ABSTRACT
BACKGROUND: Right ventricular (RV) hemodynamic performance determines the prognosis of patients with RV pressure overload. Using ultrafast ultrasound, natural wave velocity (NWV) induced by cardiac valve closure was proposed as a new surrogate to quantify myocardial stiffness. OBJECTIVES: This study aimed to assess RV NWV in rodent models and children with RV pressure overload vs control subjects and to correlate NWV with RV hemodynamic parameters. METHODS: Six-week-old rats were randomized to pulmonary artery banding (n = 6), Sugen hypoxia-induced pulmonary arterial hypertension (n = 7), or sham (n = 6) groups. They underwent natural wave imaging, echocardiography, and hemodynamic assessment at baseline and 6 weeks postoperatively. The authors analyzed NWV after tricuspid and after pulmonary valve closure (TVC and PVC, respectively). Conductance catheters were used to generate pressure-volume loops. In parallel, the authors prospectively recruited 14 children (7 RV pressure overload; 7 age-matched control subjects) and compared RV NWV with echocardiographic and invasive hemodynamic parameters. RESULTS: NWV significantly increased in RV pressure overload rat models (4.99 ± 0.27 m/s after TVC and 5.03 ± 0.32 m/s after PVC in pulmonary artery banding at 6 weeks; 4.89 ± 0.26 m/s after TVC and 4.84 ± 0.30 m/s after PVC in Sugen hypoxia at 6 weeks) compared with control subjects (2.83 ± 0.15 m/s after TVC and 2.72 ± 0.34 m/s after PVC). NWV after TVC correlated with both systolic and diastolic parameters including RV dP/dtmax (r = 0.75; P < 0.005) and RV Ees (r = 0.81; P < 0.005). NWV after PVC correlated with both diastolic and systolic parameters and notably with RV end-diastolic pressure (r = 0.65; P < 0.01). In children, NWV after both right valves closure in RV pressure overload were higher than in healthy volunteers (P < 0.01). NWV after PVC correlated with RV E/E' (r = 0.81; P = 0.008) and with RV chamber stiffness (r = 0.97; P = 0.03). CONCLUSIONS: Both RV early-systolic and early-diastolic myocardial stiffness show significant increase in response to pressure overload. Based on physiology and our observations, early-systolic myocardial stiffness may reflect contractility, whereas early-diastolic myocardial stiffness might be indicative of diastolic function.
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Background: The relationship between genotype and phenotypical vascular and cardiac properties in paediatric Loeys-Dietz syndrome (LDS) patients are not well characterized. This study explores the phenotypical differences in aortic properties and cardiac structural and functional parameters between paediatric LDS patients with TGFBR1 and TGFBR2 mutations. Methods: We included 32 LDS patients with either TGFBR1 (n = 17) or TGFBR2 (n = 15) mutations. Echocardiographic data included aortic dimensions, distensibility, strain, and stiffness at the level of the annulus, sinuses of Valsalva, sinotubular junction, ascending aorta, and descending aorta. Parameters for left ventricular size and function were also recorded. Results: Demographics were similar between the groups. Patients with TGFBR2 were more likely to have undergone aortic surgery (47% vs 12%, P = 0.057) and use angiotensin receptor blockers (93% vs 47%, P = 0.015). Aortic z scores were significantly larger in the TGFBR2 group at the level of the aortic valve annulus (P = 0.007), sinuses of Valsalva (P = 0.001), sinotubular junction (P = 0.001), and ascending aorta (P = 0.054). Patients with TGFBR2 also had significantly lower aortic distensibility and strain coupled with higher stiffness index at the level of the annulus, sinotubular junction, and ascending aorta. Parameters for the descending aorta, cardiac morphology, and cardiac function were similar between the groups. Conclusions: Paediatric LDS patients with TGFBR2 present with more severe cardiovascular phenotypes than patients with TGFBR1 with larger aortic dimensions and increased aortic stiffness. Our findings suggest that genotypes should be taken into consideration in the clinical management of paediatric LDS patients.
