Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 20
Filtrar
1.
Tech Coloproctol ; 28(1): 45, 2024 Apr 03.
Artículo en Inglés | MEDLINE | ID: mdl-38568325

RESUMEN

BACKGROUND: Faecal incontinence (FI) is common, with a significant impact on quality of life. Percutaneous tibial nerve stimulation (PTNS) is a therapy for FI; however, its role has recently been questioned. Here we report the short-term clinical and manometric outcomes in a large tertiary centre. METHODS: A retrospective review of a prospective PTNS database was performed, extracting patient-reported FI outcome measures including bowel diary, the St Marks's Incontinence Score (SMIS) and Manchester Health Questionnaire (MHQ). Successful treatment was > 50% improvement in symptoms, whilst a partial response was 25-50% improvement. High-resolution anorectal manometry (HRAM) results before and after PTNS were recorded. RESULTS: Data were available from 135 patients [119 (88%) females; median age: 60 years (range: 27-82years)]. Overall, patients reported a reduction in urge FI (2.5-1) and passive FI episodes (2-1.5; p < 0.05) alongside a reduction in SMIS (16.5-14) and MHQ (517.5-460.0; p < 0.001). Some 76 (56%) patients reported success, whilst a further 20 (15%) reported a partial response. There were statistically significant reductions in rectal balloon thresholds and an increase in incremental squeeze pressure; however, these changes were independent of treatment success. CONCLUSION: Patients report PTNS improves FI symptoms in the short term. Despite this improvement, changes in HRAM parameters were independent of this success. HRAM may be unable to measure the clinical effect of PTNS, or there remains the possibility of a placebo effect. Further work is required to define the role of PTNS in the treatment of FI.


Asunto(s)
Incontinencia Fecal , Femenino , Humanos , Masculino , Persona de Mediana Edad , Incontinencia Fecal/terapia , Manometría , Estudios Prospectivos , Calidad de Vida , Nervio Tibial , Adulto , Anciano , Anciano de 80 o más Años
2.
Tech Coloproctol ; 21(12): 937-943, 2017 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-29196959

RESUMEN

BACKGROUND: Complete mesocolic excision for right-sided colon cancer may offer an oncologically superior excision compared to traditional right hemicolectomy through high vascular tie and adherence to embryonic planes during dissection, supported by preoperative scanning to accurately define the tumour lymphovascular supply and drainage. The authors support and recommend precision oncosurgery based on these principles, with an emphasis on the importance of understanding the vascular anatomy. However, the anatomical variability of the right colic artery (RCA) has resulted in significant discord in the literature regarding its precise arrangement. METHODS: We systematically reviewed the literature on the incidence of the different origins of the RCA in cadaveric studies. An electronic search was conducted as per Preferred Reporting Items for Systematic Reviews and Meta-analyses recommendations up to October 2016 using the MESH terms 'right colic artery' and 'anatomy' (PROSPERO registration number CRD42016041578). RESULTS: Ten studies involving 1073 cadavers were identified as suitable for analysis from 211 articles retrieved. The weighted mean incidence with which the right colic artery arose from other parent vessels was calculated at 36.8% for the superior mesenteric artery, 31.9% for the ileocolic artery, 27.7% for the root of the middle colic artery and 2.5% for the right branch of the middle colic artery. In 1.1% of individuals the RCA shared a trunk with the middle colic and ileocolic arteries. The weighted mean incidence of 2 RCAs was 7.0%, and in 8.9% of cadavers the RCA was absent. CONCLUSIONS: This anatomical information will add to the technical nuances of precision oncosurgery in right-sided colon resections.


