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Biomedical subjects

Maarten Schim van der Loeff

Publications and source records attributed to Maarten Schim van der Loeff.

11 recordsLinked to original sources
PubMed2006

Vaccinia scars associated with improved survival among adults in rural Guinea-Bissau.

BACKGROUND: In urban Guinea-Bissau, adults with a vaccinia scar had better survival but also a higher prevalence of HIV-2 infection. We therefore investigated the association between vaccinia scar and survival and HIV infection in a rural area of Guinea-Bissau. METHODOLOGY/PRINCIPAL FINDINGS: In connection with a study of HIV in rural Guinea-Bissau, we assessed vaccinia and BCG scars in 193 HIV-1 or HIV-2 infected and 174 uninfected participants. Mortality was assessed after 2(1/2)-3 years of follow-up. The analyses were adjusted for age, sex, village, and HIV status. The prevalence of vaccinia scar was associated with age, village, and HIV-2 status but not with sex and schooling. Compared with individuals without any scar, individuals with a vaccinia scar had better survival (mortality rate ratio (MR) = 0.22 (95% CI 0.08-0.61)), the MR being 0.19 (95% CI 0.06-0.57) for women and 0.40 (95% CI 0.04-3.74) for men. Estimates were similar for HIV-2 infected and HIV-1 and HIV-2 uninfected individuals. The HIV-2 prevalence was higher among individuals with a vaccinia scar compared to individuals without a vaccinia scar (RR = 1.57 (95% CI 1.02-2.36)). CONCLUSION: The present study supports the hypothesis that vaccinia vaccination may have a non-specific beneficial effect on adult survival.

Adult↗
PubMed2005

Bacterial vaginosis, vaginal flora patterns and vaginal hygiene practices in patients presenting with vaginal discharge syndrome in The Gambia, West Africa.

BACKGROUND: Bacterial vaginosis (BV) - a syndrome characterised by a shift in vaginal flora - appears to be particularly common in sub-Saharan Africa, but little is known of the pattern of vaginal flora associated with BV in Africa. We conducted a study aimed at determining the prevalence of BV and patterns of BV-associated vaginal micro-flora among women with vaginal discharge syndrome (VDS) in The Gambia, West Africa. METHODS: We enrolled 227 women with VDS from a large genito-urinary medicine clinic in Fajara, The Gambia. BV was diagnosed by the Nugent's score and Amsel's clinical criteria. Vaginal swabs were collected for T vaginalis and vaginal flora microscopy, and for Lactobacillus spp, aerobic organisms, Candida spp and BV-associated bacteria (Gardnerella vaginalis, anaerobic bacteria, and Mycoplasma spp) cultures; and cervical swabs were collected for N gonorrhoeae culture and C trachomatis PCR. Sera were tested for HIV-1 and HIV-2 antibodies. Sexual health history including details on sexual hygiene were obtained by standardised questionnaire. RESULTS: BV prevalence was 47.6% by Nugent's score and 30.8% by Amsel's clinical criteria. Lactobacillus spp were isolated in 37.8% of women, and 70% of the isolates were hydrogen-peroxide (H202)-producing strains. Prevalence of BV-associated bacteria were: G vaginalis 44.4%; Bacteroides 16.7%; Prevotella 15.2%; Peptostretococcus 1.5%; Mobiluncus 0%; other anaerobes 3.1%; and Mycoplasma hominis 21.4%. BV was positively associated with isolation of G vaginalis (odds-ratio [OR] 19.42, 95%CI 7.91 - 47.6) and anaerobes (P = 0.001 [OR] could not be calculated), but not with M hominis. BV was negatively associated with presence of Lactobacillus (OR 0.07, 95%CI 0.03 - 0.15), and H2O2-producing lactobacilli (OR 0.12, 95% CI 0.05 - 0.28). Presence of H2O2-producing lactobacilli was associated with significantly lower prevalence of G vaginalis, anaerobes and C trachomatis. HIV prevalence was 12.8%. Overall, there was no association between BV and HIV, and among micro-organisms associated with BV, only Bacteroides spp. and Prevotella spp. were associated with HIV. BV or vaginal flora patterns were not associated with any of the factors relating to sexual hygiene practices (vaginal douching, menstrual hygiene, female genital cutting). CONCLUSION: In this population, BV prevalence was higher than in corresponding populations in industrialised countries, but the pattern of vaginal micro-flora associated with BV was similar. BV or vaginal flora patterns were not associated with HIV nor with any of the vaginal hygiene characteristics.

Adolescent↗
PubMed2005

No observed effect of GB virus C coinfection on disease progression in a cohort of African woman infected with HIV-1 or HIV-2.

We studied mortality among subjects with human immunodeficiency virus (HIV)-1 and HIV-2 infection in relation to GB virus (GBV)-C coinfection. No significant differences in mortality were seen between subjects with and subjects without GBV-C coinfection who also had either HIV-1 or HIV-2 infection. No association between GBV-C and HIV plasma virus loads or CD4 cell count was observed.

