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T Rinke de Wit

Publications and source records attributed to T Rinke de Wit.

12 recordsLinked to original sources
PubMed2002

Low incidence of syphilis among factory workers in Ethiopia: effect of an intervention based on education and counselling.

BACKGROUND: The prevalence and incidence of syphilis infection were examined in a cohort study of factory workers in Ethiopia. METHOD: Between February 1997 and March 1999, 409 men and 348 women were enrolled and followed in the cohort study. RESULTS: The prevalence (95% CI) of past/current syphilis (positive TPPA serology) was 28.9% (25.7% to 32.3%), and factors associated with past/current syphilis were markers of risky sexual behaviours including HIV infection. In this cohort of factory workers subject to public information/education meetings, testing for HIV antibodies, and individual counselling, the incidence (97.5% one sided CI) of new syphilis infections was 0/691 = 0 (0 to 0.5) per 100 person years. CONCLUSION: This study has documented a reduction in risky sexual behaviours and a low syphilis incidence among factory workers participating in a cohort study on HIV infection progression in Addis Ababa.

Adolescent↗
PubMed2001

Factors associated with HIV-1 infection among sex workers of Addis Ababa, Ethiopia.

OBJECTIVE: To study the prevalence and risk factors for HIV infection among sex workers of Addis Ababa, Ethiopia. DESIGN AND METHODS: Cross-sectional survey on socio-demographic characteristics, behaviours, and HIV serological status of sex workers attending two health centres of Addis Ababa. RESULTS: HIV prevalence among sex workers was 274 of 372 (73.7%). Several factors were significantly associated with an increased risk of being HIV-infected [among others, working in 'shared rooms', high number of clients, use of injectable hormones, and positive Treponema pallidum particle agglutination (TPPA) serology], and others with a decreased risk (being born in Addis Ababa, high level of education, peer education on sex work, condom use, use of oral pill, and use of condoms for contraception). Of interest, sex workers who were using condoms for contraception were, compared with others, more likely to use condoms consistently (65 versus 24%, respectively; P < 0.001), and less likely to be HIV-infected (55 versus 86%, respectively; P < 0.001). In multivariate analysis [log-binomial model, giving estimates of the prevalence ratio (PR)], being born in Addis Ababa (PR = 0.74; 95% confidence interval (CI), 0.61-0.91), using condoms for contraception (PR = 0.73; 95% CI, 0.64-0.85), and a positive TPPA serology (PR = 1.21; 95% CI, 1.09-1.36), remained significantly associated with HIV infection. CONCLUSIONS: HIV prevalence was remarkably high among sex workers of Addis Ababa. Condom use was higher, and HIV prevalence lower, in sex workers using condoms not only for prevention of HIV and sexually transmitted diseases, but also for contraceptive purpose. This finding is of particular interest for its implications for prevention strategies among sex workers in the developing world.

Adolescent↗
PubMed2000

Epidemiology of infections with intestinal parasites and human immunodeficiency virus (HIV) among sugar-estate residents in Ethiopia.

Intestinal parasitic infections could play an important role in the progression of infection with human immunodeficiency virus (HIV), by further disturbing the immune system whilst it is already engaged in the fight against HIV. HIV and intestinal parasitic infections were investigated in 1239, randomly selected individuals, aged 15-54 years, living on a sugar estate in central Ethiopia. Intestinal parasites were identified in faecal samples (one/subject) using direct, concentration, and (for Strongyloides stercoralis larvae) Baermann methods. HIV serological status was determined using ELISA, with ELISA-positive samples confirmed as positive by western blotting. Most (70.1%) of the subjects were infected with at least one intestinal parasite and 3.1% were seropositive (but asymptomatic) for HIV. The intestinal parasites identified in the study population were amoebic parasites (Entamoeba histolytica/Enta. dispar) (24.6%), hookworms (23.8%), Ascaris lumbricoides (22.2%), Trichuris trichiura (19.5%), S. stercoralis (13.0%), Taenia saginata (4.5%), Giardia lamblia (3.0%), and Enterobius vermicularis (1.3%). Overall, the HIV-positives were no more or less likely to carry intestinal parasites than the HIV-negatives (76.2% v. 69.9%; P > 0.05). However, when each parasite was considered separately, amoebic parasites were found to be more common in the HIV-positives than the HIV-negatives (43.7% v. 24.0%; P < 0.05). This difference remained significant in a multivariate analysis, after controlling for the socio-demographic characteristics of the study participants. In conclusion, there was moderate interaction between intestinal parasites and HIV at the asymptomatic stage of HIV infection. The observed association between amoebic and HIV infections requires confirmation in a prospective study, allowing for the analysis of biological mechanisms involved in the association.