Asunto(s)
Arterias/anatomía & histología , Colon Ascendente/irrigación sanguínea , Colon Transverso/irrigación sanguínea , Neoplasias del Colon/cirugía , Cadáver , Colon Ascendente/cirugía , Colon Transverso/cirugía , Humanos
3.
Ann R Coll Surg Engl ; 98(8): 560-563, 2016 Nov.
Artículo en Inglés | MEDLINE | ID: mdl-27502338

RESUMEN

INTRODUCTION Hemicolectomies are not tailored in right-sided colon cancer resections, despite significant variation in the incidence and origin of the right colic artery (RCA). Early evidence suggests that removal of the relevant lymphovascular package and associated cancer as part of complete mesocolic excision (CME), rather than the entire right colon, may produce better outcomes. Advancing laparoscopic techniques are making this possible, and so it is increasingly important to more precisely define the anatomy of the RCA. METHODS To demonstrate the incidence and variation of the RCA, 25 formalin embalmed cadavers were dissected. Consent to dissection and photography was obtained under Human Tissue Act regulations. RESULTS Eleven female and 14 male cadavers (mean age 79.7 years, range 41-95 years) were included. The RCA originated from the right branch of the middle colic artery in nine cadavers (36%), while it arose from the superior mesenteric artery in eight cases (32%) and from the ileocolic or root of the middle colic artery in a smaller number of specimens. The RCA was absent in two individuals. CONCLUSIONS The RCA arises from the right branch of the middle colic artery in a considerable number of cases. The literature to date does not reflect the precision of anatomical understanding required for CME; hence, a new definition for the right colic vessel is proposed.


Asunto(s)
Colon/irrigación sanguínea , Laparoscopía , Adulto , Anciano , Anciano de 80 o más Años , Colon/cirugía , Femenino , Humanos , Laparoscopía/métodos , Masculino , Arterias Mesentéricas/anatomía & histología , Arterias Mesentéricas/cirugía , Persona de Mediana Edad
4.
Int Health ; 4(1): 47-54, 2012 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-24030880

RESUMEN

Community sensitisation, as a component of community engagement, plays an important role in strengthening the ethics of community-based trials in developing countries and is fundamental to trial success. However, few researchers have shared their community sensitisation strategies and experiences. We report on our perspective as researchers on the sensitisation activities undertaken for a phase II malaria vaccine trial in Kilifi District (Kenya) and Korogwe District (Tanzania), with the aim of informing and guiding the operational planning of future trials. We report wide variability in recruitment rates within both sites; a variability that occurred against a backdrop of similarity in overall approaches to sensitisation across the two sites but significant differences in community exposure to biomedical research. We present a range of potential factors contributing to these differences in recruitment rates, which we believe are worth considering in future community sensitisation plans. We conclude by arguing for carefully designed social science research around the implementation and impact of community sensitisation activities.

5.
Public Health Ethics ; 4(1): 26-39, 2011 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-21416064

RESUMEN

The importance of communities in strengthening the ethics of international collaborative research is increasingly highlighted, but there has been much debate about the meaning of the term 'community' and its specific normative contribution. We argue that 'community' is a contingent concept that plays an important normative role in research through the existence of morally significant interplay between notions of community and individuality. We draw on experience of community engagement in rural Kenya to illustrate two aspects of this interplay: (i) that taking individual informed consent seriously involves understanding and addressing the influence of communities in which individuals' lives are embedded; (ii) that individual participation can generate risks and benefits for communities as part of the wider implications of research. We further argue that the contingent nature of a community means that defining boundaries is generally a normative process itself, with ethical implications. Community engagement supports the enactment of normative roles; building mutual understanding and trust between researchers and community members have been important goals in Kilifi, requiring a broad range of approaches. Ethical dilemmas are continuously generated as part of these engagement activities, including the risks of perverse outcomes related to existing social relations in communities and conditions of 'half knowing' intrinsic to processes of developing new understandings.

6.
AIDS Care ; 20(2): 188-90, 2008 Feb.
Artículo en Inglés | MEDLINE | ID: mdl-18293127

RESUMEN

In Kenya many people who have been affected by sexual violence turn to the health sector for clinical treatment and preventive therapies. This interface provides a vital opportunity to impact on the dual epidemics of HIV and sexual violence. Despite this, the uptake of post-rape care services in health facilities is low and health care providers felt ill-prepared to deal with the consequences of sexual violence. A qualitative study was conducted to better understand the reasons for the low uptake of services and to establish perceptions of sexual violence in Kenya. Thirty-four key informants were interviewed and sixteen focus group discussions with women and men were held in three districts in Kenya. Blurred boundaries between forced and consensual sex emerged. Important implications for the delivery of HIV post exposure prophylaxis (PEP) after sexual violence include the need for gender-aware patient-centred training for health providers and for HIV PEP interventions to strengthen on-going HIV-prevention counselling efforts. Further research needs to determine the feasibility of on-going risk reduction measures in the context of PEP delivery.