Adolescent↗
PubMed2004

No differences in cellular immune responses between asymptomatic HIV type 1- and type 2-infected Gambian patients.

Fewer people infected with human immunodeficiency virus (HIV) type 2 progress to acquired immunodeficiency syndrome, compared with those infected with HIV-1. To understand the immune mechanisms leading to slow progression in HIV-2 infection, cell-mediated immune responses were compared between the 2 infections in asymptomatic subjects with a CD4 cell count > or =20%. Interferon- gamma release from T lymphocytes and the cytotoxicity of CD8+ T lymphocytes were measured by ELISPOT and 51Cr release assays. The level of responses and the proportion of responders were similar in the 2 infections, despite a 20-fold difference in their geometric mean plasma virus loads. The proliferation of CD4+ T helper cells, which was evaluated by thymidine incorporation, was not different between the 2 infections. Contrary to widely held views, our results suggest that nonprogression in HIV-2 infection may not be due to more vigorous immune responses.

Adult↗
PubMed2003

Quantification of Human T-lymphotropic virus type I (HTLV-I) provirus load in a rural West African population: no enhancement of human immunodeficiency virus type 2 pathogenesis, but HTLV-I provirus load relates to mortality.

Human T-lymphotropic virus type I (HTLV-I) provirus load was examined in a cohort of a population in Guinea-Bissau among whom human immunodeficiency virus (HIV) type 2 is endemic. Geometric mean of HIV-2 RNA load among HTLV-I-coinfected subjects was significantly lower than that in subjects infected with HIV-2 alone (212 vs. 724 copies/mL; P=.02). Adjusted for age, sex, and HIV status, the risk of death increased with HTLV-I provirus load; mortality hazard ratio was 1.59 for each log10 increase in HTLV-I provirus copies (P=.038). There is no enhancing effect of HTLV-I coinfection on HIV-2 disease, but high HTLV-I provirus loads may contribute to mortality.

Acquired Immunodeficiency Syndrome↗
PubMed2003

Plasma viral load, CD4 cell percentage, HLA and survival of HIV-1, HIV-2, and dually infected Gambian patients.

OBJECTIVE: To examine baseline plasma viral loads according to the CD4 cell percentage (CD4%) in HIV-1, HIV-2 and dually infected patients (HIV-D), and to relate these measurements to survival. PATIENTS AND METHODS: A total of 119 HIV-1, 137 HIV-2 and 81 HIV-D-infected patients attending the Medical Research Council clinic in The Gambia were recruited from 1991 according to baseline CD4%, and followed until death or the end of December 2000. HIV-1 and HIV-2 RNA levels were measured by in-house reverse transcriptase polymerase chain reaction assays. RESULTS: The plasma viral load, which varied inversely with CD4%, was similar in HIV-1 singly and dually infected patients, but was significantly higher in HIV-1 than in HIV-2 singly infected patients, except in those with a CD4% less than 14%. HIV-2 plasma viral load in dually infected patients did not vary significantly with CD4%, but was significantly lower than in HIV-2 singly infected patients with CD4% less than 14%. Multivariate analysis showed that only CD4% was independently associated with survival in HIV-1 and HIV-D infections; whereas both CD4% and plasma viral load were independently associated with survival in HIV-2 infections. The mortality rate of HIV-D-infected patients was not significantly different from that of HIV-1-infected patients, but was significantly higher in the absence of HLA B58. CONCLUSION: HIV-2 infection does not alter HIV-1 replication or prolong survival in dually infected patients. In a clinical setting in Africa, where many patients present with advanced disease, CD4% may be a more important predictor of prognosis than plasma viral load.

Adolescent↗
PubMed2003

Evaluation of a new rapid diagnostic kit (FemExam) for bacterial vaginosis in patients with vaginal discharge syndrome in The Gambia.

BACKGROUND: Diagnosis of bacterial vaginosis (BV) in resource-poor primary health care settings is often overlooked; there is a need for a cheap, rapid, objective point-of-care diagnostic test. GOAL: The goal was to determine the prevalence of BV and to evaluate the performance of a new commercial diagnostic test kit in a developing country environment. STUDY DESIGN: Vaginal and cervical swabs were collected from 230 consecutive women attending a genitourinary medicine clinic with reported symptoms of vaginal discharge and/or itching. Etiological testing was carried out. BV was diagnosed on the basis of the Nugent score, the Amsel clinical criteria, and results of FemExam card tests. Card 1 is for pH and amines, and card 2 measures proline iminopeptidase (PIP) activity. RESULTS: BV prevalence was 47.9% according to the Nugent score. When compared with the Nugent score, the Amsel clinical criteria had a sensitivity of 77.9% and specificity of 58.4%, FemExam card 1 had a sensitivity of 71.4% and specificity of 72.8%, FemExam card 2 had a sensitivity of 70% and specificity of 81.0%, and FemExam cards 1 and 2 combined had a sensitivity of 91.0% and specificity of 61.5%. Cost per patient and cost per true case detected ranged from US $0.74 and US $1.54, respectively, for Gram stain diagnosis, to US $8.32 and US $18.49 for the FemExam two-card method. CONCLUSIONS: In a setting where BV was frequently associated with vaginal discharge, the FemExam test compared favorably with conventional clinical diagnosis, and it has the advantage of being rapid, less subjective, and easily performed. Cutting its cost would provide wider accessibility in developing countries.

