Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 40
Filtrar
1.
Tissue Antigens ; 81(2): 93-107, 2013 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-23330720

RESUMEN

Class I human leukocyte antigens (HLA) play an important role in the adaptive immune response by presenting antigens to CD8+ T cells. Studies have reported that several HLA class I alleles are associated with differential disease progression in human immunodeficiency virus (HIV)-infected individuals, however, few class I associations with resistance or susceptibility to HIV-1 infection have been reported. We typed HLA-A, -B and -C of >1000 women enrolled in the Pumwani Sex Worker Cohort using a sequence-based typing method. Kaplan-Meier analysis was used to identify alleles influencing seroconversion and disease progression to acquired immune deficiency syndrome (CD4 < 200/mm³). A*01 (P = 0.020), C*06:02 (P = 0.042) and C*07:01 (P = 0.050) are independently associated with protection from seroconversion. Women with any of these alleles are less likely to seroconvert [P = 0.00001, odds ratio (OR): 0.503, 95% confidence interval (CI): 0.320-0.790]. Conversely, A*23:01 (P = 0.004), B*07:02 (P = 0.003) and B*42:01 (P = 0.025) are independently associated with rapid seroconversion. Women with any of these alleles are twice as likely to seroconvert (P = 0.002, OR: 2.059, 95% CI: 1.290-3.285). The beneficial alleles confer threefold protection from seroconversion when compared with the susceptible alleles (P = 0.000001, OR: 0.268, 95% CI: 0.132-0.544). B*07:02 is the contributing allele, within the B7 supertype, to the rapid seroconversion. A*74:01 (P = 0.04/P = 0.006), B*14 (P = 0.003/P = 0.003) and B*57:03 (P = 0.012/P = 0.038) are independently associated with slower CD4+ decline and LTNP phenotype, while B*07:02 (P = 0.020), B*15:10 (P = 0.022) and B*53:01 (P = 0.007) are independently associated with rapid CD4+ T-cell decline. B7 supertype (P = 0.00006), B*35*-Py (P = 0.028) and B*35-Px (P = 0.001) were also significantly associated with rapid CD4+ T-cell decline. Understanding why these HLA class I alleles are associated with protection/susceptibility to HIV-1 acquisition and disease progression could contribute to the development of effective prophylactic and therapeutic vaccines for HIV-1.


Asunto(s)
Progresión de la Enfermedad , Predisposición Genética a la Enfermedad , Seropositividad para VIH/inmunología , Seropositividad para VIH/patología , VIH-1/inmunología , Antígenos de Histocompatibilidad Clase I/genética , Trabajadores Sexuales , Alelos , Linfocitos T CD4-Positivos/inmunología , Estudios de Cohortes , Femenino , Estudios de Asociación Genética , Sitios Genéticos/genética , Infecciones por VIH/inmunología , Antígenos HLA-A/genética , Antígenos HLA-A/inmunología , Antígenos HLA-B/genética , Antígenos HLA-B/inmunología , Antígenos HLA-C/genética , Antígenos HLA-C/inmunología , Antígenos de Histocompatibilidad Clase I/inmunología , Humanos , Estimación de Kaplan-Meier , Kenia , Desequilibrio de Ligamiento/genética , Análisis Multivariante
4.
Sex Transm Infect ; 78 Suppl 1: i114-20, 2002 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-12083429

RESUMEN

Although it seems possible in a developing country context such as Kenya, given appropriate inputs and a sound approach, to shift a sexually transmitted disease (STI) epidemic from phase II to III, it is not entirely clear how to go beyond this stage, to low levels of endemicity or even elimination. Perhaps the most important challenge now is to expand STI treatment and community STI/HIV prevention programmes to a much larger scale. Although successful programmes have been implemented in many areas of sub-Saharan Africa on a small scale, a significant impact in reducing the STI/HIV burden will not occur until programme reach is expanded to district, provincial, and national levels.


