Multiple ST clonal complexes, with a predominance of ST131, of Escherichia coli harbouring blaCTX-M-15 in a tertiary hospital in Tanzania.

The molecular epidemiology of 32 non-duplicate, CTX-M-15 extended-spectrum beta-lactamase (ESBL)-producing Escherichia coli strains, isolated from clinical samples, was investigated. Multilocus sequence typing revealed multiple sequence type clonal complexes: ST131 (12), ST405 (4), ST638 (3), ST38 (2), ST827 (2), ST224 (1), ST648 (1), ST46 (1) and two new sequence type clonal complexes (1845 and 1848) in 22 pulsed field gel electrophoresis clusters. The bla(CTX-M-15) gene was located on conjugative IncF plasmids. This is the first report of the worldwide emerging clonal complex ST131 linked to bla(CTX-M-15) in Tanzania and demonstrates the need for constant surveillance in developing countries to prevent the spread of these multiresistant isolates.

Tetanus immunity among pregnant women attending antenatal care in Dar es Salaam, Tanzania.

This study was conducted to investigate immunity to tetanus among pregnant women with verbal histories or documentation of having been vaccinated under the current five-dose tetanus toxoid (TT) schedule. It examined sera from 176 pregnant women attending antenatal care at Muhimbili Medical Centre in Dar es Salaam, Tanzania. Tetanus antitoxin level of 0.1 IU/ml was considered protective. Our findings show that 94.9% of women had tetanus antitoxin > or = 0.1 IU/ml. Multivariate analysis revealed that time after last vaccination, TT doses received and TT vaccination status explained 7.5%, 5.7% and 2.3% of variations in tetanus antitoxin levels respectively. Pregnant women with non-protective levels of tetanus antitoxin (5.1%) pose great risks of neonatal tetanus to their newborns and are also susceptible to maternal tetanus. Proper keeping of TT vaccination records is vitally important to avoid hyper-immunisation.

Immunity to tetanus in male adults in Dar es Salaam, Tanzania.

OBJECTIVE: To determine immunity to tetanus in male blood donors with previous diphtheria-pertussis-tetanus (DPT)/tetanus toxoid (TT) vaccination. DESIGN: A cross sectional study, conducted in September 1999. SETTING: Blood bank, Muhimbili Medical Centre, Dar es Salaam, Tanzania. METHODS: Using an antigen competition ELISA technique, serum tetanus anti-toxin levels in two hundred male blood donors were determined. RESULTS: Vaccination history was absent in 43 (21.5%) blood donors, whereas 60 (30%) and 97 (48.5%) reported childhood DPT and TT vaccination, respectively. Tetanus anti-toxin was undetectable in 47 (23.5%) blood donors and the levels were below that considered protective (> or = 0.1 IU/ml) in 25 (12.5%). Among those with undetectable level, 43 (91.5%) had no vaccination history. Time after last DPT/TT vaccination correlated significantly with tetanus anti-toxin levels (r2=-0.331, p=0.001). In multivariate analysis, TT doses received and time after last vaccination explained 4.8% and 29.4%, respectively, of the variations in tetanus anti-toxin levels. CONCLUSION: Seventy two (36%) male blood donors were susceptible to tetanus and the susceptibility was highest from 48 years. A regular TT booster dose at 10 yearly intervals is recommended to provide adequate and long lasting immunity in male adults. Proper keeping of vaccination records is emphasised.

Affordable CD4+ T cell counts by flow cytometry. II. The use of fixed whole blood in resource-poor settings.