Adolescent↗
PubMed2000

Epidemiology of HIV and Schistosoma mansoni infections among sugar-estate residents in Ethiopia.

Few studies have examined the interaction between schistosomiasis and infection with human immunodeficiency virus (HIV). The overlap between the two infections, and the effect of HIV infection on the egg output and worm load of individuals co-infected with Schistosoma mansoni, were therefore investigated in a sugar estate in central Ethiopia. The 1239 subjects were selected by stratified sampling of residents aged 15-54 years. The intensities of infection with S. mansoni were measured as egg output in stools (all subjects) and as the concentration of circulating cathodic antigen (CCA) in urine (a proxy for worm load, measured in 287 subjects). Schistosome infection was detected in 358 subjects [adjusted prevalence (AP) = 31.4%] and HIV infection in 52 (AP = 3.1%). The two infections clustered into different populations of the estate: the schistosome infections were predominantly found in the camps, and primarily affected young people (aged < 20 years) and those working in the field, whereas the HIV epidemic was found in the main village, primarily affecting those aged > 20 years and those who had recently arrived on the estate. Schistosome infection was detected in 348 of the 1187 HIV-negatives (AP = 31.6%) and 10 of the 52 HIV-positives (AP = 25.1%; P > 0.05). Schistosoma mansoni egg output was significantly lower in the HIV-positives than in the HIV-negatives (Mann-Whitney test; P = 0.03; ratio of geometric means = 0.74), and remained so after controlling for potential confounders (gender, age, and residence). However, CCA concentrations (i.e. worm loads) were found to be similar for these two groups, after controlling for potential confounders (age, gender, residence, and duration of residence).

Adolescent↗
PubMed1999

Sexual behaviours, perception of risk of HIV infection, and factors associated with attending HIV post-test counselling in Ethiopia.

OBJECTIVES: To describe sexual behaviours, perception of risk of HIV infection, and factors associated with attending HIV post-test counselling (PTC) among Ethiopian adults. METHODS: Data on socio-demographic characteristics, knowledge of HIV infection, sexual history, medical examination, and HIV and syphilis serological status were compared, through uni- and multivariate analysis, in relation to attending PTC within 60 days of HIV testing. RESULTS: Between February 1997 and June 1998, 751 factory workers were enrolled in a cohort study of HIV infection progression. Despite reporting high-risk sexual behaviours, mainly for males (64% of males and 6% of females had more than five sexual partners in their lifetime, 16% of males and 2% of females reported having had recent casual partners), and knowing that HIV is commonly transmitted heterosexually in Ethiopia (97% of answers being correct, both genders combined), only 17% of males and 2% of females acknowledged having had activities which had put them at risk of HIV infection. HIV prevalence was 12%, and did not differ by gender. Of all study participants, 327 (43.5%) returned for PTC within 60 days of HIV testing. PTC attendance did not differ by age, gender, or HIV serological status. Factors independently associated with PTC attendance in males were: good knowledge of HIV infection, [odds ratio (OR) = 1.661, belief that medical follow-up improves the course of HIV infection (OR = 2.02), history of genital symptoms (OR = 2.83), positive syphilis serology (OR = 2.62), recent weight loss (OR = 1.89), and, with a negative association, being a manual worker (OR = 0.40), and history of recent casual sexual relationships (OR = 0.35). In women, belief that HIV/AIDS can be cured (OR = 3.16), never having been married (OR = 5.02), having five or less children (OR = 2.16), having been raped (OR = 3.42), and having used health facilities in the past year (OR = 1.73) were all positively and independently associated with PTC attendance. CONCLUSION: Study participants reported high-risk sexual behaviours, yet had a low perception of individual risk. Men attended for PTC because of their knowledge of HIV infection, their past sexual history or their current health status. Women attended for PTC because of their plans for the future, marriage and/or children, rather than their past sexual exposure. Only in cases of rape were they willing to learn of their HIV status.