Contexte: Les liens entre le génotype des enfants atteints du syndrome de Loeys-Dietz (SLD) et les particularités phénotypiques vasculaires et cardiaques n'ont pas encore été bien caractérisés. La présente étude vise à explorer les différences phénotypiques entre les propriétés de l'aorte et les paramètres cardiaques structuraux et fonctionnels des enfants atteints du SLD qui présentent une mutation du gène TGFBR1 et ceux qui présentent une mutation du gène TGFBR2. Méthodologie: Nous avons inclus dans notre analyse 32 patients atteints du SLD présentant une mutation de TGFBR1 (n = 17) ou de TGFBR2 (n = 15). Les données échocardiographiques colligées incluaient les dimensions de l'aorte, sa distensibilité, sa déformation (strain) et sa rigidité au niveau de l'anneau aortique, des sinus de Valsalva, de la jonction sinotubulaire, de l'aorte ascendante et de l'aorte descendante. Les paramètres ayant trait à la taille et à la fonction du ventricule gauche ont également été consignés. Résultats: Les caractéristiques démographiques étaient comparables dans les deux groupes. Les patients présentant une mutation du gène TGFBR2 étaient plus susceptibles d'avoir subi une intervention chirurgicale de l'aorte (47 % vs 12 %, p = 0,057) et de prendre un antagoniste des récepteurs de l'angiotensine (93 % vs 47 %, p = 0,015). Les scores z aortiques étaient significativement plus élevés chez les patients présentant une mutation de TGFBR2 pour les dimensions de l'anneau de la valve aortique (p = 0,007), des sinus of Valsalva (p = 0,001), de la jonction sinotubulaire (p = 0,001) et de l'aorte ascendante (p = 0,054). Les patients avec une mutation de TGFBR2 présentaient aussi une élasticité et une déformation aortiques significativement plus faibles ainsi qu'une rigidité accrue au niveau de l'anneau aortique, de la jonction sinotubulaire et de l'aorte ascendante. Les paramètres de l'aorte descendante, les caractéristiques morphologiques cardiaques et la fonction cardiaque étaient comparables pour les deux groupes. Conclusions: Chez les enfants atteints du SLD, une mutation du gène TGFBR2 se traduisait par des phénotypes plus défavorables que dans le cas d'une mutation du gène TGFBR1 et se caractérisait par des dimensions et une rigidité aortiques accrues. Nos observations indiquent qu'il convient de prendre le génotype des patients en considération lors de la prise en charge clinique des enfants atteints du SLD.
ABSTRACT
OBJECTIVES: Left ventricular outflow tract obstruction (LVOTO) is a major cause of morbidity and mortality in infants with interrupted aortic arch (IAA). Left Ventricular Outflow Tract (LVOT) development may be flow-mediated, thus IAA morphology may influence LVOT diameter and subsequent reintervention. We investigated the association of IAA morphology [type and presence of aortic arch aberrancy (AAb)] with LVOT diameter and reintervention. METHODS: All surgical patients with IAA (2001-2022) were reviewed at a single institution. We compared IAA-A versus IAA-B; IAA with aortic AAb versus none; IAA-B with aberrant subclavian (AAbS) artery versus others. Primary outcomes included LVOT diameter (mm), LVOTO at discharge (≥50 mmHg), and LVOT reintervention. RESULTS: Seventy-seven infants (mean age 10 ± 19 days) were followed for 7.6 (5.5-9.7) years. Perioperative mortality was 3.9% (3/77) and long-term mortality was 5.2% (4/77). Out of 51 IAA-B (66%) and 22 IAA-A (31%) patients, 30% (n = 22) had AAb. Smaller LVOT diameter was associated with IAA-B [IAA-A: 5.40 (4.68-5.80), IAA-B: 4.60 (3.92-5.50), P = 0.007], AAb [AAb: 4.00 (3.70-5.04) versus none: 5.15 (4.30-5.68), P = 0.006], and combined IAA-B + AAbS [IAA-B + AAbS: 4.00 (3.70-5.02) versus other: 5.00 (4.30-5.68), P = 0.002]. The likelihood of LVOTO was higher among AAb [N = 6 (25%) vs N = 1 (2%), P = 0.004] and IAA-B + AAbS [N = 1 (2%) vs N = 6 (30%), P = 0.002]. Time-to-event analysis showed a signal towards increased LVOT reintervention in IAA-B + AAbS (P = 0.11). CONCLUSIONS: IAA-B and AAb are associated with small LVOT diameter and early LVOTO, especially in combination. This may reflect lower flow in the proximal arch during development. Most reinterventions occur in IAA-B + AAbS, hence these patients should be carefully considered for LVOT intervention at the time of initial repair.