Asunto(s)
Fármacos Anti-VIH/uso terapéutico , Atención a la Salud/estadística & datos numéricos , Infecciones por VIH/prevención & control , Violación/psicología , Conducta Sexual/psicología , Violencia/psicología , Adolescente , Adulto , Atención a la Salud/normas , Femenino , Grupos Focales , Infecciones por VIH/transmisión , Humanos , Kenia , Masculino , Violación/prevención & control , Violencia/prevención & control
7.
Eur Respir J ; 28(3): 505-12, 2006 Sep.
Artículo en Inglés | MEDLINE | ID: mdl-16641125

RESUMEN

Reticular basement membrane (RBM) thickening in asthma is considered to be the result of subepithelial fibrosis. Thus, the RBM in asthma should contain an excess of fibrils identified as interstitial collagen and the ratio of fibril to matrix should be increased above normal levels. Electron micrographs of the RBM were compared with those of interstitial collagen deeper in the bronchial wall using endobronchial biopsy specimens from adult asthmatics (aged 18-41 yrs (n = 10)), children with difficult asthma (aged 6-16 yrs (n = 10)), wheezy infants with reversible airflow limitation (aged 0.3-2 yrs (n = 10)) and age-matched nonasthmatic controls: 10 adults, nine children and nine symptomatic infants with normal lung function. Fibrils in the RBM were significantly thinner (median (range) width 39 (30-52) nm versus 59 (48-73) nm), and fewer fibrils were banded than in the interstitial collagen (ratio of banded to non-banded fibrils 0.08 (0-0.17) versus 0.22 (0-1.3)). The ratio of fibrils to matrix in the thickened RBM of asthmatics did not differ from that of their respective controls (1.34 (0.63-2.49) versus 1.18 (0.31-2.6)). The ratio of fibril to matrix in the thickened reticular basement membrane of asthmatics is normal, and, contrary to what is expected in fibrosis, the fibrils do not resemble those of interstitial collagen.


Asunto(s)
Asma/patología , Membrana Basal/ultraestructura , Fibrosis Pulmonar/patología , Adolescente , Adulto , Niño , Preescolar , Femenino , Colágenos Asociados a Fibrillas/ultraestructura , Humanos , Lactante , Masculino , Microscopía Electrónica , Reticulina/ultraestructura
8.
Soc Sci Med ; 61(7): 1463-73, 2005 Oct.
Artículo en Inglés | MEDLINE | ID: mdl-16005781

RESUMEN

Trust is an important theme running through the literature on the ethics of biomedical research, but it is rarely given centre stage. In this paper, we present data gathered from a study aimed at exploring community views regarding the informed consent processes carried out by a large research centre on the Kenyan Coast. The findings point to the centrality of trust and elements of mistrust in general community views, in parents' (mis)understanding of studies they consent their children to be involved in, in refusals and concerns, and in community members' views about whether informed consent is a relevant and practical model to follow. Tentative ideas on how trust and a healthy mistrust might be balanced highlight the importance of strengthening communication surrounding basic health care as well as research, and of fostering 'an inner generated ethic of service'. The latter is particularly fundamental, but cannot be built and regulated through the laws, policies and guidelines that currently govern biomedical research practice.


