226 resultados para Host Community
Resumo:
Large-scale patterns of species diversity in the gastrointestinal helminth faunas of the coral reef fish Epinephelus merra (Serranidae) were investigated in French Polynesia and the South Pacific Ocean. The richer barrier reef community in French Polynesia supported richer parasite communities in E. merra than that on the fringing reef. While parasite communities among fish from the same archipelago were similar, differences in potential host species and the distance between archipelagos may have contributed to a qualitative difference in parasite communities between archipelagos. Digenean community diversity in coral reef fishes was greater in the western South Pacific, following similar patterns in free-living species. However, overall species diversity of camallanid nematodes of coral reef fishes does not appear to have been similarly affected.
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Objectives. We sought to estimate the risk of death and recurrent myocardial infarction associated with the use of calcium antagonists after myocardial infarction in a population-based cohort study. Background. Calcium antagonists are commonly prescribed after myocardial infarction, but their long-term effects are not well established. Methods. Patients 25 to 69 years old with a suspected myocardial infarction were identified and followed up through a community-based register of myocardial infarction and cardiac death (part of the World Health Organization Monitoring Trends and Determinants in Cardiovascular Disease [MONICA] Project in Newcastle, Australia). Data were collected by review of medical records, in-hospital interview and review of death certificates. Results. From 1989 to 1993, 3,982 patients with a nonfatal suspected myocardial infarction were enrolled in the study. At hospital discharge, 1,001 patients were treated with beta-adrenergic blocking agents, 923 with calcium antagonists, 711 with both beta-blockers and calcium antagonists and 1,346 with neither drug. Compared with patients given beta-blockers, patients given calcium antagonists were more likely to suffer myocardial infarction or cardiac death (adjusted relative risk [RR] 1.4, 95% confidence interval [CI] 1.0 to 1.9), cardiac death (RR 1.6, 95% CI 1.0 to 2.7) and death from all causes (RR 1.7, 95% CI 1.1 to 2.6). Compared with patients given neither beta-blockers nor calcium antagonists, patients given calcium antagonists were not at increased risk of myocardial infarction or cardiac death (RR 1.0, 95% CI 0.8 to 1.3), cardiac death (RR 0.9, 95% CI 0.6 to 1.2) or death from all causes (RR 1.0, 95% CI 0.7 to 1.3). No excess in risk of myocardial infarction or cardiac death was observed among patients taking verapamil (RR 0.9, 95% CI 0.6 to 1.6), diltiazem (RR 1.1, 95% CI 0.8 to 1.4) or nifedipine (RR 1.3, 95% CI 0.7 to 2.2) compared,vith patients taking neither calcium antagonists nor beta-blockers. Conclusions. These results are consistent with randomized trial data showing benefit from beta blockers after myocardial infarction and no effect on the risk of recurrent myocardial infarction and death with the use of calcium antagonists. Comparisons between beta-blockers and calcium antagonists favor beta blockers because of the beneficial effects of beta-blockers and not because of adverse effects of calcium antagonists. (C) 1998 by the American College of Cardiology.
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A study was conducted to examine the relationships among eating pathology, weight dissatisfaction and dieting, and unwanted sexual experiences in childhood. An unselected community sample of 201 young and 268 middle-aged women were administered questionnaires assessing eating behaviors and attitudes, and past and current sexual abuse. Results showed differential relationships among these factors for the two age cohorts: for young women, past sexual abuse predicted weight dissatisfaction, but not dieting or disordered eating behaviors, whereas for middle-aged women, past abuse was predictive of disordered eating, but not dieting or weight dissatisfaction. Current physical or sexual abuse was also found to be predictive of disordered eating for the young women. These findings underscore the complexity of the relationships among unwanted sexual experiences and eating and weight pathology, and suggest that the timing of sexual abuse, and the age of the woman, are important mediating factors. (C) 1998 Elsevier Science Inc.
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Immature bivesiculid trematodes collected from the intestine of Thalassoma lunare (Labridae) are shown to be morphologically consistent with adults of Bivesicula claviformis from Epinephelus fasciatus (Serranidae). In addition, the immature bivesiculids have the same sequence for the second internal transcribed spacer of the ribosomal DNA. Comparison with three other species of Bivesiculidae showed differences of between 23% and 30%. These results show that bivesiculids may have three-host life-cycles in addition to the two-host life-cycles that have been demonstrated previously. The three-host life-cycle enables bivesiculids to infect large carnivorous fishes. (C) 1998 Australian Society for Parasitology. Published by Elsevier Science Ltd. All rights reserved.
