RESUMEN
BACKGROUND: A number of different treatment algorithms are recommended for the treatment of an acute pilonidal abscess and a chronic pilonidal sinus. While a 1-stage surgical procedure using excision or plastic reconstruction according to Limberg or Karydakis is suggested for chronic pilonidal sinus, a 2stage procedure is recommended for an acute pilonidal abscess. The aim of this study was to compare the results of the 1stage surgery with plastic reconstruction according to Limberg for acute pilonidal abscess and chronic pilonidal sinus in terms of recurrence, disorders of wound healing, inpatient length of stay and patient satisfaction. METHODS: From 2009 to 2014 a total of 39 patients were included in this prospective observational study: 21 patients with acute pilonidal abscess and 18 patients with chronic pilonidal sinus. All patients were surgically treated with a 1stage procedure using the Limberg flap method. The groups were compared in terms of postoperative complication rates and frequency of recurrence. RESULTS: Both groups were basically comparable with respect to demographic characteristics and risk factor profiles. Analysis of the postoperative results showed a comparable rate of postoperative wound healing disorders (10% vs. 17%, pâ¯= 0.647). In the group with acute pilonidal abscesses there was no recurrence during the observational period, while in the chronic pilonidal sinus group there were 2 (11%) recurrences (pâ¯= 0.206). CONCLUSION: The results of the Limberg flap procedure regarding acute pilonidal abscesses were comparable to those of chronic pilonidal sinus. The results of this study show a trend to a lower risk of recurrence. The use of the Limberg flaps therefore also seems to be an adequate treatment option in an acute infection situation.
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Seno Pilonidal , Absceso/cirugía , Humanos , Recurrencia Local de Neoplasia , Seno Pilonidal/cirugía , Complicaciones Posoperatorias/etiología , Recurrencia , Colgajos Quirúrgicos , Resultado del TratamientoRESUMEN
PURPOSE: Postoperative pancreatic fistulae (POPF) present a serious and life-threatening complication after pancreatic head resections (PD). Therefore, reliable risk stratification to identify those at risk is urgently needed. The aim of this study was to identify postoperative laboratory parameters for the prediction of POPF in the early postoperative period. METHODS: One hundred eighty-two patients who underwent PD from 2012 until 2017 were retrospectively analyzed. Multivariate logistic regression was performed using the GLM (general linear model) method for model building. Two nomograms were created based on the GLM models of postoperative day one and postoperative day one to five. A cohort of 48 patients operated between 2018 and 2019 served as internal validation. RESULTS: Clinically relevant pancreatic fistulae (CR-POPF) were present in 16% (n = 29) of patients. Patients with CR-POPF experienced significantly more insufficiencies of gastroenterostomies, delayed gastric emptying, and more extraluminal bleeding than patients without CR-POPF. Multivariate analysis revealed multiple postoperative predictive models, the best one including ASA, main pancreatic duct diameter, operation time, and serum lipase as well as leucocytes on day one. This model was able to predict CR-POPF with an accuracy of 90% and an AUC of 0.903. Two nomograms were created for easier use. CONCLUSION: Clinically relevant fistula can be predicted using simple laboratory and clinical parameters. Not serum amylase, but serum lipase is an independent predictor of CR-POPF. Our simple nomograms may help in the identification of patients for early postoperative interventions.