Asunto(s)
Consentimiento Informado , Confianza/psicología , Investigación Biomédica , Ética en Investigación , Humanos , Consentimiento Informado/ética , Entrevistas como Asunto , Kenia
9.
Soc Sci Med ; 61(2): 443-54, 2005 Jul.
Artículo en Inglés | MEDLINE | ID: mdl-15893058

RESUMEN

Ethical dilemmas in biomedical research, especially in vulnerable populations, often spark heated debate. Despite recommendations and guidelines, many issues remain controversial, including the relevance, prioritisation and application of individual voluntary informed consent in non-Western settings. The voices of the people likely to be the subjects of research have been notably absent from the debate. We held discussions with groups of community members living in the rural study area of a large research unit in Kenya. Discussions were facilitated by three research study vignettes outlining one field-based and two hospital-based studies being planned or taking place at the time. In addition to gathering general views about the aims and activities of the research unit, questions focused on whether consent should be sought for studies, and if so from whom (chiefs, elders, men/women, children), and on ascertaining whether there are any special concerns about the physical act of signing consent forms. The findings revealed the community's difficulty in distinguishing research from clinical investigations conducted in clinical settings. There was a spectrum of views regarding perceived appropriateness of consent procedures, in part because of difficulty in disentangling clinical from research aims, and because of other challenges to applying consent in practice. Debates between community members highlight the inadequacy of simplistic assumptions about community members' views on informed consent, and the complexity of incorporating lay opinions into biomedical research. Failure to appreciate these issues risks exaggerating differences between settings, and underestimating the time and resources required to ensure meaningful community involvement in research processes. Ultimately, it risks inadequately responding to the needs and values of those on whom the success of most biomedical research depends. Although compliance with community views does not necessarily make the research more ethical, it is argued that community opinions on local issues and practices should inform ethical decision-making in health research.


Asunto(s)
Investigación Biomédica/ética , Participación de la Comunidad , Países en Desarrollo , Consentimiento Informado , Femenino , Humanos , Entrevistas como Asunto , Kenia , Masculino
10.
Soc Sci Med ; 59(12): 2547-59, 2004 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-15474208

RESUMEN

In our research unit on the Kenyan Coast, parents sign consent for over 4000 children to be involved in research activities every year. Children are recruited into studies ranging from purely observational research to the testing of new procedures and drugs. Thousands more community members consent verbally or in writing to the interviews and sometimes invasive procedures required in community-based research. Although every study and consent form is reviewed in advance by independent national and international committees, the views and understanding of the 'subjects' of these activities had not been documented before this study. In this paper, we focus on participant understanding of one field-based and two hospital-based studies, all of which involve blood sampling. The findings highlight a range of inter-related issues for consideration in the study setting and beyond, including conceptual and linguistic barriers to communicating effectively about research, the critical and complex role of communicators (fieldworkers and nurses) in consent procedures, features of research unit-community relations which impact on these processes, and the special sensitivity of certain issues such as blood sampling. These themes and emerging recommendations are expected to be relevant to, and would benefit from, experiences and insights of researchers working elsewhere.


Asunto(s)
Comprensión , Investigación sobre Servicios de Salud/ética , Experimentación Humana/ética , Padres/psicología , Pobreza , Consentimiento por Terceros/ética , Adulto , Niño , Comunicación , Revelación , Ética en Investigación , Investigación sobre Servicios de Salud/organización & administración , Humanos , Kenia , Estudios de Casos Organizacionales , Padres/educación , Poder Psicológico , Características de la Residencia
11.
J Biosoc Sci ; 34(1): 109-31, 2002 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-11814209

RESUMEN

This study, conducted on the Kenyan coast, assesses the effect of intra-household relations on maternal treatment-seeking. Rural and urban Mijikenda mothers' responses to childhood fevers in the last 2 weeks (n=317), and to childhood convulsions in the previous year (n=43), were documented through survey work. The intra-household relations and decision-making dynamics surrounding maternal responses were explored through in-depth individual and group interviews, primarily with women (n=223). Responses to convulsions were more likely than responses to fevers to include a healer consultation (p<0.0001), and less likely to include the purchase of over-the-counter medications (p<0.0001). Mothers received financial or advisory assistance from others in 71% (n=236) of actions taken outside the household in response to fevers. In-depth interviews suggested that general agreement on appropriate therapy results in relatively few intra-household conflicts over the treatment of fevers. Disputes over perceived cause and appropriate therapy of convulsions, however, highlighted the importance of age, gender and relationship to household head in intra-household relations and treatment decision-making. Although mothers' treatment-seeking preferences are often circumscribed by these relations, a number of strategies can be drawn upon to circumvent 'inappropriate' decisions, sometimes with implications for future household responses to similar syndromes. The findings highlight the complexity of intra-household relations and treatment decision-making dynamics. Tentative implications for interventions aimed at improving the home management of malaria, and for further research, are presented.