Subject(s)
Aorta, Thoracic , Ventricular Outflow Obstruction , Humans , Aorta, Thoracic/diagnostic imaging , Aorta, Thoracic/surgery , Aorta, Thoracic/abnormalities , Ventricular Outflow Obstruction/surgery , Female , Infant, Newborn , Male , Retrospective Studies , Infant , Heart Ventricles/diagnostic imaging , Heart Ventricles/abnormalities , Heart Ventricles/pathologyABSTRACT
BACKGROUND: The Ollerenshaw forecasting model is based on rainfall and evapotranspiration and has been in use to predict losses from fasciolosis since 1959. We evaluated the performance of the model against observed data. METHODS: Weather data were used to calculate, map and plot fasciolosis risk values for each year from 1950 to 2019. We then compared the model's predictions with recorded acute fasciolosis losses in sheep from 2010 to 2019 and calculated the sensitivity and specificity of the model. RESULTS: The forecast risk has varied over time but has not markedly increased over the past 70 years. The model correctly forecasted the highest and lowest incidence years at both the regional and national (Great Britain) levels. However, the sensitivity of the model for predicting fasciolosis losses was poor. Modification to include the full May and October rainfall and evapotranspiration values made only a small improvement. LIMITATIONS: Reported acute fasciolosis losses are subject to bias and error due to unreported cases and variations in region size and livestock numbers. CONCLUSION: The Ollerenshaw forecasting model, in either its original or modified forms, is insufficiently sensitive to be relied upon as a standalone early warning system for farmers.
Subject(s)
Fascioliasis , Sheep Diseases , Animals , Sheep , Fascioliasis/epidemiology , Fascioliasis/veterinary , Weather , Forecasting , Incidence , United Kingdom/epidemiology , Sheep Diseases/epidemiologyABSTRACT
BACKGROUND: Cardiac rhabdomyoma are the most common cardiac tumour in childhood and are associated with tuberous sclerosis complex (TSC) up to 96% of infant cases. They classically manifest in the foetal and neonatal period, undergo spontaneous regression in the first years of life and are associated with arrhythmia in part due to interruption of normal conduction pathways by the tumour. CASE SUMMARY: We present a case of a 3-year-old boy with a long-standing history of atrial ectopy who was incidentally found to be in atrial flutter due to a new, rapidly growing cardiac rhabdomyoma impacting ventricular function. The boy was later confirmed with further investigation and TSC1 gene test to have TSC. DISCUSSION: Cardiac Rhabdomyoma does not always present in the infantile period. Any ongoing or new cardiac concern in patient with TSC, even if seemingly minor, should warrant more frequent cardiac evaluation and investigation.
ABSTRACT
Background: Cardiac magnetic resonance imaging (CMR) may augment 2-dimensional (2D) echocardiography in decision-making for biventricular repair in borderline hypoplastic left hearts. Objectives: This study evaluates: 1) the relationship between 2D echocardiography and CMR; 2) imaging variables affecting assignment to biventricular vs non-biventricular management; and 3) variables affecting transplant-free biventricular survival. Methods: We reviewed clinical, echocardiographic, and CMR data in 67 infants, including CMR-determined ascending aortic (AAo) flow and comparable left ventricular end-diastolic volume indexed (LVEDVi) by 2D-echocardiography and CMR. Results: Treatment assignment to biventricular repair was either direct (BV, n = 45) or with a bridging hybrid procedure (H1-BV, n = 12). Echocardiographic LVEDVi was <20 mL/m2 in 83% of biventricular repair infants and underestimated CMR-LVEDVi by 16.8 mL/m2. AAo flows had no/weak correlation with aortic and mitral valve z-scores or LVEDVi. AAo flows differed between BV, H1-BV, and single-ventricle groups (median): 2.1, 1.7, and 0.7 L/min/m2, respectively. Important variables for treatment assignment were presence of endocardial fibroelastosis, AAo flow, and mitral valve z-score. Biventricular repair was achieved in 54. The median follow-up was 8.0 (0.1-16.4) years. Transplant-free biventricular survival was 96%, 82%, and 77% at 1, 5, and 10 years, respectively. Patients without aortic coarctation repair were at higher risk of death, transplantation, or single-ventricle conversion (HR: 54.3; 95% CI: 6.3-47.1; P < 0.001) during follow-up. AAo flow had a smaller nonlinear effect with hazard ratio increasing at lower flows. Conclusions: Historical 2D echocardiographic criteria would have precluded many patients from successful biventricular repair. AAo flow, an integrative index of left heart performance, was important in assigning patients to a biventricular circulation and affected survival. Biventricular survival was strongly associated with the need for aortic coarctation repair.
