Prevalence of HIV type 1 infection, associated clinical features and mortality among hospitalized children in Dar es Salaam, Tanzania.

The aim of this study was to determine the prevalence of HIV-1 infection, the clinical spectrum of HIV-1-associated conditions and HIV-1-associated mortality among children hospitalized in the medical paediatric wards at Muhimbili Medical Centre (MMC), Dar es Salaam, Tanzania. All children admitted to the medical paediatric wards of MMC between August 1995 and January 1996 were eligible for the study. Testing for HIV antibodies was done using 2 consecutive enzyme linked immunosorbent assays (ELISAs). ELISA-reactive samples from children aged 18 months and below were further tested by a recently developed heat-denatured p24 antigen assay. The prevalence of HIV-1 infection among the 2015 children studied was 19.2%. When present for 14 days or more, fever, cough, diarrhoea, ear discharge, oral ulcers and skin rash were all significantly more common in HIV-1-infected than in HIV-uninfected children (p < 0.001). In the multivariate analysis cough, ear discharge, oropharyngeal ulcers and skin rash were found to be the most important symptoms. Clinical signs found to be significantly associated with HIV-1 infection in the univariate analysis were wasting, stunting, hair changes, oral thrush, oropharyngeal ulcers, lymphadenopathy, lung consolidation and lung crepitations (p < 0.001). In the multivariate analysis, oral thrush, lung crepitations, cervical lymphadenopathy, wasting and inguinal lymphadenopathy were found to be the most important signs. The 3 most common diagnoses in HIV-1-infected children were acute respiratory infection (ARI) (39.4%), malnutrition (38.1%) and tuberculosis (19.3%), while in HIV-uninfected children they were malaria (47.0%), ARI (25.0%) and malnutrition (16.1%). The mortality rate was 21.4% in HIV-1-infected children and 8.4% in HIV-uninfected children (p < 0.001). In conclusion, the prevalence of HIV-1 infection among hospitalized children at the main hospital in Dar es Salaam was high and associated with high mortality. Many symptoms and signs are indicative of HIV-1 infection, but appropriate laboratory testing is required for diagnosis.

Evaluation of single- and dual antigen delayed fluorescence immunoassay in comparison to an ELISA and the in vivo toxin neutralisation test for detection of diphtheria toxin antibodies.

An evaluation of the delayed fluorescence immunoassay (Delfia) against an ELISA method for determination of diphtheria antitoxin levels in serum was performed. The Delfia was also validated in the in vivo toxin neutralisation test (Txn) in rabbits. Two variants of the Delfia were studied, a single-antigen Delfia (sDelfia) with only the diphtheria toxin included and a dual-antigen Delfia (dDelfia) with tetanus toxoid included for simultaneous detection of antibodies against two antigens. The diphtheria antitoxin cut-off levels in the sDelfia and the dDelfia were 0.004 and 0.002 AU/ml, respectively, which is lower than the internationally accepted level showing any protection against diphtheria (0.01 IU/ml). Both Delfia variants showed good correlation with the ELISA procedure above the ELISA cut-off level of 0.02 AU/ml. Results from samples assayed in the in vivo Txn assay indicated that the low antitoxin levels detected by the Delfia were valid. These results show that the Delfia could be considered as an in vitro reference method for detection of diphtheria antitoxin in seroepidemiological surveys and vaccine studies.

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.

Comparison of in-house and commercial sample preparation and PCR amplification systems for detection of human immunodeficiency virus type 1 DNA in blood samples from Tanzanian adults.