We tested the feasibility and precision of affordable CD4+ T cell counting in resource-poor settings using a recently standardised fixative, TransFix in whole blood (WB) by flow cytometry (FCM). The precision of the assays was established under optimal conditions for single-platform FCM such as the volumetric CytoronAbsolute and the bead-based FACSCan. Fresh WB samples from HIV-seropositive and seronegative patients were tested in Tanzania and South Africa, fixed and sent to the UK for reanalysis 7 days later. Correlation, bias and limits of agreements were analysed by linear regression and the Bland-Altman test. Absolute CD4+ T cell counts remained stable for at least 10 days when TransFix was added to WB in 1:10 dilution at 20-25 degrees C, and for 7 days when added in 1:10 or 1:5 dilution to samples stored to mimic 'tropical' conditions at 37 degrees C. Higher temperatures such as 42 degrees C were tolerated for only short periods since the recovery had decreased to 63% by day 3. The reproducibility of lymphocyte subset analysis remained unchanged by TransFix with coefficient of variations <6% for all T cell subsets. Absolute CD4+ T cell counts and CD4+ T cell % values on fixed samples in the UK showed a high correlation with the results using fresh samples in Tanzania (r=0.993 and 0.969, respectively) and with the samples handled in Johannesburg (r=0.991 and 0.981) with minimal bias. Primary CD4 gating using only a single CD4 antibody also remained accurate in TransFixed samples (r=0.999). Thus, TransFix permits optimal fixation and transport of WB samples in the developing world for FCM to local regional laboratories and for quality assurance in international centres. When used together with inexpensive primary CD4 gating, TransFix will allow reliable and affordable CD4+ T cell counting by FCM in resource-poor settings.

Antibodies to tetanus toxoid in women of childbearing age in Dar es Salaam and Bagamoyo, Tanzania.

Our aim was to determine tetanus immunity in women of childbearing age (15-44 years) with histories and/or documentation of having been vaccinated with Tetanus Toxoid (TT) under the Expanded Programme on Immunization in Dar es Salaam and Bagamoyo, Tanzania. Using an ELISA technique, serum levels of TT antibody, antibody avidity and distribution of TT IgG subclass antibodies were determined in 207 apparently healthy women. A TT antibody level of 0.1 IU/ml was considered protective. 99% and 100% of women in Dar es Salaam and Bagamoyo, respectively, had a TT antibody level > or = 0.1 IU/ml. Anti-toxin binding avidity was found to be high in most of the women. In addition to TT IgG3 subclass antibody, TT IgG1 subclass antibody was the most dominant subclass type. A substantial number of women also had TT IgG2 and TT IgG4 subclass antibody responses. A better recording system on TT immunization is recommended to avoid hyper-immunization of women and to optimize the cost-effectiveness of the immunization programme.

Risk factors for HIV-1 seroprevalence among family planning clients in Dar es Salaam, Tanzania.

Between March and September of 1995, women receiving family planning (FP) services in three large clinics in Dar es Salaam, Tanzania were invited to participate in a cross-sectional study. Consenting women were interviewed to obtain information about HIV risk factors, and blood for HIV testing was collected. The prevalence of HIV was 16.9% (95% CI: 14.4%-19.3%). The risk of HIV increased significantly with age. Compared with married women, the risk of HIV was significantly higher among cohabiting women (age-adjusted OR = 2.3; 95% CI = 1.5-3.5) and among women who were single, divorced or widowed (age-adjusted OR = 2.3; 95% CI = 1.2-4.4). The risk of HIV was also significantly higher among hotel workers (age-adjusted OR = 4.3; 95% CI = 1.4-12.9). Women with laboratory evidence of sexually transmitted diseases were at increased risk of HIV. This study shows that HIV is a major public health problem among FP clients in Tanzania. Innovative HIV interventions are needed to reduce further spread of HIV infection.

Levels and avidity of antibodies to tetanus toxoid in children aged 1-15 years in Dar es Salaam and Bagamoyo, Tanzania.

A study was undertaken to determine the serological response in children (aged 1-15 years) immunized with diphtheria-pertussis-tetanus vaccine (DPT) alone or with a tetanus toxoid (TT) booster dose under the Expanded Programme on Immunization in Dar es Salaam and Bagamoyo, Tanzania. Using an ELISA technique, serum levels of anti-TT antibody, antibody avidity and anti-TT IgG subclasses were determined in 138 apparently healthy children. Our findings revealed that 94.7% and 98% of children aged 1-5 years in Dar es Salaam and Bagamoyo, respectively, had anti-TT antibody levels above that considered protective (> or = 0.1 IU/ml). Among 6-15-year-old children, 53.3% in Dar es Salaam and 55% in Bagamoyo had anti-TT antibody levels > or = 0.1 IU/ml. The avidity index of anti-TT antibodies was high in most of the younger children, 84.2% in Dar es Salaam and 92% in Bagamoyo. Significantly fewer older children in Dar es Salaam and Bagamoyo (53.3% and 50%, respectively) had high avidity index antibodies. The predominant anti-TT IgG subclasses were IgG1 and IgG3. It is concluded that the current DPT immunization schedule provides adequate tetanus immunity for children under 5. However, about half of the older children had no protection against tetanus.