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Fístula Pancreática , Pancreaticoduodenectomía , Humanos , Nomogramas , Fístula Pancreática/diagnóstico , Fístula Pancreática/etiología , Pancreaticoduodenectomía/efectos adversos , Periodo Posoperatorio , Estudios Retrospectivos , Factores de RiesgoRESUMEN
BACKGROUND: Nationwide audits facilitate quality and outcome assessment of pancreatoduodenectomy. Differences may exist between countries but studies comparing nationwide outcomes of pancreatoduodenectomy based on audits are lacking. This study aimed to compare the German and Dutch audits for external data validation. METHODS: Anonymized data from patients undergoing pancreatoduodenectomy between 2014 and 2016 were extracted from the German Society for General and Visceral Surgery StuDoQ|Pancreas and Dutch Pancreatic Cancer Audit, and compared using descriptive statistics. Univariable and multivariable risk analyses were undertaken. RESULTS: Overall, 4495 patients were included, 2489 in Germany and 2006 in the Netherlands. Adenocarcinoma was a more frequent indication for pancreatoduodenectomy in the Netherlands. German patients had worse ASA fitness grades, but Dutch patients had more pulmonary co-morbidity. Dutch patients underwent more minimally invasive surgery and venous resections, but fewer multivisceral resections. No difference was found in rates of grade B/C postoperative pancreatic fistula, grade C postpancreatectomy haemorrhage and in-hospital mortality. There was more centralization in the Netherlands (1·3 versus 13·3 per cent of pancreatoduodenectomies in very low-volume centres; P < 0·001). In multivariable analysis, both hospital stay (difference 2·49 (95 per cent c.i. 1·18 to 3·80) days) and risk of reoperation (odds ratio (OR) 1·55, 95 per cent c.i. 1·22 to 1·97) were higher in the German audit, whereas risk of postoperative pneumonia (OR 0·57, 0·37 to 0·88) and readmission (OR 0·38, 0·30 to 0·49) were lower. Several baseline and surgical characteristics, including hospital volume, but not country, predicted mortality. CONCLUSION: This comparison of the German and Dutch audits showed variation in case mix, surgical technique and centralization for pancreatoduodenectomy, but no difference in mortality and pancreas-specific complications.
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Auditoría Médica , Pancreaticoduodenectomía/normas , Pautas de la Práctica en Medicina/estadística & datos numéricos , Indicadores de Calidad de la Atención de Salud/estadística & datos numéricos , Adulto , Anciano , Anciano de 80 o más Años , Femenino , Alemania , Humanos , Masculino , Persona de Mediana Edad , Análisis Multivariante , Países Bajos , Evaluación de Resultado en la Atención de Salud , Pancreaticoduodenectomía/métodos , Pancreaticoduodenectomía/mortalidad , Pancreaticoduodenectomía/estadística & datos numéricos , Complicaciones Posoperatorias/epidemiología , Sistema de RegistrosRESUMEN
INTRODUCTION AND PURPOSE: Despite being technically challenging, laparoscopic surgical procedures are increasingly being used also in pancreatic surgery. This review attempts to evaluate these procedures based on the currently available literature against the background of the high mortality of pancreatic surgery observed nationwide and the as yet unclear oncological validation of these procedures. MATERIAL AND METHODS: Recently published retrospective cohort and register trials have evaluated not only perioperative outcome but also long-term survival after laparoscopic pancreatic resection. RESULTS AND CONCLUSION: Laparoscopic interventions are increasingly being used for treatment of malignant tumors of the pancreas. The advantages of laparoscopy, such as less intraoperative blood loss, reduced postoperative pain and a shorter duration of hospital stay, have all been demonstrated in retrospective trials. Equivalent long-term survival after oncological laparoscopic pancreatic surgery compared to open procedures was also observed in these trials; however, mortality even after laparoscopic pancreatic surgery was found to be significantly increased in low-volume centers. Prospective trials are still needed to prove adequate oncological treatment. Laparoskopische Verfahren haben sich in den letzten Jahren in fast allen Bereichen der Chirurgie quasi zum Standard entwickelt und werden von Patienten zunehmend nachgefragt. Die kosmetischen Ergebnisse sind deutlich besser als bei konventionellem Vorgehen und sie reduzieren unter anderem den postoperativen Schmerz, Schmerzmittelbedarf sowie den Krankenhausaufenthalt [29]. Daher ist es wenig überraschend, dass minimal-invasive Verfahren auch bei technisch hochkomplexen Eingriffen, wie z. B. am Pankreas, zunehmend eingesetzt werden. Allerdings wird ihr Einsatz hier noch immer kontrovers diskutiert.