AIDS Serodiagnosis↗
PubMed1998

Age- and sex-specific HIV-1 prevalence in the urban community setting of Addis Ababa, Ethiopia.

OBJECTIVE: To estimate the age and sex-specific prevalence of HIV infection in the population of Addis Ababa, Ethiopia. DESIGN: Two-stage cluster sampling of the population aged 0-49 years of Addis Ababa, using kebeles (urban dwelling associations) as clusters. METHODS: The sera used for this study were collected in an earlier study (1994) on the rate of acquisition of antibodies against measles, rubella, and hepatitis B. After separate approvals were obtained from the institutional ethics committees, sera were tested by enzyme-linked immunosorbent assay confirmed by Western blot. Age- and sex-specific HIV prevalence rates were estimated. The prevalence of HIV in men and women over 15 years of age was compared by calculating age-standardized HIV prevalence, using the age distribution of the census population as the standard. A time-dependent catalytic model was used to obtain crude estimates of HIV incidence from age-prevalence data. RESULTS: A total of 3853 sera were available for analysis. The prevalence of HIV in adults was 6.0% [95% confidence interval (CI), 4.5-7.4%] for men and 6.9% (95% CI, 5.3-8.5%) for women, with peak prevalence in the 25-29 year age group of 16.3 and 11.8%, respectively. After standardization for age using the direct method, the HIV prevalence ratio comparing adult men with women was 0.97:1 (95% CI, 0.70:1 - 1.35:1). Three children aged less than 5 years were HIV-positive. The prevalence of HIV among adults ranged from 0-21.3% in different clusters, indicating the heterogeneity of the spread of HIV in the city. HIV prevalence estimates among the antenatal clinic patients of Addis Ababa in 1996 far exceeded the estimates obtained during the community survey, particularly in the youngest age group (15-24 years). Estimates of HIV incidence (per susceptible person per annum) for the age group 16-22 years ranged from 1.3-2.25% for men and from 2.1-2.4% for women. CONCLUSION: By 1994, a substantial proportion of the adult population of Addis Ababa was infected with HIV. Promotion of behavioural changes and the control of sexually transmitted diseases should be strongly supported to limit the spread of the HIV epidemic in Ethiopia.

Adolescent↗
PubMed1998

Identification of a site for a cohort study on natural history of HIV infection in Ethiopia.

A cross-sectional survey was carried out in a sugar estate in central Ethiopia to identify a subgroup for a cohort study on the natural history of HIV infection. HIV prevalence was 2.8% (95% confidence interval [CI], 1.7%-3.9%) in 957 adults aged 15 to 54 years randomly selected for the initial survey. A follow-up survey including only factory workers of the estate aged 18 to 45 years (n = 280) showed a higher HIV prevalence in male factory workers (n = 262) compared with the male estate workers of the same age of the initial survey (n = 484; 8.8% versus 3.1 %; p < .05). Factors independently associated with HIV infection in male factory workers were number of lifetime sexual partners, positive syphilis serology, higher income, and absence of travel outside the residential area. Among male estate workers, only older age was associated with HIV infection. Both factory workers and male estate workers were stable residents and were willing to participate in a long-term study on HIV/ AIDS. However, because of the higher HIV prevalence in factory workers and the higher prevalence of behaviors associated with an increased risk for HIV infection, factory workers were selected for the long-term cohort study on the natural history of HIV infection.

Adolescent↗
PubMed1994

Characterization of a Mycobacterium leprae antigen related to the secreted Mycobacterium tuberculosis protein MPT32.