Asunto(s)
Toma de Decisiones , Composición Familiar/etnología , Relaciones Familiares/etnología , Fiebre/etnología , Aceptación de la Atención de Salud/etnología , Convulsiones/etnología , Adaptación Psicológica , Adolescente , Adulto , Niño , Preescolar , Femenino , Fiebre/epidemiología , Humanos , Lactante , Kenia/epidemiología , Padres/psicología , Aceptación de la Atención de Salud/estadística & datos numéricos , Vigilancia de la Población , Rol , Convulsiones/epidemiología , Percepción Social
12.
Environ Urban ; 14(1): 203-217, 2002 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-23814409

RESUMEN

This paper describes the mobility patterns, rural-urban linkages and household structures for a low-income neighbourhood on the outskirts of Mombasa, Kenya's main port, and a rural settlement 60 kilometres away. Drawing on interviews with a sample of mothers resident in each location, it documents their perceptions of the advantages and disadvantages of rural and urban life, and shows the continuous interchange between the two areas. It also highlights how most rural to urban migrants are familiar with urban environments before moving and how, having moved, many maintain strong rural ties. The ways in which households are split across rural and urban areas is influenced by intra-household relations and by household efforts to balance the income-earning opportunities in town, the relatively low cost of living in rural areas and future family security. This produces dramatic differences between and among rural and urban mothers and suggests a need for policy makers and planners to recognize diversity and to build upon complex livelihood strategies that span the rural-urban divide.

14.
Trop Med Int Health ; 5(5): 377-83, 2000 May.
Artículo en Inglés | MEDLINE | ID: mdl-10886803

RESUMEN

The district general hospital (DGH) is a common feature of health service provision in many developing countries. We have used linked demographic and clinical surveillance in a rural community located close to a DGH on the Kenyan coast to define the use and public health significance of essential clinical services provided by it. Of a birth cohort of over 4000 children followed for approximately 6 years, about a third were admitted to hospital at least once. Significantly more children admitted with major infectious diseases such as malaria and acute respiratory tract infections were readmitted with the same condition during the surveillance period than would have been expected by chance. Among surviving admissions, mortality post-discharge was significantly higher than in the cohort which had not been admitted within 3, 6 and 12 months. Most of the patients who died after discharge had been admitted with a diagnosis of gastroenteritis. Most children admitted to the DGH survive hospitalization and the remaining period of childhood. Despite no clinical trial evidence to support the claim, it seems reasonable to assume that in the absence of intensive clinical management provided by a DGH, a significant proportion of these children would not have survived. However, the DGH is able to define a group of at-risk children who re-present with severe complications of infectious disease, and of these several may have underlying conditions not amenable to DGH intervention and continue to have a poor prognosis. Both groups of children represent statistically significant subsets of a rural paediatric community and the future organization and co-ordination of DGH and primary care services need to work in unison to strengthen the service needs of children at risk.


Asunto(s)
Hospitalización , Malaria/mortalidad , Niño , Estudios de Seguimiento , Humanos , Readmisión del Paciente , Riesgo
15.
Health Policy Plan ; 14(1): 18-25, 1999 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-10351466

RESUMEN

The results of recently completed trials in Africa of insecticide-treated bed nets (ITBN) offer new possibilities for malaria control. These experimental trials aimed for high ITBN coverage combined with high re-treatment rates. Whilst necessary to understand protective efficacy, the approaches used to deliver the intervention provide few indications of what coverage of net re-treatment would be under operational conditions. Varied delivery and financing strategies have been proposed for the sustainable delivery of ITBNs and re-treatment programmes. Following the completion of a randomized, controlled trial on the Kenyan coast, a series of suitable delivery strategies were used to continue net re-treatment in the area. The trial adopted a bi-annual, house-to-house re-treatment schedule free of charge using research project staff and resulted in over 95% coverage of nets issued to children. During the year following the trial, sentinel dipping stations were situated throughout the community and household members informed of their position and opening times. This free re-treatment service achieved between 61-67% coverage of nets used by children for three years. In 1997 a social marketing approach, that introduced cost-retrieval, was used to deliver the net re-treatment services. The immediate result of this transition was that significantly fewer of the mothers who had used the previous re-treatment services adopted this revised approach and coverage declined to 7%. The future of new delivery services and their financing are discussed in the context of their likely impact upon previously defined protective efficacy and cost-effectiveness estimates.


