39 results on '"Clements, Archie"'
Search Results
2. Measuring the Effect of Soil-Transmitted Helminth Infections on Cognitive Function in Children
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Owada, Kei, primary, Nielsen, Mark, additional, Lau, Colleen L., additional, Clements, Archie C.A., additional, Yakob, Laith, additional, and Soares Magalhães, Ricardo J., additional
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- 2017
- Full Text
- View/download PDF
3. Cross-Border Malaria: A Major Obstacle for Malaria Elimination
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Wangdi, Kinley, primary, Gatton, Michelle L., additional, Kelly, Gerard C., additional, and Clements, Archie CA., additional
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- 2015
- Full Text
- View/download PDF
4. Epidemiology and challenges of dengue surveillance in the WHO South-East Asia Region
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Tsheten, Gray, Darren, Clements, Archie, Wangdi, Kinley, Tsheten, Gray, Darren, Clements, Archie, and Wangdi, Kinley
- Abstract
engue is an arthropod-borne disease caused by one or more of the four dengue viruses (DENV1–4), which belong to the genus Flavivirus and family Flaviviridae.
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- 2021
5. The Applications of Model-Based Geostatistics in Helminth Epidemiology and Control
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Magalhães, Ricardo J. Soares, primary, Clements, Archie C.A., additional, Patil, Anand P., additional, Gething, Peter W., additional, and Brooker, Simon, additional
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- 2011
- Full Text
- View/download PDF
6. Risk factors for infection with soil-transmitted helminths during an integrated community level water, sanitation, and hygiene and deworming intervention in Timor-Leste
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Vaz Nery, Susana, Clarke, Naomi, Richardson, Alice, Traub, Rebecca, McCarthy, James, Gray, Darren, Vallely, Andrew, Williams, Gail, Andrews, Ross, Campbell, Suzy, Clements, Archie, Vaz Nery, Susana, Clarke, Naomi, Richardson, Alice, Traub, Rebecca, McCarthy, James, Gray, Darren, Vallely, Andrew, Williams, Gail, Andrews, Ross, Campbell, Suzy, and Clements, Archie
- Abstract
Water, sanitation and hygiene interventions have been advocated as important complements to deworming programs to improve soil-transmitted helminth control. Evidence for the impact of water, sanitation and hygiene on soil-transmitted helminth infections is mixed, and based mainly on cross-sectional studies. In this study, we assessed associations between individual- and household-level water, sanitation and hygiene variables and soil-transmitted helminth infections, using data collected during the 2 year follow-up study period of the WASH for WORMS randomised controlled trial in Timor-Leste. Data were collected across four surveys, conducted at 6 monthly intervals in 23 communities. We analysed water, sanitation and hygiene and sociodemographic variables as risk factors for infection with Necator americanus, Ascaris spp., and undifferentiated soil-transmitted helminth infection, using generalised linear mixed models to account for clustering at community, household and participant levels. Water, sanitation and hygiene risk factors were examined both concurrently and with a 6 month lag period that coincided with the most recent deworming. The analysis included 2333 participants. Factors associated with N. americanus infection included age group, male sex (adjusted odds ratio (aOR) 3.1, 95% confidence interval (CI) 2.4–4.2), working as a farmer (aOR 1.7, 95% CI 1.2–2.4), and completing secondary school or higher (aOR 0.29, 95% CI 0.16–0.53). Risk factors for Ascaris spp. infection included age group, living in a dwelling with more than six people (aOR 1.6, 95% CI 1.1–2.3), having a tube well or borehole as the household water source (aOR 3.7, 95% CI 1.3–10.8), and using a latrine shared between households 6 months previously (aOR 2.3, 95% CI 1.2–4.3). Handwashing before eating was protective against infection with any soil-transmitted helminth (aOR 0.79, 95% CI 0.65–0.95). In the context of regular deworming, few water, sanitation and hygiene-related factors were asso
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- 2019
7. Major inpatient surgeries and in-hospital mortality in New South Wales public hospitals in Australia: A state-wide retrospective cohort study
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Du, Wei, Glasgow, Nicholas, Smith, Paul, Sedrakyan, Art, Clements, Archie, Du, Wei, Glasgow, Nicholas, Smith, Paul, Sedrakyan, Art, and Clements, Archie
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BACKGROUND Surgical interventions save lives and are important focus for health services research worldwide. Investigating variation in postoperative mortality may improve understanding of unwarranted variations and promote safety and quality in surgical care. We aimed to evaluate trends of in-hospital mortality rates among adult inpatients receiving major elective surgeries and determine the variation in mortality among New South Wales (NSW) public hospitals. MATERIALS AND METHODS In this study, we used the all-inclusive population-based NSW Admitted Patient Data from July 2001 to June 2014. We retrospectively included adult patients aged 18 + years receiving Abdominal Aortic Aneurysm (AAA) repair, Peripheral bypass, Colorectal surgeries, Joint replacement, Spinal surgeries, or Cardiac surgeries. The primary outcome was in-hospital mortality for selected surgeries. Changes in mortality rates over time and hospital standardised mortality rates were modelled using multivariate logistic regression models adjusting for case-mix factors. RESULTS Over 13-year study period, the in-hospital mortality rates declined annually by 6.4% (95% Confidence Interval (CI): 4.3, 8.4) for Colorectal surgery by 5.7% (95%CI: 2.0, 9.3) for Joint replacement and by 4.2% (95%CI: 1.9, 6.4) for Cardiac surgery. After controlling for patient-level factors, little variation was observed among hospitals for in-hospital mortality. There was a greater variability for cardiac surgery compared with the other surgical groups but no outlier hospital was consistently associated with significantly higher than expected mortality rate. CONCLUSIONS Mortality has declined for major surgeries in the past 15 years. There was some variation among hospitals regarding in-hospital mortality that was mostly explained by patients demographic and admission characteristics. Our findings are reassuring for patients and contribute to knowledge that can help further improve surgical care.
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- 2017
8. Clostridium difficile classification overestimates hospital acquired infections
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McLure, Angus, Clements, Archie, Glass, Kathryn, Kirk, Martyn, McLure, Angus, Clements, Archie, Glass, Kathryn, and Kirk, Martyn
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BACKGROUND Clostridium difficile infections are common among hospitalised patients, with some infections acquired in hospital and others in the community. International guidelines classify cases as hospital-acquired if symptom onset occurs >2 days after admission. This classification informs surveillance and infection control, but has not been verified by empirical or modelling studies. AIMS To assess current classification of C. difficile acquisition using a simulation model as a gold standard. METHODS We simulated C. difficile transmission in a range of hospital scenarios. We calculated the sensitivity, specificity and precision of classifications that use cut-offs ranging from 0.25 hours to 40 days. We identified the optimal cut-off that correctly estimated the proportion of cases that were hospital acquired and the balanced cut-off that had equal sensitivity and specificity. FINDINGS The recommended two-day cut-off overestimated the incidence of hospital-acquired cases in all scenarios and by >100% in the base scenario. The two-day cut-off had good sensitivity (96%) but poor specificity (48%) and precision (52%) to identify cases acquired during the current hospitalisation. A five-day cut-off was balanced and a six-day cut-off was optimal in the base scenario. The optimal and balanced cut-offs were more than two days for nearly all scenarios considered (ranges four to nine days and two to eight days). CONCLUSIONS Current guidelines for classifying C. difficile infections overestimate the proportion of cases acquired in hospital in all model scenarios. To reduce misclassification bias, an infection should be classified as being acquired prior to admission if symptoms begin within five days of admission.
