Publications (15)162.72 Total impact
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Article: Prevalence of HIV type 1 infection, associated clinical features and mortality among hospitalized children in Dar es Salaam, Tanzania.
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ABSTRACT: 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.Scandinavian Journal of Infectious Diseases 02/2000; 32(4):357-63. · 1.72 Impact Factor -
Article: 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.
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ABSTRACT: 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.Journal of Clinical Microbiology 02/1997; 35(1):278-80. · 4.15 Impact Factor -
Article: Nested PCR assays with novel primers yield greater sensitivity to Tanzanian HIV-1 samples than a commercial PCR detection kit.
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ABSTRACT: 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.Journal of Virological Methods 12/1996; 62(2):131-41. · 2.01 Impact Factor -
Article: 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.
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ABSTRACT: 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.Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology 08/1996; 12(4):421-6. -
Article: Early diagnosis of HIV-1 infection in infants in Dar es Salaam, Tanzania.
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ABSTRACT: 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. 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. 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. 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%. 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.Clinical and Diagnostic Virology 09/1995; 4(2):163-73. -
Article: Predictive markers for mother-to-child transmission of HIV-1 in Dar es Salaam, Tanzania.
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ABSTRACT: 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)Journal of Acquired Immune Deficiency Syndromes and Human Retrovirology 02/1995; 8(2):182-7. -
Article: Alternative confirmatory strategies in HIV-1 antibody testing.
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ABSTRACT: 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.Journal of acquired immune deficiency syndromes 02/1992; 5(2):170-6. -
Article: Selection of primers of optimal sensitivity for the detection of HIV-1 from Africa and Europe by polymerase chain reaction.
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ABSTRACT: 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.AIDS 06/1991; 5(5):575-8. · 6.24 Impact Factor -
Article: Prevalence of HIV-1 infection in the Kagera region of Tanzania: a population-based study.
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ABSTRACT: A population-based survey was carried out in the Kagera region of the United Republic of Tanzania in 1987 to determine the magnitude of HIV-1 infection and to study associated risk factors. The region was divided into one urban and three rural zones. A multistage cluster sampling technique was adopted. Antibodies to HIV-1 were determined by enzyme-linked immunosorbent assay and confirmed by Western blot analysis. A total of 2,475 adults (aged 15-54 years) and 1,961 children (aged 0-14 years) was studied. The overall prevalence of HIV-1 infection among adults was 9.6%, with a higher prevalence in the urban zone (24.2%) than in the three rural zones (10.0, 4.5 and 0.4%, respectively). The corresponding figures for children were 1.3% overall: 3.9% in the urban area and for the rural areas 1.2, 0.8 and 0.0%, respectively. The age-specific seroprevalence for adults was highest in the age group 25-34 years. The age-standardized sex-specific prevalence was higher among women than men in the urban zone, while it was the same in the rural zones. Change of sexual partners among adults was associated with an increased risk of HIV-1 seropositivity. Travelling outside the region but within the country was also found to be associated with increased risk of HIV-1 infection but only in the rural population.AIDS 12/1990; 4(11):1081-5. · 6.24 Impact Factor -
Article: Evaluation of commercial enzyme immunoassays for anti-HIV-1 using East African sera.