PIP: Recent trials of insecticide-treated bednets (ITBN) in Africa sought to achieve high ITBN coverage together with high net retreatment rates. Following the completion of a randomized, controlled trial on the coast of Kenya, a series of delivery strategies were used to continue net retreatment in the area. Adherence to a free bi-annual, house-to-house retreatment schedule resulted in a more than 95% coverage of nets issued to children. During the year following the trial, sentinel dipping stations were situated throughout the community and household members informed of their locations and opening times. More than 85% of bednets were re-impregnated between October 1993 and October 1995, and 61-67% coverage of nets used by children for 3 years after the free retreatment service was launched beginning in 1996. The introduction of a social marketing approach at sentinel sites in 1997 to retrieve some of the costs of the net retreatment services caused coverage to drop to 7.1% among children still resident in the study area who had had nets since 1993. The future of new delivery services and their financing are discussed with regard to their likely impact upon previously defined protective efficacy and cost-effectiveness estimates.


Asunto(s)
Lechos , Mordeduras y Picaduras de Insectos/prevención & control , Insecticidas/uso terapéutico , Malaria/prevención & control , Plasmodium malariae , Servicios Preventivos de Salud/métodos , Equipos de Seguridad , Piretrinas/uso terapéutico , Animales , Recolección de Datos , Países en Desarrollo , Estudios de Evaluación como Asunto , Humanos , Kenia/epidemiología , Permetrina
16.
Trop Med Int Health ; 4(12): 836-45, 1999 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-10632992

RESUMEN

Urbanization is an important demographic phenomenon in sub-Saharan Africa, and rural-urban migration remains a major contributor to urban growth. In a context of sustained economic recession, these demographic processes have been associated with a rise in urban poverty and ill health. Developments in health service provision need to reflect new needs arising from demographic and disease ecology change. In malaria-endemic coastal Kenya, we compared lifelong rural (n = 248) and urban resident (n = 284) Mijikenda mothers' responses to childhood fevers. Despite marked differences between the rural and urban study areas in demographic structure and physical access to biomedical services, rural and urban mothers' treatment-seeking patterns were similar: most mothers sought only biomedical treatment (88%). Shop-bought medicines were used first or only in 69% of the rural and urban fevers that were treated, and government or private clinics were contacted in 49%. A higher proportion of urban informal vendors stocked prescription-only drugs, and urban mothers more likely to contact a private than a government facility. We conclude that improving self-treatment has enormous potential to reduce morbidity and mortality in low-income urban areas, as has frequently been argued for rural areas. However, because of the underlying socio-economic, cultural and structural differences between rural and urban areas, rural approaches to tackle this may have to be modified in urban environments.


Asunto(s)
Actitud Frente a la Salud , Protección a la Infancia/psicología , Fiebre/terapia , Accesibilidad a los Servicios de Salud , Madres/psicología , Adulto , Factores de Edad , Antimaláricos , Niño , Preescolar , Femenino , Humanos , Lactante , Kenia , Población Rural , Población Urbana
17.
Nat Med ; 4(3): 358-60, 1998 Mar.
Artículo en Inglés | MEDLINE | ID: mdl-9500614