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Laparoscopía/métodos , Pancreatectomía/métodos , Neoplasias Pancreáticas/cirugía , Estudios de Cohortes , Alemania , Hospitales de Alto Volumen/estadística & datos numéricos , Hospitales de Bajo Volumen/estadística & datos numéricos , Laparoscopía/instrumentación , Pancreatectomía/instrumentación , Neoplasias Pancreáticas/mortalidad , Estudios Retrospectivos , Análisis de SupervivenciaAsunto(s)
Líquidos Corporales/virología , Ebolavirus/aislamiento & purificación , Personal de Salud , Fiebre Hemorrágica Ebola/transmisión , Fiebre Hemorrágica Ebola/virología , Transmisión de Enfermedad Infecciosa de Paciente a Profesional , Humanos , Recurrencia , Medición de Riesgo , Factores de TiempoRESUMEN
There is an increasing role for bioinformatic and phylogenetic analysis in tropical medicine research. However, scientists working in low- and middle-income regions may lack access to training opportunities in these methods. To help address this gap, a 5-day intensive bioinformatics workshop was offered in Lima, Peru. The syllabus is presented here for others who want to develop similar programs. To assess knowledge gained, a 20-point knowledge questionnaire was administered to participants (21 participants) before and after the workshop, covering topics on sequence quality control, alignment/formatting, database retrieval, models of evolution, sequence statistics, tree building, and results interpretation. Evolution/tree-building methods represented the lowest scoring domain at baseline and after the workshop. There was a considerable median gain in total knowledge scores (increase of 30%, p<0.001) with gains as high as 55%. A 5-day workshop model was effective in improving the pathogen-applied bioinformatics knowledge of scientists working in a middle-income country setting.
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Biología Computacional , Filogenia , Estudios de Factibilidad , Humanos , Renta , Perú , Encuestas y CuestionariosRESUMEN
Cancer cell invasion takes place at the cancer-host interface and is a prerequisite for distant metastasis. The relationships between current biological and clinical concepts such as cell migration modes, tumour budding and epithelial-mesenchymal transition (EMT) remains unclear in several aspects, especially for the 'real' situation in human cancer. We developed a novel method that provides exact three-dimensional (3D) information on both microscopic morphology and gene expression, over a virtually unlimited spatial range, by reconstruction from serial immunostained tissue slices. Quantitative 3D assessment of tumour budding at the cancer-host interface in human pancreatic, colorectal, lung and breast adenocarcinoma suggests collective cell migration as the mechanism of cancer cell invasion, while single cancer cell migration seems to be virtually absent. Budding tumour cells display a shift towards spindle-like as well as a rounded morphology. This is associated with decreased E-cadherin staining intensity and a shift from membranous to cytoplasmic staining, as well as increased nuclear ZEB1 expression.
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Adenocarcinoma/patología , Transición Epitelial-Mesenquimal , Invasividad Neoplásica/patología , Biomarcadores de Tumor/análisis , Humanos , Imagenología Tridimensional , InmunohistoquímicaRESUMEN
INTRODUCTION AND PURPOSE: Despite being technically challenging, minimally-invasive pancreatic surgery is increasingly being used to treat pancreatic diseases. Therefore, the evaluation of its oncological safety and its advantages arebecoming increasingly more important. This review focuses on these questions based on the currently available literature. MATERIAL AND METHODS: The technically less demanding laparoscopic distal pancreatectomy has been evaluated in numerous meta-analyses. Minimally invasive pancreaticoduodenectomy has only been reported from a few centers worldwide. RESULTS AND CONCLUSION: Minimally invasive pancreatic surgery, in particular laparoscopic distal pancreatectomy, is increasingly being used to treat pancreatic tumors. The advantages of laparoscopy, such as less intraoperative blood loss, reduced postoperative pain and a shorter length of stay have all been demonstrated in large trials. However, a sufficient oncological treatment was only assessed via indirect surrogate parameters, such as the number of lymph nodes obtained and R0 resection rates; therefore, larger prospective trials are needed to prove adequate oncological treatment. To date, minimally invasive techniques should only be employed in trials on treatment of pancreatic malignancies.