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ABSTRACT: Sera from 622 blood donors collected in 1986 and 1987 in Tanzania were screened for antibodies to HIV-1 by seven different commercial enzyme-linked immunosorbent assay (ELISA) kits. All ELISA-positive sera were tested by Western blot analysis and many of them also by radioimmunoprecipitation assay (RIPA). Sixty-seven sera were confirmed positive. Eight sera, which were repeatedly positive on only one or two of the ELISA kits and showed weak, doubtful reactions on Western blot and RIPA, were considered indeterminate and were not included in the calculations of sensitivity and specificity of the various ELISA kits. The sensitivity of the ELISAs was as follows: Organon Vironostika: low cut-off 74.6%; Organon Vironostika: high cut-off 62.7%; Du Pont: 85.1%; Pasteur: 78.7%; Abbott: 80.8%; Abbott recombinant: 94.0%; Wellcozyme: 82.1%; Wellcozyme monoclonal: 98.5%. The specificity was as follows: Organon Vironostika: low and high cut-off 100%; Du Pont: 94.7%; Pasteur: 99.3%; Abbott: 100%; Abbott recombinant 98.7%; Wellcozyme: 99.8%; Wellcozyme monoclonal: 98.5%. In conclusion, the two new generation kits tested, Wellcozyme monoclonal and Abbott recombinant, had the highest sensitivity whereas the sensitivity of the first-generation tests was unexpectedly low.AIDS 09/1988; 2(4):281-5. · 6.24 Impact Factor -
Article: Prevalence of HIV infection in healthy subjects and groups of patients in Tanzania.
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ABSTRACT: During 1986 sera from 2508 individuals representing various groups of healthy subjects and patients in Dar es Salaam (the capital city of Tanzania), Bukoba (the capital of Kagera region in the northwest corner of Tanzania), Arusha (in the northeast of Tanzania) and Mbeya (in the southwest of Tanzania) were screened for antibodies to HIV by enzyme-linked immunosorbent assay (ELISA). All ELISA-positive sera were also tested by Western blot analysis. In Dar es Salaam HIV antibodies were demonstrated in 3.6% of 192 pregnant women, 5.2% of 784 blood donors, 29.0% of 224 barmaids, 8.0% of 50 male bar workers, 9.25% of 400 male and 12.2% of 90 female patients attending a clinic for sexually transmitted diseases (STDs), 85.7% of 35 patients with herpes zoster and in 97.6% of 84 patients clinically suspected of AIDS. Among the barmaids the seropositivity rate was higher in younger women (45%) than in middle-aged women (11%). Only three (4.6%) out of 65 HIV-seropositive barmaids had HIV-related symptoms. The prevalence of HIV seropositivity among healthy low-risk subjects was highest in Bukoba, namely 16% of 100 pregnant women and 13.9% of 36 blood donors, while in Arusha only one (0.7%) of the 144 pregnant women and none of 41 bar workers, none of 42 blood donors and none of 61 patients with STD were positive. In Mbeya, 3.4% of 118 pregnant women and 11.8% of 34 men with STD were seropositive. Thus the prevalence of HIV infection differs considerably in various population groups and in various parts of Tanzania.AIDS 01/1988; 1(4):217-21. · 6.24 Impact Factor -
Article: Findings in four HTLV-IV seropositive women from West Africa.
The Lancet 01/1987; 2(8519):1330-1. · 38.28 Impact Factor -
Article: Blood donor sera with false-positive Western blot reactions to human immunodeficiency virus.
The Lancet 09/1986; 2(8501):289-90. · 38.28 Impact Factor -
Article: Impaired specific cellular response to HTLV-III before other immune defects in patients with HTLV-III infection.
New England Journal of Medicine 09/1986; 315(6):393-4. · 53.30 Impact Factor -
Article: [A simple method for determination of antibodies to AIDS associated virus (HTLV-III)].
Lakartidningen 10/1984; 81(39):3482-3.
Top co-authors
Top Journals
Institutions
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1996–2000
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Muhimbili University of Health and Allied Sciences
Dar es Salaam, Dar es Salaam Region, Tanzania
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1988–1997
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University of Dar es Salaam (UDSM)
Dar es Salaam, Dar es Salaam Region, Tanzania
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1995
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Swedish Institute for Communicable Disease Control
Stockholm, Stockholm, Sweden -
Karolinska Institute
- Department of Clinical Immunology
Stockholm, Stockholm, Sweden
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1991
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Umeå University
Umeå, Vaesterbotten, Sweden
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1990
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Muhimbili National Hospital
Dar es Salaam, Dar es Salaam Region, Tanzania
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