputum smear conversion during directly observed treatment for tuberculosis.

SETTING: Treatment program for tuberculosis in a refugee camp in Thailand. OBJECTIVES: To determine the cumulative frequency of conversion of sputum smears examined by direct microscopy by month of treatment and to identify factors predicting failure to convert. METHODS: Analysis of conversion based on three sputum smear examinations (performed monthly) in a cohort of patients with sputum smear-positive tuberculosis treated with a directly observed daily regimen containing rifampicin throughout. Nested case-control study of patients failing to convert definitively within four months compared to controls who did convert. RESULTS: Sputum conversion after the 2-month intensive phase was 75.0%, with a range from 61.7% to 90.9% in patients with initially strongly- and weakly-positive smears, respectively. The strongest predictor identified for no definitive conversion within four months of treatment was a positive sputum smear result at the end of the 2-month intensive phase (adjusted relative odds 4.2, 95% confidence interval 1.5-11.4). Of those patients who did not convert, positive smears were an isolated phenomenon in 15, repeatedly in four who definitely converted with a prolongation of treatment, and persistently positive in two requiring a re-treatment regimen. CONCLUSIONS: Definitive sputum smear conversion is judged to be slower if a strict program of sputum smear examination is undertaken than under routine program conditions, but positive results late in the course are commonly an isolated phenomenon and possibly of little significance. Sputum smear results at two months strongly predict bacteriologic results beyond three months of treatment, and thus identify cases who might benefit from a prolongation of the intensive phase.

Case-Control Studies↗