This study compared the performance of several in-house nested PCR systems and the Amplicor human immunodeficiency virus type 1 (HIV-1) PCR kit in the detection of HIV-1 DNA in Tanzanian samples prepared by two different methods. All six of the in-house primer sets evaluated had a higher sensitivity for HIV DNA detection in samples prepared by the Amplicor PCR sample preparation method than in those prepared by the Ficoll-Isopaque (FIP) density gradient centrifugation method. A sensitivity of 100% was achieved by combining two in-house primer sets. The sensitivity of the standard Amplicor HIV-1 PCR kit was only 59%, whereas a modified Amplicor HIV-1 PCR test had a sensitivity of 98%. Our data show that Tanzanian samples prepared by the Amplicor preparation method are more suitable for HIV-1 PCR testing than samples prepared by the FIP method. The modified, but not the standard, Amplicor HIV-1 PCR kit provides an alternative to the nested in-house PCR technique for the diagnosis of HIV infection.

PIP: Blood samples were collected from 73 pregnant mothers attending an antenatal clinic and from 14 adult females recruited into ongoing studies of the incidence and natural history of HIV-1 infection in Dar es Salaam, Tanzania. Study subjects were asymptomatic for HIV infection, but 65 tested HIV-positive. The authors compared the performance of several in-house nested polymerase chain reaction (PCR) systems and the Amplicor HIV-1 PCR kit in detecting HIV-1 DNA in the seropositive samples prepared by two different methods. All six of the in-house primer sets evaluated were more sensitive for HIV DNA detection in samples prepared by the Amplicor PCR sample preparation method than in those prepared by the Ficoll-Isopaque (FIP) density gradient centrifugation method. A sensitivity of 100% was achieved by combining two in-house primer sets. The sensitivity of the standard Amplicor HIV-1 PCR kit was only 59%, while a modified Amplicor HIV-1 PCR test had a sensitivity of 98%. These data indicate that Tanzanian samples prepared by the Amplicor preparation method are more suitable for HIV-1 PCR testing than samples prepared by the FIP method.

Nested PCR assays with novel primers yield greater sensitivity to Tanzanian HIV-1 samples than a commercial PCR detection kit.

To investigate the efficacy of the SK431/SK145 primer pair and two nested primer assays in amplifying African HIV-1 samples, a total of 35 Tanzanian PBMC samples were examined. These were assayed by two HIV-1 specific nested in-house PCR assays and a commercial HIV-1 PCR kit (GeneAmp) using SK431/SK145 as the primer pair. One of the nested PCR assays has been evaluated previously (old assay), whereas the modified assay was constructed from the HIV-1 sequence alignment released in August 1993. The modified nested primer assay showed increased sensitivity in the gag and env regions compared to the old nested primer assay. However, both the old and the modified nested primer assays displayed higher sensitivity for the detection of Tanzanian HIV-1 proviruses than the GeneAmp assay. When two regions were used (gag and env) as targets for the amplification, the modified nested primer assay detected 97.1% (34/35) of the proteinase K lysed samples, compared to 68.6% (24/35) using the SK431/SK145 primer pair (P < 0.01**). The results indicate that the SK431/SK145 primer pair may be less suitable when HIV-1 samples from Africa are analysed. The results also show that continuous modification of primer sequences can improve and maintain high sensitivity for the detection of highly divergent HIV-1 strains.

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.

Performance of a modified HIV-1 p24 antigen assay for early diagnosis of HIV-1 infection in infants and prediction of mother-to-infant transmission of HIV-1 in Dar es Salaam, Tanzania.

