Lymphocyte subset enumeration in HIV seronegative and HIV-1 seropositive adults in Dar es Salaam, Tanzania: determination of reference values in males and females and comparison of two flow cytometric methods.

The level of CD4(+) T-lymphocytes represents a useful marker with which to monitor the progression of HIV infection. Sex and geographical differences in the reference values of lymphocyte subsets have been reported. We have compared two flow cytometric methods (MultiSET and SimulSET) for the quantification of lymphocyte subsets using whole blood from 92 HIV seropositive and 241 seronegative adults, and determined the reference values of lymphocyte subsets in HIV seronegative Tanzanian subjects. In seronegative Tanzanian subjects, the percentages of CD3(+) and CD4(+) T-lymphocytes and the CD4(+):CD8(+) T-lymphocyte ratios were lower while the percentage of natural killer cells was higher compared to the levels of the corresponding parameters reported for Europeans. Seronegative Tanzanian females had significantly higher levels of CD3(+) and CD4(+) T-lymphocytes and CD4(+):CD8(+) T-lymphocyte ratios compared to seronegative males. The correlation coefficients of CD3(+), CD4(+) and CD8(+) T lymphocyte counts and percentages obtained by the two flow cytometric methods were high. The median values of the number of CD4(+) T-lymphocytes obtained by the two methods were not significantly different. In conclusion, determination of the reference values of lymphocyte subsets in HIV seronegative Tanzanian adults showed significant sex differences and differences in percentage values compared to those reported in certain other geographical areas. There was acceptable agreement in the levels of CD4(+) T-lymphocyte values obtained by the two flow cytometric methods.

Monitoring of HIV-1 infection prevalence and trends in the general population using pregnant women as a sentinel population: 9 years experience from the Kagera region of Tanzania.

In the Kagera region of Tanzania, a population-based study was initiated in 1987 followed by the establishment of antenatal-clinic-based sentinel surveillance system in the town of Bukoba in 1990. Repeat studies in both populations in Bukoba in 1993 and 1996 made it possible to study the dynamics of HIV infection prevalence and incidence in the area. This study aims at comparing the findings from this sentinel surveillance system with those of cross-sectional studies in the general population to assess its validity in estimating HIV prevalence and their trends in the general population. A multistage cluster sampling technique was used in the population-based studies whereas the antenatal-clinic-based population was obtained by consecutively recruiting antenatal care attenders coming for the first time during a given pregnancy. Antibodies against HIV infection were tested using two independent enzyme-linked immunosorbent assay (ELISA) antibody detection tests. Unlinked anonymous testing strategy was adopted for the sentinel population. Age-adjusted prevalence among antenatal care attenders decreased from 22.4% (95% confidence interval [CI], 20.6-25.2) in 1990 to 16.1% (95% CI, 15.9-18.8) in 1993 and further to 13.7% (95% CI, 11.8-14.3) in 1996. These results closely resemble those of the general population of adult women in the clinic's catchment area (the town of Bukoba) where the age-adjusted prevalence of 29.1% (95% CI, 24.4-34.6) in 1987 showed a decrease in the studies in 1993 18.7% (95% CI, 15.1-23.0) and in 1996 14.9% (95% CI, 12.0-17.1). The study indicates that general population trend estimates can be generated using sentinel surveillance data based on pregnant women visiting an antenatal clinic for the first time during a given pregnancy. The benefits of using this group outweigh its limitations that are brought about by possible selection bias. Continued surveillance of the epidemic based on antenatal care patients as a sentinel population is therefore recommended.

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.

Decline in the prevalence of HIV-1 infection in young women in the Kagera region of Tanzania.