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Background and Purpose-Few community-based studies have examined the long-term risk of recurrent stroke after an acute first-ever stroke. This study aimed to determine the absolute and relative risks of a first recurrent stroke over the first 5 years after a first-ever stroke and the predictors of such recurrence in a population-based series of people with first-ever stroke in Perth, Western Australia. Methods-Between February 1989 and August 1990, all people with a suspected acute stroke or transient ischemic attack of the brain who were resident in a geographically defined region of Perth, Western Australia, with a population of 138 708 people, were registered prospectively and assessed according to standardized diagnostic criteria. Patients were followed up prospectively at 4 months, 12 months, and 5 years after the index event. Results-Three hundred seventy patients with a first-ever stroke were registered, of whom 351 survived >2 days. Data were available for 98% of the cohort at 5 years, by which time 199 patients (58%) had died and 52 (15%) had experienced a recurrent stroke, 12 (23%) of which were fatal within 28 days. The 5-year cumulative risk of first recurrent stroke was 22.5% (95% confidence limits [CL], 16.8%, 28.1%). The risk of recurrent stroke was greatest in the first 6 months after stroke, at 8.8% (95% CL, 5.4%, 12.1%). After adjustment for age and sex, the prognostic factors for recurrent stroke were advanced, but not extreme, age (75 to 84 years) (hazard ratio [HR], 2.6; 95% CL, 1.1, 6.2), hemorrhagic index stroke (HR, 2.1; 95% CL, 0.98, 4.4), and diabetes mellitus (HR, 2.1; 95% CL, 0.95, 4.4). Conclusions-Approximately 1 in 6 survivors (15%) of a first-ever stroke experience a recurrent stroke over the next 5 years, of which 25% are fatal within 28 days. The pathological subtype of the recurrent stroke is the same as that of the index stroke in 88% of cases. The predictors of first recurrent stroke in this study were advanced age, hemorrhagic index stroke, and diabetes mellitus, but numbers of recurrent events were modest. Because the risk of recurrent stroke is highest (8.8%) in the first 6 months after stroke, strategies for secondary prevention should be initiated as soon as possible after the index event.
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We examined the effect of age-specific fecundity, mated status, and egg load on host-plant selection, by Helicoverpa armigera under laboratory conditions. The physiological state of a female moth (number of mature eggs produced) greatly influences her host-plant specificity and propensity to oviposit (oviposition motivation). Female moths were less discriminating against cowpea (a low-ranked host) relative to maize (a high-ranked host) as egg load increased. Similarly, increased egg load led to a greater propensity to oviposit on both cowpea and maize. Distribution of oviposition with age of mated females peaked shortly after mating and declined steadily thereafter until death. Most mated females (88%) carried only a single spermatophore, a few females (12%) contained two. The significance of these findings in relation to host-plant selection by H. armigera, and its management, are discussed.
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Coronary heart disease is a leading cause of death in Australia with the Coalfields district of New South Wales having one of the country's highest rates. Identification of the Coalfields epidemic in the 1970's led to the formation of a community awareness program in the late 1980's (the healthy heart support group) followed by a more intense community action program in 1990, the Coalfields Healthy Heartbeat (CHHB). CHHB is a coalition of community members, local government officers, health workers and University researchers. We evaluate the CHHB program, examining both the nature and sustainability of heart health activities undertaken, as well as trends in risk factor levels and rates of coronary events in the Coalfields in comparison with nearby local government areas. Process data reveal difficulties mobilising the community as a whole; activities had to be selected for interested subgroups such as families of heart disease patients, school children, retired people and women concerned with family nutrition and body maintenance. Outcome data show a significantly larger reduction in case fatality for Coalfields men (although nonfatal heart attacks did not decline) while changes in risk factors levels were comparable with surrounding areas. We explain positive responses to the CHHB by schools, heart attack survivors and women interested in body maintenance in terms of the meaning these subgroups find in health promotion discourses based on their embodied experiences. When faced with a threat to one's identity, health discourse suddenly becomes meaningful along with the regimens for health improvement. General public disinterest in heart health promotion is examined in the context of historical patterns of outsiders criticising the lifestyle of miners, an orientation toward communal lather than individual responsibility for health (i.e, community 'owned' emergency services and hospitals) and anger about risks from environmental hazards imposed by industrialists. (C) 1999 Elsevier Science Ltd. All rights reserved.
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The co-evolution of papillomaviruses (PV) and their mammalian hosts has produced mechanisms by which PV might avoid specific and non-specific host immune responses. Low level expression of PV proteins in infected basal epithelial cells, together with an absence of inflammation and of virus-induced cell lysis, restricts the opportunity for effective PV protein presentation to immunocytes by dendritic cells. Additionally, PV early proteins, by a range of mechanisms, may restrict the efficacy of antigen presentation by these cells. Should an immune response be induced to PV antigens, resting keratinocytes (KC) appear resistant to interferon-gamma-enhanced mechanisms of cytotoxic T-lymphocyte (CTL)-mediated lysis, and expression of PV antigens by resting KC can tolerise PV-specific CTL. Thus, KC, in the absence of inflammation, may represent an immunologically privileged site for PV infection. Together, these mechanisms play a parr in allowing persistence of PV-induced proliferative skin lesions for months to years, even in immunocompetent hosts.