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Laparoscopía/métodos , Neoplasias Pancreáticas/cirugía , Complicaciones Posoperatorias/etiología , Carcinoma Ductal Pancreático/mortalidad , Carcinoma Ductal Pancreático/patología , Carcinoma Ductal Pancreático/cirugía , Terapia Combinada , Cistadenoma Seroso/mortalidad , Cistadenoma Seroso/patología , Cistadenoma Seroso/cirugía , Estudios de Factibilidad , Humanos , Tumores Neuroendocrinos/mortalidad , Tumores Neuroendocrinos/patología , Tumores Neuroendocrinos/cirugía , Páncreas/patología , Páncreas/cirugía , Neoplasias Pancreáticas/mortalidad , Neoplasias Pancreáticas/patología , Complicaciones Posoperatorias/mortalidad , Lesiones Precancerosas/mortalidad , Lesiones Precancerosas/patología , Lesiones Precancerosas/cirugíaRESUMEN
BACKGROUND: Postpancreatectomy hemorrhage is a rare but often severe complication after pancreatic resection. The aim of this retrospective study was to define incidence and risk factors of postpancreatectomy hemorrhage and to evaluate treatment options and outcome. PATIENTS AND METHODS: Clinical data was extracted from a prospectively maintained database. Descriptive statistics, univariate and multivariate risk factor analysis by binary logistic regression were performed with SPSS software at a significance level of p = 0.05. RESULTS: N = 1,082 patients with pancreatic resections between 1994 and 2012 were included. Interventional angiography was successful in about half of extraluminal bleeding. A total of 78 patients (7.2 %) had postpancreatectomy hemorrhage (PPH), and 29 (2.7 %) were grade C PPH. Multivariate modeling disclosed a learning effect, age, BMI, male sex, intraoperative transfusion, portal venous and multivisceral resection, pancreatic fistula and preoperative biliary drainage as independent predictors of severe postpancreatectomy hemorrhage. High-risk histopathology, age, transfusion, pancreatic fistula, postpancreatectomy hemorrhage and pancreatojejunostomy in pancreatoduodenectomies were independent predictors of mortality. CONCLUSIONS: Our study identifies clinically relevant risk factors for postpancreatectomy hemorrhage and mortality. Interventional treatment of extraluminal hemorrhage is successful in about half of the cases and if unsuccessful constitutes a valuable adjunct to operative hemostasis. Based on our observations, we propose a treatment scheme for PPH. Risk factor analysis suggests appropriate patient selection especially for extended resections and pancreatogastrostomy for reconstruction in pancreatoduodenectomy.
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Hemostasis Endoscópica , Pancreatectomía/mortalidad , Fístula Pancreática/mortalidad , Hemorragia Posoperatoria , Adolescente , Adulto , Factores de Edad , Anciano , Anciano de 80 o más Años , Angiografía , Transfusión Sanguínea , Índice de Masa Corporal , Niño , Competencia Clínica , Femenino , Humanos , Incidencia , Masculino , Persona de Mediana Edad , Pancreatectomía/efectos adversos , Enfermedades Pancreáticas/patología , Enfermedades Pancreáticas/cirugía , Fístula Pancreática/etiología , Pancreaticoduodenectomía/efectos adversos , Pancreaticoduodenectomía/mortalidad , Pancreatoyeyunostomía/efectos adversos , Pancreatoyeyunostomía/mortalidad , Hemorragia Posoperatoria/epidemiología , Hemorragia Posoperatoria/etiología , Hemorragia Posoperatoria/mortalidad , Hemorragia Posoperatoria/terapia , Reoperación , Estudios Retrospectivos , Factores de Riesgo , Índice de Severidad de la Enfermedad , Factores Sexuales , Adulto JovenRESUMEN
Pneumatosis intestinalis (PI) describes the existence of gas in the wall of the gastrointestinal tract; portal gas (PG) describes gas in the portovenous system. Both are predominantly diagnosed radiologically (computed tomography as the most sensitive method) and do not represent per se self-contained syndromes, but PI and PG are possible symptoms of a variety of diseases. Possible sources of gas are bacterial gas (e. g., bowel wall invasion by aerogenic bacteria), intraluminal and extraluminal enteric gas (e. g., increased intraluminal pressure e.g. endoscopy), and pulmonary gas (e. g., COPD). The treatment of PI /PG depends on the underlying disease. The decision for laparotomy/ laparoscopy should be a conclusion of clinical and possibly radiological signs. Since in many cases, the simultaneous detection of PI and PG, is caused by mesenterial ischemia and has a poor prognosis, in these cases, the decision for operation (laparotomy/ laparoscopy) should be made liberally. A symptomatic therapy with metronidazole and oxygen should be considered, if despite the adequate treatment of the underlying disease, PI continues with abdominal symptoms (such as intestinal pseudo-obstruction or nonspecific abdominal pain).