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- 2017
9. Malaria burden and costs of intensifi ed control in Bhutan, 2006-14: an observational study and situation analysis
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Wangdi, Kinley, Banwell, Cathy, Gatton, Michelle L, Kelly, Gerard, Namgay, Rinzin, Clements, Archie, Wangdi, Kinley, Banwell, Cathy, Gatton, Michelle L, Kelly, Gerard, Namgay, Rinzin, and Clements, Archie
- Abstract
INTRODUCTION: The number of malaria cases has fallen in Bhutan in the past two decades, and the country has a goal of complete elimination of malaria by 2016. The aims of this study are to ascertain the trends and burden of malaria, the costs of intensified control activities, the main donors of funding for the control activities, and the costs of different preventive measures in the pre-elimination phase (2006-14) in Bhutan. METHODS: We undertook a descriptive analysis of malaria surveillance data from 2006 to 2014, using data from the Vector-borne Disease Control Programme (VDCP) run by the Department of Public Health of Bhutan's Ministry of Health. Malaria morbidity and mortality in local Bhutanese people and foreign nationals were analysed. The cost of different control and preventive measures were calculated, and the average numbers of long-lasting insecticidal nests per person were estimated. FINDINGS: A total of 5491 confirmed malaria cases occurred in Bhutan between 2006 and 2014. By 2013, there was an average of one long-lasting insecticidal net for every 1·51 individuals. The cost of procuring long-lasting insecticidal nets accounted for more than 90% of the total cost of prevention measures. The Global Fund to Fight AIDS, Tuberculosis and Malaria was the main international donor, accounting for more than 80% of the total funds. INTERPRETATION: The malaria burden in Bhutan decreased significantly during the study period with high coverage of long-lasting insecticidal nets. The foreseeable challenges that require national attention to maintain a malaria-free status after elimination are importation of malaria, especially from India; continued protection of the population in endemic districts through complete coverage with long-lasting insecticidal nets and indoor residual spraying; and exploration of local funding modalities post-elimination in the event of a reduction in international funding.
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- 2016
10. Associations between animal characteristic and environmental risk factors and bovine respiratory disease in Australian feedlot cattle
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Hay, K E, Morton, J M, Mahony, T J, Barnes, Tamsin S, Clements, Archie, Hay, K E, Morton, J M, Mahony, T J, Barnes, Tamsin S, and Clements, Archie
- Abstract
A prospective longitudinal study was conducted in a population of Australian feedlot cattle to assess associations between animal characteristic and environmental risk factors and risk of bovine respiratory disease (BRD). Animal characteristics were recorded at induction, when animals were individually identified and enrolled into study cohorts (comprising animals in a feedlot pen). Environmental risk factors included the year and season of induction, source region and feedlot region and summary variables describing weather during the first week of follow-up. In total, 35,131 animals inducted into 170 cohorts within 14 feedlots were included in statistical analyses. Causal diagrams were used to inform model building and multilevel mixed effects logistic regression models were fitted within the Bayesian framework. Breed, induction weight and season of induction were significantly and strongly associated with risk of BRD. Compared to Angus cattle, Herefords were at markedly increased risk (OR: 2.0, 95% credible interval: 1.5–2.6) and tropically adapted breeds and their crosses were at markedly reduced risk (OR: 0.5, 95% credible interval: 0.3–0.7) of developing BRD. Risk of BRD declined with increased induction weight, with cattle in the heaviest weight category (≥480 kg) at moderately reduced risk compared to cattle weighing <400 kg at induction (OR: 0.6, 95% credible interval: 0.5–0.7). Animals inducted into feedlots during summer (OR: 2.4, 95% credible interval: 1.4–3.8) and autumn (OR: 2.1, 95% credible interval: 1.2–3.2) were at markedly increased risk compared to animals inducted during spring. Knowledge of these risk factors may be useful in predicting BRD risk for incoming groups of cattle in Australian feedlots. This would then provide the opportunity for feedlot managers to tailor management strategies for specific subsets of animals according to predicted BRD risk.
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- 2016
11. Effects of exposure to Bovine viral diarrhoea virus 1 on risk of bovine respiratory disease in Australian feedlot cattle
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Hay, K E, Ambrose, R C K, Morton, J M, Horwood, P F, Gravel, J L, Waldron, S, Commins, M A, Fowler, E V, Barnes, Tamsin S, Mahony, T J, Clements, Archie, Hay, K E, Ambrose, R C K, Morton, J M, Horwood, P F, Gravel, J L, Waldron, S, Commins, M A, Fowler, E V, Barnes, Tamsin S, Mahony, T J, and Clements, Archie
- Abstract
Viruses play a key role in the complex aetiology of bovine respiratory disease (BRD). Bovine viral diarrhoea virus 1 (BVDV-1) is widespread in Australia and has been shown to contribute to BRD occurrence. As part of a prospective longitudinal study on BRD, effects of exposure to BVDV-1 on risk of BRD in Australian feedlot cattle were investigated. A total of 35,160 animals were enrolled at induction (when animals were identified and characteristics recorded), held in feedlot pens with other cattle (cohorts) and monitored for occurrence of BRD over the first 50 days following induction. Biological samples collected from all animals were tested to determine which animals were persistently infected (PI) with BVDV-1. Data obtained from the Australian National Livestock Identification System database were used to determine which groups of animals that were together at the farm of origin and at 28 days prior to induction (and were enrolled in the study) contained a PI animal and hence to identify animals that had probably been exposed to a PI animal prior to induction. Multi-level Bayesian logistic regression models were fitted to estimate the effects of exposure to BVDV-1 on the risk of occurrence of BRD. Although only a total of 85 study animals (0.24%) were identified as being PI with BVDV-1, BVDV-1 was detected on quantitative polymerase chain reaction in 59% of cohorts. The PI animals were at moderately increased risk of BRD (OR 1.9; 95% credible interval 1.0–3.2). Exposure to BVDV-1 in the cohort was also associated with a moderately increased risk of BRD (OR 1.7; 95% credible interval 1.1–2.5) regardless of whether or not a PI animal was identified within the cohort. Additional analyses indicated that a single quantitative real-time PCR test is useful for distinguishing PI animals from transiently infected animals. The results of the study suggest that removal of PI animals and/or vaccination, both before feedlot entry, would reduce the impact of BVDV-1 on BRD risk
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- 2016
12. Associations between exposure to viruses and bovine respiratory disease in Australian feedlot cattle
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Hay, K E, Barnes, Tamsin S, Morton, J M, Gravel, J L, Commins, M A, Horwood, P F, Ambrose, R C K, Mahony, T J, Clements, Archie, Hay, K E, Barnes, Tamsin S, Morton, J M, Gravel, J L, Commins, M A, Horwood, P F, Ambrose, R C K, Mahony, T J, and Clements, Archie
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- 2016
13. Associations between prior management of cattle and risk of bovine respiratory disease in feedlot cattle
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Hay, K E, Morton, J M, Schibrowski, M L, Mahony, T J, Barnes, Tamsin S, Clements, Archie, Hay, K E, Morton, J M, Schibrowski, M L, Mahony, T J, Barnes, Tamsin S, and Clements, Archie
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- 2016
14. A Critical Appraisal of Control Strategies for Soil-Transmitted Helminths
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Campbell, Suzy, Vaz da Silva de Castro Nery, Susana, McCarthy, James, Gray, Darren, Magalhaes, Ricardo Soares, Clements, Archie, Campbell, Suzy, Vaz da Silva de Castro Nery, Susana, McCarthy, James, Gray, Darren, Magalhaes, Ricardo Soares, and Clements, Archie
- Abstract
Interventions that lead to reductions in soil-transmitted helminths (STHs) include chemotherapy with anthelmintic drugs and improvements in water, sanitation, and hygiene (WASH). In this opinion article we aim to determine the evidence for optimal approaches for STH control. First we explore the evidence for the above interventions. We then appraise two integration strategies: current chemotherapy-oriented integrated neglected tropical disease (NTD) control and expanded ‘multicomponent integration’, which includes integrated chemotherapy, WASH, and other intervention strategies. While multicomponent integrated control may be an effective approach to sustainably reduce STH transmission, there is a need for evidence to prove the feasibility of this approach.