Immunoglobulin profile in HIV-1 infected children in Dar es Salaam.

OBJECTIVE: To determine immunoglobulin levels in HIV-1 seronegative and HIV-1 seropositive children at different clinical stages of HIV infection. DESIGN: Cross-sectional study. SETTING: Lugalo and Mwanayamala mother and child clinics in Dar es Salaam. SUBJECTS: Two hundred and ninety-nine children aged 18 months to five years. MAIN OUTCOME MEASURES: Estimation of immunoglobulin classes (IgG, IgA, IgM, IgD and IgE). RESULTS: Mean serum levels of all immunoglobulin classes were significantly higher (p < 0.0001) among the HIV-1 seropositive children (IgG = 22.9 g/l, IgA = 2.2 g/l, IgM 2.7 g/l, IgD 101.5 IU/ml and IgE 887.7 IU/ml) than among the HIV-1 seronegative children (IgG = 11.3 g/l, IgA = 1.0 g/l, IgM = 1.5 g/l, IgD = 27.8 UI/ml and IgE 341.3 UI/ml). The percentages of HIV-infected children with immunoglobulin concentrations above mean level were 83% for IgG, 77% for IgA, 78% for IgM, 73% for IgD and 78% for IgE. CONCLUSION: HIV seropositive children have higher levels of immunoglobulin than seronegative children. There was no correlation between the levels of immunoglobulin classes and CDC clinical staging.

PIP: This cross-sectional analysis examined serum levels of the 5 immunoglobulin (Ig) isotypes in HIV-1 seronegative and HIV-1 seropositive children at different clinical stages of HIV infection in Dar es Salaam, Tanzania. The study employed 299 children between 18 months and 5 years of age attending the mother and child health clinics at Lugalo and Mwanayamala. Blood samples from 150 HIV-1 seropositive (75 males and 75 females) and 149 HIV-1 seronegative (82 males and 67 females) were collected and examined via Ig assay and HIV serology. Results revealed that the mean serum Ig levels were higher (p 0.0001) among HIV-1 seropositive children (IgG = 22.9 g/l, IgA = 2.2 g/l, IgM = 2.7 g/l, IgD = 101.5 IU/ml, IgE = 887.7 IU/ml) than among HIV-1 seronegative children (IgG = 11.3 g/l, IgA = 1.0 g/l, IgM = 1.5 g/l, IgD = 27.8 IU/ml, IgE = 341.3 IU/ml). The percentage of Ig concentrations were significantly higher in the HIV-1 seropositive than in the HIV-1 seronegative children (83% for IgG, 77% for IgA, 78% for IgM, 73% for IgD, and 78% for IgE). In conclusion, this study confirms the increase in serum Ig levels in HIV-1 seropositive children and the insignificant correlation between high Ig levels and US Centers for Disease Control clinical staging.

Prevalence of transfusion-associated viral infections and syphilis among blood donors in Muhimbili Medical Centre, Dar es Salaam, Tanzania.

