Tanzanian Population Research Articles

Caries status and opinions of people living with HIV/AIDS on oral health care providers' desired behaviour

Aim The aim of this study was to investigate the dental caries status and opinions of the People Living with HIV/AIDS (PLHA) on how they should be handled by oral health care providers. Design: A cross sectional study. Study subjects and Methods The study was carried out among PLHA in Dar es Salaam, Tanzania. Data was collected using a face to face interview utilizing a structured questionnaire which inquired on participants' views on how they should be handled by oral health care providers. An intra oral examination to assess dental caries status was done according to WHO recommendation. Results The response rate was 43.9%. Majority of the participants suggested that dental professionals should have empathy to PLHA (95%), should avoid stigmatization of PLHA (94%) and should observe sterile procedures to control cross infection. The mean decayed component was 2.45, mean missing 3.63, mean filled 0.25 and the mean decayed missing and filled teeth (DMFT) 6.34. Only 8.9% of the participants were caries free, 15.8% had one decayed tooth, 13.9% had one missing tooth, 5.9% had one filled tooth and 10.9% had one DMFT. The most affected teeth were third molars, observed on the upper right jaw of 42.5% of the participants and on the lower left jaw of 56.4%. Extensive destruction of the tooth structure was frequently observed. Conclusion We conclude that the study group of PLHA has a higher caries experience than the general Tanzanian population, requires dental professionals to observe social requirements and to offer them professional services. Keywords: HIV/AIDS, PLHA, Dental caries, Dental services Tanzania Dental Journal Vol. 13(2) November 2006: 56-63

Immunogenetic Control of Antibody Responsiveness in a Malaria Endemic Area

This study builds upon the established genetic control of antimalarial immune responses and prior association studies by using a family-based approach, transmission disequilibrium testing, to identify immune response genes that influence antibody responses to Plasmodium falciparum infection in an endemic Tanzanian population. Candidate polymorphisms are within the interleukin-1 (IL-1) gene cluster, the IL-10 promoter, Major histocompatibility complex class II and III, the 5q31-q33 region, and the T-Cell Receptor beta variable region. There was a significant association between the IL1RN alleles and total IgE. Weak evidence for association was present between polymorphisms in the IL10 promoter region and both anti- P falciparum IgE and IgG4 antibodies.

Multiclonal asymptomatic Plasmodium falciparum infections predict a reduced risk of malaria disease in a Tanzanian population

Protective immunity to malaria is acquired after repeated exposure to the polymorphic Plasmodium falciparum parasite. Whether the number of concurrent antigenically diverse clones in asymptomatic infections predicts the risk of subsequent clinical malaria needs further understanding. We assessed the diversity of P. falciparum infections by merozoite surface protein 2 genotyping in a longitudinal population based study in Tanzania. The number of clones was highest in children 6–10 years and in individuals with long time to previous anti-malarial treatment. Individual exposure, analysed by circumsporozoite protein antibody levels, was associated with parasite prevalence but not with the number of clones. The risk of subsequent clinical malaria in children free of acute disease or recent treatment was, compared to one clone, reduced in individuals with multiclonal infections or without detectable parasites, with the lowest hazard ratio 0.28 (95% confidence interval 0.10–0.78 Cox regression) for 2–3 clones. The number of clones was not associated with haemoglobin levels. A reduced risk of malaria in asymptomatic individuals with multiclonal persistent P. falciparum infections suggests that controlled maintenance of diverse infections is important for clinical protection in continuously exposed individuals, and needs to be considered in the design and evaluation of new malaria control strategies.