Asunto(s)
Países en Desarrollo/estadística & datos numéricos , Práctica de Salud Pública , Enfermedades de Transmisión Sexual/epidemiología , Adulto , Brotes de Enfermedades , Femenino , Humanos , Kenia/epidemiología , Masculino , Tamizaje Masivo , Servicio Ambulatorio en Hospital , Embarazo , Trabajo Sexual , Conducta Sexual , Enfermedades de Transmisión Sexual/prevención & control , Enfermedades de Transmisión Sexual/transmisión
6.
Sex Transm Infect ; 77(4): 271-5, 2001 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-11463927

RESUMEN

OBJECTIVE: To assess the association between vaginal douching and sexually transmitted infections (STI) among a group of female sex workers (FSWs) in Nairobi, Kenya. METHODS: This study was part of a randomised, placebo controlled trial of monthly prophylaxis with 1 g of azithromycin to prevent STIs and HIV infection in a cohort of Nairobi FSWs. Consenting women were administered a questionnaire and screened for STIs. RESULTS: The seroprevalence of HIV-1 among 543 FSWs screened was 30%. HIV infection was significantly associated with bacterial vaginosis (BV), trichomoniasis, gonorrhoea, and the presence of a genital ulcer. Regular douching was reported by 72% of the women, of whom the majority inserted fluids in the vagina, generally after each sexual intercourse. Water with soap was the fluid most often used (81%), followed by salty water (18%), water alone (9%), and a commercial antiseptic (5%). Douching in general and douching with soap and water were significantly associated with bacterial vaginosis (p = 0.05 and p = 0.04 respectively). There was a significant trend for increased frequency of douching and higher prevalence of BV. There was no direct relation observed between douching and risk for HIV infection or other STIs. CONCLUSION: The widespread habit of douching among African female sex workers was confirmed. The association between vaginal douching and BV is of concern, given the increased risk of HIV infection with BV, which has now been shown in several studies. It is unclear why we could not demonstrate a direct association between douching and HIV infection. Further research is required to better understand the complex relation between douching, risk for bacterial vaginosis, and risk for HIV and other STIs.


Asunto(s)
Trabajo Sexual , Enfermedades de Transmisión Sexual/etiología , Irrigación Terapéutica/efectos adversos , Adulto , Femenino , Infecciones por VIH/epidemiología , Infecciones por VIH/etiología , VIH-1 , Humanos , Kenia/epidemiología , Modelos Logísticos , Análisis Multivariante , Riesgo , Estudios Seroepidemiológicos , Enfermedades de Transmisión Sexual/epidemiología , Vagina , Vaginosis Bacteriana/epidemiología , Vaginosis Bacteriana/etiología
8.
J Acquir Immune Defic Syndr ; 24(5): 458-64, 2000 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-11035617

RESUMEN

BACKGROUND: Accurate predictions of HIV-1 incidence in potential study populations are essential for designing HIV-1 vaccine efficacy trials. Little information is available on the estimated incidence of HIV-1 in such populations, especially information on incidence over time and incidence while participating in risk-reduction programs. OBJECTIVES: To examine time trends in HIV-1 incidence in a vaccine preparedness cohort. DESIGN: Prospective cohort study of female prostitutes in Mombasa, Kenya. METHODS: HIV-1 incidence was determined using open and closed cohort designs. Generalized estimating equations were used to model HIV-1 and sexually transmitted disease (STD) incidence and sexual risk behaviors over time. RESULTS: When analyzed as a closed cohort, HIV-1 incidence declined 10-fold during 3 years of follow-up (from 17.4 to 1.7 cases/100 person-years; p <.001). More than 50% of the cases of HIV-1 occurred during the first 6 months after enrollment, and 73% during the first 12 months. When analyzed as an open cohort, HIV-1 incidence density fell during the first 4 calendar years, influenced by accumulation of lower risk participants and variations in study recruitment. Significant declines occurred in both STD incidence and high-risk sexual behaviors during follow-up. CONCLUSIONS: This study documents a dramatic decline in the risk of HIV-1 infection while participating in a prospective cohort, with most seroconversions occurring within 1 year of enrollment. Variations in HIV-1 incidence within high-risk populations should be anticipated during the design of vaccine trials.