The aim of this study was to determine the utility of an amplified human immunodeficiency virus type 1 (HIV-1) p24 antigen (ag) assay using heated plasma or serum samples for the early diagnosis of HIV-1 infection in infants and for the prediction of the risk of mother-to-infant (MTI) transmission of HIV-1 in Dar es Salaam, Tanzania. The study included 125 samples from 76 infants positive for HIV-1 DNA by the polymerase chain reaction (PCR), 106 samples from 101 PCR-negative infants and 116 and 160 samples from seropositive and seronegative mothers, respectively. Samples were boiled to dissociate immune complexes and tested for HIV-1 p24 ag using a p24 ag amplification assay. Reactive samples were confirmed by a neutralization assay. Altogether, 123 of 125 samples from 76 PCR-positive infants were positive for p24 ag (sensitivity = 98.7%). HIV-1 p24 ag was found in all 18 samples collected at 1-8 weeks, in 35 of 36 samples collected at 9-26 weeks, in all 40 samples collected at 27-52 weeks, and in 30 of 31 samples collected > 52 weeks after birth. Detection of HIV-1 p24 ag was significantly more common in transmitting mothers (12 of 29, 41.4%) than in nontransmitting mothers (nine of 87, 10.3%) (p < 0.001). Among mothers with p24 antigenemia, the vertical transmission rate was significantly higher (12 of 21, 57%) than in mothers without p24 antigenemia (17 of 95, 18%) (p < 0.001). All samples from 101 PCR-negative children and 160 seronegative mothers were negative for p24 ag (specificity = 100%). We conclude that using heated plasma or serum increases the sensitivity of the p24 ag assay significantly. This modified simple test may be sufficient for the early diagnosis of HIV-1 infection in infants in settings with limited laboratory facilities. It is also useful for prediction of the risk of MTI transmission of HIV-1.

Pattern of HIV viraemia and CD4 levels in relation to pregnancy in HIV-1 infected women.

The objective was to study HIV-1 viraemia and CD4 levels during and 6 months after pregnancy. HIV cultures on peripheral blood mononuclear cells (PBMC) and plasma from 225 samples were performed in 90 HIV-1 infected women with 59 continued and 35 terminated pregnancies. P-24 antigen and HIV-DNA were also studied. 34 women originated from European, 44 from African and 10 from other countries while 2 were of unknown origin. HIV was detected in 30% of the plasma cultures from the first trimester and in approximately 50% thereafter. Repeated plasma isolations did not give an indication of HIV activation, nor did the cross-sectional time-to-culture positivity in plasma and in PBMC, PBMC isolation frequencies, HIV-DNA and CD4 levels. The plasma viraemia frequencies were generally higher and the CD4 levels lower in the African women than in the European ones. Six months after delivery there was a significant decrease in the CD4 cell counts compared to delivery, but not when compared to the values during the first or second trimesters. The results showed that HIV activity during pregnancy was relatively stable, followed by indications of resumed activity during the first 6 months after delivery.

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)

Prevalence and incidence of syphilis and its association with HIV-1 infection in a population-based study in the Kagera region of Tanzania.

Population-based prevalence and incidence studies on HIV-1 infection were started in the Kagera region of Tanzania in 1987. The prevalence and incidence of infection with Treponema pallidum was studied to enable development of better strategies for STD control. Serological diagnosis of a past or treated infection with Troponema pallidum was made by seropositivity only to TPHA testing while active syphilis was diagnosed by seropositivity to both VDRL and TPHA tests. Seroconversion was measured in 1989 by finding TPHA serologically positive individuals during the follow-up period among the initially seronegative study population of 1987. The overall prevalence of active syphilis in the total sample of adults in the region was found to be 5.9% while that of past syphilis was 13.5%. The association between the prevalence of HIV-1 infection and syphilis of both types was found to be highly significant. However, the association between one pre-existing infection and seroconversion in the other was present but not statistically significant. The overall incidence of syphilis based on seroconversion in a cohort of adults in the region was found to be 11.6 per 1000 person-years at risk. In view of these findings, syphilis is a significant health problem in the region with a high level of transmission and efforts should be made to control it. Intervention studies should use these base-line data and monitor changes in syphilis incidence which may indicate changes in sexual behaviour. Such indicators could also be useful for evaluating the impact of interventions directed at reducing the transmission of HIV, syphilis and other STDs in the region.

