Cohort study of HIV-positive and HIV-negative tuberculosis, Nairobi, Kenya: comparison of bacteriological results.

We have set up a cohort of human immunodeficiency virus (HIV) positive and negative patients with tuberculosis in order to address the problems associated with HIV-related tuberculosis. We present here the results of sputum smear microscopy, culture, mycobacterial identification tests and drug susceptibility assays from specimens taken at presentation. In this selected population of largely pulmonary tuberculosis cases, HIV infection is not associated with significant differences in sputum smear positivity rate, culture positivity rate or initial drug resistance. No atypical mycobacteria were found. Direct sputum smear examination remains specific for the diagnosis of tuberculosis in Kenya in spite of the presence of HIV. HIV infection was not associated with an increase in the proportion of pulmonary cases still culture-positive at 6 months. However a significant increase in the proportion of cases still culture-positive at 6 months was seen in those with initially resistant strains and also in those treated with standard regimen (streptomycin, thiacetazone and isoniazid for 1 month followed by thiacetazone and isoniazid for 11 months, 1STH/11TH) rather than a short-course, rifampicin-containing regimen (rifampicin, pyrazinamide and isoniazid for 2 months, together with streptomycin for the first month and followed by 6 months of thiacetazone and isoniazid, SHRZ/6TH).     

Quality control in the laboratory diagnosis of tuberculosis

The study was conducted in 4 hospital laboratories to assess the value of smear re-examination, duplicate smear and culture in quality control in the diagnosis of pulmonary tuberculosis. In each hospital 1 to 3 sputum specimens were collected from each suspect and examined by the Ziehl-Neelsen method. Smears along with corresponding specimens were sent to the reference laboratory for re-examination and examination of fresh duplicate smears and culture. A total of 994 specimens plus 23 known negative and 23 known positive controls were analysed. For each assessment method, both over-diagnosis and underdiagnosis were indicated with under-diagnosis being a more common problem in the four hospital laboratories. The limitations of these assessment methods are presented.     

Predictors of nutritional status among participants in a rice irrigation scheme in Kenya

Over the short term, irrigation projects often negatively influence the nutrition and health of target populations through factors which are either directly or indirectly related to the development process of the project. A cross-sectional survey of 187 households in, and 168 households from surrounding areas of the Mwea-Tebere rice irrigation scheme (MTIS) in Kenya was conducted to study the individual and social characteristics associated with childhood malnutrition. The cultivated area in the MTIS grew from 7000 acres in 1965 to 31,000 in 1987. However, during the same period, the population grew from 16,000 to 40,000, with most or all of the tenants' children continuing to live with their parents and overcrowding scheme villages. The proportion of under-fives who had weight/age, weight/height, and height/age indices under -2 standard deviations of the WHO-NCHS reference values was higher among MTIS residents than among nonresidents. Maternal education was the only variable significantly associated to all indicators of malnutrition used in the study. the area of residence, the number of resident dependents upon proceeds from the same farm, recent episode of diarrhea, child's age, mother's occupation, mother's age, type of caretaker of the child in the mother's absence, and mother's marital status were associated to one or two indicators of malnutrition. The level of maternal education is significantly higher at MTIS than off-scheme. However, the influence of MTIS' crowding and poor sanitation conditions is strong enough to make the nutritional status of preschool children worse within the scheme. Maternal education should be promoted, facilities provided to improve sanitary conditions, and programs launched to control population density in on-scheme villages.     

Cohort study of human immunodeficiency virus infection in patients with tuberculosis in Nairobi, Kenya. Analysis of early (6-month) mortality.

Retrospective studies suggest that the mortality rate from HIV-1-associated tuberculosis is greater than that from tuberculosis alone, but it is not clear if this is due to failure of antituberculosis treatment or to the complications of HIV-1 infection. We have carried out a prospective cohort study of patients with tuberculosis in Nairobi, Kenya, to compare mortality rates, risk factors, and causes of death in HIV-1 positive and HIV-1 negative patients. One hundred seven HIV-1 positive and 174 HIV-1 negative patients with tuberculosis attending two tuberculosis treatment centers in Nairobi were enrolled and followed monthly. Mortality was significantly higher in HIV-1 positive than in HIV-1 negative patients within 6 months of the start of antituberculosis treatment after adjustment for age, sex, and education (rate ratio = 3.8; 95% confidence interval, 1.7 to 8.1; p less than 0.001). Most of the excess mortality occurred after the first month of treatment and was due to nontuberculous infections. Predictors for mortality differed greatly between HIV-1 positive and HIV-1 negative patients. Mortality was greater in HIV-1 positive patients treated with a "standard" regimen for tuberculosis than in HIV-1 positive patients receiving a "short-course" regimen (p = 0.08 when adjusted for all independent risk factors). Tuberculosis control programs in developing countries need to implement "short-course" regimens and train health workers to recognize and treat nontuberculous infections to maintain their effectiveness in the face of the HIV epidemic.     

Cross-sectional survey of HIV infection among patients with tuberculosis in Nairobi, Kenya.

Evidence from many countries suggests an association of human immunodeficiency virus (HIV) infection and tuberculosis of major public health significance. In order to begin assessing the impact of HIV on tuberculosis in Kenya, we have determined the HIV-1 seroprevalence among tuberculosis patients and compared the clinical characteristics of tuberculosis in HIV-positive and HIV-negative patients in two cross-sectional studies at the Infectious Disease Hospital (IDH) and the Ngaira Avenue Chest Clinic (NACC), Nairobi, Kenya. The diagnosis in 92% of all patients with pulmonary tuberculosis was confirmed by culture. The remainder were diagnosed on histological, clinical or radiological grounds. HIV seroprevalence among tuberculosis patients at IDH was 26.5% (52/196) compared to 9.2% (18/195) at NACC (P less than 0.001). There was no association between numbers of streptomycin injections in the previous 5 years and HIV infection. Positive sputum smear rates in HIV-positive patients were slightly lower than in HIV-negative patients at both study sites (71% vs 83% at IDH and 73% vs 82% at NACC) but the difference was not significant. Only Mycobacterium tuberculosis was isolated. Miliary disease was not associated with HIV infection. Persistent diarrhoea, oral candidiasis, generalized itchy rash, herpes zoster and generalized lymphadenopathy were all associated with HIV infection, but 46% (95% CI:38-54%) of all HIV-positive patients had none of the clinical features listed in the WHO Clinical Criteria for the Diagnosis of AIDS, apart from fever, cough and weight loss. Stevens-Johnson Syndrome was reported in 7/52 (13%) patients with HIV infection, and in 4/144 (3%) patients without (RR 4.85, 95% CI: 1.45-15.88).(ABSTRACT TRUNCATED AT 250 WORDS)