Asunto(s)
Vacunas contra el SIDA , Infecciones por VIH/epidemiología , VIH-1 , Trabajo Sexual/estadística & datos numéricos , Adolescente , Adulto , Ensayos Clínicos como Asunto/estadística & datos numéricos , Estudios de Cohortes , Femenino , Estudios de Seguimiento , Infecciones por VIH/prevención & control , VIH-1/inmunología , Humanos , Incidencia , Kenia/epidemiología , Persona de Mediana Edad , Prevalencia , Estudios Prospectivos , Factores de Riesgo , Conducta Sexual , Enfermedades de Transmisión Sexual/epidemiología
9.
J Infect Dis ; 182(2): 459-66, 2000 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-10915076

RESUMEN

In Kenya, the median incubation time to AIDS in seroconverting sex workers is 4 years; this incubation time is specific to female sex workers. We studied the influence of acute sexually transmitted infections (STIs) on several immunologic parameters in 32 human immunodeficiency virus type 1 (HIV-1)-positive and 10 HIV-1-negative women sex workers who were followed for 1-5 months. Plasma cytokines, soluble cytokine receptors, CD4 and CD8 T cell counts, and HIV-1 plasma viremia were quantitated before, during, and after episodes of STI. Increases in interleukin (IL)-4, IL-6, IL-10, soluble tumor necrosis factor (TNF)-alpha, and viremia and a decline in CD4(+) T cell counts occurred during gonococcal cervicitis and returned to baseline after treatment. Increases in viremia correlated with increased IL-4 and decreased IL-6 concentrations. Similar changes were seen among women with acute pelvic inflammatory disease. Acute bacterial STI resulted in increased HIV-1 viremia. This may be mediated through increased inflammatory cytokines or through modulation of immune responses that control HIV-1 viremia.


Asunto(s)
Linfocitos T CD4-Positivos/citología , Citocinas/sangre , Infecciones por VIH/complicaciones , VIH-1 , Enfermedades de Transmisión Sexual/complicaciones , Viremia/complicaciones , Síndrome de Inmunodeficiencia Adquirida/etiología , Enfermedad Aguda , Adolescente , Adulto , Recuento de Linfocito CD4 , Estudios de Cohortes , Progresión de la Enfermedad , Femenino , Humanos , Interleucinas/sangre , Kenia , Persona de Mediana Edad , Trabajo Sexual , Factor de Necrosis Tumoral alfa/análisis
10.
Int J STD AIDS ; 11(12): 804-11, 2000 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11138916

RESUMEN

Our objectives were to describe the baseline findings of a trial of antibiotic prophylaxis to prevent sexually transmitted infections (STIs) and HIV-1 in a cohort of Nairobi female sex workers (FSWs). A questionnaire was administered and a medical examination was performed. HIV-negative women were randomly assigned to either one gram azithromycin or placebo monthly. Mean age of the 318 women was 32 years, mean duration of sex work 7 years and mean number of clients was 4 per day. High-risk behaviour was frequent: 14% practised anal intercourse, 23% sex during menses, and 3% used intravenous drugs. While 20% reported condom use with all clients, 37% never use condoms. However, STI prevalence was relatively low: HIV-1 27%, bacterial vaginosis 46%, Trichomonas vaginalis 13%, Neisseria gonorrhoeae 8%, Chlamydia trachomatis 7%, syphilis 6% and cervical intraepithelial neoplasia (CIN) 3%. It appears feasible to access a population of high-risk FSWs in Nairobi with prevention programmes, including a proposed trial of HIV prevention through STI chemoprophylaxis.


Asunto(s)
Antibacterianos/uso terapéutico , Azitromicina/uso terapéutico , Infecciones por VIH/prevención & control , VIH-1 , Trabajo Sexual , Enfermedades de Transmisión Sexual/prevención & control , Adolescente , Adulto , Antibacterianos/administración & dosificación , Azitromicina/administración & dosificación , Estudios de Cohortes , Esquema de Medicación , Femenino , Infecciones por VIH/microbiología , Humanos , Incidencia , Kenia/epidemiología , Persona de Mediana Edad , Prevalencia , Asunción de Riesgos , Conducta Sexual , Enfermedades de Transmisión Sexual/epidemiología , Vaginosis Bacteriana/epidemiología
11.
AIDS ; 13(5): 583-9, 1999 Apr 01.
Artículo en Inglés | MEDLINE | ID: mdl-10203383