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Embolia Aérea/diagnóstico , Neumatosis Cistoide Intestinal/diagnóstico , Vena Porta , Adulto , Anciano , Colon/irrigación sanguínea , Terapia Combinada , Embolia Aérea/etiología , Embolia Aérea/cirugía , Embolia Aérea/terapia , Femenino , Humanos , Íleon/irrigación sanguínea , Isquemia/diagnóstico , Isquemia/etiología , Isquemia/cirugía , Isquemia/terapia , Masculino , Oclusión Vascular Mesentérica/diagnóstico , Oclusión Vascular Mesentérica/etiología , Oclusión Vascular Mesentérica/terapia , Persona de Mediana Edad , Neumatosis Cistoide Intestinal/etiología , Neumatosis Cistoide Intestinal/cirugía , Pronóstico , Sensibilidad y Especificidad , Tomografía Computarizada por Rayos XRESUMEN
Outbreaks of Ebola virus haemorrhagic fever have been reported from 1994 to 1996 in the province of Ogooué Ivindo, a forest zone situated in the Northeast of Gabon. Each time, the great primates had been identified as the initial source of human infection. End of November 2001 a new alert came from this province, rapidly confirmed as a EVHV outbreak. The response was given by the Ministry of Health with the help of an international team under the aegis of WHO. An active monitoring system was implemented in the three districts hit by the epidemic (Zadié, Ivindo and Mpassa) to organize the detection of cases and their follow-up. A case definition has been set up, the suspected cases were isolated at hospital, at home or in lazarets and serological tests were performed. These tests consisted of the detection of antigen or specific IgG and the RT-PCR. A classification of cases was made according to the results of biological tests, clinical and epidemiological data. The contact subjects were kept watch over for 21 days. 65 cases were recorded among which 53 deaths. The first human case, a hunter died on the 28th of October 2001. The epidemic spreads over through family transmission and nosocomial contamination. Four distinct primary foci have been identified together with an isolated case situated in the South East of Gabon, 580 km away from the epicenter. Deaths happened within a delay of 6 days. The last death has been recorded on the 22nd of March 2002 and the end of the outbreak was declared on the 6th of May 2002. The epidemic spreads over the Gabon just next. Unexplained deaths of animals had been mentionned in the nearby forests as soon as August 2001: great primates and cephalophus. Samples taken from their carcasses confirmed a concomitant animal epidemic.
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Brotes de Enfermedades , Fiebre Hemorrágica Ebola/epidemiología , Enfermedades de los Primates/epidemiología , Primates/virología , Animales , Antílopes/virología , Anticuerpos Antivirales/sangre , Anticuerpos Antivirales/inmunología , Análisis por Conglomerados , Trazado de Contacto , Infección Hospitalaria/epidemiología , Infección Hospitalaria/transmisión , Reservorios de Enfermedades , Ebolavirus/genética , Ebolavirus/inmunología , Ebolavirus/aislamiento & purificación , Ebolavirus/patogenicidad , Estudios de Seguimiento , Microbiología de Alimentos , Gabón/epidemiología , Gorilla gorilla/virología , Haplorrinos/virología , Fiebre Hemorrágica Ebola/diagnóstico , Fiebre Hemorrágica Ebola/mortalidad , Fiebre Hemorrágica Ebola/prevención & control , Fiebre Hemorrágica Ebola/transmisión , Fiebre Hemorrágica Ebola/veterinaria , Humanos , Cooperación Internacional , Carne/virología , Aislamiento de Pacientes , Puercoespines/virología , Enfermedades de los Primates/transmisión , Enfermedades de los Primates/virología , Cuarentena , ARN Viral/sangre , Estudios Retrospectivos , Pruebas Serológicas , Organización Mundial de la SaludRESUMEN
To investigate the role of inflammatory mediators in the pathogenesis of Lassa fever, the levels of a number of pro- and anti-inflammatory cytokines and chemokines in serum samples collected from hospitalized patients with fatal and nonfatal acute Lassa fever were compared with those from 2 control groups: patients with other febrile illnesses and uninfected individuals. Serum interleukin (IL)-8 and interferon (IFN)-inducible protein (IP)-10 levels were significantly higher in patients with acute nonfatal Lassa fever than in control subjects. In striking contrast, levels of these chemokines were low or undetectable in patients with fatal Lassa fever. IFN-gamma, IL-12, IL-6, and RANTES levels were elevated in all the febrile study groups. Tumor necrosis factor-alpha levels were not elevated in patients with fatal or nonfatal Lassa fever. These data indicate that acute nonfatal Lassa fever is associated with high levels of circulating IL-8 and IP-10 and that low levels or absence of these mediators correlates with a poor outcome.