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- 2015
15. Cross-border malaria: a major obstacle for malaria elimination
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Wangdi, Kinley, Gatton, Michelle L., Kelly, Gerard C., Clements, Archie, Wangdi, Kinley, Gatton, Michelle L., Kelly, Gerard C., and Clements, Archie
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Movement of malaria across international borders poses a major obstacle to achieving malaria elimination in the 34 countries that have committed to this goal. In border areas, malaria prevalence is often higher than in other areas due to lower access to health services, treatment-seeking behaviour of marginalized populations that typically inhabit border areas, difficulties in deploying prevention programmes to hard-to-reach communities, often in difficult terrain, and constant movement of people across porous national boundaries. Malaria elimination in border areas will be challenging and key to addressing the challenges is strengthening of surveillance activities for rapid identification of any importation or reintroduction of malaria. This could involve taking advantage of technological advances, such as spatial decision support systems, which can be deployed to assist programme managers to carry out preventive and reactive measures, and mobile phone technology, which can be used to capture the movement of people in the border areas and likely sources of malaria importation. Additionally, joint collaboration in the prevention and control of cross-border malaria by neighbouring countries, and reinforcement of early diagnosis and prompt treatment are ways forward in addressing the problem of cross-border malaria.
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- 2015
16. Risk factors for bovine respiratory disease in Australian feedlot cattle: Use of a causal diagram-informed approach to estimate effects of animal mixing and movements before feedlot entry
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Hay, K E, Barnes, Tamsin S, Morton, J M, Mahony, T J, Clements, Archie, Hay, K E, Barnes, Tamsin S, Morton, J M, Mahony, T J, and Clements, Archie
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- 2014
17. Impact of “Grain to Green” Programme on echinococcosis infection in Ningxia Hui Autonomous Region of China
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Cleary, Eimear, Barnes, Tamsin S., Xu, Yangyang, Zhao, Hengbo, Clements, Archie C. A., Gray, Darren J., McManus, Donald P., Atkinson, Jo-An M., Williams, Gail M., Yang, YuRong, Cleary, Eimear, Barnes, Tamsin S., Xu, Yangyang, Zhao, Hengbo, Clements, Archie C. A., Gray, Darren J., McManus, Donald P., Atkinson, Jo-An M., Williams, Gail M., and Yang, YuRong
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Cystic echinococcosis (CE) is endemic among the human population of Xiji County, Ningxia Hui Autonomous Region, China, where the prevalence is estimated to be between 2.2% and 3.6%. Government-run sheep abattoirs in Xiji County have closed in recent years and, as a consequence, slaughter is carried out mostly at rural market places. The market place in Xinglong Township, Xiji County, is home to an increasing number of stray dogs and the lack of government control over slaughter practices potentially favours Echinococcus granulosus transmission. A survey of sheep, goats and cattle reared in Xiji County was conducted in Xinglong Market and Xinglong Township to determine prevalence and transmission dynamics of E. granulosus infection. The liver and lungs of all livestock aged one year and older were examined macroscopically post mortem; visual examination and palpation of organs determined overall prevalence of E. granulosus. Cysts consistent in appearance with E. granulosus were observed in 2/184 sheep (prevalence 1.0%) and 1/55 of the cattle examined (prevalence 1.8%); 0/13 goats were found to be infected. However, microscopic examination of these suspected cysts failed to confirm these samples as E. granulosus, giving a prevalence of confirmed infection of zero percent in all three species. The prevalence of liver fluke was 61.3% in sheep and 12.7% in cattle with a significant difference between males and females (p ≤ 0.001). Considering the high prevalence of echinococcosis in the local human population, the absence of CE observed among commercially slaughtered livestock was surprising. Several explanations for this discrepancy and their implications are proposed.
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- 2014
18. Geographical distribution of human Schistosoma japonicum infection in The Philippines: Tools to support disease control and further elimination
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Magalhaes, Ricardo Soares, Salamat, Maria Sonia, Leonardo, Lydia, Gray, Darren, Carabin, Helene, Halton, Kate, McManus, Donald P, Williams, Gail, Rivera, Pularita, Saniel, Ofelia, Hernandez, Leda, Yakob, Laith, McGarvey, S.T, Clements, Archie, Magalhaes, Ricardo Soares, Salamat, Maria Sonia, Leonardo, Lydia, Gray, Darren, Carabin, Helene, Halton, Kate, McManus, Donald P, Williams, Gail, Rivera, Pularita, Saniel, Ofelia, Hernandez, Leda, Yakob, Laith, McGarvey, S.T, and Clements, Archie
- Abstract
Schistosoma japonicum infection is believed to be endemic in 28 of the 80 provinces of The Philippines and the most recent data on schistosomiasis prevalence have shown considerable variability between provinces. In order to increase the efficient allocation of parasitic disease control resources in the country, we aimed to describe the small-scale spatial variation in S. japonicum prevalence across The Philippines, quantify the role of the physical environment in driving the spatial variation of S. japonicum, and develop a predictive risk map of S. japonicum infection. Data on S. japonicum infection from 35,754 individuals across the country were geo-located at the barangay level and included in the analysis. The analysis was then stratified geographically for the regions of Luzon, the Visayas and Mindanao. Zero-inflated binomial Bayesian geostatistical models of S. japonicum prevalence were developed and diagnostic uncertainty was incorporated. Results of the analysis show that in the three regions, males and individuals aged ≥20. years had significantly higher prevalence of S. japonicum compared with females and children <5. years. The role of the environmental variables differed between regions of The Philippines. Schistosoma japonicum infection was widespread in the Visayas whereas it was much more focal in Luzon and Mindanao. This analysis revealed significant spatial variation in the prevalence of S. japonicum infection in The Philippines. This suggests that a spatially targeted approach to schistosomiasis interventions, including mass drug administration, is warranted. When financially possible, additional schistosomiasis surveys should be prioritised for areas identified to be at high risk but which were under-represented in our dataset.
