Trend in HIV prevalence among tuberculosis patients in Tanzania, 1991-1998.

OBJECTIVE: To determine the trend in human immunodeficiency virus (HIV) prevalence among tuberculosis patients in Tanzania and estimate what proportion of the increase in notification rates between the surveys was directly attributable to HIV infection. METHODS: Consecutive tuberculosis patients were enrolled over 6-month periods in most regions. Demographic and clinical data were collected on standard forms and a single HIV ELISA test performed. Trends in tuberculosis incidence were estimated from regional notification data. RESULTS: Of 10612 eligible tuberculosis patients, 44% had HIV infection, compared with 32% in the previous survey. The largest increase was observed in the youngest birth cohorts, suggesting active HIV transmission. Approximately 60% of the increase in notification rates of smear-positive tuberculosis between surveys was directly attributable to HIV infection. CONCLUSION: The HIV epidemic has had a strong influence on tuberculosis incidence. However, since 1995, tuberculosis notification data have increased less steeply, AIDS notifications have gone down, and HIV prevalence in blood donors has not increased a great deal. Another survey among tuberculosis patients in 5 years' time may show whether the HIV epidemic in Tanzania has reached a maximum or steady state.

Evaluation of the MycoDot test in patients with suspected tuberculosis in a field setting in Tanzania.

SETTING: Rapid, simple and inexpensive methods are needed to improve the diagnosis of tuberculosis in low-income countries. The MycoDot test has these characteristics. OBJECTIVE: To assess the utility of the MycoDot test in screening patients with suspected tuberculosis. DESIGN: Ambulatory patients presenting with symptoms of pulmonary tuberculosis were evaluated by physical examination and sputum acid-fast bacilli (AFB) microscopy. Separately, the MycoDot test was performed on whole blood. Patients with AFB-negative smears were treated with a 10-day course of erythromycin. Those remaining symptomatic had a chest radiograph. All sputum specimens were cultured for mycobacteria. Patients with culture-negative tuberculosis and those without a tuberculosis diagnosis were reassessed at 2 months. RESULTS: Among the 241 patients who were evaluated, the MycoDot test was positive in 26% of patients with AFB-positive/culture-positive tuberculosis, 7% with AFB-negative/culture-positive tuberculosis, 7% with culture-negative tuberculosis, 19% treated for tuberculosis who did not meet study case definitions, and 16% without tuberculosis. Twenty four patients did not complete the assessment. Test sensitivity was 16%, specificity 84% and positive predictive value 45%. Sensitivity was highest (41%) in AFB-positive/HIV-negative patients and lowest (3%) in AFB-negative/HIV-positive patients. CONCLUSION: The MycoDot test is not useful for the diagnosis of tuberculosis in sub-Saharan African countries, especially where HIV infection is prevalent.

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.

PIP: The tuberculosis (TB) patient treatment card proposed by the International Union Against Tuberculosis and Lung and Disease provides both patient and protocol-specific information. In addition to data on age and gender, the cards contain information on body weight, drug dosing, sputum smear microscopy results, and the use of chest radiography for diagnosis. All 279 treatment cards of patients scheduled to attend one specific TB clinic day in Kinondoni district, Dar es Salaam, Tanzania, were analyzed as an example of a rapid operations evaluation method for identifying issues important to a national tuberculosis program (NTP). 225 patients were diagnosed with pulmonary TB, of which males comprised 61%. 92% were cases with no prior history of treatment. Patients under age 15 years and those aged 25-54 were more likely than other age groups to be sputum smear-negative. A chest radiograph was obtained to support the diagnosis in 61 of 160 cases diagnosed as sputum smear-negative pulmonary TB. Initial drug dosing based upon patient's weight revealed frequent dosing errors of isoniazid and pyrazinamide in sputum smear-positive patients. Observed error was almost exclusively overdosing.

The yield of acid-fast bacilli from serial smears in routine microscopy laboratories in rural Tanzania.

Routine results of direct examination of sputum smears for acid-fast bacilli from 34 laboratories in Tanzania were analysed. These represented 8 regions providing 94 laboratory-years of work; 61,580 tuberculosis suspects were evaluated with the aid of 141,371 smears. The average proportion of cases found among suspects was 18.9% (range 14.3-23.8% in the 8 regions). The number of cases missed among suspects with incomplete examinations was calculated based on the number observed among suspects with a complete set of 3 smears examined, and an incremental yield of 83.4% with the first, 12.2% with the second, and 4.4% with the third smear was estimated for the total number of expected cases. These data suggest that (i) the method frequently employed for calculating requirements for laboratory supplies in low income countries, based on the estimate that 10 suspects need examination to identify one case of sputum smear-positive tuberculosis, is generous in the context of Tanzania and (ii) under routine conditions the incremental yield from a third smear examination after 2 negative examinations is relatively small.

Adverse cutaneous reactions to thiacetazone for tuberculosis treatment in Tanzania.