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Quimiocinas CXC/sangre , Interleucina-8/sangre , Fiebre de Lassa/inmunología , Fiebre de Lassa/mortalidad , Enfermedad Aguda , Estudios de Casos y Controles , Quimiocina CCL5/sangre , Quimiocina CCL5/inmunología , Quimiocina CXCL10 , Quimiocinas CXC/inmunología , Ensayo de Inmunoadsorción Enzimática , Hospitalización , Humanos , Interferón gamma/sangre , Interferón gamma/inmunología , Interleucina-12/sangre , Interleucina-12/inmunología , Interleucina-6/sangre , Interleucina-6/inmunología , Interleucina-8/inmunología , CinéticaRESUMEN
The arenavirus Lassa is found in West Africa, where it sometimes causes a severe illness called Lassa fever. Lassa fever has been seldom investigated outside of a few hyperendemic regions, where the described epidemiology may differ from that in areas of low or moderate incidence of disease. Through a prospective cohort study, we investigated the epidemiology and clinical presentation of Lassa fever in Guinea, where the disease has been infrequently recognized. A surveillance system was established, and suspected cases were enrolled at five Guinean hospitals. Clinical observations were made, and blood was taken for enzyme-linked immunosorbent assay testing and isolation of Lassa virus. Lassa fever was confirmed in 22 (7%) of 311 suspected cases. Another 43 (14%) had Lassa IgG antibodies, indicating past exposure. Both sexes and a wide variety of age and ethnic groups were affected. The disease was more frequently found, and the IgG seroprevalence generally higher, in the southeastern forest region. In some areas, there were significant discrepancies between the incidence of Lassa fever and the prevalence of antibody. Clinical presentations between those with Lassa fever and other febrile illnesses were essentially indistinguishable. Clinical predictors of a poor outcome were noted, but again were not specific for Lassa fever. Case-fatality rates for those with Lassa fever and non-Lassa febrile illnesses were 18% and 15%, respectively. Seasonal fluctuation in the incidence of Lassa fever was noted, but occurred similarly with non-Lassa febrile illnesses. Our results, perhaps typical of the scenario throughout much of West Africa, indicate Lassa virus infection to be widespread in certain areas of Guinea, but difficult to distinguish clinically.
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Fiebre de Lassa/epidemiología , Fiebre de Lassa/fisiopatología , Adolescente , Adulto , Factores de Edad , Anticuerpos Antivirales/análisis , Etnicidad , Femenino , Guinea/epidemiología , Humanos , Incidencia , Fiebre de Lassa/diagnóstico , Virus Lassa/aislamiento & purificación , Masculino , Persona de Mediana Edad , Prevalencia , Pronóstico , Lluvia , Estaciones del Año , Factores SexualesRESUMEN
Rodents of the genus Mastomys form the reservoir for Lassa virus (LV), an arenavirus that causes a potentially severe hemorrhagic illness, Lassa fever (LF). Although Mastomys rodents exist throughout sub-Saharan Africa, areas of human LF appear to be quite focal. The distribution of small mammals and LV-infected Mastomys has been assessed in only a few countries. We conducted a survey of small mammals in selected regions of Guinea to assess the degree to which LV poses a public health risk in that country. A total of 1,616 small mammals, including 956 (59%) Mastomys, were captured from 444 households and seven bush sites. Mastomys made up > 90% of the captured animals in the savannah, savannah-forest transition, and forest regions of Guinea, while Mus musculus dominated in coastal and urban sites. Animals were analyzed via enzyme-linked immunosorbent assay (ELISA) for LV-specific antigen (blood and spleen homogenate) and IgG antibody (blood only). Virus isolation from spleen homogenates was also performed on a subset of animals. Lassa antibody and antigen were found in 96 (11%) and 46 (5%), respectively, of 884 tested Mastomys. Antibody and antigen were essentially mutually exclusive and showed profiles consistent with vertical transmission of both LV and antibody. LV was isolated only from Mastomys. ELISA antigen constituted an acceptable surrogate for virus isolation, with a sensitivity and specificity when performed on blood of 78% (95% confidence interval: 68-83%) and 98% (95-99%), respectively. The proportion of LV-infected Mastomys per region ranged from 0 to 9% and was highest in the savannah and forest zones. The proportion of infected animals per village varied considerably, even between villages in close proximity. Infected animals tended to cluster in relatively few houses, suggesting the existence of focal "hot spots" of LV-infected Mastomys that may account for the observed heterogeneous distribution of LF.