In northwestern Tanzania, a population-based survey of HIV-1 infection in the Kagera region in 1987 demonstrated a high prevalence (24.2%) in adults of Bukoba town, whereas it was lower (10.0%) in the surrounding rural district of Bukoba. In 1993 and 1996, population-based cross-sectional studies were carried out in urban and rural Bukoba districts, respectively, to monitor the time trend in the prevalence of HIV-1 infection in the region. In both studies, a multistage cluster sampling technique was adopted in selecting study individuals. Consenting individuals between 15 and 54 years of age were interviewed using a structured questionnaire. Following individual counseling, blood samples were drawn and tested for HIV infection using enzyme-linked immunosorbent assay (ELISA) antibody detection tests. The overall age-adjusted HIV-1 seroprevalence in urban Bukoba decreased from 24.2% (134 of 553) in 1987 to 18.3% (118 of 653) in 1993 (p = .008). The age-adjusted gender-specific prevalence declined significantly in women, from 29.1% (95 of 325) to 18.7% (74 of 395; p = .0009). Except for men > or = 35 years of age, whose prevalence appeared to have an upward trend between the two studies, all other age groups in both genders had a downward trend; this finding was most significant in women between 15 and 24 years of age (from 27.6% to 11.2%; p = .0004). For the rural population, the overall prevalence decreased from 10.0% (54 of 538) in 1987 to 6.8% (118 of 1728) in 1996 (p = .01). Except for rural women between 15 and 24 years of age whose prevalence decreased from 9.7% (12 of 124) to 3.1% (12 of 383; p = .002), other age groups in the rural populations showed no change in prevalence. Ongoing interventions in this area leading to behavioral change may have contributed to this observation. An incidence study is under way to confirm this observation and to investigate the factors that are responsible for the decline in the HIV-1 prevalence.

PIP: A population-based survey of HIV-1 infection conducted in northwestern Tanzania's Kagera region in 1987 identified a 24.2% HIV prevalence among adults in Bukoba town and a prevalence of 10.0% in the surrounding rural district. In response to these findings, various interventions and community support activities (e.g., IEC, condom distribution, spiritual counseling, home-based care for AIDS patients, and the supply of safe blood for transfusion) were initiated. Additional population-based cross-sectional studies were conducted in the region in 1993 (urban population) and 1996 (rural population) to assess HIV prevalence trends over time. The overall age-adjusted HIV-1 seroprevalence among adults in urban Bukoba decreased from 24.2% in 1987 to 18.3% in 1993; most significant was the decline among women, from 29.1% in 1987 to 18.7% in 1993. With the exception of men 35 years of age and above, whose prevalence showed an upward trend between studies, all other age groups and both genders had a downward trend; this trend was most significant among women 15-24 years of age (from 27.6% to 11.2%). For the rural population, overall HIV-1 seroprevalence declined from 10.0% in 1987 to 6.8% in 1996. With the exception of rural women 15-24 years of age, whose prevalence decreased from 9.7% to 3.1%, other age groups showed no significant change in prevalence. An incidence study is underway to confirm these trends and identify the specific interventions responsible for the decline in HIV-1 prevalence.

Late postnatal transmission of human immunodeficiency virus type 1 infection from mothers to infants in Dar es Salaam, Tanzania.

OBJECTIVE: To study late postnatal transmission of human immunodeficiency virus type 1 in a cohort of children born to HIV-1-seropositive mothers who delivered at Muhimbili Medical Centre in Dar es Salaam, Tanzania. MATERIALS AND METHODS: Since 1991 a prospective cohort study of mother-to-child transmission of HIV-1 has been conducted at Muhimbili Medical Centre in Dar es Salaam. HIV-1-seropositive mothers and age-matched seronegative controls were recruited into the cohort at delivery together with their newborns. Diagnosis of HIV-1 infection in children was based on polymerase chain reaction, HIV-1 p24 antigen tests and HIV antibody tests. Late postnatal transmission was defined as HIV-1 infection occurring after 6 months of age in a child who was uninfected at 6 months of age and who had an HIV-1-seropositive mother. Children born to HIV-seronegative mothers were used as controls. Breast-feeding was universal in this cohort. CD4 and CD8 T lymphocytes were assayed by flow cytometry in the mothers. RESULTS: Among 139 children born to HIV-1-seropositive mothers and known to be HIV-uninfected at 6 months of age, 8 children became HIV-1-infected at the end of their first year of life or later. No conversions were observed in children younger than 11 months. The 8 conversions were observed during a follow-up covering 1555 child months between 6 and 27 months of age corresponding to a conversion rate of 6.2 per 100 child years. Among 260 children with HIV-seronegative mothers no child became HIV-infected during the follow-up. The percentage of CD4 T lymphocytes was similar in mothers with early and late transmission but was significantly lower in transmitting than in nontransmitting mothers. CONCLUSION: Because no HIV-1 infection occurred in children with HIV-seronegative mothers, we conclude that the observed infections at the end of the first year of life or later among children born to HIV-seropositive women were caused by late transmission from mother to child, most likely through breast-feeding.