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- 2014
19. Malaria burden and control in Bangladesh and prospects for elimination: An epidemiological and economic assessment
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Haque, Ubydul, Overgaard, Hans, Norris, Douglas, Islam, Nazrul, Karim, Jahirul, Roy, Shyamal, Haque, Waziul, Kabir, Moktadir, Smith, David L, Glass, Gregory E, Clements, Archie, Haque, Ubydul, Overgaard, Hans, Norris, Douglas, Islam, Nazrul, Karim, Jahirul, Roy, Shyamal, Haque, Waziul, Kabir, Moktadir, Smith, David L, Glass, Gregory E, and Clements, Archie
- Abstract
Background: Malaria is endemic in 13 of 64 districts in Bangladesh. About 14 million people are at risk. Some evidence suggests that the prevalence of malaria in Bangladesh has decreased since the the Global Fund to Fight AIDS, Tuberculosis and Malaria started to support the National Malaria Control Program (NMCP) in 2007. We did an epidemiological and economic assessment of malaria control in Bangladesh. Methods: We obtained annually reported, district-level aggregated malaria case data and information about disbursed funds from the NMCP. We used a Poisson regression model to examine the associations between total malaria, severe malaria, malaria-attributable mortality, and insecticide-treated net coverage. We identified and mapped malaria hotspots using the Getis-Ord Gi* statistic. We estimated the cost-effectiveness of the NMCP by estimating the cost per confirmed case, cost per treated case, and cost per person of insecticide-treated net coverage. Findings: During the study period (from Jan 1, 2008, to Dec 31, 2012) there were 285731 confirmed malaria cases. Malaria decreased from 6·2 cases per 1000 population in 2008, to 2·1 cases per 1000 population in 2012. Prevalence of all malaria decreased by 65% (95% CI 65-66), severe malaria decreased by 79% (78-80), and malaria-associated mortality decreased by 91% (83-95). By 2012, there was one insecticide-treated net for every 2·6 individuals (SD 0·20). Districts with more than 0·5 insecticide-treated nets per person had a decrease in prevalence of 21% (95% CI 19-23) for all malaria, 25% (17-32) for severe malaria, and 76% (35-91) for malaria-associated mortality among all age groups. Malaria hotspots remained in the highly endemic districts in the Chittagong Hill Tracts. The cost per diagnosed case was US$0·39 (SD 0·02) and per treated case was $0·51 (0·27); $0·05 (0·04) was invested per person per year for health education and $0·68 (0·30) was spent per person per year for insecticide-treated net coverage. Interpre
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- 2014
20. Modelling parasite aggregation: Disentangling statistical and ecological approaches
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Yakob, Laith, Soares Magalhaes, Ricardo, Gray, Darren, Milinovich, Gabriel, Wardrop, Nicola A, Dunning, Rebecca, Barendregt, Jan, Bieri, Franziska A, Williams, Gail, Clements, Archie, Yakob, Laith, Soares Magalhaes, Ricardo, Gray, Darren, Milinovich, Gabriel, Wardrop, Nicola A, Dunning, Rebecca, Barendregt, Jan, Bieri, Franziska A, Williams, Gail, and Clements, Archie
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The overdispersion in macroparasite infection intensity among host populations is commonly simulated using a constant negative binomial aggregation parameter. We describe an alternative to utilising the negative binomial approach and demonstrate important disparities in intervention efficacy projections that can come about from opting for pattern-fitting models that are not process-explicit. We present model output in the context of the epidemiology and control of soil-transmitted helminths due to the significant public health burden imposed by these parasites, but our methods are applicable to other infections with demonstrable aggregation in parasite numbers among hosts.
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- 2014
21. Malaria elimination: moving forward with spatial decision support systems
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Kelly, Gerard C, Tanner, Marcel, Vallely, Andrew, Clements, Archie, Kelly, Gerard C, Tanner, Marcel, Vallely, Andrew, and Clements, Archie
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Operational challenges facing contemporary malaria elimination have distinct geospatial elements including the need for high-resolution location-based surveillance, targeted prevention and response interventions, and effective delivery of essential services at optimum levels of coverage. Although mapping and geographical reconnaissance (GR) has traditionally played an important role in supporting malaria control and eradication, its full potential as an applied health systems tool has not yet been fully realised. As accessibility to global positioning system (GPS), geographic information system (GIS) and mobile computing technology increases, the role of an integrated spatial decision support system (SDSS) framework for supporting the increased operational demands of malaria elimination requires further exploration, validation and application; particularly in the context of resource-poor settings.
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- 2012
22. Using a checklist to identify barriers to compliance with evidence-based guidelines for central line management: A mixed methods study in Mongolia
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Ider, B-E, Adams, J, Morton, Anthony, Whitby, M, Muugolog, T, Lundeg, Ganbold, Clements, Archie, Ider, B-E, Adams, J, Morton, Anthony, Whitby, M, Muugolog, T, Lundeg, Ganbold, and Clements, Archie
- Abstract
Objectives: This study aimed to determine the extent to which a checklist has potential for identifying barriers to compliance with central line management guidelines, to evaluate the potential utility of checklists to improve the management of central lines in Mongolia, and to define the gap between current and best practices. Methods: A 22-item checklist was developed based on the Centers for Disease Control and Prevention (CDC, USA) guidelines and existing central line-associated bloodstream infection (CLABSI) checklists. The checklist was used to observe 375 central line procedures performed in the intensive care units of four tertiary hospitals of Mongolia between July and December 2010. In parallel, 36 face-to-face interviews were conducted in six other tertiary hospitals to explain practice variations and identify barriers. Results: The baseline compliance level across all components of the checklist was 68.5%. The main factors explaining low levels of compliance were outdated local standards, a lack of updated guidelines, poor control over compliance with existing clinical guidelines, poor supply of medical consumables, and insufficient knowledge of contemporary infection control measures among health care providers. Conclusions: The health authorities of Mongolia need to adequately address the prevention and control of CLABSIs in their hospitals. Updating local standards and guidelines and implementing adequate multifaceted interventions with behavioral, educational, and logistical components are required. Use of a checklist as a baseline evaluation tool was feasible. It described current practice, showed areas that need urgent attention, and provided important information needed for future planning of CLABSI interventions.
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- 2012
23. Social and environmental determinants of malaria in space and time in Viet Nam
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Manh, Bui H, Thieu, Nguyen Q, Hung, Nguyen M, Hung, Le X, Hay, Simon I, Hien, Tran Tinh, Wertheim, Heiman F L, Snow, Robert W, Horby, Peter, Clements, Archie, Manh, Bui H, Thieu, Nguyen Q, Hung, Nguyen M, Hung, Le X, Hay, Simon I, Hien, Tran Tinh, Wertheim, Heiman F L, Snow, Robert W, Horby, Peter, and Clements, Archie
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The malaria burden in Viet Nam has been in decline in recent decades, but localised areas of high transmission remain. We used spatiotemporal analytical tools to determine the social and environmental drivers of malaria risk and to identify residual high-risk areas where control and surveillance resources can be targeted. Counts of reported Plasmodium falciparum and Plasmodium vivax malaria cases by month (January 2007-December 2008) and by district were assembled. Zero-inflated Poisson regression models were developed in a Bayesian framework. Models had the percentage of the district's population living below the poverty line, percent of the district covered by forest, median elevation, median long-term average precipitation, and minimum temperature included as fixed effects, and terms for temporal trend and residual district-level spatial autocorrelation. Strong temporal and spatial heterogeneity in counts of malaria cases was apparent. Poverty and forest cover were significantly associated with an increased count of malaria cases but the magnitude and direction of associations between climate and malaria varied by socio-ecological zone. There was a declining trend in counts of malaria cases during the study period. After accounting for the social and environmental fixed effects, substantial spatial heterogeneity was still evident. Unmeasured factors which may contribute to this residual variation include malaria control activities, population migration and accessibility to health care. Forest-related activities and factors encompassed by poverty indicators are major drivers of malaria incidence in Viet Nam.