RESUMEN

OBJECTIVES: To monitor and analyse trends in HIV-1 seroprevalence among antenatal women in Nairobi, Kenya. DESIGN: Six sequential surveys were carried out among antenatal clinic attenders at four Nairobi City Council health centres between November 1991 and April 1997. METHODS: A total of 6828 women attending for first antenatal clinic visit were administered a standard questionnaire to obtain demographic information and were screened for HIV-1. RESULTS: HIV-1 seroprevalence rose from 12.1% in the first survey to 16.2% in the third, completed in October 1993. No rise was observed in subsequent surveys, and seroprevalence among women under the age of 20 declined after the third survey. Significant differences in seroprevalence (P < 0.001) were observed in all survey rounds between women who reported that their province of origin was Nyanza (22.4% overall), compared with those from other provinces in western Kenya (14.1%), and the eastern group of provinces (8.9%). The rise in HIV-1 seroprevalence observed between 1991 and 1993 was almost entirely attributable to the rising seroprevalence among women from Nyanza. There were considerable differences in HIV-1 seroprevalence among the four health centres, partly accounted for by differences in the proportion of clinic attenders from different provinces of origin, which also changed significantly over time. CONCLUSIONS: HIV-1 seroprevalence has stabilized in antenatal women attending these health centres in Nairobi, and may be declining among women in the youngest age group. This may reflect stabilization of HIV-1 incidence, but further observation is required. The levels of infection among Nairobi residents reflect the evolution of the HIV epidemic in their provinces of origin, and changing client composition influences HIV-1 seroprevalence at different clinics. HIV sentinel surveillance should be carried out at multiple sites in large urban centres to monitor accurately the evolution of the HIV epidemic and the impact of control efforts in reducing transmission.


Asunto(s)
Infecciones por VIH/epidemiología , VIH-1 , Adolescente , Adulto , Femenino , Infecciones por VIH/sangre , Humanos , Kenia/epidemiología , Tamizaje Masivo , Persona de Mediana Edad , Prevalencia
12.
AIDS ; 13(1): 23-9, 1999 Jan 14.
Artículo en Inglés | MEDLINE | ID: mdl-10207541

RESUMEN

OBJECTIVES: Most HIV-1 transmission is sexual; therefore, immune responses in the genital mucosa may be important in mediating protection against HIV infection. This study examined HIV-1-specific mucosal IgA in a cohort of HIV-1-resistant Kenyan female sex workers. METHODS: HIV-1-specific immune responses were compared in HIV-1-resistant and HIV-1-infected sex workers, and in lower risk uninfected women. Cervical and vaginal samples from each group were tested for HIV-1-specific IgA and IgG by enzyme immunoassay. Systemic T-helper lymphocyte cell responses to HIV-1 envelope peptide epitopes were assayed using an interleukin 2 bioassay. HIV-1 risk-taking behaviours were assessed using standardized questionnaires. RESULTS: HIV-1-specific IgA was present in the genital tract of 16 out of 21 (76%) HIV-1-resistant sex workers, five out of 19 (26%) infected women, and three out of 28 (11%) lower risk women (P < 0.0001). Among lower risk women, the presence of HIV-1-specific IgA was associated with HIV-1 risk-taking behaviour. Systemic T-helper lymphocyte responses to HIV-1 envelope peptides were present in 11 out of 20 (55%) HIV-1-resistant women, four out of 18 (22%) infected women, and one out of 25 (4%) lower risk women (P < 0.001). T-helper lymphocyte responses did not correlate with the presence or titre of virus-specific mucosal IgA in any study group. CONCLUSIONS: HIV-1-specific IgA is present in the genital tract of most HIV-1-resistant Kenyan sex workers, and of a minority of lower risk uninfected women, where it is associated with risk-taking behaviour. These data suggest a role for mucosal HIV-1-specific IgA responses in HIV-1 resistance, independent of host cellular responses.


Asunto(s)
Cuello del Útero/inmunología , Anticuerpos Anti-VIH/inmunología , Infecciones por VIH/inmunología , VIH-1/inmunología , Inmunoglobulina A/inmunología , Trabajo Sexual , Vagina/inmunología , Recuento de Linfocito CD4 , Estudios de Cohortes , Femenino , Infecciones por VIH/epidemiología , Humanos , Inmunidad Innata/inmunología , Inmunoglobulina G , Kenia/epidemiología , Membrana Mucosa/inmunología
13.
Sex Transm Dis ; 24(7): 387-92, 1997 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-9263358