ABSTRACT
The parasitic liver fluke, Fasciola hepatica, has a detrimental impact on food security and poses a welfare concern to ruminant livestock. F. hepatica metacercariae, shed from an intermediate mud snail host, encyst on vegetation and present a source of infection to grazing livestock. Feeding grass silage to ruminants is a common practice, however the role it plays in the transmission of F. hepatica remains largely unknown. Our current understanding relies on historical studies that are not representative of current silage production and did not apply molecular methods to detect F. hepatica DNA persistence within silages. This study determined the impact of specific fermentation factors, including grass dry matter (DM) content (20, 30 & 40 %), length of ensiling period and maintaining an anaerobic environment on F. hepatica metacercariae viability. In vitro excystment assays demonstrated that regardless of grass DM content, metacercariae ensiled under anaerobic conditions were not viable from two weeks post-sealing. Metacercariae recovered from ensiled grass of 20 % DM content subjected to aerobic spoilage, remained viable for up to 10 weeks. DNA of F. hepatica remained detectable for up to 10 weeks in both anaerobic and spoiled silages. This study highlights i) the importance of maintaining an anaerobic ensiling environment to eliminate the risk of F. hepatica transmission from silage and ii) an inverse relationship between grass DM content and duration of metacercariae survival within spoiled silages. Improving our understanding of trematode metacercariae survival rates within silages, especially of highly pathogenic species such as F. hepatica, allows farmers to make informed decisions regarding on-farm parasite control.
Subject(s)
Fasciola hepatica/physiology , Fascioliasis/veterinary , Fermentation , Metacercariae/physiology , Poaceae/metabolism , Poaceae/parasitology , Silage/parasitology , Anaerobiosis , Animals , Fascioliasis/prevention & controlABSTRACT
Fasciola hepatica, Fasciola gigantica, and Fascioloides magna are liver flukes causing disease in cattle and sheep. Damage to the liver due to F hepatica and F gigantica results in clinical disease and/or production losses. F magna seems to have little effect in cattle but causes high mortality in sheep. The fluke life cycle involves an aquatic or amphibious snail intermediate host and thus requires suitable moisture and temperature conditions. F magna requires the presence of deer. Drug treatment is the mainstay of control and needs to be applied considering the life cycle and epidemiology of the parasite.
Subject(s)
Cattle Diseases/epidemiology , Cattle Diseases/prevention & control , Fasciola hepatica/isolation & purification , Fascioliasis/veterinary , Sheep Diseases/epidemiology , Sheep Diseases/prevention & control , Animals , Cattle , Cattle Diseases/parasitology , Fascioliasis/epidemiology , Fascioliasis/prevention & control , Sheep , Sheep Diseases/parasitologyABSTRACT
The liver flukes, Fasciola hepatica and F. gigantica, are common trematode parasites of livestock. F. hepatica is known to modulate the immune response, including altering the response to co-infecting pathogens. Bovine tuberculosis (bTB), caused by Mycobacterium bovis, is a chronic disease which is difficult to control and is of both animal welfare and public health concern. Previous research has suggested that infection with liver fluke may affect the accuracy of the bTB skin test, but direction of the effect differs between studies. In a systematic review of the literature, all experimental and observational studies concerning co-infection with these two pathogens were sought. Data were extracted on the association between fluke infection and four measures of bTB diagnosis or pathology, namely, the bTB skin test, interferon γ test, lesion detection and culture/bacterial recovery. Of a large body of literature dating from 1950 to 2019, only thirteen studies met the inclusion criteria. These included studies of experimentally infected calves, case control studies on adult cows, cross sectional abattoir studies and a herd level study. All the studies had a medium or high risk of bias. The balance of evidence from the 13 studies included in the review suggests that liver fluke exposure was associated with either no effect or a decreased response to all of the four aspects of bTB diagnosis assessed: skin test, IFN γ, lesion detection and mycobacteria cultured or recovered. Most studies showed a small and/or non-significant effect so the clinical and practical importance of the observed effect is likely to be modest, although it could be more significant in particular groups of animals, such as dairy cattle.