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- 2011
24. Spatial heterogeneity of parasite co-infection: Determinants and geostatistical prediction at regional scales
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Brooker, S, Clements, Archie, Brooker, S, and Clements, Archie
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Multiple parasite infections are widespread in the developing world and understanding their geographical distribution is important for spatial targeting of differing intervention packages. We investigated the spatial epidemiology of mono- and co-infection with helminth parasites in East Africa and developed a geostatistical model to predict infection risk. The data used for the analysis were taken from standardised school surveys of Schistosoma mansoni and hookworm (Ancylostoma duodenale/Necator americanus) carried out between 1999 and 2005 in East Africa. Prevalence of mono- and co-infection was modelled using satellite-derived environmental and demographic variables as potential predictors. A Bayesian multi-nominal geostatistical model was developed for each infection category for producing maps of predicted co-infection risk. We show that heterogeneities in co-infection with S. mansoni and hookworm are influenced primarily by the distribution of S. mansoni, rather than the distribution of hookworm, and that temperature, elevation and distance to large water bodies are reliable predictors of the spatial large-scale distribution of co-infection. On the basis of these results, we developed a validated geostatistical model of the distribution of co-infection at a scale that is relevant for planning regional disease control efforts that simultaneously target multiple parasite species.
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- 2009
25. Bayesian spatial analysis of a national urinary schistosomiasis questionnaire to assist geographic targeting of schistosomiasis control in Tanzania, East Africa
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Brooker, S, Nyandindi, U, Fenwick, A, Blair, L, Clements, Archie, Brooker, S, Nyandindi, U, Fenwick, A, Blair, L, and Clements, Archie
- Abstract
Spatial modelling was applied to self-reported schistosomiasis data from over 2.5 million school students from 12,399 schools in all regions of mainland Tanzania. The aims were to derive statistically robust prevalence estimates in small geographical units (wards), to identify spatial clusters of high and low prevalence and to quantify uncertainty surrounding prevalence estimates. The objective was to permit informed decision-making for targeting of resources by the Tanzanian national schistosomiasis control programme. Bayesian logistic regression models were constructed to investigate the risk of schistosomiasis in each ward, based on the prevalence of self-reported schistosomiasis and blood in urine. Models contained covariates representing climatic and demographic effects and random effects for spatial clustering. Degree of urbanisation, median elevation of the ward and median normalised difference vegetation index (NDVI) were significantly and negatively associated with schistosomiasis prevalence. Most regions contained wards that had >95% certainty of schistosomiasis prevalence being >10%, the selected threshold for bi-annual mass chemotherapy of school-age children. Wards with >95% certainty of schistosomiasis prevalence being >30%, the selected threshold for annual mass chemotherapy of school-age children, were clustered in north-western, south-western and south-eastern regions. Large sample sizes in most wards meant raw prevalence estimates were robust. However, when uncertainties were investigated, intervention status was equivocal in 6.7-13.0% of wards depending on the criterion used. The resulting maps are being used to plan the distribution of praziquantel to participating districts; they will be applied to prioritising control in those wards where prevalence was unequivocally above thresholds for intervention and might direct decision-makers to obtain more information in wards where intervention status was uncertain.
- Published
- 2008
26. Liver and cardiometabolic markers and conditions in a cross-sectional study of three Australian communities living with environmental per- and polyfluoroalkyl substances contamination.
- Author
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Lazarevic N, Smurthwaite KS, D'Este C, Lucas RM, Armstrong B, Clements AC, Trevenar SM, Gad I, Hosking R, Law HD, Mueller J, Bräunig J, Nilsson S, Lane J, Lal A, Lidbury BA, Korda RJ, and Kirk MD
- Subjects
- Adult, Humans, Cross-Sectional Studies, Bayes Theorem, Australia epidemiology, Liver, Cholesterol, Diabetes Mellitus, Type 2, Alkanesulfonic Acids, Environmental Pollutants, Fluorocarbons
- Abstract
Background: Per- and polyfluoroalkyl substances (PFAS) have been associated with higher cholesterol and liver function markers in some studies, but the evidence for specific cardiometabolic conditions has been inconclusive., Objectives: We quantified the associations of single and combined PFAS with cardiometabolic markers and conditions in a cross-sectional study of three Australian communities with PFAS-contaminated water from the historical use of aqueous film-forming foam in firefighting activities, and three comparison communities., Methods: Participants gave blood samples for measurement of nine PFAS, four lipids, six liver function markers, and completed a survey on sociodemographic characteristics and eight cardiometabolic conditions. We estimated differences in mean biomarker concentrations per doubling in single PFAS concentrations (linear regression) and per interquartile range increase in the PFAS mixture (Bayesian kernel machine regression). We estimated prevalence ratios of biomarker concentrations outside reference limits and self-reported cardiometabolic conditions (Poisson regression)., Results: We recruited 881 adults in exposed communities and 801 in comparison communities. We observed higher mean total cholesterol with higher single and mixture PFAS concentrations in blood serum (e.g., 0.18 mmol/L, 95% credible interval -0.06 to 0.42, higher total cholesterol concentrations with an interquartile range increase in all PFAS concentrations in Williamtown, New South Wales), with varying certainty across communities and PFAS. There was less consistency in direction of associations for liver function markers. Serum perfluorooctanoic acid (PFOA) concentrations were positively associated with the prevalence of self-reported hypercholesterolemia in one of three communities, but PFAS concentrations were not associated with self-reported type II diabetes, liver disease, or cardiovascular disease., Discussion: Our study is one of few that has simultaneously quantified the associations of blood PFAS concentrations with multiple biomarkers and cardiometabolic conditions in multiple communities. Our findings for total cholesterol were consistent with previous studies; however, substantial uncertainty in our estimates and the cross-sectional design limit causal inference., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Professor Martyn Kirk worked part-time for the Australian Government Department of Health between 2020 and 2022 on the Australian national COVID-19 response., (Copyright © 2023 The Authors. Published by Elsevier Inc. All rights reserved.)
- Published
- 2023
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27. Psychological distress in three Australian communities living with environmental per- and polyfluoroalkyl substances contamination.