Development of written information for antiretroviral therapy: comprehension in a Tanzanian population

To design and develop a simple, easily readable patient information leaflet (PIL) for a commonly used antiretroviral (ARV) regimen and to evaluate its readability and acceptability in a Tanzanian population. A PIL incorporating simple text and pictograms was designed for the antiretroviral regimen of stavudine, lamivudine and efavirenz. The PIL was designed according to established good design guidelines, modified during a multi-stage iterative testing process and piloted in a South African Xhosa population. The PIL was made available in both English and Kiswahili. Sixty Tanzanian participants who were not taking ARVs were interviewed. They were asked to read the PIL in the language of their choice and were then asked a series of two-part questions; the first part required participants to locate the information in the PIL, after which they were asked to explain the information in their own words. Acceptability was assessed through close-ended questions and open-ended feedback. The influence of selected patient characteristics on comprehension of the PIL was investigated using one-way ANOVA and t-tests for independent samples with a significance level set at 0.05. Comprehension of the written information in an overall percentage understanding. The overall average percentage comprehension of the PIL was 95%. The target set by the EC guideline that at least 80% of participants correctly locate and understand the information was achieved for 19 of the 20 questions. Five of the six instructions illustrated by pictograms were correctly understood by all participants. The only patient characteristics significantly associated with comprehension were educational level and self-reported ease of reading the PIL. Acceptability of the PIL was high and positive comments were associated with simplicity, good design, easy readability and user-friendliness, the latter enhanced by the inclusion of pictograms. The PIL designed for this study was shown to be effective in communicating information about ARVs. Patient characteristics must be taken into account when developing written information, and the final document must be tested for comprehension in the target population.

H. pylori-infection and antibody immune response in a rural Tanzanian population

BackgroundHelicobacter pylori (H. pylori) infection is ubiquitous in sub-Saharan Africa, but paradoxically gastric cancer is rare.MethodsSera collected during a household-based survey in rural Tanzania in 1985 were tested for anti-H. pylori IgG and IgG subclass antibodies by enzyme immunoassay. Odds ratios (OR) and confidence intervals (CI) of association of seropositivity with demographic variables were computed by logistic regression models.ResultsOf 788 participants, 513 were aged ≤17 years. H. pylori seropositivity increased from 76% at 0–4 years to 99% by ≥18 years of age. Seropositivity was associated with age (OR 11.5, 95% CI 4.2–31.4 for 10–17 vs. 0–4 years), higher birth-order (11.1; 3.6–34.1 for ≥3rd vs. 1st born), and having a seropositive next-older sibling (2.7; 0.9–8.3). Median values of IgG subclass were 7.2 for IgG1 and 2.0 for IgG2. The median IgG1/IgG2 ratio was 3.1 (IQR: 1.7–5.6), consistent with a Th2-dominant immune profile. Th2-dominant response was more frequent in children than adults (OR 2.4, 95% CI 1.3–4.4).ConclusionH. pylori seropositivity was highly prevalent in Tanzania and the immunological response was Th2-dominant. Th2-dominant immune response, possibly caused by concurrent bacterial or parasitic infections, could explain, in part, the lower risk of H. pylori-associated gastric cancer in Africa.

The costs and benefits of kin : Kin networks and children's health among the Pimbwe of Tanzania.

In this paper data from a Tanzanian horticultural population are used to assess whether mother's kin network size predicts several measures of children's health and well-being, and whether any kin effects are modified by household socioeconomic status. This hypothesis is further tested with a questionnaire on maternal attitudes towards kin. Results show small associations between measures of maternal kin network size and child mortality and children's growth performance. Together these results suggest that kin positively influence child health, but the effects are small and it is unlikely that the high prevalence of undernutrition observed in this setting is influenced by the availability of kin.

Oral tumours in Tanzanian children based on biopsy materials examined over a 15-year period from 1982 to 1997

To provide information on the types and distribution of oral tumours and tumour-like lesions occurring in a Tanzanian child population aged 0-16 years. Retrospective study of biopsy results from hospital records from 1982-1997. Department of Histopathology, the Muhimbili Medical Centre (MMC) in Dar es Salaam. INTERVENTION/ METHODS: A total of 158 biopsy results, from 75 girls and 83 boys, were retrieved and studied. Malignant tumours were the most frequent (43.0%) followed by benign tumours (30.4%) and tumour-like lesions (26.6%). Burkitt's lymphoma was the most frequent malignant tumour accounting for 88.2% of all malignancies followed by squamous cell carcinoma (4.4%) and oral Kaposi's sarcoma (2.9%). Fibroma, papilloma and haemangioma were the most frequent benign tumours constituting 27.1%, 14.6% and 12.5%, respectively. Odontogenic cysts were the most frequent tumour-like lesions (28.6%) followed by fibrous dysplasia (19%) and giant cell granuloma (16.7%). The six most common oral lesions were Burkitt's lymphoma, fibroma, odontogenic cysts, fibrous dysplasia, papilloma and giant cell granuloma.