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.

Scarring trachoma is associated with polymorphism in the tumor necrosis factor alpha (TNF-alpha) gene promoter and with elevated TNF-alpha levels in tear fluid.

Tumor necrosis factor alpha (TNF-alpha) may play a central role in the disease pathogenesis which occurs as a consequence of chlamydial infection. To investigate the importance of TNF-alpha gene promoter polymorphisms and TNF-alpha levels in tear fluid in scarring trachoma, a large matched-pair case-control study was performed in The Gambia. The -308A allele was present in a higher proportion of patients (28.4%) than controls (18.4%), with an increasing association for homozygotes (chi2 for trend, P = 0.032; allele frequency, 0.163 in patients and 0.099 in controls; chi2, P = 0.025). For the -238A allele, the association was similar but not significant. The disease association was highly significant when the number of either -308A or -238A sites in an individual was considered (P = 0.003). TNF-alpha promoter alleles are tightly linked to some HLA class I and II alleles, but multivariate analysis confirmed that the disease associations were independent of HLA, although a class I allele, A*6802, is also associated with disease. TNF-alpha was more frequently detected in tear samples from patients (27.6%) than from controls (15.9%), increasingly so for higher levels of detectable TNF-alpha (P = 0.015). Among patients, detectable TNF-alpha in tears was highly associated with the presence of ocular chlamydial infection (P < 0.001). The results indicate that TNF-alpha plays a major role in the tissue damage and scarring which occurs as a consequence of Chlamydia trachomatis infection.

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.

The importance of clinical features in differentiating HIV related from non-HIV related Kaposi's sarcoma: experience from Dar es Salaam, Tanzania.

PIP: HIV-associated Kaposi's sarcoma (KS) is reported to be the most common tumor among people infected with HIV and accounts for significant morbidity and mortality. A study was conducted at Muhimbili Medical Center among consecutive patients presenting at the skin clinic or admitted to the surgical or medical wards during April-December 1992 and suspected to have KS. Patients completed a questionnaire, had venous blood samples and biopsies of the suspicion skin lesion taken, and were tested for infection with HIV. 81 adult patients with histologically proven KS were seen during the study period. Epidemic KS (EKS) was diagnosed in 72 patients of whom 49 were male, while African endemic Kaposi's sarcoma (AEKS) was diagnosed in nine patients of whom seven were male. No patient presented with classical KS. Compared to AEKS, EKS was more aggressive and disseminated in patients. The mean duration of illness for patients with AEKS was 37.3 months compared to 8.3 months for those with EKS. The presenting symptoms and past history of HIV-related illness were most pronounced among patients with EKS. Patients with EKS also demonstrated profound T4 lymphopenia and inverted T4:T8 ratio suggestive of advanced HIV infection.^ieng

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.

Early diagnosis of HIV-1 infection in infants in Dar es Salaam, Tanzania.