Because thiacetazone has been linked with serious adverse cutaneous reactions, we undertook 1 year of systematic surveillance for cutaneous thiacetazone-associated adverse reactions within the national tuberculosis programme of Tanzania. For individual cases, we collected information on age, sex, interval between commencing thiacetazone-containing treatment and occurrence of adverse reaction, most severe clinical presentation (toxic epidermal necrolysis, rash without necrolysis, itching without rash), and outcome (dead or alive) within 2 weeks of onset. Univariate and multivariate analyses were done of variables relevant to outcome. 1273 patients with adverse reactions were reported. The frequency of fatal outcome from any cutaneous reaction was 3.1 per 1000 among all tuberculosis patients, and 19.1% among patients with toxic epidermal necrolysis. About 60% of all adverse reactions and deaths occurred within 20 days of starting thiacetazone. Case fatality from adverse cutaneous reactions was considerably less frequent than reported previously, suggesting that improved management might allow retention of thiacetazone in the armamentarium of national tuberculosis programmes even where infection with HIV is prevalent.

PIP: Thiacetazone is a useful and inexpensive companion drug in the treatment of tuberculosis (TB). Its main contribution is its ability to prevent failure and relapse in patients with initially isoniazid-resistant strains. Early toxicity studies showed that the drug was generally better tolerated in East Africa than in many other countries. Thiacetazone is an essential drug in the Tanzania National Tuberculosis/Leprosy Program. Under trial conditions in Tanzania, before the HIV epidemic, adverse reactions associated with thiacetazone were uncommon. Serious, and occasionally fatal, toxic cutaneous reactions to sulphur-containing drugs in HIV-infected patients have been recognized for several years. Recently, the use of thiacetazone in HIV-infected patients has been linked with serious adverse cutaneous reactions, including toxic epidermal necrolysis. Most reports, however, concerned only patients admitted to referral hospitals, so the Tanzania National Tuberculosis Program began a nationwide one-year systematic surveillance study to determine the frequency and severity of adverse cutaneous reactions. Individual-level data were collected on each case's age, sex, interval between commencing thiacetazone-containing treatment and occurrence of adverse reaction, most severe clinical presentation, and outcome within two weeks of onset. The study identified 1273 patients with adverse reactions. The frequency of fatal outcome from any cutaneous reaction was 3.1 per 1000 among all tuberculosis patients and 19.1% among patients with toxic epidermal necrolysis. Approximately 60% of all adverse reactions and deaths occurred within twenty days of starting thiacetazone. Case fatality from adverse cutaneous reactions was considerably less frequent than previously reported, suggesting that improved management may allow the retention of thiacetazone as a weapon against TB even where infection with HIV is prevalent.

Impact of the change from an injectable to a fully oral regimen on patient adherence to ambulatory tuberculosis treatment in Dar es Salaam, Tanzania.

OBJECTIVE: To measure the impact on patient adherence to directly observed ambulatory tuberculosis treatment substituting an all-oral treatment regimen for a regimen containing streptomycin. METHODS: The expected and observed attendance of patients during the intensive phase of anti-tuberculosis treatment was measured daily at two out-patient clinics in Dar es Salaam. During the observation period, treatment was changed from a regimen containing streptomycin to an all-oral regimen, and attendance proportions were compared for the three periods during which patients always, sometimes or never received streptomycin during the intensive phase of treatment. RESULTS: In Kinondoni, an average of 98 patients was expected every day, in Ilala 127. No significant difference was observed in attendance in Kinondoni between periods when patients always (median attendance 95.9%) and never (median 95.7%) received streptomycin injections as part of their intensive phase treatment for tuberculosis. In Ilala, no difference was noted in attendance between the period in which patients received streptomycin for at least part of their treatment (median 91.3%) and the period when ethambutol had fully replaced streptomycin (median 91.8%). CONCLUSIONS: In these two districts of Dar es Salaam, patient adherence to a completely oral treatment regimen was indistinguishable from that to a streptomycin-containing regimen. Given the potential of iatrogenic transmission of HIV and the advantages in reduced staff time and drug costs, the results clearly justify the replacement of streptomycin with ethambutol in Tanzania for new patients receiving an ambulatory rifampicin-containing regimen.

PIP: In a comparative study conducted among outpatients at tuberculosis clinics in the Ilala and Kinondoni districts of Dar es Salaam, no difference in patient compliance was recorded between streptomycin injection and an all-oral treatment regimen. An all-oral regimen was considered desirable because of concerns about injection-related human immunodeficiency virus (HIV) transmission, the high cost of streptomycin, and the staff time involved in providing injections; on the other hand, it was unclear whether patients would accept a change to oral ethambutol. In Kinondoni District, where an average of 127 tuberculosis patients are expected daily, 95.9% of the expected patients attended in the initial phase when streptomycin was still given, 97.1% in the transition period, and 95.7% once the oral regimen had been fully implemented. In Ilala, where there was no baseline survey due to nonavailability of streptomycin, attendance was 91.8% of expected when the oral regimen was put into place. Encouraged by these findings, Tanzania's national tuberculosis control program has replaced streptomycin injection with oral ethambutol administration. It is speculated that the shorter clinic waiting times involved in this regimen have helped to maintain a high level of attendance. In this culture, at least, oral regimens do not appear to be perceived as less effective or important than injections.