Adolescent↗
PubMed2002

Low level viremia and high CD4% predict normal survival in a cohort of HIV type-2-infected villagers.

A community-based study of human immunodeficiency virus type 2 (HIV-2) infection was conducted in a rural village in northern Guinea Bissau, West Africa to assess the relationship between plasma HIV-2 RNA levels, CD4 lymphocyte percentage, and survival over an 8-year period. The cohort of 133 HIV-2-infected individuals and 160 HIV-uninfected controls enrolled in 1991 were followed up at home until 1998. Thirty-one (23%) HIV-2-infected and 24 (16%) HIV-uninfected individuals died over the follow-up period (mortality hazard ratio 1.7, 95% CI 1.0, 2.9; p= 0.06). In HIV-2-infected individuals, the median HIV-2 RNA level was 347 copies/ml and the mean CD4% was 28.6. Both plasma viremia and CD4% were independent predictors of survival, with hazard ratios increasing by 1.6 (95% CI, 1.1, 2.3) for each log(10) increase of plasma viremia and 1.7 (1.1, 2.6) for each 10% decrease of CD4%. Infected subjects with a plasma viral load >or= the median (347 copies/ml) and a CD4% <or= the mean (28.6%) had a mortality hazard ratio of 3.1 (95% CI 1.7, 5.8) compared to uninfected controls, whereas the remaining infected subjects had a mortality rate similar to uninfected controls, the mortality hazard ratio being 1.0 (95% CI, 0.5, 2.1.) In those who survived between 1991 and 1996, HIV-2 RNA levels were unchanged overall and CD4 lymphocyte counts remained high. In conclusion, baseline HIV-2 RNA levels predicted a normal survival for the majority, with low and stable levels of plasma viremia characterizing HIV-2 infections in this rural West African community.

Adult↗
PubMed2002

Increased prevalence of HTLV-1 among HIV-2-infected women but not HIV-2-infected men in rural Guinea-Bissau.

OBJECTIVE: To assess the prevalence of HTLV infection and its association with HIV and other potential risk factors. DESIGN AND SETTING: A cross-sectional survey and a case-control study in a rural community in Guinea-Bissau. METHODS: A total of 2770 people were included in an HIV and HTLV seroepidemiologic survey. Three hundred of these participants were selected for a case-control study on HIV-2. Sera from both studies were tested for HTLV. RESULTS: In all, 2501 and 298 subjects in the survey and case-control study, respectively, were tested for HTLV. Overall HTLV-1 prevalence was 5.2% and it was higher in women (odds ratio [OR], 1.36; confidence interval [CI], 0.92-2.02). Apart from an infected spouse, no significant risk factors could be identified for men. In women, HIV-2 infection (adjusted OR, 5.58; CI, 3.09-10.1), having an infected spouse, and area of residence were significantly associated with HTLV-1 infection. The association between HTLV-1 and HIV-2 was significantly different for men and women (test of interaction, p =.002). CONCLUSIONS: In women, the most important determinant of HTLV-1 seropositivity was HIV-2 infection. Because the pattern was significantly different for men and women, common sexual risk factors may not be sufficient to explain the co-occurrence of HIV-2 and HTLV-1 in women. These observations may have implications in geographic areas where both types of retroviruses are prevalent.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

The effect of mass administration of sulfadoxine-pyrimethamine combined with artesunate on malaria incidence: a double-blind, community-randomized, placebo-controlled trial in The Gambia.

A double-blind, community-randomized, placebo-controlled trial was conducted in a rural area of The Gambia between June and December 1999 to test whether a reduction in the infectious reservoir can reduce malaria transmission. Overall 14,017 (85%) individuals living in the study area were treated with either placebo or sulfadoxine-pyrimethamine (SP) combined with a single dose of artesunate (AS). Following the mass drug administration (MDA) 1375 children aged 6 months to 10 years were kept under surveillance for clinical malaria in 18 villages throughout the 1999 malaria transmission season. During a 20-week surveillance period 637 episodes of malaria were detected. The mean incidence rate was 2.5/100 child-weeks in the placebo villages, and 2.3/100 child-weeks in villages that received SP + AS. The mean rate ratio, adjusted for individual and village-level covariates, was 0.91 (95% CI 0.68-1.22, P = 0.49). During the first 2 months of surveillance, the malaria incidence was lower in treated villages. After 2 months the incidence was slightly higher in the MDA group but this was not statistically significant. Overall, no benefit of the MDA could be detected. The reason for the absence of an impact on malaria transmission is probably the very high basic reproductive number of malaria, and the persistence of mature gametocytes, which are not affected by AS treatment.

Adult↗