Internet Cafés in Tanzania: a study of the knowledge and skills of end-users

Reports the results of a survey of users of Internet cafés in Dar es Salaam, Tanzania, to assess their knowledge and awareness of Internet resources. Findings showed the largely male, Tanzanian population used the Internet primarily for personal communication and visiting recreational sites (mainly obscene materials). Low levels of awareness and training among end-users and staff were noted. Recommends better awareness raising, sensitization and training for end-users and staff.

Characterization of the CYP2D6*29 allele commonly present in a black Tanzanian population causing reduced catalytic activity.

Debrisoquine metabolism among Tanzanians has been found to be slower than expected from the CYP2D6 genotype. In order to evaluate any genetic explanation, the coding sequence and intron-exon boundaries of the CYP2D6 gene from three Black Tanzanian volunteers with a CYP2D6*1/*1 or CYP2D6*2/*2 genotype and debrisoquine metabolic ratios (MRs) > 1 were fully sequenced to screen for new mutations. Two functional mutations, G1747 to A (causing V136I) and G3271 to A (causing V338M), were identified in the CYP2D6*2/*2 sample. Thirty-six subjects (34%) out of a total 106 subjects were heterozygous and three subjects (3%) were homozygous for the allele, yielding an allele frequency of 20%. The CYP2D6*29 allele, having also the mutations of the CYP2D6*2 allele, was subsequently expressed in yeast and mammalian COS-1 cells. No differences were seen with respect to the affinity (Km) or maximal velocity (Vmax) of the CYP2D6 substrate bufuralol between the wild-type and mutant when expression was carried out in yeast cells. By contrast, the 1'-hydroxybufuralol catalytic activity of the mutant expressed in COS-1 cells was only 26% of the wild-type (P < 0.01; Mann-Whitney U-test) and its debrisoquine hydroxylation activity was 63% of that of CYP2D6.1. The single mutants V136I and V338M had reduced capacity for bufuralol hydroxylation, but the effect was even stronger when both mutations were present together as in CYP2D6.29. Analysis of the distribution of CYP2D6*29 in subjects phenotyped for debrisoquine revealed that this allele significantly causes a reduction in the rate of debrisoquine hydroxylation in vivo. The results indicate the common existence in Tanzanians of a variant CYP2D6 form with different substrate specificity as compared to the wild-type form of the enzyme causing reduced capacity for debrisoquine metabolism.

Tropical diabetic hand syndrome: Risk factors in an adult diabetes population

Objectives: To determine risk factors for the tropical diabetic hand syndrome, a condition associated with significant morbidity and mortality in Africa. Methods: This was a case-control study of a Tanzanian diabetes population presenting with the syndrome during February 1998 to March 2000. A case patient was defined as any patient with diabetes presenting with hand cellulitis, ulceration, or gangrene. Control patients were randomly selected patients with diabetes who had no hand symptoms. Results: Thirty-one case patients and 96 control patients were identified. The median age of case patients was 52 years (range, 28–76 y); 58% were male; 4 patients (16%) died. Precipitating events included papule (n = 6), insect bites (n = 6), boils (n = 5), burns (n = 2), or trauma (n = 3). Case and control patients were similar for presence of micro- and macrovascular disease and occupation. On logistic regression analysis, independent risk factors were body mass index of 20 or less (odds ratio [OR] = 18.0; 95% confidence interval [CI] = 4.3−97.0; P < 0.001), peripheral neuropathy (OR = 23.0; 95% Cl = 5.3−124.0; P < 0.001), or type I diabetes, (OR = 6.7; 95% Cl = 2.0−24.0, P < 0.01). Conclusion: The major risk factors for the tropical diabetic hand syndrome are intrinsically related to the underlying disease. Thus, prevention of hand infections may require aggressive glucose control, and education on hand care and the importance of seeing a doctor promptly at the onset of symptoms.