PIP: Population-based prevalence and incidence studies on HIV-1 infection were started in the Kagera region of Tanzania in 1987. In 1989, a follow-up population-based serosurvey was conducted in the same population with the aim of determining the incidence of HIV-1 infection in the region. In 1987 multi-stage cluster sampling technique was employed to visit all the households selected and to choose at random 1 adult between 15 and 54 years old and 1 child under 15 years old. Syphilis serological examination was done on 2307 adults; 135 had active infection (both VDRL and TPHA positive), 1837 were negative, and 24 had false positive serology (VDRL positive and TPHA negative). The overall prevalence of active syphilis in the regional study sample was 5.9%, while that of past syphilis infection was 13.5%. The prevalence of past infection with syphilis in the rural areas (12.1%) was statistically significantly different from that in the urban area (17.8%, p 0.001). The prevalence of both types of infection increased with age in both rural and urban areas (p 0.001), except for active infection in the urban area (p 0.05). Analysis determining the association between HIV-1 infection and treponemal disease of both types found that there was a highly significant association between the 2 infections after controlling for the number of sexual partners in 3 categories of 0-1, 2-4, and 5 or more sexual partners an individual had had during the 8 years before 1987 (Mantel Haenszel weighted odds ratio 2.38). Between 1987 and 1989 the mean risk period for syphilis seroconversion of the 1133 individuals tested, was 1.82 years with a range between 1.20 and 2.49 years. The overall incidence was 11.6 per 1000 person-years at risk. The highest incidence was in the urban zone (15.4 per 1000 person-years at risk) and the lowest in the Karagwe rural zone (6.5 per 1000 person-years at risk). There was but a weak association between 1 pre-existing infection and seroconversion in the other as indicated by the risk ratios, which were more than unity.

Evaluation of the WHO human immunodeficiency virus (HIV) antibody testing strategy for the diagnosis of HIV infection.

OBJECTIVE: To evaluate a WHO testing strategy based on the use of two consecutive enzyme-linked immunosorbent assays (ELISA) as an alternative to ELISA followed by Western blotting (WB) for the serologic diagnosis of HIV infection. STUDY DESIGN: The study was of 2069 consecutive serum specimens from patients suspected of HIV infection received for HIV diagnostic testing at the HIV laboratory, Muhimbili Medical Centre, Dar es Salaam. The strategy involved testing all sera with Behring indirect anti-HIV 1 + 2 peptide ELISA, followed by Wellcozyme anti-HIV-1 recombinant competitive ELISA on those sera reactive by the first ELISA. WB was done on a sample of the sera reactive on both ELISAs and on all those giving discordant results on the two ELISAs. Of the 2069 sera tested, 837 (40.5%) were negative on the first ELISA, 1172 (56.6%) were reactive on both ELISAs and 60 (2.9%) were initially reactive on the first test but not on the second assay. RESULTS: Of the 1172 sera reactive on both ELISAs, 329 (28.1%) were tested by WB. The diagnostic accuracy of the WHO alternative testing strategy using WB confirmation as the 'gold' standard was as follows: sensitivity 99.4% (326/328), specificity 99.7%, (893/896), positive predictive value 99.1% (328/331) and negative predictive value 99.8% (893/895). Repeated testing by ELISA of the sera which initially gave discordant results on the two ELISAs increased the sensitivity to 100%. Three sera giving false positive reactions on both ELISAs became negative on both ELISAs after retesting. In order to achieve a specificity and a positive predictive value of 100%, it would have been necessary to subject all sera reacting on both ELISAs to retesting on one ELISA. CONCLUSIONS: A second ELISA based on different antigens and a different test principle compared with the first ELISA could be used as an alternative to the WB assay for confirmation of HIV antibodies. However, some modifications of the WHO strategy for diagnostic HIV antibody testing were required in order to maximize the diagnostic accuracy.

Incidence of HIV-1 infection among adults in the Kagera region of Tanzania.