Subject(s)
Cattle Diseases/immunology , Coinfection/veterinary , Fascioliasis/veterinary , Tuberculosis, Bovine/diagnosis , Animals , Cattle , Coinfection/microbiology , Coinfection/parasitology , Cross-Sectional Studies , Fasciola hepatica/immunology , Fascioliasis/complications , Fascioliasis/immunology , Interferon-gamma Release Tests , Mycobacterium bovis/pathogenicity , Observational Studies as Topic , Sensitivity and Specificity , Tuberculin TestABSTRACT
The liver fluke Fasciola hepatica is a parasitic trematode that has a major impact on livestock production and human health. Control of F hepatica is difficult and relies on anthelmintics, particularly triclabendazole, due to its efficacy against both adult and juvenile stages of the parasite. Emergence of triclabendazole-resistant F hepatica populations has been reported in a number of countries, including the UK, but the overall prevalence and distribution of triclabendazole resistance is unknown. In this study, the authors established the presence of reduced efficacy of triclabendazole in sheep flocks in England and Wales, using a validated composite faecal egg count reduction test. Seventy-four sheep farms were sampled from Wales, southwest, northwest and northeast England between Autumn 2013 and Spring 2015. F hepatica eggs were detected in samples from 42/74 farms. Evidence of a lack of efficacy of triclabendazole was detected on 21/26 farms on which the faecal egg count reduction test was completed, with faecal egg count reductions ranging from 89 per cent to 0per cent. Regression analysis suggested that both prevalence of F hepatica and lack of efficacy of triclabendazole were spatially correlated, with higher faecal egg counts and lower percentage reductions on farms located in the northwest of England, and Wales. Overall, the results show that reduced efficacy of triclabendazole is present across England and Wales, with a complete lack of therapeutic efficacy observed on 9/26 farms.
Subject(s)
Antiplatyhelmintic Agents/therapeutic use , Drug Resistance , Fasciola hepatica/drug effects , Fascioliasis/veterinary , Sheep Diseases/drug therapy , Triclabendazole/therapeutic use , Animals , England/epidemiology , Fascioliasis/drug therapy , Feces/parasitology , Sheep , Wales/epidemiologyABSTRACT
Escherichia coli O157 is a zoonotic bacterium that can cause haemorrhagic diarrhoea in humans and is of worldwide public health concern. Cattle are considered to be the main reservoir for human infection. Fasciola hepatica is a globally important parasite of ruminant livestock that is known to modulate its host's immune response and affect susceptibility to bacterial pathogens such as Salmonella Dublin. Shedding of E. coli O157 is triggered by unknown events, but the immune system is thought to play a part. We investigated the hypothesis that shedding of E. coli O157 is associated with F. hepatica infection in cattle. Three hundred and thirty four cattle destined for the food chain, from 14 British farms, were tested between January and October 2015. E. coli O157 was detected by immunomagnetic separation and bacterial load enumerated. F. hepatica infection status was assessed by copro-antigen ELISA. A significant association (p=0.01) was found between the log percent positivity (PP) of the F. hepatica copro-antigen ELISA and E. coli O157 shedding when the fixed effects of day of sampling and the age of the youngest animal in the group, plus the random effect of farm were adjusted for. The results should be interpreted cautiously due to the lower than predicted level of fluke infection in the animals sampled. Nevertheless these results indicate that control of F. hepatica infection may have an impact on the shedding of E. coli O157 in cattle destined for the human food chain.
Subject(s)
Bacterial Shedding , Cattle Diseases/microbiology , Cattle Diseases/parasitology , Escherichia coli Infections/veterinary , Fascioliasis/veterinary , Animals , Cattle , Coinfection/microbiology , Coinfection/parasitology , Escherichia coli Infections/microbiology , Escherichia coli O157/physiology , Fasciola hepatica/physiology , Fascioliasis/parasitology , Feces/microbiology , Feces/parasitology , Risk , United Kingdom , Zoonoses/microbiologyABSTRACT
BACKGROUND: Mental health is increasingly finding a place on global health and international development agendas. Advocates for Global Mental Health (GMH), and international organizations such as the World Health Organization (WHO) and the World Bank, argue that treatments available in high-income countries should also be made available in low- and middle-income countries. Such arguments are often made by comparing mental health to infectious diseases, including the relative disease and economic burdens they impose, and pointing to the applicability of the right to access treatment for mental health, not only infectious diseases. HIV/AIDS advocacy in particular has been held up by GMH advocates as offering an appropriate strategy for generating global commitment. DISCUSSION: There is a need to assess how health issues are framed not only in relation to social goods outside of health (such as human rights, security or development), but also in relation to other health or disease models, and how health policy and practice is shaped as a result. The article debates the merits and consequences of likening mental health to HIV/AIDS, and identifies four major problems with the model for GMH advocacy being developed through these analogies: 1. An inappropriately universalizing global approach to context-specific problems; 2. A conception of human rights that focuses on the right to access treatment at the expense of the right to refuse it; 3. A tendency to treat poverty as a psychiatric issue, rather than recognizing that mental distress can be the result of poverty and other forms of inequality; 4. The prioritization of destigmatization of disease over social justice models. CONCLUSION: There are significant problems with the wholesale adoption of an (often simplified) version of HIV/AIDS advocacy as a model for GMH. Yet critical engagement with the important and nuanced differences between HIV/AIDS and mental health may nevertheless point to some possibilities for productive engagement and cross-fertilisation between advocates, activists and scholars in both fields.