Phenotypes and genotypes for CYP2D6 and CYP2C19 in a black Tanzanian population.

CYP2D6 and CYP2C19 are polymorphically expressed enzymes that show marked interindividual and interethnic variation. The aim of this study was to determine the frequency of the defective alleles in CYP2D6 and CYP2C19 in Africans and to test whether the genotype for CYP2C19 is better correlated with the proguanil/cylcoguanil ratio than the mephenytoin S/R ratio. Two hundred and sixteen black Tanzanians were phenotyped for CYP2D6 with the use of sparteine, and for CYP2C19 with the use of mephenytoin and proguanil. Of these 196 subjects were also genotyped for CYP2D6 (including the CYP2D6*1, CYP2D6*3 and CYP2D6*4 alleles) and 195 were genotyped for CYP2C19 (including the CYP2C19*1, CYP2C19*2 and the CYP2C19*3 alleles). Furthermore 100 subjects were examined for the allele duplication in CYP2D6, leading to ultrarapid metabolism, with long PCR. The sparteine metabolic ratio (MR) was statistically significantly higher in the Tanzanian group of homozygous, extensive metabolizers compared to a historical control group of white Danish extensive metabolizers. Only one poor metabolizer for CYP2D6 (MR=124 and genotype CYP2D6*1/CYP2D6*4 ) was found. The gene frequencies were 0.96 for the CYP2D6*1 allele and 0.04 for the CYP2D6*4 allele. No CYP2D6*3 alleles were found. Nine subjects had an allele duplication in CYP2D6 (9%). For CYP2C19 there were seven subjects (3. 6%) who were phenotyped as poor metabolizers, but only three subjects (1.5%) had a genotype (CYP2C19*2/CYP2C19*2 ) indicative of poor metabolism. The gene frequencies were 0.90 for the CYP2C19*1 allele and 0.10 for the CYP2C19*2 allele. No CYP2C19*3 alleles were found. The mephenytoin S/R ratios were not bimodally distributed. Both the genotyping and phenotyping results show that there is a substantial difference between an African black population and a Caucasian population in the capacity to metabolize drugs via CYP2D6 and CYP2C19.

Severe dental fluorosis in a Tanzanian population consuming water with negligible fluoride concentration.

To identify risk factors for dental fluorosis that cannot be explained by drinking water fluoride concentration alone. Two hundred eighty-four Tanzanian children ages 9 to 19 (mean 14.0+/-SD 1.69), who were lifetime residents at differing altitudes (Chanika, 100 m; Rundugai, 840 m; and Kibosho, 1,463 m; Sites 1, 2, and 3 respectively) were examined for dental fluorosis and caries. They were interviewed about their food habits, environmental characteristics and use of a fluoride-containing food tenderizer known locally as magadi. Meal, urine, water and magadi samples supplied by the participants were analyzed for fluoride content. Urine samples were also analyzed for creatinine concentration. Four magadi samples from Sites 1 and 3 were analyzed for complete element composition. Of the 13 water samples from Site 2, 10 contained > or =4 mg/L F, ranging from 1.26 to 12.36 mg/L with a mean+/-SD of 5.72+/-4.71 mg/L. Sites 1 and 3 had negligible water fluoride of 0.05+/-0.05 and 0.18+/-0.32 mg/L respectively. Mean TFI fluorosis scores (range 0-9) for Site 2 were high: 4.44+/-1.68. In Sites 1 and 3, which both had negligible water fluoride, fluorosis scores varied dramatically: Site 1 mean maximum TFI was 0.01+/-0.07 and Site 3 TFI was 4.39+/-1.52. Mean DMFS was 1.39+/-2.45, 0.15+/-0.73 and 0.19+/-0.61 at Sites 1, 2, and 3, respectively. There were no restorations present. Urinary fluoride values were 0.52+/-0.70, 4.34+/-7.62, and 1.43+/-1.80 mg/L F at Sites 1, 2, and 3, respectively. Mean urinary fluoride values at Site 3 were within the normal urinary fluoride reference value range in spite of pervasive severe pitting fluorosis. Meal and magadi analyses revealed widely varied fluoride concentrations. Concentrations ranged from 0.01 to 22.04 mg/L F for meals and from 189 to 83211 mg/L F for magadi. Complete element analysis revealed the presence of aluminum, iron, magnesium, manganese, strontium and titanium in four magadi samples. There were much higher concentrations of these elements in samples from Site 3, which was at the highest altitude and had severe enamel disturbances in spite of negligible water fluoride concentration. An analysis of covariance model supported the research hypothesis that the three communities differed significantly in mean fluorosis scores (P<0.0001). Controlling for urinary fluoride concentration and urinary fluoride:urinary creatinine ratio, location appeared to significantly affect fluorosis severity. Urinary fluoride:urinary creatinine ratio had a stronger correlation than urinary fluoride concentration with mean TFI fluorosis scores (r=0.43 vs r= 0.25). The severity of enamel disturbances at Site 3 (1463 m) was not consistent with the low fluoride concentration in drinking water, and was more severe than would be expected from the subjects' normal urinary fluoride values. Location, fluoride in magadi, other elements found in magadi, and malnutrition are variables which may be contributing to the severity of dental enamel disturbances occurring in Site 3. Altitude was a variable which differentiated the locations.