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Application of geographic information system (GIS) and global positioning system (GPS) technology in the Hlabisa community-based tuberculosis treatment programme documents the increase in accessibility to treatment after the expansion of the service from health facilities to include community workers and volunteers.
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OBJECTIVE: Although little studied in developing countries, multidrug-resistant tuberculosis (MDR-TB) is considered a major threat. We report the molecular epidemiology, clinical features and outcome of an emerging MDR-TB epidemic. METHODS: In 1996 all tuberculosis suspects in the rural Hlabisa district, South Africa, had sputum cultured, and drug susceptibility patterns of mycobacterial isolates were determined. Isolates with MDR-TB (resistant to both isoniazid and rifampicin) were DNA fingerprinted by restriction fragment length polymorphism (RFLP) using IS6110 and polymorphic guanine-cytosine-rich sequence-based (PGRS) probes. Patients with MDR-TB were traced to determine outcome. Data were compared with results from a survey of drug susceptibility done in 1994. RESULTS: The rate of MDR-TB among smear-positive patients increased six-fold from 0.36% (1/275) in 1994 to 2.3% (13/561) in 1996 (P = 0.04). A further eight smear-negative cases were identified in 1996 from culture, six of whom had not been diagnosed with tuberculosis. MDR disease was clinically suspected in only five of the 21 cases (24%). Prevalence of primary and acquired MDR-TB was 1.8% and 4.1%, respectively. Twelve MDR-TB cases (67%) were in five RFLP-defined clusters. Among 20 traced patients, 10 (50%) had died, five had active disease (25%) and five (25%) were apparently cured. CONCLUSIONS: The rate of MDR-TB has risen rapidly in Hlabisa, apparently due to both reactivation disease and recent transmission. Many patients were not diagnosed with tuberculosis and many were not suspected of drug-resistant disease, and outcome was poor.
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SETTING: Hlabisa Tuberculosis Programme, Hlabisa, South Africa. OBJECTIVE: To determine trends in and risk factors for interruption of tuberculosis treatment. METHODS: Data were extracted from the control programme database starting in 1991. Temporal trends in treatment interruption are described; independent risk factors for treatment interruption were determined with a multiple logistic regression model, and Kaplan-Meier survival curves for treatment interruption were constructed for patients treated in 1994-1995. RESULTS: Overall 629 of 3610 surviving patients (17%) failed to complete treatment; this proportion increased from 11% (n = 79) in 1991/1992 to 22% (n = 201) in 1996. Independent risk factors for treatment interruption were diagnosis between 1994-1996 compared with 1991-1393 (odds ratio [OR] 1.9, 95% confidence interval [CT] 1.6-2.4); human immunodeficiency virus (HIV) positivity compared with HIV negativity (OR 1.8, 95% CI 1.4-2.4); supervised by village clinic compared with community health worker (OR 1.9, 95% CI 1.4-2.6); and male versus female sex (OR 1.3, 95% CI 1.1-1.6). Few patients interrupted treatment during the first 2 weeks, and the treatment interruption rate thereafter was constant at 1% per 14 days. CONCLUSIONS: Frequency of treatment interruption from this programme has increased recently. The strongest risk factor was year of diagnosis, perhaps reflecting the impact of an increased caseload on programme performance. Ensuring adherence to therapy in communities with a high level of migration remains a challenge even within community-based directly observed therapy programmes.
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We investigated the role of chemoreception in the host selection and oviposition behaviour of Helicoverpa armigera in the laboratory using five cotton genotypes and synthetic volatile terpenes. Female moths oviposited on substrates treated with methanol, ethanol, acetone and pentane extracts of leaves, squares and flowers of the cotton genotypes. Phytochemicals soluble in pentane were the most efficient in eliciting oviposition behaviour. In a two-way bioassay, pentane extracts of leaves or squares of a Multiple Host-plant Resistance genotype (MHR11), Deltapine commercial (DP90), and Smith Red Leaf (SRL) received significantly more eggs than solvent-treated controls. Extracts of squares of the native genotype Gossypium nelsonii did not receive more eggs. Females preferred DP90 and MHR11 to SRL and G. nelsonii. Female moths also laid more eggs on pentane extracts of MHR11 flowers than MHR11 leaves from preflowering, early flowering and peak-flowering plants. In a flight chamber, female moths used olfactory cues at short range to mediate oviposition and discrimination between host plants. Egg-laying, mated females were attracted at a distance (1.5 m) to volatile compounds released by whole plants and odours emanating from filter papers treated with synthetic volatile terpenes. Individually, the terpenes did not stimulate any significant oviposition response. However, there was a significant oviposition response to a mixture of equal volumes of the terpenes (trans-beta-caryophyllene, alpha-pinene, beta-pinene, myrcene, beta-bisabolol, and alpha-humulene). Conversely, antennectomised (moths with transected antennae), egg-laying, mated females did not stimulate any significant oviposition response. The significance of these findings in relation to H. armigera hostplant selection are discussed.