OBJECTIVES: To evaluate two simple methods, an immune complex dissociation (ICD) p24 antigen assay and an HIV-1-specific IgA antibody assay, for the early demonstration of HIV-1 infection in infants, using the polymerase chain reaction (PCR) as the reference method. DESIGN AND SETTING: Group A: 143 HIV-1-seropositive and 134 -seronegative mothers and their infants were recruited at delivery at the main hospital in Dar es Salaam, Tanzania. Group B: 26 HIV-PCR-positive hospitalized children in Dar es Salaam, 3-15 months old and suspected of having an HIV-related illness. METHODS: Blood samples were taken from mothers and infants in group A at intervals during the children's first 24 months and once from each of the children in group B. Peripheral blood mononuclear cells were tested by nested PCR for viral DNA. Plasma samples were tested by the Coulter p24 antigen (ag) enzyme-linked immunosorbent assay (ELISA) after acid dissociation of p24 antigen-antibody complexes. All p24-ag-positive reactions were confirmed by neutralization. Viral specific IgA antibodies were demonstrated in plasma by a modified ELISA. RESULTS: One hundred and sixty-three of 174 samples from seropositive mothers were PCR-positive (sensitivity 93.7%) and 612 of 614 samples from seronegative mothers and children of seronegative mothers were PCR-negative (specificity 99.7%). Twenty-nine of 145 (20.0%) children born to seropositive mothers were positive by PCR when tested during the first year of life. By use of both the p24 ag ELISA and the IgA antibody ELISA in combination, HIV-1 infection was detected in 9 of 17 (53%) PCR-positive children 1-8 weeks old, in 15 of 18 (83%) PCR-positive children 9-26 weeks old and in 23 of 24 (96%) PCR-positive children 27-52 weeks old. The specificities of the p24 ag ELISA and the IgA ELISA were 100%. CONCLUSIONS: The p24 ag assay and the IgA antibody ELISA, when used in combination, had a high sensitivity and specificity for detection of HIV-1 infection in infants, especially in those above the age of 6 months.

Predictive markers for mother-to-child transmission of HIV-1 in Dar es Salaam, Tanzania.

The aim of this study was to determine immunological factors associated with increased risk of mother-to-child transmission of HIV-1 that could be used as predictive markers in Tanzanian women. One hundred and thirty-eight HIV-1-seropositive and 117-seronegative mothers and their newborns were recruited at delivery and followed up at Muhimbili Medical Centre in Dar es Salaam, Tanzania. Blood specimens from the mothers were analyzed for HIV-1 p24 antigen, beta 2-microglobulin (B2M), T-lymphocyte subsets, and presence of viral DNA in blood mononuclear cells by the polymerase chain reaction (PCR). Among 138 seropositive mothers, 30 (21.7%) had transmitted HIV-1 to their children, as shown by a positive PCR in the child. The vertical transmission rate was significantly higher in women with a percentage of CD4 lymphocytes < or = 20 (eight of 24, 33%) or a level of B2M > or = 2 mg/L (21 of 62, 34%) than in women with a higher percentage of CD4 lymphocytes (10 of 73, 14%) or a lower level of B2M (eight of 57, 14%) (p = 0.034 and 0.018, respectively). In eight of 18 (44%) transmitting mothers the percentage of CD4 lymphocytes was < or = 20, and in 21 of 29 (72%) transmitting mothers the B2M level was > or = 2 mg/L. In women with both a low percentage of CD4 lymphocytes (< or = 20) and a high level of B2M (> or = 2 mg/L), the vertical transmission rate was 54%.(ABSTRACT TRUNCATED AT 250 WORDS)

Aetiology of acute viral hepatitis B virus endemic population of Dar es Salaam

Sera from 250 patients admitted to Muhimbili hospital in Dar es Salaam; Tanzania; with viral hepatitis were examined for hepatitis B virus surface antigen (HBsAg); antibodies to hepatitis D (delta) virus; antibodies to hepatitis B virus core and for antibodies to hepatitis A virus; The latter two of the IgM class. Using the ELISA technique; 102 (40.8 percent) of the cases were verified as acute hepatitis B and 16 (6.4 percent) as acute hepatitis A. The aetiology of the remaining 131 (52 percent) of the patients could not be established and was due to either non-A; non-B viruses or other viruses. Only one of the HBsAg positive patients had antibodies to the hepatitis D virus. the results show the necessity of testing for markers of acute hepatitis infection (specific Igm) when acute hepatitis is diagnosed in a community where hepatitis B is endemic

Alternative confirmatory strategies in HIV-1 antibody testing.