Secreted proteins may serve as major targets in the immune response to mycobacteria. To identify potentially secreted Mycobacterium leprae antigens, antisera specific for culture filtrate proteins of Mycobacterium tuberculosis were used to screen a panel of recombinant antigens selected previously by leprosy patient sera. Four potentially secreted antigens were identified by this approach, and one was recognized by antibodies specific for MPT32, a secreted M. tuberculosis protein. The DNA coding for the M. leprae antigen, which we have designated 43L, was isolated and characterized and found to encode a 25.5-kDa protein that is preceded by a consensus signal peptide of 39 amino acids. The N-terminal amino acid sequence of 43L shows 50% homology with the 20 known N-terminal amino acids of MPT32, and 47% homology was found with the N terminus of a 45/47-kDa antigen complex identified in Mycobacterium bovis BCG. These findings indicate that 43L represents an antigen related to MPT32 and the M. bovis BCG 45/47-kDa complex and that 43L is likely to be a protein secreted by M. leprae. Purified recombinant 43L protein is recognized by antibodies and T cells from healthy contacts and leprosy patients, illustrating that secreted proteins are of importance in the immune response to M. leprae.

Amino Acid Sequence↗
PubMed1992

A personal computer program for large-scale comparisons of related nucleotide sequences.

A personal computer program (COMPSEQ) has been developed which can present an informative listing of pre-aligned exonic nucleotide sequences and of their translations to amino acid sequences as well run triplet-oriented analyses on these sequences in a given reading frame. The sequence listing focuses on the differences between related sequences by suppressing the concordances between them.

Algorithms↗
PubMed1991

Cellular immune recognition of HLA-G-expressing choriocarcinoma cell line Jeg-3.

Jeg-3 choriocarcinoma cells express class-I MHC HLA-G and low levels of a novel HLA-C product. The functional significance of such novel MHC class-I expression in regard of the cellular immune response has been investigated. Jeg-3 cells are NK-insensitive, but susceptible to LAK cytotoxicity, some of which is mediated by T cells. No Jeg-3-specific CTL or proliferative responses could be generated in allogeneic responder PBMC from several different donors. There was no detectable xenogeneic recognition of Jeg-3 cells even when preceded by in vivo priming. Jeg-3 cells are able to suppress proliferative responses in humans and others species. This is not reproduced by conditioned medium from the Jeg-3 cells, but can be overridden by IL-2. The ability of the Jeg-3 choriocarcinoma (trophoblast) cells to suppress in the MLR may reflect the processes which are shared to enable the survival of the foetus in a semi-allogeneic mother or a tumour in its host. It is not clear whether there is any relationship between the unusual class-I-MHC expression by trophoblast and the putative regulatory properties of the latter.

Animals↗
PubMed1988

MHC class I expression by developmental tumors: teratocarcinoma stem cells are TCA positive.

We have investigated the expression of antigens recognized by several alloantisera and monoclonal antibodies to class I and class I-like MHC gene products on four developmental tumor cell lines derived from teratocarcinoma and choriocarcinoma. The analysis by cytotoxicity, immunoprecipitation, and Northern blotting analysis was also performed following treatment of the cells with gamma interferon. Three of four of the cell lines apparently do not express polymorphic determinants of HLA-A,B,C class I MHC genes. Immunoprecipitation with antibodies to HLA monomorphic determinants or beta 2m showed that some cell lines express distinct novel class I MHC-like molecules; the latter show molecular sizes different from regular HLA molecules and are associated with beta 2m. The Northern blotting showed class I mRNA present in three out of four of the developmental tumor cell lines but at at least tenfold lower levels than in lymphoid cells; it is possible that the RNAs homologous to class I DNA probes include transcripts of non-HLA-A,B,C genes. The cells were serologically typed for one such locus, TCA, which lies telomeric to HLA-A; the choriocarcinomas are negative and the teratocarcinomas are positive. The relationship between the different antigenic molecules and their possible functional significance is discussed in terms of maternofetal interactions, cancer, and transplantation.

Choriocarcinoma↗