RESUMEN

BACKGROUND AND OBJECTIVES: Genital ulcer disease (GUD) is a major risk factor for human immunodeficiency virus (HIV) transmission. Cross-sectional studies have suggested that HIV infection may itself predispose to genital ulceration (GU). GOAL: To prospectively study the effects of HIV type 1 (HIV-1) infection and behavioral variables on GU incidence. METHODS: A cohort of 302 Kenyan female sex-workers was established in April 1991. Women were scheduled for assessment every 2 weeks, and bloods were collected every 6 months for HIV serology, rapid plasma reagin (RPR) and CD4 counts. Logistic regression was used to study risk factors for incident genital ulcers. RESULTS: 189 women (62.5%) had at least one incident ulcer over 24.3 +/- 15.3 months. GU incidence was higher in seropositive than initially seronegative women (82% vs. 48%; odds ratio [OR]) = 4.33; P < 0.01). Only HIV-1 seropositivity (OR = 3.42), a CD4 count < 200/ml (OR = 1.94), and oral contraceptive use (OR = 1.35) were associated (P < 0.05) with GU incidence in regression analysis. For those ulcers where an etiology was actively sought, Hemophilus ducreyi was confirmed in 54 (19%) of cases, and syphilis in 30 (29%). CONCLUSION: GU incidence in Kenyan sex workers is independently affected by HIV-1 serostatus, degree of immunosuppression, and oral contraceptive use.


PIP: Both cross-sectional and prospective studies in Africa have revealed an association between genital ulcer disease (GUD) and HIV-1; it is unclear, however, which of these infections facilitates the other. The epidemiology of GUD was investigated in a prospective cohort study of 302 female sex workers from a slum area in Nairobi, Kenya. At study intake in 1985, 157 women (52%) were HIV-1 seropositive. After a mean follow-up duration of 27.2 months, 36 (25%) initially HIV-negative women seroconverted. 189 women (62.5%) had at least 1 incident ulcer in the follow-up period and a total of 541 new cases were diagnosed. GUD incidence was significantly higher in HIV-positive women (82%) than initially seronegative women (48%). The mean number of new genital ulcerations recorded during the follow-up period was 1.8 (2.7 in initially seropositive women and 1.0 in initially seronegative women). The only significant risk factors for GUD incidence in the regression analyses were HIV-1 seropositivity (odds ratio (OR), 3.42), a CD4 count under 200/ml (OR, 1.94), and oral contraceptive use (OR, 1.35). The significant increase in GUD incidence observed relatively soon after primary HIV infection among the 36 seroconverters strongly suggests that HIV-1 itself plays a causal role in the etiology of genital ulcers. Moreover, the finding that the duration of prostitution was negatively associated with the incidence of ulcers in HIV-negative but not HIV-positive women implies that HIV-1 infection may attenuate the acquisition or retention of effective immune responses against the etiologic agents of GUD.


Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/complicaciones , Enfermedades de los Genitales Femeninos/etiología , VIH-1 , Trabajo Sexual , Úlcera/etiología , Adulto , Anticonceptivos Orales/efectos adversos , Femenino , Humanos , Estudios Prospectivos , Factores de Riesgo
14.
AIDS ; 11(7): 875-82, 1997 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-9189212

RESUMEN

OBJECTIVES: To determine the efficacy of isoniazid 300 mg daily for 6 months in the prevention of tuberculosis in HIV-1-infected adults and to determine whether tuberculosis preventive therapy prolongs survival in HIV-1-infected adults. DESIGN AND SETTING: Randomized, double-blind, placebo-controlled trial in Nairobi, Kenya. SUBJECTS: Six hundred and eighty-four HIV-1-infected adults. MAIN OUTCOME MEASURES: Development of tuberculosis and death. RESULTS: Three hundred and forty-two subjects received isoniazid and 342 received placebo. The median CD4 lymphocyte counts at enrolment were 322 and 346 x 10(6)/l in the isoniazid and placebo groups, respectively. The overall median follow-up from enrolment was 1.83 years (range, 0-3.4 years). The incidence of tuberculosis in the isoniazid group was 4.29 per 100 person-years (PY) of observation [95% confidence interval (CI) 2.78-6.33] and 3.86 per 100 PY of observation (95% CI, 2.45-5.79) in the placebo group, giving an adjusted rate ratio for isoniazid versus placebo of 0.92 (95% CI, 0.49-1.71). The adjusted rate ratio for tuberculosis for isoniazid versus placebo for tuberculin skin test (TST)-positive subjects was 0.60 (95% CI, 0.23-1.60) and for the TST-negative subjects, 1.23 (95% CI, 0.55-2.76). The overall adjusted mortality rate ratio for isoniazid versus placebo was 1.18 (95% CI, 0.79-1.75). Stratifying by TST reactivity gave an adjusted mortality rate ratio in those who were TST-positive of 0.33 (95% CI, 0.09-1.23) and for TST-negative subjects, 1.39 (95% CI, 0.90-2.12). CONCLUSIONS: Overall there was no statistically significant protective effect of daily isoniazid for 6 months in the prevention of tuberculosis. In the TST-positive subjects, where reactivation is likely to be the more important pathogenetic mechanism, there was some protection and some reduction in mortality, although this was not statistically significant. The small number of individuals in this subgroup made the power to detect a statistically significant difference in this subgroup low. Other influences that may have diluted the efficacy of isoniazid include a high rate of transmission of new infection and rapid progression to disease or insufficient duration of isoniazid in subjects with relatively advanced immunosuppression. The rate of drug resistance observed in subjects who received isoniazid and subsequently developed tuberculosis was low.