OBJECTIVE: To determine the seroprevalence of the main transfusion-associated viral infections and syphilis among blood donors in Muhimbili Medical Centre, Dar es salaam, Tanzania. DESIGN: Cross sectional study. SETTING: The blood bank unit of Muhimbili Medical Centre in Dar es salaam, Tanzania. SUBJECTS: A consecutive sample of 300 blood donors. INVESTIGATIONS: Search for the presence of antibodies to: human immunodeficiency virus (anti-HIV), hepatitis C virus (anti-HCV), hepatitis B surface antigen (anti-HBs), human T-lymphotropic virus type 1 (anti-HTLV-1), syphilis and for hepatitis B surface antigen (HbsAg). RESULTS: The overall frequency of anti-HIV, anti-HCV, anti-HBs, HbsAg, anti-HTLV-1, and syphilis antibodies were 8.7%, 8%, 20%, 11%, 0%, and 12.7%, respectively. Among the HIV seronegative donors, the frequency of anti-HCV, anti-HBs, HBsAg, anti-HTLV-1, and syphilis antibodies were 8.8%, 22%, 11%, 0%, and 10.9%, respectively. HIV-seropositive donors had an increased risk for being positive for syphilis antibodies (OR = 3.6, 95% CI 1.4-9.0) and HBsAg (OR = 4.0, 95% CI 1.0-18.8), but not anti-HCV (OR = 0.9, 95% CI 0.86-0.97), anti-HBs (OR = 1.0, 95% CI 0.2-5.3) or anti-HTLV-1 (OR = 0.0). CONCLUSION: Donor blood including that from HIV-seronegative donors, has high frequency of HCV, HBV, and syphilis antibodies but not anti-HTLV-1. A significant association exists in the occurrence of HIV, HBV and syphilis; and due to the association of syphilis and HIV, clients with history of sexually transmitted disease should be excluded during donor selection. From these observations were recommend: (i) routine screening of donor blood for HIV, HCV, HBV, and syphilis antibodies but not HTLV-1 and; (ii) a larger study to generate more accurate estimates of the magnitude the transfusion-transmissible infectious diseases.

Serum levels of measles IgG antibody activity in children under 5 years in Dar-es-Salaam, Tanzania.

Measles IgG antibody levels were estimated in sera from 685 Tanzanian children, 374 (54.6%) boys and 311 (45.4%) girls aged 18 months to 5 years, using an enzyme-linked immunosorbent assay (ELISA). The children were screened for HIV-1 and 2 antibodies using ELISA, and reactive sera were confirmed by Western blot. Nutritional status was assessed by anthropometry. Overall measles vaccination coverage was 98.8%. Measles antibody activity was not detected in 41 (6.0%) children, and ten (1.5%) had antibody levels below 200 mIU/ml, the cut-off level considered to be protective. The non-reactive samples were from one unvaccinated child, one child with unknown vaccination status and 39 vaccinated children. Measles IgG antibody levels were higher in girls (3452.1 mIU/ml) than in boys (2928.2 mIU/ml) (p = 0.02). Higher mean levels were found in children with a history of low birthweight (< 2.5 kg) (p = 0.03). There were no significant differences in measles antibody levels with regard to variations in nutritional status. No correlation (r2 = 0.002) was found between antibody levels and time elapsed since vaccination. In a multivariable logistic regression analysis, children who were HIV-seropositive (n = 9) were more likely to have non-protective antibody levels < 200 mIU/ml (OR = 5.85; 95% CI: 1.37-24.93).

The incidence of HIV infection among women using family planning methods in Dar es Salaam, Tanzania.

OBJECTIVES: To determine the risk factors for HIV seroconversion and assess the association between contraceptive use and HIV infection among women attending three large family planning clinics in Dar es Salaam, Tanzania. DESIGN: Prospective cohort study. METHODS: Between 1992 and 1995, 2471 HIV-negative women were followed prospectively. Information about sociodemographic characteristics, sexual behavior, contraceptive use and other risk factors was collected at recruitment and updated at follow-up visits. At the end of the study, specimens were collected for HIV testing and laboratory diagnosis of sexually transmitted diseases. RESULTS: The overall HIV incidence was 3.4 per 100 person-years [95% confidence interval (Cl), 2.6-4.1]. The risk of HIV seroconversion decreased with increasing age (P=0.04, test for trend). Women reporting three or more sex partners during the follow-up period had the highest risk of HIV [age-adjusted relative risk (RR), 4.89; 95% Cl, 2.61-9.17]. Having an uncircumcised husband was associated with a significantly increased risk of HIV (age-adjusted RR, 3.60; 95% Cl, 1.12-11.59). The risk of HIV was also significantly increased among women with gonorrhoea (age-adjusted RR, 3.51; 95% Cl, 1.60-7.71) and candidiasis at baseline (age-adjusted RR, 1.98; 95% Cl, 1.17-3.33) and among women reporting alcohol consumption during the follow-up period. After controlling for other risk factors, the risk of HIV infection amongst users of oral contraceptive, intrauterine device and injectable contraceptive was not significantly increased. Similarly, there was no significant trend associated with increasing duration of use of any of these contraceptive methods. CONCLUSION: These findings confirm that a large number of new HIV infections continue to occur in this population. Reassuringly, no significant association was observed between HIV and use of specific contraceptive methods. Interventions to reduce further spread of HIV are still urgently needed.