Bantu Tanzanians have a decreased capacity to metabolize omeprazole and mephenytoin in relation to their CYP2C19 genotype.

To investigate the CYP2C19 polymorphism in Tanzanians because this enzyme shows large interindividual differences in activity and metabolizes several drugs of importance in Africa, especially the antimalarial agent chloroguanide (INN, proguanil). Two hundred fifty-one Tanzanian healthy volunteers were phenotyped with respect to CYP2C19 with use of a single oral dose of mephenytoin (n = 106), a single oral dose of omeprazole (n = 207), or both. Sixty-two were phenotyped with both probe drugs. The urinary 0- to 8-hour S/R-mephenytoin ratio and the plasma omeprazole metabolic ratio (MR) (omeprazole/hydroxyomeprazole) 3 hours after drug intake were determined. The genotype was determined by analysis for CYP2C19*1 (wt), CYP2C19*2 (m1), and CYP2C19*3 (m2). Ten subjects with high omeprazole MR were screened for new mutations in the CYP2C19 gene by searching for single-strand conformation polymorphisms (SSCP). Eight subjects were classified as mephenytoin poor metabolizers (7.5%). Only 5 of these were homozygous for mutated alleles. The S/R ratio was skewed to the right (lower CYP2C19 activity) compared with other ethnic groups studied previously. No new mutations were found with polymerase chain reaction (PCR)-SSCP. We found 30 volunteers (14.5%) with an MR > 7, which is the antimode found previously in white subjects and Asian subjects. Of the 251 volunteers genotyped, 3.2% were homozygous for mutated alleles and 66.1% were homozygous for the wild-type allele. The allele frequencies of CYP2C19*1, *2, and *3 were 81.5%, 17.9%, and 0.6%, respectively. The correlation between the S/R-mephenytoin ratio and the omeprazole MR was significant (Spearman r = 0.59; P < .01). Tanzanians have a decreased capacity to metabolize both omeprazole and mephenytoin when their genotype is compared with metabolic capacity and genotype in other previously studied populations. We identified a low frequency of the Asian allele (CYP2C19*3). Although we did not find any new mutations, our results may be consistent with the presence of yet-unidentified mutations of CYP2C19 that causes decreased CYP2C19 activity in the Tanzanian population.