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Lazarevic N, Smurthwaite KS, Batterham PJ, Lane J, Trevenar SM, D'Este C, Clements ACA, Joshy AL, Hosking R, Gad I, Lal A, Law HD, Banwell C, Randall DA, Miller A, Housen T, Korda RJ, and Kirk MD
- Subjects
- Adult, Humans, Australia epidemiology, Cross-Sectional Studies, Environmental Exposure, Water, Alkanesulfonic Acids analysis, Environmental Pollutants, Fluorocarbons analysis
- Abstract
Background: Environmental chemical contamination is a recognised risk factor for psychological distress, but has been seldom studied in the context of per- and polyfluoroalkyl substances (PFAS) contamination. We examined psychological distress in a cross-sectional study of three Australian communities exposed to PFAS from the historical use of aqueous film-forming foam in firefighting activities, and three comparison communities without environmental contamination., Methods: Participation was voluntary following recruitment from a PFAS blood-testing program (exposed) or random selection (comparison). Participants provided blood samples and completed a survey on their exposure history, sociodemographic characteristics, and four measures of psychological distress (Kessler-6, Distress Questionnaire-5, Patient Health Questionnaire-15, and Generalised Anxiety Disorder-7). We estimated prevalence ratios (PR) of clinically-significant psychological distress scores, and differences in mean scores: (1) between exposed and comparison communities; (2) per doubling in PFAS serum concentrations in exposed communities; (3) for factors that affect the perceived risk of living in a community exposed to PFAS; and (4) in relation to self-reported health concerns., Results: We recruited 881 adults in exposed communities and 801 in comparison communities. We observed higher levels of self-reported psychological distress in exposed communities than in comparison communities (e.g., Katherine compared to Alice Springs, Northern Territory: clinically-significant anxiety scores, adjusted PR = 2.82, 95 % CI 1.16-6.89). We found little evidence to suggest that psychological distress was associated with PFAS serum concentrations (e.g., Katherine, PFOS and anxiety, adjusted PR = 0.85, 95 % CI 0.65-1.10). Psychological distress was higher among exposed participants who were occupationally exposed to firefighting foam, used bore water on their properties, or were concerned about their health., Conclusion: Psychological distress was substantially more prevalent in exposed communities than in comparison communities. Our findings suggest that the perception of risks to health, rather than PFAS exposure, contribute to psychological distress in communities with PFAS contamination., Competing Interests: Declaration of competing interest MDK worked part-time for the Australian Government Department of Health between 2020 and 2022 on the Australian national COVID-19 response team. The other authors declare that they have no competing interests., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2023
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28. Opisthorchis viverrini and Strongyloides stercoralis mono- and co-infections: Bayesian geostatistical analysis in an endemic area, Thailand.
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Suwannatrai AT, Thinkhamrop K, Suwannatrai K, Pratumchart K, Wangdi K, Kelly M, Restrepo AMC, Gray DJ, Clements ACA, Tangkawattana S, and Sripa B
- Subjects
- Adult, Animals, Bayes Theorem, Female, Humans, Male, Middle Aged, Opisthorchis, Prevalence, Strongyloides stercoralis, Thailand epidemiology, Young Adult, Coinfection epidemiology, Coinfection parasitology, Opisthorchiasis complications, Opisthorchiasis epidemiology, Strongyloidiasis complications, Strongyloidiasis epidemiology
- Abstract
Parasitic infections caused by Opisthorchis viverrini and Strongyloides stercoralis remain a major public health threat in the Greater Mekong Sub-region. An understanding of climate and other environmental influences on the geographical distribution and emergence of parasitic diseases is a crucial step to guide targeted control and prevention programs. A parasitological survey was conducted from 2008 to 2013 and included 12,554 individuals (age between 20 and 60 years) from 142 villages in five districts in Khon Kaen Province, Thailand. Geographical information systems, remote sensing technologies and a Bayesian geostatistical framework were used to develop models for O. viverrini and S. stercoralis mono- and co-infections in areas where both parasites are known to co-occur. The results indicate that male sex, increased age, altitude, precipitation, and land surface temperature have influenced the infection rate and geographical distribution of mono- and co-infections of O. viverrini and S. stercoralis in this area. Males were 6.69 times (95% CrI: 5.26-8.58) more likely to have O. viverrini - S. stercoralis co-infection. We observed that O. viverrini and S. stercoralis mono-infections display distinct spatial pattern, while co-infection is predicted in the center and southeast of the study area. The observed spatial clustering of O. viverrini and S. stercoralis provides valuable information for the spatial targeting of prevention interventions in this area., (Copyright © 2021. Published by Elsevier B.V.)
- Published
- 2021
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29. GEOFIL: A spatially-explicit agent-based modelling framework for predicting the long-term transmission dynamics of lymphatic filariasis in American Samoa.
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Xu Z, Graves PM, Lau CL, Clements A, Geard N, and Glass K
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- Adolescent, Adult, Aedes, American Samoa epidemiology, Animals, Child, Child, Preschool, Elephantiasis, Filarial transmission, Female, Humans, Male, Models, Theoretical, Prevalence, Seroepidemiologic Studies, Surveys and Questionnaires, Time, Young Adult, Elephantiasis, Filarial epidemiology, Insect Bites and Stings epidemiology
- Abstract
In this study, a spatially-explicit agent-based modelling framework GEOFIL was developed to predict lymphatic filariasis (LF) transmission dynamics in American Samoa. GEOFIL included individual-level information on age, gender, disease status, household location, household members, workplace/school location and colleagues/schoolmates at each time step during the simulation. In American Samoa, annual mass drug administration from 2000 to 2006 successfully reduced LF prevalence dramatically. However, GEOFIL predicted continual increase in microfilaraemia prevalence in the absence of further intervention. Evidence from seroprevalence and transmission assessment surveys conducted from 2010 to 2016 indicated a resurgence of LF in American Samoa, corroborating GEOFIL's predictions. The microfilaraemia and antigenaemia prevalence in 6-7-yo children were much lower than in the overall population. Mosquito biting rates were found to be a critical determinant of infection risk. Transmission hotspots are likely to disappear with lower biting rates. GEOFIL highlights current knowledge gaps, such as data on mosquito abundance, biting rates and within-host parasite dynamics, which are important for improving the accuracy of model predictions., (Copyright © 2019 The Authors. Published by Elsevier B.V. All rights reserved.)
- Published
- 2019
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30. Reducing length of stay to improve Clostridium difficile-related health outcomes.
- Author
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Brain DC, Barnett AG, Yakob L, Clements A, Riley TV, Halton K, and Graves N
- Abstract
Background: Clostridium difficile infection is a serious hospital-acquired infection, causing negative outcomes for those who are afflicted by it. Hospital length of stay is known to be a risk factor for transmission and significant reductions in infection numbers can be realised if transmission is reduced., Methods: A Markov model was constructed to compare the impact that five alternative healthcare scenarios had on total C. difficile infections, QALYs gained and total number of patients requiring treatment in ICU. A previously published stochastic transmission model for C. difficile informed scenario effectiveness, while other parameters were estimated from published literature, administrative datasets and expert opinion., Results: Reducing inpatient LOS disrupts transmission of C. difficile and results in a large reduction of total infections. In turn, an increase in QALYs is expected when the number of infections is reduced. A reduction in infections reduces the number of ICU admissions, which is likely to have a large economic benefit in the Australian setting. Coupling a reduction in overall inpatient LOS with a 'traditional' infection control intervention, such as hand hygiene or antimicrobial stewardship, improves results further than reducing LOS on its own., Conclusion: Implementing a LOS-focused intervention would be a practical challenge, especially for clinicians who already juggle high demand. However, it is not unattainable with the right local endorsement and could have significant benefits for health services., (Copyright © 2018 The Author(s). Published by Elsevier B.V. All rights reserved.)