Subject(s)
Global Health , Health Services Accessibility , Mental Disorders/therapy , Acquired Immunodeficiency Syndrome , Communicable Diseases , Human Rights , Humans , Mental HealthABSTRACT
BACKGROUND: Intestinal schistosomiasis is of public health importance in Uganda but communities living above 1400 m are not targeted for control as natural transmission is thought unlikely. To assess altitudinal boundaries and at-risk populations, conjoint malacological and epidemiological surveys were undertaken on Mount Elgon (1139 m-3937 m), in Fort Portal crater lakes and in the Rwenzori Mountains (1123 m-4050 m). METHODS: Seventy freshwater habitats [Mount Elgon (37), Fort Portal crater lakes (23), Rwenzori Mountains (8) and Lake Albert (2)] were inspected for Biomphalaria species. Water temperature, pH and conductivity were recorded. A parasitological examination of 756 schoolchildren [Mount Elgon (300), Fort Portal crater lakes (456)] by faecal microscopy of duplicate Kato-Katz smears from two consecutive stool samples was bolstered by antigen (urine-CCA dipstick) and antibody (SEA-ELISA) diagnostic assays. RESULTS: Biomphalaria spp. was found up to 1951 m on Mount Elgon and 1567 m in the Fort Portal crater lakes. Although no snail from Mount Elgon shed cercariae, molecular analysis judged 7.1% of snails sampled at altitudes above 1400 m as having DNA of Schistosoma mansoni; in Fort Portal crater lakes three snails shed schistosome cercariae. Prevalence of intestinal schistosomiasis as measured in schoolchildren by Kato-Katz (Mount Elgon = 5.3% v. Fort Portal crater lakes = 10.7%), CCA urine-dipsticks (18.3% v. 34.4%) and SEA-ELISA (42.3% v. 63.7%) showed negative associations with increasing altitude with some evidence of infection up to 2000 m. CONCLUSIONS: Contrary to expectations, these surveys clearly show that natural transmission of intestinal schistosomiasis occurs above 1400 m, possibly extending up to 2000 m. Using spatial epidemiological predictions, this now places some extra six million people at-risk, denoting an expansion of preventive chemotherapy needs in Uganda.
Subject(s)
Schistosomiasis mansoni/epidemiology , Schistosomiasis mansoni/parasitology , Schistosomiasis mansoni/transmission , Adolescent , Altitude , Animals , Anthelmintics , Child , Geographic Information Systems , Humans , Lakes/parasitology , Praziquantel , Prevalence , Preventive Medicine , Risk Factors , Schistosoma mansoni/genetics , Schistosoma mansoni/isolation & purification , Snails/parasitology , Uganda/epidemiologyABSTRACT
Fasciola hepatica, common liver fluke, infects cattle and sheep causing disease and production losses costing approximately $3 billion annually. Current control relies on drugs designed to kill the parasite. However, resistance is evident worldwide and widespread in some areas. Work towards a vaccine has identified several antigens of F. hepatica that show partial efficacy in terms of reducing worm burden and egg output. A critical question is what level of efficacy is required for such a vaccine to be useful? We have created the first mathematical model to assess the effectiveness of liver fluke vaccines under simulated field conditions. The model describes development of fluke within a group of animals and includes heterogeneity in host susceptibility, seasonal exposure to metacercariae and seasonal changes in temperature affecting metacercarial survival. Our analysis suggests that the potential vaccine candidates could reduce total fluke burden and egg output by up to 43% and 99%, respectively, on average under field conditions. It also suggests that for a vaccine to be effective, it must protect at least 90% of animals for the whole season. In conclusion, novel, partial, vaccines could contribute substantially towards fasciolosis control, reducing usage of anthelmintics and thus delaying the spread of anthelmintic resistance.