Evaluation of sexually transmitted diseases diagnostic algorithms among family planning clients in Dar es Salaam, Tanzania.

OBJECTIVES: To determine the prevalence of sexually transmitted diseases (STDs) and to assess the validity of STD screening approaches among family planning clients in Dar es Salaam, Tanzania. METHODS: Between March and September 1995, information about sociodemographic characteristics, contraceptive use, sexual behaviour, and medical history was obtained from consenting women (n = 908). After interview, blood and genital specimens were collected for diagnosis of STDs and HIV. Based on the information obtained at interview and clinical examination, STD diagnostic algorithms were developed and validated. RESULTS: The prevalence of STDs was HIV (16.9%), gonococcal and/or chlamydial cervicitis (8.2%), and Trichomonas vaginalis and/or Candida albicans (27.2%). The risk of cervicitis was increased among unmarried women and among women with a husband < or = 25 years of age and women having more than one sex partners in the past 3 months or a new sex partner during the past month. Most women with cervicitis (62.2%) and vaginitis (67.6%) were asymptomatic. A screening strategy for cervicitis based on symptoms had a sensitivity of 29.7%, a specificity of 84.1%, and a positive predictive value (PPV) of 15.9%. The corresponding figures for an algorithm based on clinical signs were 20.3%, 90.2%, and 15.6%. The sensitivity of a simple risk assessment algorithm ranged from 20.3% to 73%. An approach based on both risk assessment (risk score > or = 1) and clinical signs (cervical mucopus and friability) had a sensitivity of 37.8%, a specificity of 87.5%, and a PPV of 21.4%. A syndromic approach for vaginitis resulted in a higher sensitivity than the approach based on the type of vaginal discharge. CONCLUSION: Although there is no single screening strategy for cervicitis which can be advocated for large scale application, risk assessment might be the only cost effective strategy for identifying women with cervicitis in family planning clinics in Tanzania.

Association between carriage of oral yeasts, malnutrition and HIV-1 infection among Tanzanian children aged 18 months to 5 years.

The objective was to determine whether there is an association between carriage of oral yeasts, malnutrition and HIV-1 infection among Tanzanian children. A case-control study design within a cross-sectional study was used, and the outcome was carriage of oral yeasts. The exposure variables were malnutrition and HIV-1 antibody, and confounders to be adjusted for were age, sex, and breastfeeding. The study was carried out in Dar-es-Salaam, Tanzania, in two maternal and child health (MCH) clinics that offer routine medical checkups to all expectant mothers and children aged between 0 and 5 years in the catchment area. A total of 882 children aged between 18 months and 5 years participated. Smears from the tongue and buccal mucosa were examined for oral yeasts. Malnutrition was categorized according to standards on the MCH chart and World Health Organization/Centers for Disease Control (WHO/CDC) standards as weight-for-height (wasted), weight-for-age (underweight), and height-for-age (stunted). HIV-1 infection was determined by an enzyme-linked immunosorbent assay. Reactive sera were confirmed by Western Blot. About 27% of the children were slightly or severely malnourished according to standards on the MCH chart. According to WHO/CDC standards, 2.6% were wasted, 16.3% were underweight, and 29.6% were stunted. Fourteen (1.6%) were seropositive for HIV-1 antibody. Hyphal forms and blastospores were much more frequent among children infected with HIV-1 with odds ratios ranging from 3.8 (95% CI: 1.3;11.2) to 6.2 (95% CI: 2.1;18.4) depending on categorization of malnutrition. Malnutrition was a risk factor, too, albeit to a much lesser and insignificant degree. The study supports our previous findings that malnutrition may predispose to carriage of oral yeasts and subsequent infection. However, in this study population HIV infection was clearly the predominant risk factor.