- Published
- 2018
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31. Land cover change during a period of extensive landscape restoration in Ningxia Hui Autonomous Region, China.
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Cadavid Restrepo AM, Yang YR, Hamm NAS, Gray DJ, Barnes TS, Williams GM, Soares Magalhães RJ, McManus DP, Guo D, and Clements ACA
- Abstract
Environmental change has been a topic of great interest over the last century due to its potential impact on ecosystem services that are fundamental for sustainable development and human well-being. Here, we assess and quantify the spatial and temporal variation in land cover in Ningxia Hui Autonomous Region (NHAR), China. With high-resolution (30m) imagery from Landsat 4/5-TM and 8-OLI for the entire region, land cover maps of the region were created to explore local land cover changes in a spatially explicit way. The results suggest that land cover changes observed in NHAR from 1991 to 2015 reflect the main goals of a national policy implemented there to recover degraded landscapes. Forest, herbaceous vegetation and cultivated land increased by approximately 410,200ha, 708,600ha and 164,300ha, respectively. The largest relative land cover change over the entire study period was the increase in forestland. Forest growth resulted mainly from the conversion of herbaceous vegetation (53.8%) and cultivated land (30.8%). Accurate information on the local patterns of land cover in NHAR may contribute to the future establishment of better landscape policies for ecosystem management and protection. Spatially explicit information on land cover change may also help decision makers to understand and respond appropriately to emerging environmental risks for the local population., (Copyright © 2017 Elsevier B.V. All rights reserved.)
- Published
- 2017
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32. The expansion of soil-transmitted helminth control strategies - Authors' reply.
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Clarke NE, Doi SA, Clements AC, Gray D, Campbell S, Wang D, and Nery SV
- Subjects
- Animals, Helminthiasis, Humans, Prevalence, Helminths, Soil
- Published
- 2017
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33. Differential effect of mass deworming and targeted deworming for soil-transmitted helminth control in children: a systematic review and meta-analysis.
- Author
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Clarke NE, Clements AC, Doi SA, Wang D, Campbell SJ, Gray D, and Nery SV
- Subjects
- Adolescent, Ancylostomatoidea, Animals, Ascaris lumbricoides, Child, Child, Preschool, Communicable Disease Control methods, Humans, Soil parasitology, Trichuris, Anthelmintics therapeutic use, Helminthiasis prevention & control
- Abstract
Background: Soil-transmitted helminth infections are a major global health issue, causing substantial morbidity in the world's poorest populations. Regular delivery of anthelmintic drugs is the mainstay for global soil-transmitted helminth control. Deworming campaigns are often targeted to school-aged children, who are at high risk of soil-transmitted-helminth-associated morbidity. However, findings from modelling studies suggest that deworming campaigns should be expanded community-wide for effective control of soil-transmitted helminth transmission. We aimed to do a systematic review and meta-analysis to compare the effect of mass (community-wide) and targeted (children only) anthelmintic delivery strategies on soil-transmitted helminth prevalence in school-aged children., Methods: In this systematic review and meta-analysis, we searched MEDLINE, Embase, and Web of Science for articles published on or before Nov 5, 2015, reporting soil-transmitted helminth prevalence before and after distribution of albendazole or mebendazole, either targeted to children or delivered to the whole community. We excluded studies in which drug delivery was restricted to infected individuals or to a subset of the community or school, or if follow-up time was less than 3 months or greater than 18 months after drug delivery. We extracted data on study year, country, drug administration strategy, drug dose, number of deworming rounds, treatment coverage, diagnostic method, follow-up interval, and soil-transmitted helminth prevalence before and after treatment. We used inverse variance weighted generalised linear models, with prevalence reduction as the outcome variable, to examine the effect of mass versus targeted drug administration, as well as baseline prevalence, number of drug doses, and follow-up time. This study is registered with PROSPERO, number CRD42016026929., Findings: Of 10 538 studies identified, 56 studies were eligible for the systematic review and 38 of these were included in meta-analysis. Results of the regression models showed that mass deworming led to a significantly greater reduction in prevalence in children than targeted deworming, for both hookworm (odds ratio 4·6, 95% CI 1·8-11·6; p=0·0020) and Ascaris lumbricoides (16·4, 2·1-125·8; p=0·0092), with no effect seen for Trichuris trichiura. There was significant heterogeneity across studies; for targeted studies I
2 was 97% for A lumbricoides and hookworm, and 96% for T trichiura, and for mass studies, I2 was 89% for A lumbricoides, 49% for hookworm, and 66% for T trichiura., Interpretation: The results of this meta-analysis suggest that expanding deworming programmes community-wide is likely to reduce the prevalence of soil-transmitted helminths in the high-risk group of school-aged children, which could lead to improved morbidity outcomes. These findings are in support of recent calls for re-evaluation of global soil-transmitted helminth control guidelines., Funding: None., (Copyright © 2017 Elsevier Ltd. All rights reserved.)- Published
- 2017
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34. Bayesian estimation of the dynamics of pandemic (H1N1) 2009 influenza transmission in Queensland: A space-time SIR-based model.
- Author
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Huang X, Clements AC, Williams G, Mengersen K, Tong S, and Hu W
- Subjects
- Bayes Theorem, Humans, Influenza, Human virology, Queensland epidemiology, Regression Analysis, Socioeconomic Factors, Weather, Influenza A Virus, H1N1 Subtype physiology, Influenza, Human epidemiology, Influenza, Human transmission, Models, Theoretical, Pandemics
- Abstract
Background: A pandemic strain of influenza A spread rapidly around the world in 2009, now referred to as pandemic (H1N1) 2009. This study aimed to examine the spatiotemporal variation in the transmission rate of pandemic (H1N1) 2009 associated with changes in local socio-environmental conditions from May 7-December 31, 2009, at a postal area level in Queensland, Australia., Method: We used the data on laboratory-confirmed H1N1 cases to examine the spatiotemporal dynamics of transmission using a flexible Bayesian, space-time, Susceptible-Infected-Recovered (SIR) modelling approach. The model incorporated parameters describing spatiotemporal variation in H1N1 infection and local socio-environmental factors., Results: The weekly transmission rate of pandemic (H1N1) 2009 was negatively associated with the weekly area-mean maximum temperature at a lag of 1 week (LMXT) (posterior mean: -0.341; 95% credible interval (CI): -0.370--0.311) and the socio-economic index for area (SEIFA) (posterior mean: -0.003; 95% CI: -0.004--0.001), and was positively associated with the product of LMXT and the weekly area-mean vapour pressure at a lag of 1 week (LVAP) (posterior mean: 0.008; 95% CI: 0.007-0.009). There was substantial spatiotemporal variation in transmission rate of pandemic (H1N1) 2009 across Queensland over the epidemic period. High random effects of estimated transmission rates were apparent in remote areas and some postal areas with higher proportion of indigenous populations and smaller overall populations., Conclusions: Local SEIFA and local atmospheric conditions were associated with the transmission rate of pandemic (H1N1) 2009. The more populated regions displayed consistent and synchronized epidemics with low average transmission rates. The less populated regions had high average transmission rates with more variations during the H1N1 epidemic period., (Copyright © 2016 Elsevier Inc. All rights reserved.)
- Published
- 2016
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35. Weather variability and influenza A (H7N9) transmission in Shanghai, China: a Bayesian spatial analysis.