Subject(s)
Fascioliasis/prevention & control , Fascioliasis/veterinary , Protozoan Vaccines/pharmacology , Animals , Cattle , Cattle Diseases/parasitology , Cattle Diseases/prevention & control , Fasciola hepatica/drug effects , Models, Biological , Sheep , Sheep Diseases/parasitology , Sheep Diseases/prevention & controlABSTRACT
The liver fluke Fasciola hepatica is a trematode parasite with a worldwide distribution and is the cause of important production losses in the dairy industry. The aim of this observational study was to assess the prevalence of exposure to F. hepatica in a group of high yielding dairy herds, to determine the risk factors and investigate their associations with production and fertility parameters. Bulk milk tank samples from 606 herds that supply a single retailer with liquid milk were tested with an antibody ELISA for F. hepatica. Multivariable linear regression was used to investigate the effect of farm management and environmental risk factors on F. hepatica exposure. Higher rainfall, grazing boggy pasture, presence of beef cattle on farm, access to a stream or pond and smaller herd size were associated with an increased risk of exposure. Univariable regression was used to look for associations between fluke exposure and production-related variables including milk yield, composition, somatic cell count and calving index. Although causation cannot be assumed, a significant (p<0.001) negative association was seen between F. hepatica exposure and estimated milk yield at the herd level, representing a 15% decrease in yield for an increase in F. hepatica exposure from the 25th to the 75th percentile. This remained significant when fertility, farm management and environmental factors were controlled for. No associations were found between F. hepatica exposure and any of the other production, disease or fertility variables.
Subject(s)
Cattle Diseases/economics , Cattle Diseases/epidemiology , Dairying/methods , Fascioliasis/economics , Fascioliasis/epidemiology , Animals , Antibodies, Helminth/analysis , Cattle , Cattle Diseases/parasitology , Climate , England/epidemiology , Environment , Enzyme-Linked Immunosorbent Assay/veterinary , Fasciola hepatica/isolation & purification , Fascioliasis/parasitology , Female , Lactation , Milk/metabolism , Prevalence , Risk Factors , Scotland/epidemiology , Wales/epidemiologyABSTRACT
BACKGROUND: To clarify the extent and putative transmission zone of bovine fasciolosis on the slopes of Mount Elgon, Uganda, conjoint parasitological and malacological surveys, inclusive of inspection of animals at slaughter, were undertaken at increasing altitudes. RESULTS: A total of 239 cattle were sampled across eight locations ranging in elevation from 1112-2072 m. Faecal material was examined for presence of Fasciola eggs and sera were tested by ELISA for antibodies against Fasciola antigens. Bolstering this, 38 cattle at slaughter from 2 abattoir sites at 1150 m and 1947 m were inspected; in addition, wild buffalo stool (n=10) opportunistically picked within Mount Elgon National Park (MENP) at 3640 m was examined. By faecal egg detection, prevalence of Fasciola gigantica at low (<1500 m) and high (>1500 m) altitude sites was 43.7% (95% CI 35.4-52.2) and 1.1% (95% CI 0.0-6.0), respectively, while by ELISA was much higher, low altitude--77.9% (95% CI 69.7-85.4) and high altitude--64.5% (95% CI 51.3-76.3). The decline in prevalence with increasing altitude was corroborated by abattoir sampling. Thirty seven aquatic habitats, ranging from 1139-3937 m in altitude were inspected for freshwater snails, 12 of which were within MENP. At lower altitudes, Lymnaea (Radix) natalensis was common, and often abundant, but at higher altitudes became much rarer ceasing to be found above 1800 m. On the other hand, Lymnaea (Galba) truncatula was found only at altitudes above 3000 m and within MENP alone. The snail identifications were confirmed by DNA analysis of the ribosomal 18S gene. CONCLUSIONS: Active infections of F. gigantica in cattle are common in lower altitude settings but appear to diminish with increasing elevation. This is likely due to a growing paucity of intermediate hosts, specifically populations of L. natalensis for which a natural boundary of 1800 m appeared. Although F. hepatica was not encountered, the presence of several populations of L. truncatula at elevations over 3000 m point towards a potential transmission zone within MENP should this parasite be introduced.
Subject(s)
Altitude , Cattle Diseases/epidemiology , Cattle Diseases/parasitology , Fascioliasis/veterinary , Snails/physiology , Abattoirs , Animals , Antibodies, Helminth/blood , Cattle , DNA Primers/genetics , Disease Vectors , Enzyme-Linked Immunosorbent Assay/veterinary , Fascioliasis/epidemiology , Feces/parasitology , Liver/parasitology , Polymerase Chain Reaction , RNA, Ribosomal, 18S/genetics , Regression Analysis , Snails/genetics , Uganda/epidemiologyABSTRACT
PURPOSE: Active participation is considered to be a key factor in stroke rehabilitation. Patient engagement in learning is an important part of this process. This study sets out to explore how active participation and engagement are 'produced' in the course of day-to-day multi-disciplinary stroke rehabilitation. METHOD: Ethnographic observation, analytic concepts drawn from discourse analysis (DA) and the perspective and methods of conversation analysis (CA) were applied to videotaped data from three sessions of rehabilitation therapy each for two patients with communication impairments (dysarthria, aphasia). FINDINGS: Engagement was facilitated (and hindered) through the interactional work of patients and healthcare professionals. An institutional ethos of 'right practice' was evidenced in the working practices of therapists and aligned with or resisted by patients; therapeutic activity type (impairment, activity or functional focus) impacted on the ways in which patient engagement was developed and sustained. CONCLUSIONS: This exploration of multi-disciplinary rehabilitation practice adds a new dimension to our understanding of the barriers and facilitators to patient engagement in the learning process and provides scope for further research. Harmonising the rehabilitation process across disciplines through more focused attention to ways in which patient participation is enhanced may help improve the consistency and quality of patient engagement.