Asunto(s)
Infecciones Oportunistas Relacionadas con el SIDA/prevención & control , Antituberculosos/uso terapéutico , Isoniazida/uso terapéutico , Tuberculosis/prevención & control , Infecciones Oportunistas Relacionadas con el SIDA/mortalidad , Adolescente , Adulto , Anciano , Antituberculosos/efectos adversos , Antituberculosos/orina , Progresión de la Enfermedad , Método Doble Ciego , Femenino , Estudios de Seguimiento , Humanos , Isoniazida/efectos adversos , Isoniazida/orina , Masculino , Cooperación del Paciente , Estudios Retrospectivos , Análisis de Supervivencia , Resultado del Tratamiento , Tuberculosis/complicaciones , Tuberculosis/mortalidad
15.
Lancet ; 348(9038): 1347-51, 1996 Nov 16.
Artículo en Inglés | MEDLINE | ID: mdl-8918278

RESUMEN

BACKGROUND: There is indirect evidence that HIV-1 exposure does not inevitably lead to persistent infection. Heterogeneity in susceptibility to infection could be due to protective immunity. The objective of this study was to find out whether in highly HIV-1-exposed populations some individuals are resistant to infection. METHODS: We did an observational cohort study of incident HIV-1 infection-among 424 initially HIV-1-seronegative prostitutes in Nairobi, Kenya, between 1985 and 1994. 239 women seroconverted to HIV-1 during the study period. Exponential, Weibull, and mixture survival models were used to examine the effect of the duration of follow-up on incidence of HIV-1 infection. The influence of the duration of exposure to HIV-1 through prostitution on seroconversion risk was examined by Cox proportional hazards modelling, with control for other known or suspected risk factors for incident HIV-1 infection. HIV-1 PCR with env, nef, and vif gene primers was done on 43 persistently seronegative prostitutes who remained seronegative after 3 or more years of follow-up. FINDINGS: Modelling of the time to HIV-1 seroconversion showed that the incidence of HIV-1 seroconversion decreased with increasing duration of exposure, which indicates that there is heterogeneity in HIV-1 susceptibility or acquired immunity to HIV-1. Each weighted year of exposure through prostitution resulted in a 1.2-fold reduction in HIV-1 seroconversion risk (hazard ratio 0.83 [95% CI 0.79-0.88], p < 0.0001). Analyses of epidemiological and laboratory data, show that persistent seronegativity is not explained by seronegative HIV-1 infection or by differences in risk factors for HIV-1 infection such as safer sexual behaviours or the incidence of other sexually transmitted infections. INTERPRETATION: We conclude that a small proportion of highly exposed individuals, who may have natural protective immunity to HIV-1, are resistant to HIV-1.


PIP: A cohort study conducted in 1985-94 among 424 prostitutes from Nairobi, Kenya, who were initially human immunodeficiency virus (HIV)-1 seronegative, tended to provide support for the observation that some individuals in highly exposed populations may be resistant to infection. During the 10-year study period, 239 of these women seroconverted. The overall HIV-1 incidence was 42/100 person-years. After the first 2 years of follow up, in which the majority of seroconversions occurred, HIV-1 prevalence reached a plateau and then began a steep decline. To determine whether the risk of HIV-1 infection declined over time as a result of the selection of resistance, incidence rates among women with less than 3 years' versus more than 3 years' duration of prostitution were compared for 1989-93. An increasing protective effect for each seronegative year of exposure was observed. The estimated cumulative protective effect for women practicing prostitution from 1984-93 and remaining seronegative, compared to women who entered prostitution in 1994, was over 100-fold. To rule out the possibility that the decrease in seroconversion with duration of exposure reflected differences in sexual behavior or immunity to sexually transmitted diseases that facilitate HIV transmission, Cox proportional hazards modelling was performed. The weighted duration of prostitution was independently associated with a decreased risk of seroconversion. Each weighted year of exposure resulted in a 1.2-fold decrease in risk. Women who seroconverted were more likely to report 1 or more regular partners and to use condoms with these partners than their counterparts who remained seronegative. Elucidation of the protective mechanisms and the factors mediating the development of immunity against HIV-1 could be important to HIV-1 vaccine research.


Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/inmunología , Seronegatividad para VIH/inmunología , VIH-1 , Trabajo Sexual , Estudios de Cohortes , Femenino , Seropositividad para VIH/epidemiología , Humanos , Inmunidad Innata , Incidencia , Kenia/epidemiología , Exposición Profesional , Modelos de Riesgos Proporcionales , Estudios Prospectivos , Factores de Riesgo
16.
J Infect Dis ; 174 Suppl 2: S240-7, 1996 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-8843254

RESUMEN

Peer-mediated education programs in Kenya and Zimbabwe focusing on female sex workers for the control of human immunodeficiency virus (HIV) infection and other sexually transmitted diseases (STDs) have led to increased condom use and increased adoption of other safer sex practices, as well as declines in STD and HIV incidence among female sex workers. It is likely that similar declines have occurred among their clients and possibly in the general community, although supporting data are limited. These results are encouraging. However, progress in increasing the scale and coverage of intervention programs among female sex workers has been slow. Constraints to expanding program coverage include inadequate political commitment; deficiencies in program planning, management, and human resources; and insufficient funding. The challenges currently are to show that behavioral change can be sustained and to scale up activities from small demonstration projects to district, provincial, and national levels.


Asunto(s)
Educación en Salud , Promoción de la Salud , Trabajo Sexual , Enfermedades de Transmisión Sexual/prevención & control , Áreas de Influencia de Salud , Medicina Comunitaria , Condones , Femenino , Infecciones por VIH/prevención & control , Humanos , Kenia , Grupo Paritario , Factores de Riesgo , Conducta Sexual , Zimbabwe
17.
J Acquir Immune Defic Syndr Hum Retrovirol ; 10(4): 457-61, 1995 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-7583442

RESUMEN

Studies from Kenya have reported rapid clinical disease progression among HIV-infected professional sex workers. The reasons for this rapid decline are unknown. To better understand factors influencing the course of disease, HIV-1 disease progression was explored in terms of declines in CD4 counts. Two samples from Nairobi, Kenya, were studied, one from a cohort of female sex workers and another, as a comparison group, from mothers enrolled in an HIV-1 vertical-transmission study. A Markov model was used to analyze transitions between HIV-1 disease stages as defined by CD4 counts. It appears that sex workers experience a rapid decline in CD4 counts, consistent with earlier findings of rapid clinical disease progression among individuals in this group. The rate of decline in CD4 counts among the mothers appears to be lower. It is speculated that either intensive exposure to sexually transmitted pathogens or infection with several strains of HIV-1 may account for the rapid disease progression among female sex workers.


Asunto(s)
Linfocitos T CD4-Positivos/inmunología , Seropositividad para VIH/inmunología , VIH-1 , Trabajo Sexual , Adulto , Recuento de Linfocito CD4 , Estudios de Cohortes , Progresión de la Enfermedad , Femenino , Infecciones por VIH/transmisión , Seropositividad para VIH/transmisión , Humanos , Transmisión Vertical de Enfermedad Infecciosa , Kenia , Cadenas de Markov
18.
Sex Transm Dis ; 22(4): 231-5, 1995.
Artículo en Inglés | MEDLINE | ID: mdl-7482106

RESUMEN

BACKGROUND: Controlling sexually transmitted diseases requires that partners of patients with a sexually transmitted disease be notified and treated. However, many countries in the developing world lack the infrastructure and resources for effective partner referral. GOAL OF THIS STUDY: To provide information on rates of partner referral in primary-level health centers in Kenya, to identify characteristics of patients with sexually transmitted diseases who inform their partners about the need for treatment, and to evaluate the impact of a brief counseling intervention on rates of partner notification. STUDY DESIGN: Two-hundred-fifty-four patients presenting for treatment of a sexually transmitted disease were given 5 to 10 minutes of additional counseling on the importance of referring partners for sexually transmitted disease treatment. All patients who returned for follow-up 1 week later were interviewed to determine whether they had notified their sex partners. RESULTS: Sixty-eight percent of patients who returned for follow-up reported they had referred their partners for treatment of a sexually transmitted disease. The highest rates of partner notification occurred among women attending maternal child health/family planning clinics and married men and women attending general outpatient clinics. CONCLUSION: Strengthening and directing counseling toward women in maternal child health/family planning clinics and married men and women in general clinics may be an effective and inexpensive way to increase partner notification in the developing world.