RESUMEN

The feasibility of a malaria vaccine is supported by the fact that children in endemic areas develop naturally acquired immunity to disease. Development of disease immunity is characterized by a decrease in the frequency and severity of disease episodes over several years despite almost continuous infection, suggesting that immunity may develop through the acquisition of a repertoire of specific, protective antibodies directed against polymorphic target antigens. Plasmodium falciparum erythrocyte membrane protein 1 (PfEMP1) is a potentially important family of target antigens, because these proteins are inserted into the red cell surface and are prominently exposed and because they are highly polymorphic and undergo clonal antigenic variation, a mechanism of immune evasion maintained by a large family of var genes. In a large prospective study of Kenyan children, we have used the fact that anti-PfEMP1 antibodies agglutinate infected erythrocytes in a variant-specific manner, to show that the PfEMP1 variants expressed during episodes of clinical malaria were less likely to be recognized by the corresponding child's own preexisting antibody response than by that of children of the same age from the same community. In contrast, a heterologous parasite isolate was just as likely to be recognized. The apparent selective pressure exerted by established anti-PfEMP1 antibodies on infecting parasites supports the idea that such responses provide variant-specific protection against disease.


Asunto(s)
Variación Antigénica/inmunología , Antígenos de Protozoos/inmunología , Proteínas Sanguíneas/inmunología , Eritrocitos/parasitología , Malaria Falciparum/inmunología , Proteínas Protozoarias/inmunología , Factores de Edad , Pruebas de Aglutinación , Anticuerpos Antiprotozoarios/sangre , Especificidad de Anticuerpos , Niño , Preescolar , Estudios Transversales , Humanos , Lactante , Kenia/epidemiología , Malaria Falciparum/epidemiología , Oportunidad Relativa , Vigilancia de la Población , Estudios Prospectivos
18.
Lancet ; 349(9066): 1650-4, 1997 Jun 07.
Artículo en Inglés | MEDLINE | ID: mdl-9186382

RESUMEN

BACKGROUND: Malaria remains a major cause of mortality and morbidity in Africa. Many approaches to malaria control involve reducing the chances of infection but little is known of the relations between parasite exposure and the development of effective clinical immunity so the long-term effect of such approaches to control on the pattern and frequency of malaria cannot be predicted. METHODS: We have prospectively recorded paediatric admissions with severe malaria over three to five years from five discrete communities in The Gambia and Kenya. Demographic analysis of the communities exposed to disease risk allowed the estimation of age-specific rates for severe malaria. Within each community the exposure to Plasmodium falciparum infection was determined through repeated parasitological and serological surveys among children and infants. We used acute respiratory-tract infections (ARI) as a comparison. FINDINGS: 3556 malaria admissions were recorded for the five sites. Marked differences were observed in age, clinical spectrum and rates of severe malaria between the five sites. Paradoxically, the risks of severe disease in childhood were lowest among populations with the highest transmission intensities, and the highest disease risks were observed among populations exposed to low-to-moderate intensities of transmission. For severe malaria, for example, admission rates (per 1000 per year) for children up to their 10th birthday were estimated as 3.9, 25.8, 25.9, 16.7, and 18.0 in the five communities; the forces of infection estimated for those communities (new infections per infant per month) were 0.001, 0.034, 0.050, 0.093, and 0.176, respectively. Similar trends were noted for cerebral malaria and for severe malaria anaemia but not for ARI. Mean age of disease decreased with increasing transmission intensity. INTERPRETATION: We propose that a critical determinant of life-time disease risk is the ability to develop clinical immunity early in life during a period when other protective mechanisms may operate. In highly endemic areas measures which reduce parasite transmission, and thus immunity, may lead to a change in both the clinical spectrum of severe disease and the overall burden of severe malaria morbidity.


PIP: 3556 pediatric admissions with severe malaria over 3-5 years from five discrete communities in the Gambia and Kenya were recorded prospectively in a study of the relationship between parasite exposure and the development of effective clinical immunity against malaria. The exposure to Plasmodium falciparum infection in each community was determined through repeated parasitological and serological surveys among children and infants, while acute respiratory tract infections (ARI) were used as a comparison. Clear differences were observed in age, clinical spectrum, and rates of severe malaria between the five sites. The risks of severe disease in childhood were lowest in populations with the highest transmission intensities, while the highest disease risks were observed among populations exposed to low-to-moderate intensities of transmission. Similar trends were observed for cerebral malaria and severe malaria anemia, but not for ARI. The mean age of disease decreased with increasing transmission intensity.