PIP: The association between carriage of oral yeasts, malnutrition, and HIV-1 infection was investigated in a case-control study involving 403 girls and 479 boys 18 months-5 years of age attending 2 maternal-child health clinics in Dar-es-Salaam, Tanzania, in a 4-month period in 1994. The children designated as cases had Candida-like microorganisms on smears from the tongue and buccal mucosa. 14 children (1.6%) were HIV-positive; 11 of these children were under 3 years of age. 241 (27%) were moderately or severely malnourished. 20.0% had hyphal forms and 17.5% had blastospores. Presence of HIV infection was the most significant risk factor for hyphal forms or blastospores consistent with Candida-like microorganisms (unadjusted odds ratios, 5.5 and 3.8, respectively). Although malnutrition was also a risk factor for oral yeasts, the association was not significant. The study findings suggest that malnutrition may predispose to carriage of oral yeasts and subsequent infection. The rates of oral yeasts detected among these children were lower than expected and may reflect a reduced secretion of stimulated whole saliva associated with malnutrition and HIV infection.

Nutritional status of under fives attending maternal and child health clinics in Dar es Salaam, Tanzania.

We designed a study to assess the nutritional status of children under five years of age attending MCH clinics in Dar es Salaam. This was a cross-sectional anthropometric study involving children 6-24 months who from July to August 1993 were attending Magomeni MCH clinic and those aged 18 months to five years who were attending Lugalo and Mwananyamala MCH clinics for routine growth monitoring and for vaccination between May to August 1994. The data collected included age, birthweight, sex, weight, height, breastfeeding status and HIV-1 serostatus. Of the 1854 children enrolled (961 boys and 893 girls) 31.6% were stunted, 14.6% were underweight and 2.9% were wasted. The highest percentage of stunting and wasting was observed between 11 and 25 months and 36 to 40 months. Of the 849 children tested for HIV-1, 14 (1.7%) were seropositive and two out of 770 (0.3%) were born with low weight. HIV seropositivity and low birthweight were both associated with stunting and wasting. We conclude that malnutrition is still a sizeable problem among children attending urban MCH clinics in Dar es Salaam especially among those aged less than three years, to whom special malnutrition control strategies should be targeted. There is also a need to identify factors responsible for the observed decline in MCH attendance with age and correct the situation.

PIP: The nutritional status of 1854 children under 5 years of age attending 3 maternal-child health clinics in Dar es Salaam, Tanzania, was assessed in an anthropometric study conducted in 1993-94. Clinic attendance declined markedly after 2 years of age. Overall, 31.6% of children were stunted, 14.6% were underweight, and 2.9% were wasted, with higher prevalences among girls. The highest percentage of stunting and wasting was observed among children in the 11-25 and 36-40 month age groups. Peak stunting and wasting occurred at 12 months for girls and 18 months for boys; the decline from peak was faster among boys than girls. Of the 849 children tested for HIV, 14 (1.7%) were seropositive. Both HIV seropositivity and low birth weight were associated with stunting and wasting (odds ratios, 2.8 and 3.61, respectively); breast feeding was protective against stunting and wasting (odds ratio, 0.8). These findings confirm malnutrition continues to be a major problem among small children in Dar es Salaam and suggest a need for special malnutrition control interventions that target this population.

Immunohaematological findings in healthy and HIV-1 infected adults in Dar es Salaam, Tanzania.

In order to assess the prognostic value of lymphocyte subsets and immune activation markers in HIV-1 infected Tanzanian patients, peripheral white blood cell(WBC) count, total lymphocytes, CD4+ and CD8+ T-lymphocytes and Beta-2 microglobulin (B-2M) concentrations were determined among healthy HIV-1 seronegative Tanzanian blood donors and in infected Tanzania individuals in different clinical stages of HIV-1 infection. CD4+ T-lymphocytes, CD8+ T-lymphocyte percentages, CD4:CD8 lymphocyte ratios and the concentrations of B-2M were strongly correlated with the clinical stages of HIV-1 infection. These results suggest that B-2M could be a useful prognostic marker in HIV-1 infection in settings where T-lymphocyte subset determinations cannot be done.