- Author
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Hu W, Zhang W, Huang X, Clements A, Mengersen K, and Tong S
- Subjects
- China epidemiology, Humans, Influenza, Human virology, Bayes Theorem, Influenza A Virus, H7N9 Subtype isolation & purification, Influenza, Human transmission, Weather
- Abstract
Background: A novel avian influenza A (H7N9) virus was first found in humans in Shanghai, and infected over 433 patients in China. To date, very little is known about the spatiotemporal variability or environmental drivers of the risk of H7N9 infection. This study explored the spatial and temporal variation of H7N9 infection and assessed the effects of temperature and rainfall on H7N9 incidence., Methods: A Bayesian spatial conditional autoregressive (CAR) model was used to assess the spatiotemporal distribution of the risk of H7N9 infection in Shanghai, by district and fortnight for the period 19th February-14th April 2013. Data on daily laboratory-confirmed H7N9 cases, and weather variability including temperature (°C) and rainfall (mm) were obtained from the Chinese Information System for Diseases Control and Prevention and Chinese Meteorological Data Sharing Service System, respectively, and aggregated by fortnight., Results: High spatial variations in the H7N9 risk were mainly observed in the east and centre of Shanghai municipality. H7N9 incidence rate was significantly associated with fortnightly mean temperature (Relative Risk (RR): 1.54; 95% credible interval (CI): 1.22-1.94) and fortnightly mean rainfall (RR: 2.86; 95% CI: 1.47-5.56)., Conclusion: There was a substantial variation in the spatiotemporal distribution of H7N9 infection across different districts in Shanghai. Optimal temperature and rainfall may be one of the driving forces for H7N9., (Copyright © 2014 Elsevier Inc. All rights reserved.)
- Published
- 2015
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36. Impact of "Grain to Green" Programme on echinococcosis infection in Ningxia Hui Autonomous Region of China.
- Author
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Cleary E, Barnes TS, Xu Y, Zhao H, Clements AC, Gray DJ, McManus DP, Atkinson JA, Williams GM, and Yang Y
- Subjects
- Abattoirs, Animals, Cattle, Cattle Diseases parasitology, China epidemiology, Dog Diseases parasitology, Dogs, Echinococcosis parasitology, Echinococcosis transmission, Female, Goat Diseases parasitology, Goats, Humans, Liver parasitology, Livestock, Lung parasitology, Male, Prevalence, Sheep, Sheep Diseases parasitology, Cattle Diseases epidemiology, Dog Diseases epidemiology, Echinococcosis veterinary, Echinococcus granulosus isolation & purification, Goat Diseases epidemiology, Sheep Diseases epidemiology
- Abstract
Cystic echinococcosis (CE) is endemic among the human population of Xiji County, Ningxia Hui Autonomous Region, China, where the prevalence is estimated to be between 2.2% and 3.6%. Government-run sheep abattoirs in Xiji County have closed in recent years and, as a consequence, slaughter is carried out mostly at rural market places. The market place in Xinglong Township, Xiji County, is home to an increasing number of stray dogs and the lack of government control over slaughter practices potentially favours Echinococcus granulosus transmission. A survey of sheep, goats and cattle reared in Xiji County was conducted in Xinglong Market and Xinglong Township to determine prevalence and transmission dynamics of E. granulosus infection. The liver and lungs of all livestock aged one year and older were examined macroscopically post mortem; visual examination and palpation of organs determined overall prevalence of E. granulosus. Cysts consistent in appearance with E. granulosus were observed in 2/184 sheep (prevalence 1.0%) and 1/55 of the cattle examined (prevalence 1.8%); 0/13 goats were found to be infected. However, microscopic examination of these suspected cysts failed to confirm these samples as E. granulosus, giving a prevalence of confirmed infection of zero percent in all three species. The prevalence of liver fluke was 61.3% in sheep and 12.7% in cattle with a significant difference between males and females (p ≤ 0.001). Considering the high prevalence of echinococcosis in the local human population, the absence of CE observed among commercially slaughtered livestock was surprising. Several explanations for this discrepancy and their implications are proposed., (Copyright © 2014 Elsevier B.V. All rights reserved.)
- Published
- 2014
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37. Using a checklist to identify barriers to compliance with evidence-based guidelines for central line management: a mixed methods study in Mongolia.
- Author
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Ider BE, Adams J, Morton A, Whitby M, Muugolog T, Lundeg G, and Clements A
- Subjects
- Adolescent, Adult, Bacteremia epidemiology, Catheter-Related Infections epidemiology, Catheter-Related Infections prevention & control, Catheterization, Central Venous adverse effects, Child, Child, Preschool, Female, Hospitals standards, Humans, Infant, Infant, Newborn, Infection Control methods, Intensive Care Units statistics & numerical data, Male, Middle Aged, Mongolia, Young Adult, Bacteremia prevention & control, Catheterization, Central Venous standards, Checklist, Evidence-Based Medicine standards, Guideline Adherence, Practice Guidelines as Topic
- Abstract
Objectives: This study aimed to determine the extent to which a checklist has potential for identifying barriers to compliance with central line management guidelines, to evaluate the potential utility of checklists to improve the management of central lines in Mongolia, and to define the gap between current and best practices., Methods: A 22-item checklist was developed based on the Centers for Disease Control and Prevention (CDC, USA) guidelines and existing central line-associated bloodstream infection (CLABSI) checklists. The checklist was used to observe 375 central line procedures performed in the intensive care units of four tertiary hospitals of Mongolia between July and December 2010. In parallel, 36 face-to-face interviews were conducted in six other tertiary hospitals to explain practice variations and identify barriers., Results: The baseline compliance level across all components of the checklist was 68.5%. The main factors explaining low levels of compliance were outdated local standards, a lack of updated guidelines, poor control over compliance with existing clinical guidelines, poor supply of medical consumables, and insufficient knowledge of contemporary infection control measures among health care providers., Conclusions: The health authorities of Mongolia need to adequately address the prevention and control of CLABSIs in their hospitals. Updating local standards and guidelines and implementing adequate multifaceted interventions with behavioral, educational, and logistical components are required. Use of a checklist as a baseline evaluation tool was feasible. It described current practice, showed areas that need urgent attention, and provided important information needed for future planning of CLABSI interventions., (Copyright © 2012 International Society for Infectious Diseases. Published by Elsevier Ltd. All rights reserved.)
- Published
- 2012
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38. Reply to commentary "Time series analysis on the health effects of temperature: two areas for future research" by Gasparrini and Armstrong.
- Author
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Barnett AG, Tong S, and Clements AC
- Subjects
- Humans, Models, Theoretical, Statistics as Topic, Time, Cold Temperature, Hot Temperature
- Published
- 2010
- Full Text
- View/download PDF
39. Schistosomiasis control.
- Author
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Brooker S, Kabatereine ND, Clements AC, and Stothard JR
- Subjects
- Altitude, Communicable Disease Control instrumentation, Communicable Disease Control methods, Fresh Water, Health Surveys, Humans, Prevalence, Rain, Rivers, Schistosomiasis epidemiology, Schistosomiasis transmission, Uganda epidemiology, Schistosomiasis prevention & control
- Published
- 2004
- Full Text
- View/download PDF
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