Asunto(s)
Malaria Falciparum/epidemiología , Anemia/epidemiología , Anemia/etiología , Niño , Preescolar , Gambia/epidemiología , Hospitalización/estadística & datos numéricos , Humanos , Lactante , Recién Nacido , Kenia/epidemiología , Malaria Cerebral/epidemiología , Malaria Cerebral/parasitología , Malaria Cerebral/transmisión , Malaria Falciparum/inmunología , Malaria Falciparum/parasitología , Malaria Falciparum/transmisión , Oportunidad Relativa , Vigilancia de la Población , Infecciones del Sistema Respiratorio/epidemiología , Riesgo
19.
Acta Trop ; 65(1): 1-10, 1997 Apr 30.
Artículo en Inglés | MEDLINE | ID: mdl-9140509

RESUMEN

Both malaria and undernutrition are major causes of paediatric mortality and morbidity in sub-Saharan Africa. The introduction of insecticide-treated bed nets (ITBN) during a randomized controlled trial on the Kenyan coast significantly reduced severe, life-threatening malaria and all-cause childhood mortality. This paper describes the effects of the intervention upon the nutritional status of infants aged between 1 and 11 months of age. Seven hundred and eighty seven infants who slept under ITBN and 692 contemporaneous control infants, were seen during one of three cross-sectional surveys conducted during a one year period. Standardized weight-for-age and mid-upper arm circumference measures were significantly higher among infants who used ITBN compared with control infants. Whether these improvements in markers of nutritional status were a direct result of concomitant reductions in clinical malaria episodes remains uncertain. Never-the-less evidence suggests that even moderate increases in weight-for-age scores can significantly reduce the probability of mortality in childhood and ITBN may provide additional gains to child survival beyond their impressive effects upon malaria-specific events.


Asunto(s)
Fenómenos Fisiológicos Nutricionales del Lactante , Insecticidas/farmacología , Malaria Falciparum/prevención & control , Control de Mosquitos , Ropa de Cama y Ropa Blanca , Biomarcadores , Estudios Transversales , Humanos , Lactante , Recién Nacido , Aumento de Peso
20.
Am J Trop Med Hyg ; 55(2): 144-9, 1996 Aug.
Artículo en Inglés | MEDLINE | ID: mdl-8780451

RESUMEN

Repeated cross-sectional surveys among infants sleeping under insecticide-treated bed nets (ITBN) and contemporary control infants were used to estimate changes in Plasmodium falciparum exposure due to ITBN use on the Kenyan coast. Presence of P. falciparum parasites or total P. falciparum Immunoglobulin M (IgM) seropositivity were used independently and in combination in a constant risk catalytic conversion model to estimate the force of infection in ITBN and control communities. Such studies during infancy avoid problems of early saturation of prevalence due to high forces of infection and persistence of infection, minimize problems of self-treatment, and can be conducted among large populations covering a wide geographic area. These contrast previous parasitologic studies of ITBN among older children and the traditional entomologic studies of transmission that are logistically demanding. Our investigations demonstrated that parasite prevalence, IgM seropositivity, and the force of transmission were all significantly reduced by 50%. In addition, more infants under ITBN entered their second year of life without previous exposure to P. falciparum than control infants. These effects upon delayed acquisition of effective immunity require careful monitoring during future vector control programs using ITBN.


Asunto(s)
Ropa de Cama y Ropa Blanca , Inmunoglobulina M/sangre , Malaria Falciparum/epidemiología , Parasitemia/epidemiología , Plasmodium falciparum/inmunología , Factores de Edad , Animales , Anticuerpos Antiprotozoarios/sangre , Estudios Transversales , Humanos , Lactante , Insecticidas , Kenia/epidemiología , Malaria Falciparum/prevención & control , Parasitemia/prevención & control , Permetrina , Plasmodium falciparum/aislamiento & purificación , Prevalencia , Piretrinas , Estaciones del Año
SELECCIÓN DE REFERENCIAS
DETALLE DE LA BÚSQUEDA
...