PIP: Lymphocyte subsets and concentrations of beta-2 microglobulin (B2M) were determined among 119 HIV-1 seronegative and 183 HIV-1 seropositive individuals at Muhimbili Medical Center (MMC) to assess their prognostic value in HIV-1 infected Tanzanian patients. The HIV-negative individuals were blood donors at MMC, while the HIV-positive participants were blood donors, patients admitted to one medical ward, and those seen at MMC's outpatient clinic who were found to be HIV-positive during the study period. HIV-negative blood donors were of mean age 28.8 years and patients were of mean age 33.5. The measurement of peripheral white blood cell (WBC) count, total lymphocytes, CD4 and CD8 T-lymphocytes, and B2M concentrations found CD4 T-lymphocytes, CD8 T-lymphocyte percentages, CD4:CD8 lymphocyte ratios, and the concentrations of B2M to be strongly correlated with the clinical stages of HIV-1 infection. These findings suggest that B2M could be a useful prognostic marker in HIV-1 infection in settings where T-lymphocyte subset determinations cannot be made.

Evaluation of the FACScount, TRAx CD4 and Dynabeads methods for CD4 lymphocyte determination.

A study to evaluate the performance of the FACScount, TRAx CD4 and Dynabeads methods for the determination of CD4+ T lymphocyte subset levels was conducted in Tanzania as part of a World Health Organization (WHO) collaborative multicenter field evaluation of alternative methodologies for the enumeration of CD4+ T lymphocytes. The objective was to compare the performance of these alternative methods in a developing country setting, against that of flow cytometry as the reference standard. T lymphocyte subset levels were determined in 91 HIV seronegative and 98 HIV-1 seropositive adults using the three alternative methods. CD4+ and CD8+ T lymphocyte counts were determined by all methods except for TRAx CD4 enzyme linked immunosorbent assay (ELISA) which measures CD4+ T lymphocyte levels only. Linear regression analysis was done to correlate the counts obtained by the alternative methods to those obtained by flow cytometry. The overall correlation coefficients of FACScount and Dynabeads CD4+ and CD8+ T lymphocyte counts with those of flow cytometry were high (r > 0.9). A lower correlation (r = 0.631) was obtained when TRAx CD4+ ELISA counts were compared to those of the reference method. These results show that two of these alternative methodologies are suitable for the determination of CD4+ and CD8+ T lymphocyte counts with the use of African blood samples. Since the methods are simpler and cheaper than flow cytometry, they provide an alternative option for the enumeration of T lymphocyte subsets in laboratories with limited facilities.

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.

Detection of anti-HIV-1 IgG antibodies in whole saliva by GACELISA and Western blot assays.

The present study, based on 158 HIV seropositives and 167 HIV seronegatives, demonstrates that saliva collected with the Omni-SAL device and tested with GACELISA (an IgG antibody capture ELISA) is an effective non-invasive alternative to serum for anti-HIV IgG antibody screening. The study also shows that a conventional serum Western blot kit can be used, with slight modifications, for confirmatory testing of saliva specimens. Collecting saliva with the Omni-SAL device had a very good acceptance rate among Tanzanian subjects, and although this diagnostic method is not yet known by the general public, 65% of the study participants preferred to give saliva instead of blood for HIV testing.