Psychosocial study of epilepsy in Africa

As documented by many authors, the social position of epileptics in many small scale societies of Africa is marginal at best, and is often characterized by rejection, discrimination, even ostracism. Such negative and noxious attitudes toward persons suffering from epilepsy are rooted in traditional beliefs about causes and nature of convulsive disorders and these have parallels in European history. This article focuses on the psychosociocultural aspects and indigenous concepts of epilepsy, on popular attitudes towards, and social status of, sufferers from epilepsy in a Tanzanian tribal population. The authors present a comparative analysis of focus group discussions conducted with epileptics and with matched controls in two isolated communities. In one community (Mahenge) a clinic for epilepsy has been operating for over 36 years, with a public education component during the last four years, whereas in the other community (Ruaha) epileptics have only been sporadically treated in a small mission dispensary and people have had little opportunity to learn about the nature and modern treatment of convulsive disorders. The responses obtained in focus group discussions reflect the significant change in notions about the illness, in the attitude toward and in the social status of epileptics in Mahenge, while the people of Ruaha still regard epilepsy as a typical “African” affliction fraught with supernatural danger and not effectively treatable by modern medicine.

Sexual behaviour patterns and other risk factors for HIV infection in rural Tanzania: a case-control study.

To examine the association between HIV infection and patterns of sexual behaviour and other risk factors in a rural Tanzanian population in a case-control study, nested within a randomized trial of improved sexually transmitted disease treatment. All HIV-positive patients from the baseline survey of the randomized trial were eligible as cases. Cases (n = 338) and controls (a random sample of one in eight HIV-negative persons; n = 1078) were interviewed about risk factors for HIV infection using a structured questionnaire. A significantly higher HIV prevalence was found among men and women not currently employed in farming [men: odds ratio (OR), 2.08; women: OR, 3.65], women who had travelled (OR, 3.27), educated women (OR, 4.51), and widowed/ divorced people compared with those currently married (men: OR, 3.10; women: OR, 3.54). Two spouse-related factors were significantly associated with HIV, even after adjustment for the sexual behaviour of the index case: HIV was more prevalent in men with younger spouses (P = 0.020 for trend) and in women married to men currently employed in manual work, office work or business (OR, 2.20). In women only, blood transfusions were associated with a higher HIV prevalence (OR, 2.40), but only a small population attributable fraction (4%). There was an increased HIV prevalence associated with increasing numbers of injections. Reported number of lifetime sexual partners was significantly associated with HIV infection (women: OR, 7.33 if > or = 10 lifetime partners compared with < or = 1; men: OR, 4.35 for > or = 50 compared with < or = 1). After adjustment for confounders, male circumcision was associated with a lower HIV prevalence (OR, 0.65; P = 0.11). In these rural communities, many HIV infections occur through sexual transmission. Some people are at high risk of HIV infection through large numbers of sex partners, whereas some are at risk through their spouse or regular partner. The role of circumcision in HIV transmission is unclear. Commercial sex seems to play a negligible role in HIV transmission in these communities. Our results confirm marked heterogeneity in HIV risk, indicating the scope for risk reduction strategies.

Biotypes of oral Candida albicans isolates in a Tanzanian child population

Although biotypes of Candida albicans from adult populations, especially in the West, have been described, there are no data either from a child population, or from the African continent. Hence a total of 200 oral C. albicans isolates from Tanzanian children aged 6-24 months were biotyped using two commercially available API micromethod kit systems and a boric acid resistance test. The predominant biotypes, which comprised two thirds of the organisms isolated, were J1S (19.5%), A1S (16.0%), J1R (14.5%), A1R (9.5%) and P1R (7.5%). In total, 16 new biotypes comprising 44 (22%) isolates which have not hitherto been described were found in this Tanzanian population and, of these, the P1R biotype predominated with 15 (7.5%) isolates. There was no significant association between predominant biotypes (with clusters > or = 15 isolates) and age, gender, breast feeding and malnutrition. These data indicate that the biotype profile of C. albicans isolates may differ in paediatric and adult populations, and/or global distribution of various subtypes of this common opportunistic pathogen.

Dental caries in relation to diet, saliva and cariogenic microorganisms in Tanzanians of selected age groups.