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Reservorios de Enfermedades/veterinaria , Fiebre de Lassa/epidemiología , Fiebre de Lassa/veterinaria , Muridae/virología , Animales , Anticuerpos Antivirales/sangre , Antígenos Virales/sangre , Femenino , Geografía , Guinea/epidemiología , Transmisión Vertical de Enfermedad Infecciosa , Fiebre de Lassa/inmunología , Fiebre de Lassa/transmisión , Virus Lassa/genética , Virus Lassa/inmunología , Virus Lassa/aislamiento & purificación , Masculino , Prevalencia , Estaciones del Año , Bazo/virologíaRESUMEN
The arenavirus Lassa virus causes Lassa fever, a viral hemorrhagic fever that is endemic in the countries of Nigeria, Sierra Leone, Liberia, and Guinea and perhaps elsewhere in West Africa. To determine the degree of genetic diversity among Lassa virus strains, partial nucleoprotein (NP) gene sequences were obtained from 54 strains and analyzed. Phylogenetic analyses showed that Lassa viruses comprise four lineages, three of which are found in Nigeria and the fourth in Guinea, Liberia, and Sierra Leone. Overall strain variation in the partial NP gene sequence was found to be as high as 27% at the nucleotide level and 15% at the amino acid level. Genetic distance among Lassa strains was found to correlate with geographic distance rather than time, and no evidence of a "molecular clock" was found. A method for amplifying and cloning full-length arenavirus S RNAs was developed and used to obtain the complete NP and glycoprotein gene (GP1 and GP2) sequences for two representative Nigerian strains of Lassa virus. Comparison of full-length gene sequences for four Lassa virus strains representing the four lineages showed that the NP gene (up to 23.8% nucleotide difference and 12.0% amino acid difference) is more variable than the glycoprotein genes. Although the evolutionary order of descent within Lassa virus strains was not completely resolved, the phylogenetic analyses of full-length NP, GP1, and GP2 gene sequences suggested that Nigerian strains of Lassa virus were ancestral to strains from Guinea, Liberia, and Sierra Leone. Compared to the New World arenaviruses, Lassa and the other Old World arenaviruses have either undergone a shorter period of diverisification or are evolving at a slower rate. This study represents the first large-scale examination of Lassa virus genetic variation.
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Variación Genética , Fiebre de Lassa/virología , Virus Lassa/genética , Nucleoproteínas/genética , Proteínas Virales/genética , África Occidental , Animales , Arenaviridae/genética , Secuencia de Bases , Evolución Molecular , Humanos , Fiebre de Lassa/epidemiología , Virus Lassa/clasificación , Virus Lassa/aislamiento & purificación , Datos de Secuencia Molecular , Filogenia , ARN Viral/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADN , Proteínas del Envoltorio Viral/genéticaRESUMEN
The Lassa virus (an arenavirus) is found in West Africa, where it sometimes causes a severe hemorrhagic illness called Lassa fever. Laboratory diagnosis has traditionally been by the indirect fluorescent-antibody (IFA) test. However, enzyme-linked immunosorbent assays (ELISAs) for Lassa virus antigen and immunoglobulin M (IgM) and G (IgG) antibodies have been developed that are thought to be more sensitive and specific. We compared ELISA and IFA testing on sera from 305 suspected cases of Lassa fever by using virus isolation with a positive reverse transcription-PCR (RT-PCR) test as the "gold standard." Virus isolation and RT-PCR were positive on 50 (16%) of the 305 suspected cases. Taken together, Lassa virus antigen and IgM ELISAs were 88% (95% confidence interval [CI], 77 to 95%) sensitive and 90% (95% CI, 88 to 91%) specific for acute infection. Due to the stringent gold standard used, these likely represent underestimates. Diagnosis could often be made on a single serum specimen. Antigen detection was particularly useful in providing early diagnosis as well as prognostic information. Level of antigenemia varied inversely with survival. Detection by ELISA of IgG antibody early in the course of illness helped rule out acute Lassa virus infection. The presence of IFA during both acute and convalescent stages of infection, as well as significant interobserver variation in reading the slides, made interpretation difficult. However, the assay provided useful prognostic information, the presence of IFA early in the course of illness correlating with death. The high sensitivity and specificity, capability for early diagnosis, and prognostic value of the ELISAs make them the diagnostic tests of choice for the detection of Lassa fever.