Subject(s)
Learning , Professional-Patient Relations , Stroke Rehabilitation , Aphasia/etiology , Aphasia/rehabilitation , Communication , Dysarthria/etiology , Dysarthria/rehabilitation , Female , Humans , Male , Occupational Therapy/methods , Patient Care Team/organization & administration , Patient Participation , Physical Therapy Modalities , Sampling Studies , Speech Therapy/methods , Stroke/complications , Treatment Outcome , Video RecordingABSTRACT
AIM: Staphylococcus aureus is an important cause of serious illness in children. Antibiotic resistance is an international problem and affects initial antibiotic choice. We aimed to describe susceptibility patterns of S. aureus isolates from Australian children to inform optimal empiric treatment of staphylococcal infections in this population. METHODS: We analysed susceptibility data for all S. aureus isolates from children at Australian tertiary paediatric hospitals in 2006. Susceptibility rates were compared between hospitals and states, and with published studies of S. aureus isolates from Australian adults. RESULTS: Overall, the proportion of methicillin-resistant S. aureus (MRSA) in Australian children was low (9.8%), and in each state it was less than for the comparable adult population. There were significant differences in susceptibility patterns between different states. Most MRSA isolates were susceptible to clindamycin (73%) and all isolates were reported as susceptible to vancomycin. Susceptibility patterns for isolates from bacteraemic patients were similar to those for isolates from all patients. CONCLUSIONS: These data support current Australian recommendations for the use of flucloxacillin or a first-generation cephalosporin as initial treatment of non-life-threatening staphylococcal infections. However, broad spectrum antibiotic therapy including agents that are effective against MRSA should be considered for more serious infections. Appropriate specimens should be collected for susceptibility testing to enable directed treatment for MRSA and other resistant organisms. This study highlights the importance of using local, age-specific data in planning antibiotic treatment guidelines, as results vary substantially from city to city and between adults and children.
Subject(s)
Anti-Bacterial Agents/pharmacology , Drug Resistance, Microbial/drug effects , Staphylococcus aureus/drug effects , Anti-Bacterial Agents/administration & dosage , Australia , Child , Child, Preschool , Clindamycin/pharmacology , Clindamycin/therapeutic use , Hospitals, Pediatric , Humans , Methicillin-Resistant Staphylococcus aureus , Staphylococcal Infections/drug therapyABSTRACT
AIM: To determine the prevalence of common diseases in newly arrived refugee children, resettled in Sydney, by region of birth. To identify health needs of refugee children in Australia. METHODS: We prospectively screened for common diseases in refugee children attending a specialist paediatric refugee clinic, the Children's Hospital, Westmead, between May 2005 and December 2006. Screening tests included full blood count, Mantoux, vitamin D level, hepatitis B serology, syphilis serology, Schistosomiasis serology and malarial antigens. RESULTS: There were 239 patients, the majority (75%) from Africa, with 127 girls and 112 boys. Thirty-six percent were 0-7 years old, 45% were 8-12 years old and 19% were 13-17 years old. Of those tested, 16% had Schistosomiasis, 5% had malaria and 4% were hepatitis B carriers. Of 216 children who had Mantoux tests, 33% were > or =10 mm and 24% were > or =15 mm, including four children with active disease (2 lymphadenitis, 1 pulmonary and 1 gastric). Vitamin D deficiency was the most common diagnosis: 61% had serum 25(OH)D3 <50 nmol/L. Anaemia was present in 15%. Disease prevalence was higher in children from Africa than Asia or the Middle East, and most of the children were asymptomatic. Given that we have only seen about 10% of the refugee children resettled in New South Wales, our results may not be generalisable to all refugees. CONCLUSION: Our findings suggest that screening refugee children for common treatable conditions, even if they are asymptomatic, is paramount. In addition to infectious diseases screening, nutritional deficiencies should routinely be screened for.