The relationship between diet and dental caries in a Tanzanian population was studied. Mutans streptococci, lactobacilli, yeasts, salivary flow rate as well as buffer effect were also analyzed. A random sample of 12-, 35-44- and 65- to 74- year olds was drawn from Msongola (rural) and Ukombozi (urban), Dar-es-Salaam. The mean of two 24-h recalls was used for the assessment of food intake. The percentage of those with at least one carious tooth ranged from 30% in the 12-year-olds to 80% in the oldest age group. The mean number of decayed teeth (DT) increased significantly with age (P = 0.000) but was not significantly associated with the area of residence. DT increased significantly (P = 0.048) with the number of snacks per day and was also associated with dietary sucrose (P = 0.025), total carbohydrates (P = 0.002) and fiber (P = 0.002). Among salivary variables lactobacilli (P = 0.000) correlated positively with DT. Our study did not reveal any strong association between total energy intake and dental caries in rural or urban populations in Tanzania but snacking and sucrose intake were significantly associated with caries, in particular in the urban area.

Thyroid function studies in normal pregnant Tanzanian women.

Iodine deficiency is well known as a cause of several disorders such as endemic goiter and cretinism, along with a wide spectrum of psychoneurologic development disorders including endemic mental deficiency, which are generally correlated with damage to the fetus. Since as much as 40% of the Tanzanian population is at risk for iodine deficiency disorders (IDD) because they live in iodine-deficient areas, and although the effects of iodine deficiency on human reproduction in Tanzania have not been objectively studied, it is estimated that there are approximately 600,000 cretins and cretinoids in the country as a result of IDD. As a baseline study for future research on iodine deficiency and its effects on human reproduction in Tanzania, we assayed serum thyroxine (T4), triiodothyronine (T3), thyrotropin (TSH), and free thyroxine (FT4) in 93 clinically euthyroid pregnant women and 34 nonpregnant women as controls. Pregnancy was accompanied by significantly increased levels of total T3 and T4, decreased FT4, and increased TSH concentration in serum. However, biochemical euthyroidism (assessed by FT4 and basal TSH) was demonstrated in almost all (99%) of the pregnant subjects in conformity with most of the previous findings elsewhere. We conclude that pregnant Tanzanian women residing in areas without iodine deficiency experience changes in biochemical parameters of thyroid function similar to their counterparts in other places.

Bacitracin zinc for intestinal amoebiasis: a dose-response study

This study was performed to establish the efficacy of orally administered bacitracin zinc for asymptomatic and symptomatic intestinal infections with Entamoeba histolytica and to determine a recommended treatment regimen for use in future comparative clinical trials. The drug was assessed in a Tanzanian population during the long rain season of 1990. In symptomatic patients receiving single daily doses of 90,000 to 120,000 U (USP) bacitracin zinc for at least 3 days, signs and symptoms of infection were eradicated. In a limited, parallel-group trial of the effects of 3- and 5-day treatment regimens on asymptomatic infections, the signs of infection were similarly eradicated in all but one patient. When relapses were observed, they occurred more than 1 week after completion of treatment and were therefore indistinguishable from new infections. Thus the results indicate that both 3- and 5-day treatment regimens may be effective; further comparative clinical trials should be performed using the 3-day regimen.

Humoral response to Mycobacterium tuberculosis-specific antigens in African tuberculosis patients with high prevalence of Human immunodeficiency virus infection

Setting: The applicability of serodiagnosis of tuberculosis using Mycobacterium tuberculosis-complex-specific antigens in a Tanzanian population with high prevalence of HIV. Objective: This study was performed to evaluate the usefulness, sensitivity and specificity of serology using M. tuberculosis-specific antigens in the diagnosis of tuberculosis in patients with and without HIV co-infection. Design: Patients with proven pulmonary and extrapulmonary tuberculosis at a major referral centre in Tanzania were enrolled in the study. The control group consisted of patients without a history of previous tuberculosis admitted to the trauma ward and of healthy volunteers. Sera were analysed by an enzyme linked immunoassay (ELISA) using two M. tuberculosis specific proteins as antigen: the 38 kDa protein [3t]and a 17 kDa protein. In addition was recorded presence or absence of BCG scar and tuberculin sensitivity and the sera were tested for HIV and analysed for β-2-microglobulin content. Result: Sensitivity and specificity were markedly reduced in tuberculosis patients with HIV co-infection compared to patients without this disease (73% and 70% versus 52% and 50% respectively). Conclusion: Serology for diagnosis of tuberculosis is not feasible in an HIV endemic region.