Alternatives to confirmation of human immunodeficiency virus (HIV)-1 seropositivity by Western blot analysis were evaluated retrospectively using combinations of six anti-HIV-1 screening assays, including four enzyme-linked immunosorbent assays (ELISA) and two simple tests (a rapid dot immunoassay and an agglutination assay), according to an algorithm where sera are first screened by one assay and those repeatedly reactive on this assay are tested repeatedly by a second assay. Two panels of sera collected in Dar es Salaam, Tanzania, were used. Panel 1 was composed of 1,465 consecutive blood donor sera of which 99 (6.8%) were confirmed HIV-1 antibody positive, and panel 2 was composed of sera from 396 consecutively admitted patients at two medical wards of which 116 (29.3%) were confirmed HIV-1 antibody positive. Sera reactive on any of the six screening assays were also tested by a confirmatory Western blot assay. The sensitivity of the assays at the initial valid testing were as follows: Abbott 99.5%, Behring 99.5%, Organon 97.7%, Wellcozyme 100%, HIV CHEK-1 95.8%, and Serodia 95.8%. After repeat testing of sera that initially gave false-negative results all assays showed 100% sensitivity except HIV CHEK-1 (98.6%). The specificities after repeat testing were between 99.6 and 99.9% for all assays except for the Behring ELISA (98.1%). Several combinations of screening assays were found to give the same diagnostic accuracy as the screening assay followed by Western blot analysis. We conclude that an alternative confirmatory strategy can be fully satisfactory for some testing purposes.

The role of HIV infection in pregnancy wastage in Dar es Salaam, Tanzania.

PIP: This study examined the effect of HIV infection on pregnancy wastage in Dar es Salaam, Tanzania, by comparing women presenting with spontaneous abortion to women presenting for delivery from the same geographical region. Data were collected in 2 stages. In the first stage, 400 pregnant women were matched to 186 women presenting with spontaneous abortion (excluding all women who admitted to or were suspected of having a voluntary abortion) by age, parity, and marital status. Each woman was interviewed for obstetric history during the past 4 years, each was given a physical examination, and each had blood drawn to test for HIV seropositivity. In addition, details about birth weight and gestation at delivery were gleaned from the pregnant mothers upon delivery. For the evaluation of the effect of HIV infection on pregnancy wastage and the prevalence of clinical signs in the infected group, an additional 290 women (51 abortion patients and 239 pregnant controls) were screened in a similar manner. Researchers found that: 1) women presenting with spontaneous abortion had a significantly higher rate of HIV infection (20.7%) than those presenting for antenatal care or delivery (11.9%) (p = 0.05); 2) the infected group had a much higher rate of recent history of fetal wastage (late abortions, neonatal deaths, premature delivery) than the noninfected group (p 0.05); and 3) HIV-infected mothers delivered lower birth weight babies than the noninfected group (p 0.01). The authors point out that these results contradict those from Europe and the US, where no adverse pregnancy outcomes have been found in HIV-infected women. They suggest that future studies account for the immunological state of the women and the physical and other social characteristics which are likely to affect pregnancy outcome.^ieng

The role of HIV infection in pregnancy wastage in Dar es Salaam; Tanzania

Since AIDS and HIV infections were recognised in Tanzania; The prevalence of HIV infections among pregnant women in this country has been increasing. If studies from the Western World show no adverse effects; studies and observation in East and Central Africa indicate adverse pregnancy outcome. There is probably yet undetermined factors operating

A cross-sectional study of a program for HIV infection control among public house workers.

We report results of a cross-sectional study of a program for human immunodeficiency virus (HIV) infection control among public house workers in Dar es Salaam. Forty percent of the 605 workers sampled had been part of this program, which included behavioral counseling and provision of condoms, for 1 year. The remaining 60% were new recruits. Program participation was associated with both enhanced condom use (p less than 0.001) and behavioral modification (p less than 0.001). Females, and specifically barmaids, were more likely to be condom users but were less likely to have changed their behavior in other respects. Seropositivity to both HIV and Treponema pallidum tended to be higher among females, especially the barmaids. Since barmaids and waitresses in public houses in Dar es Salaam often engage in prostitution, it is felt that to effect a reduction of numbers of their sexual partners, there is a need to address the social and economic factors underlying high-risk sexual behavior.