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Ensayo de Inmunoadsorción Enzimática/métodos , Técnica del Anticuerpo Fluorescente Indirecta , Fiebre de Lassa/diagnóstico , Virus Lassa/inmunología , Virus Lassa/aislamiento & purificación , Anticuerpos Antivirales/sangre , Antígenos Virales/sangre , Humanos , Inmunoglobulina G/sangre , Inmunoglobulina M/sangre , Fiebre de Lassa/virología , Pronóstico , ARN Viral/análisis , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Sensibilidad y EspecificidadRESUMEN
As part of a program to integrate schistosomiasis control into the primary health care system in northern Cameroon, an unexpected opportunity to undertake a controlled evaluation of the impact of interventions was recognized. Inadvertently, a large part of Mindjil, one of four assessment villages, had been essentially excluded from the program, creating a unique natural control. The prevalence of infection with Schistosoma hematobium in school-aged children was 7% in the areas where the control program was implemented, and 71% in the excluded areas (P < 0.0002). High intensity infection was 1% and 26% in the two areas, respectively (P < 0.0002). Children in the school where the control interventions were implemented had a significantly lower prevalence of infection with Schistosoma hematobium (P < 0.005). Subjects in intervention areas demonstrated greater knowledge about the transmission of schistosomiasis than those in the control area. This study documented and quantified program impact in a controlled manner not usually possible in field studies and also illustrated how unrecognized intracultural diversity (within culture differences) in target populations may effect disease control programs in communities.
Asunto(s)
Educación en Salud , Schistosoma haematobium/aislamiento & purificación , Esquistosomiasis Urinaria/epidemiología , Esquistosomiasis Urinaria/prevención & control , Adolescente , Animales , Antiplatelmínticos/uso terapéutico , Camerún/epidemiología , Niño , Preescolar , Características Culturales , Atención a la Salud , Femenino , Estudios de Seguimiento , Conocimientos, Actitudes y Práctica en Salud , Humanos , Masculino , Recuento de Huevos de Parásitos , Proyectos Piloto , Praziquantel/uso terapéutico , Prevalencia , Instituciones Académicas , Orina/parasitologíaRESUMEN
It was shown previously that in sheep calcium-dependent anti-GAT there is a subpopulation which reacts with and can be precipitated with poly G [Liberti (1975) Immunochemistry 12, 303-310]. This entire subpopulation was also found to react with the cross-reacting polypeptides GA and GT. Furthermore, from hydrogen exchange experiments, it was found that only the immunizing antigen GAT completely filled the combining sites of these antibodies whereas poly G was shown to occupy an average of 47% of all sites, and GA and GT, 75 and 85% respectively. Since precipitins formed with this subpopulation and each of these antigens should have reasonably similar densities and orientations of 'aggregated' IgG but differing combining sites occupancies, we have used this system to explore the relative role of Fc aggregation and/or IgG distortion vs combining site-transmitted effects on the binding of Clq to antibody. For two preparations of this subpopulation (one of high avidity, the other obtained via poly G-Sepharose and of lower avidity) there is only a 5% difference in the delta G (10.2-10.8 kcal/mole) of Clq-IgG interaction for a change in combining site occupancy of 47-100%. For the high-avidity preparation there is a correlation between delta G and degree of ligand occupancy of combining site. This could reflect combining site-transmitted effects or may be related to small differences in the molecular architecture of these precipitins. Clq saturation curves support the latter notion. In view of the very moderate effect of combining site filling (from 47 to 100%) on Clq-IgG interaction for the high-avidity preparation and the absence of any correlation for the lower-avidity preparation. It appears that an allosteric model for antibody initiation of complement is untenable. Unless combining site-originating contributions are completed when less than 50% of an antibody-binding site is occupied by ligand, it would seem that Clq binding to immune complexes must be governed either by enhanced interactions resulting from Fc clustering which occurs via antibody interactions with antigen or by distortion of the antibody molecular upon ligand binding or some combination thereof.