The results of a population-based follow-up study are presented. The baseline study which started in August 1987, was carried out to determine the prevalence of human immunodeficiency virus (HIV-1) infection in the Kagera region of Tanzania. A multistage cluster sampling technique was adopted in the selection of the study population. In the follow-up survey which started in June 1988, members of the same study population were revisited and studied in order to determine the incidence of HIV-1 infection among those who were HIV seronegative in the initial survey. HIV serology was conducted by using enzyme-linked immunosorbent assay and all positive sera were confirmed by the Western blot technique. A total population of 1316 adults aged 15-54 years was studied, constituting an average follow-up response rate of 69% in the rural areas and of 59% in the urban area. The overall incidence of HIV-1 infection among the adult population sample was 13.7 per 1000 person-years at risk with the highest incidence in the urban zone (47.5 per 1000 person-years at risk) and the lowest incidence in one of the three rural zones (4.9 per 1000 person-years at risk). The age-specific annual incidence was highest in the age group 25-34 years for males and in the age group 15-24 for females. From these results it was estimated that the number of newly infected adults in the region each year is about 8200 with a range between 5400 and 11,000 corresponding to the 95% confidence limits on the overall incidence.(ABSTRACT TRUNCATED AT 250 WORDS)

Improved detection of HIV-2 DNA in clinical samples using a nested primer-based polymerase chain reaction.

A two-step polymerase chain reaction (PCR), with four double (nested) primer pairs, used for the detection of HIV-2 in clinical samples is described. With these four nested primer pairs we could detect HIV-2 DNA in 17 of 17 virus isolates and in blood mononuclear cell samples from 31 of 37 (83.7%) seropositive individuals after ethidium bromide staining of the amplified DNA. The nested primer PCR was also compared with a single primer pair-based PCR followed by hybridization. The sensitivities of the two methods were almost equal, but the nested primer PCR offered obvious technical advantages.

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.

Selection of primers of optimal sensitivity for the detection of HIV-1 from Africa and Europe by polymerase chain reaction.

In order to facilitate the detection of integrated HIV-1 proviral DNA from African as well as European patients, four new primer pairs for use in the polymerase chain reaction (PCR), localised in the gag, pol, vif and env genes of HIV-1, were constructed. The primer pairs were compared to all accessible HIV-1 sequences from African and European isolates and to some of the earlier published and most commonly used primer pairs. HIV-1 DNA was detected in blood drawn from 13 out of 13 individuals infected in Africa, in three out of three Tanzanian HIV-1 isolates and in three out of three asymptomatic Swedes infected in Europe. The new selection of primer pairs can be used as an alternative to enhance the detection of HIV-1 of different origins.

PIP: In order to facilitate the detection of integrated HIV-1 proviral DNA from African as well as European patients, 4 new primer pairs for use in the polymerase chain reaction (PCR), localized in the gag, pool, vif, and env genes of HIV-1, were constructed. The primer pairs were compared to all accessible HIV-1 sequences from African and European isolates and to some of the earlier published and most commonly used primer pairs. HIV-1 DNA was detected in blood drawn from 13 infected individuals in Africa, in 3 Tanzanian HIV-1 isolates, and in the 3 asymptomatic Swedes infected in Europe. The new selection of primer parts can be used as an alternative to enhance the detection of HIV-1 of different origins.

Prevalence of HIV-1 infection and symptomatology of AIDS in severely malnourished children in Dar Es Salaam, Tanzania.

In Dar es Salaam, Tanzania, 200 children with severe malnutrition and controls matched for age, sex, and area of residence were screened for serological evidence of infection with the human immunodeficiency virus type 1 (HIV-1) over 5 months in 1988. The prevalence of HIV-1 antibodies in the malnourished group was 25.5% (51 of 200) compared with 1.5% (three of 200) in the controls. The seroprevalence rate was equally high in malnourished children above the age of 18 months (26 of 102; 25.5%), as in those below this age (25 of 98; 25.5%). The prevalence rate was higher in children with marasmus (38.2%) as compared to children with marasmic-kwashiorkor (12.3%) or kwashiorkor (12.2%). The prevalence of clinical features known to be associated with AIDS was higher in the HIV seropositive malnourished children as compared to the seronegative children. The modified World Health Organization clinical case definition of AIDS in children was also evaluated and found to have a low sensitivity and positive predictive value (62.8 and 57.1%, respectively) but a fairly high specificity (83.9%). It is recommended to routinely rule out HIV infection in malnourished children, especially those with marasmus.

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.