PIP: In Dar es Salaam, Tanzania, health workers at Muhimbili Medical Centre collected serum and saliva samples from 135 HIV-positive persons attending the AIDS Clinical Trial Clinic, 130 people who came for voluntary HIV testing, and 60 hospital patients. Researchers aimed to assess the suitability of the Omni-SAL device in collecting saliva and the sensitivity, specificity, and feasibility of detecting HIV-1 IgG antibodies in saliva using GACELISA (an IgG capture ELISA) and Western blot assays. Laboratory personnel optimized Western blot for confirmatory testing of saliva specimens by using a biotin/avidin detection as suggested by McMahan and Hofman. All 135 patients attending the AIDS Clinical Trial Clinic, 8 (6.15%) people undergoing voluntary HIV testing, and 15 (25%) of hospital patients tested positive for HIV (total = 158). GACELISA detected all HIV-1 seropositive individuals and did not detect HIV-1 in any of the HIV-1 seronegative individuals (sensitivity 100%; specificity 100%). The saliva optical density to cut-off value for the HIV-1 seropositives was 5.26-9.82, indicating no ambiguity in the results. All saliva specimens on GACELISA reacted strongly to HIV-1 viral proteins Env, Pol, and Gag on the Western blot optimized for testing saliva specimens. It took more than 10 minutes to saturate the collecting pad (Omni-SAL) in 2% of individuals. Saturation of the collecting pad took less than 3 minutes in most cases (64%). Most individuals preferred saliva to be collected for HIV testing than serum and urine (65% vs. 23% and 12%, respectively). 96% of all individuals thought the Omni-SAL device to be easy. These findings suggest that saliva is an adequate specimen for screening and diagnosis of HIV infection. Since many saliva samples can be collected quickly, easily, and safely, Omni-SAL and GACELISA can be done under any field situation by people with minimal training.

Clinical predictors of HIV-1 infection among preschool children in Dar es Salaam, Tanzania.

Seroprevalence of HIV-1 infection was determined in children aged between eighteen months and five years, attending maternal and child health (MCH) clinics in Dar es Salaam, Tanzania. A total of 889 children were eligible for the study, however seven children could not be enrolled because their mothers/guardians absconded and blood could not be drawn from 21 children due to refusal of mothers/guardians and from another 12 children due to technical reasons. Therefore, the participation rate was 95.5%. Of the 849 children screened, 14 (1.65%) were found to have IgG anti HIV-1 antibodies in their sera. The main clinical features found in children with symptomatic HIV-1 disease were weight loss, generalized lymphadenopathy, recurrent fevers, and prolonged diarrhoea. The utility of clinical features suggestive of HIV-1 infection (according to CDC classification) in identifying HIV-1 infection in children was evaluated and found to have high sensitivity (100%), specificity (96.9%) and negative predictive value (100%), but a low positive predictive value (35%). Marked variations in progression to symptomatic phase were noted, whereby some relatively young children had progressed to symptomatic phase (CDC class P-2A), while some older children were still in the asymptomatic stage (CDC class P-1 C). None of the symptomatic HIV-1 infected children presented with neurological disease, severe opportunistic infections, or malignancies. Although reduced mid-upper arm circumference and weight-for-age were associated with HIV seropositivity, these clinical parameters had low positive predictive values compared to the CDC classification.

PIP: Serologic testing of 849 children 18 months-5 years of age attending the Lugalo and Mwananyamala maternal-child health clinics in Dar es Salaam, Tanzania, during May-August 1994 identified 14 cases (1.65%) of HIV infection. The sample represented 95.5% of children making mandatory monthly clinic visits during the 3-month study period. The main clinical symptoms in HIV-infected children were weight loss, generalized lymphadenopathy, recurrent fever, and prolonged diarrhea, all included in the Centers for Disease Control and Prevention (CDC) classification scheme. Children with symptomatic HIV infection were younger than those with asymptomatic infection. None of the children with symptomatic HIV infection presented with neurologic impairment, severe opportunistic infections, or cancers. The clinical features included in the CDC classification for HIV had a 100% sensitivity, a 96.9% specificity, and a 100% negative predictive value, but the positive predictive value was only 35%. Although the model with the best fit included mid-upper arm circumference less than 14 cm and a reduced weight-for-age (odds ratios, 3.8 and 1.9, respectively), the positive predictive values for these two factors were only 4.3% and 4.1%, respectively. The 1.65% HIV seroprevalence rate recorded in this community-based study is lower than the 2.4% rate estimated among newborns in Dar es Salaam, presumably because of high infant mortality and hospitalization among HIV-infected newborns. Use of a simplified version of the CDC classification of HIV infection in children is recommended for routine clinical use in Tanzania.