PIP: In developing countries, patient referral is a more feasible means of notifying partners of sexually transmitted disease (STD) clients than the costly, labor-intensive provider referral approach. However, enhancement strategies such as education and counseling, contact cards, educational materials, follow-up, and monetary incentives may be necessary. To assess the impact of brief counseling on patient referral rates, a study was conducted at five primary health care centers in low-income areas of Nairobi, Kenya. All 254 STD patients who attended the clinic in a two-week period in 1992 were enrolled in the study. Subjects were given 5-10 minutes of counseling, asked to identify their sexual partners, and given a return appointment for the following week. Of the 93 patients who returned to the clinic and provided partner referral data, 63 (68%) reported they informed their partner of the need for STD treatment and 54 (58%) claimed that their partners had been treated. Multivariate analysis indicated that partner notification rates were highest for females, married individuals or those with regular partners, and maternal-child health/family planning clinic patients. Although 84% of unmarried men, 66% of unmarried women, and 47% of married men were infected by a casual sex partner, only 35% of those in the casual partner group attempted notification. Before the study, only 15% of partners presented to the clinics for treatment as a result of partner referral. This provides some evidence of the effectiveness of the counseling strategy, at least for married men and women, although more detailed guidelines on methods of partner notification are recommended.


Asunto(s)
Centros Comunitarios de Salud/organización & administración , Trazado de Contacto , Centros de Salud Materno-Infantil/organización & administración , Derivación y Consulta , Enfermedades de Transmisión Sexual/prevención & control , Adulto , Distribución de Chi-Cuadrado , Femenino , Estudios de Seguimiento , Humanos , Kenia , Masculino
19.
J Infect Dis ; 171(3): 686-9, 1995 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-7876618

RESUMEN

From a cohort of female sex workers in Nairobi, Kenya, 163 women were observed to seroconvert to human immunodeficiency virus type 1 (HIV-1) and followed to study progression to HIV-1-related disease. The effect of several covariables on disease progression was studied using a Weibull proportional hazards model. The Weibull survival model was fitted to the observed incubation times. Estimates of the median duration to CDC stage IV-A and IV-C disease were 3.5 and 4.4 years, respectively. Condom use before seroconversion was associated with a reduced risk of CDC stage IV-A disease (relative risk = .64, P < .05). The incubation time of HIV-1-related disease is extremely short in this population.


Asunto(s)
Síndrome de Inmunodeficiencia Adquirida/complicaciones , VIH-1 , Trabajo Sexual , Adulto , Femenino , Estudios de Seguimiento , Humanos
20.
Am J Public Health ; 84(12): 1947-51, 1994 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-7998635

RESUMEN

OBJECTIVES: The purpose of this study was to identify health-care seeking and related behaviors relevant to controlling sexually transmitted diseases in Kenya. METHODS: A total of 380 patients with sexually transmitted diseases (n = 189 men and 191 women) at eight public clinics were questioned about their health-care seeking and sexual behaviors. RESULTS: Women waited longer than men to attend study clinics and were more likely to continue to have sex while symptomatic. A large proportion of patients had sought treatment previously in both the public and private sectors without relief of symptoms, resulting in delays in presenting to study clinics. For women, being married and giving a recent history of selling sex were both independently associated with continuing to have sex while symptomatic. CONCLUSIONS: Reducing the transmission of sexually transmitted diseases in Kenya will require improved access, particularly for women, to effective health services, preferably at the point of first contact with the health system. It is also critical to encourage people to reduce sexual activity while symptomatic, seek treatment promptly, and increase condom use.


Asunto(s)
Aceptación de la Atención de Salud , Enfermedades de Transmisión Sexual/transmisión , Femenino , Humanos , Kenia , Masculino , Conducta Sexual , Enfermedades de Transmisión Sexual/diagnóstico
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA