Mapping the risk of anaemia in preschool-age children: the contribution of malnutrition, malaria, and helminth infections in West Africa

BACKGROUND Childhood anaemia is considered a severe public health problem in most countries of sub-Saharan Africa. We investigated the geographical distribution of prevalence of anaemia and mean haemoglobin concentration (Hb) in children aged 1-4 y (preschool children) in West Africa. The aim was to estimate the geographical risk profile of anaemia accounting for malnutrition, malaria, and helminth infections, the risk of anaemia attributable to these factors, and the number of anaemia cases in preschool children for 2011. METHODS AND FINDINGS National cross-sectional household-based demographic health surveys were conducted in 7,147 children aged 1-4 y in Burkina Faso, Ghana, and Mali in 2003-2006. Bayesian geostatistical models were developed to predict the geographical distribution of mean Hb and anaemia risk, adjusting for the nutritional status of preschool children, the location of their residence, predicted Plasmodium falciparum parasite rate in the 2- to 10-y age group (Pf PR(2-10)), and predicted prevalence of Schistosoma haematobium and hookworm infections. In the four countries, prevalence of mild, moderate, and severe anaemia was 21%, 66%, and 13% in Burkina Faso; 28%, 65%, and 7% in Ghana, and 26%, 62%, and 12% in Mali. The mean Hb was lowest in Burkina Faso (89 g/l), in males (93 g/l), and for children 1-2 y (88 g/l). In West Africa, severe malnutrition, Pf PR(2-10), and biological synergisms between S. haematobium and hookworm infections were significantly associated with anaemia risk; an estimated 36.8%, 14.9%, 3.7%, 4.2%, and 0.9% of anaemia cases could be averted by treating malnutrition, malaria, S. haematobium infections, hookworm infections, and S. haematobium/hookworm coinfections, respectively. A large spatial cluster of low mean Hb (95%) was predicted for an area shared by Burkina Faso and Mali. We estimate that in 2011, approximately 6.7 million children aged 1-4 y are anaemic in the three study countries. CONCLUSIONS By mapping the distribution of anaemia risk in preschool children adjusted for malnutrition and parasitic infections, we provide a means to identify the geographical limits of anaemia burden and the contribution that malnutrition and parasites make to anaemia. Spatial targeting of ancillary micronutrient supplementation and control of other anaemia causes, such as malaria and helminth infection, can contribute to efficiently reducing the burden of anaemia in preschool children in Africa.Funded by the University of Queensland and National Health and Medical Research Council (NHMRC), Australia

Ending Malaria Transmission in the Asia Pacific Malaria Elimination Network (APMEN) Countries: Challenges and the Way Forward

Member countries in the Asia Pacific Malaria Elimination Network (APMEN) are pursuing the global goal of malaria elimination by 2030. Different countries are in various phases of malaria elimination and this review aims to present a compilation of available evidence on the challenges and way forward for malaria elimination in APMEN countries. Malaria transmission in these States is complex. APMEN member countries include the largest populations living in areas of malaria transmission risk outside Africa. They are a global source for spread of artemisinin-based combination therapy (ACT) resistance, include the biggest burden of Plasmodium vivax and zoonotic malaria, and face many geopolitical and socio-economic factors that will challenge malaria elimination efforts. These challenges can be addressed in part through operational research to identify country-specific solutions, making better use of operational data such as through spatial decision support system (SDSS) approaches, strengthening surveillance, and cross-border initiative for coordinated action

Prevalence of asymptomatic malaria and bed net ownership and use in Bhutan, 2013: a country earmarked for malaria elimination

BACKGROUND With dwindling malaria cases in Bhutan in recent years, the government of Bhutan has made plans for malaria elimination by 2016. This study aimed to determine coverage, use and ownership of LLINs, as well as the prevalence of asymptomatic malaria at a single time-point, in four sub-districts of Bhutan. METHODS A cross-sectional study was carried out in August 2013. Structured questionnaires were administered to a single respondent in each household (HH) in four sub-districts. Four members from 25 HH, randomly selected from each sub-district, were tested using rapid diagnostic tests (RDT) for asymptomatic Plasmodium falciparum and Plasmodium vivax infection. Multivariable logistic regression models were used to identify factors associated with LLIN use and maintenance. RESULTS All blood samples from 380 participants tested negative for Plasmodium infections. A total of 1,223 HH (92.5% of total HH) were surveyed for LLIN coverage and use. Coverage of LLINs was 99.0% (1,203/1,223 HH). Factors associated with decreased odds of sleeping under a LLIN included: washing LLINs nine months compared to washing LLINs every six months; HH in the least poor compared to the most poor socio-economic quintile; a HH income of Nu 5,001-10,000 (US$1 = Nu 59.55), and Nu >10,000, compared to HH with income of <Nu 1,500; HH located one to three hours walking distance to a health centre compared to being located closer to a health centre; a reported lack of knowledge as to what to do in event of LLINs being torn; and keeping LLINs in a box compared to keeping them hanging in the place of use. Factors associated with use of LLINs for purposes other than the intended use included: income group Nu 1,501-3,000 and HH located one to three hours walking distance from a health centre. CONCLUSIONS There was high coverage of LLINs in the study area with regular use of LLINs throughout the year. LLIN use for purposes other than malaria prevention was low. With high coverage and regular use of LLINs, and a zero prevalence of malaria infection found in historically high-risk communities during the peak malaria season, it appears Bhutan is on course to achieve malaria elimination.We acknowledge Queensland Infectious Disease Unit for providing funds to carry out this study

Space-time variation of malaria incidence in Yunnan province, China

BACKGROUND Understanding spatio-temporal variation in malaria incidence provides a basis for effective disease control planning and monitoring. METHODS Monthly surveillance data between 1991 and 2006 for Plasmodium vivax and Plasmodium falciparum malaria across 128 counties were assembled for Yunnan, a province of China with one of the highest burdens of malaria. County-level Bayesian Poisson regression models of incidence were constructed, with effects for rainfall, maximum temperature and temporal trend. The model also allowed for spatial variation in county-level incidence and temporal trend, and dependence between incidence in June-September and the preceding January-February. RESULTS Models revealed strong associations between malaria incidence and both rainfall and maximum temperature. There was a significant association between incidence in June-September and the preceding January-February. Raw standardised morbidity ratios showed a high incidence in some counties bordering Myanmar, Laos and Vietnam, and counties in the Red River valley. Clusters of counties in south-western and northern Yunnan were identified that had high incidence not explained by climate. The overall trend in incidence decreased, but there was significant variation between counties. CONCLUSION Dependence between incidence in summer and the preceding January-February suggests a role of intrinsic host-pathogen dynamics. Incidence during the summer peak might be predictable based on incidence in January-February, facilitating malaria control planning, scaled months in advance to the magnitude of the summer malaria burden. Heterogeneities in county-level temporal trends suggest that reductions in the burden of malaria have been unevenly distributed throughout the province.This project was supported by a University of Queensland New Research Scientist Start-Up Fund grant. RWS is a Wellcome Trust Principal Research Fellow (#079080) and receives additional support from the Wellcome Trust for the Malaria Atlas Project (MAP, http://www.map.ox.ac.uk)

Clostridium difficile classification overestimates hospital acquired infections

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

Modelling diverse sources of Clostridium difficile in the community: importance of animals, infants and asymptomatic carriers

Clostridium difficile infections (CDIs) affect patients in hospitals and in the community, but the relative importance of transmission in each setting is unknown. We developed a mathematical model of C. difficile transmission in a hospital and surrounding community that included infants, adults, and transmission from animal reservoirs. We assessed the role of these transmission routes in maintaining disease and evaluated the recommended classification system for hospital and community-acquired CDIs.This work was supported by an Australian National Health and Medical Council Senior Research Fellowship [#1058878 to A.C.A.C.] and an Australian Government Research Training Program Scholarship to A.M

Application of knowledge-driven spatial modelling approaches and uncertainty management to a study of Rift Valley fever in Africa

BACKGROUND: There are few studies that have investigated uncertainties surrounding the scientific community's knowledge of the geographical distribution of major animal diseases. This is particularly relevant to Rift Valley fever (RVF), a zoonotic disease causing destructive outbreaks in livestock and man, as the geographical range of the disease is widening to involve previously unaffected regions. In the current study we investigate the application of methods developed in the decision sciences: multiple criteria decision making using weighted linear combination and ordered weighted averages, and Dempster-Shafer theory, implemented within the geographical information system IDRISI, to obtain a greater understanding of uncertainty related to the geographical distribution of RVF. The focus is on presenting alternate methods where extensive field data are not available and traditional, model-based approaches to disease mapping are impossible to conduct. RESULTS: Using a compensatory multiple criteria decision making model based on weighted linear combination, most of sub-Saharan Africa was suitable for endemic circulation of RVF. In contrast, areas where rivers and lakes traversed semi-arid regions, such as those bordering the Sahara, were highly suitable for RVF epidemics and wet, tropical areas of central Africa had low suitability. Using a moderately non-compensatory model based on ordered weighted averages, the areas considered suitable for endemic and epidemic RVF were more restricted. Varying the relative weights of the different factors in the models did not affect suitability estimates to a large degree, but variations in model structure had a large impact on our suitability estimates. Our Dempster-Shafer analysis supported the belief that a range of semi-arid areas were suitable for RVF epidemics and the plausibility that many other areas of the continent were suitable. Areas where high levels of uncertainty were highlighted included the Ethiopian Highlands, southwest Kenya and parts of West Africa. CONCLUSION: We have demonstrated the potential of methods developed in the decision sciences to improve our understanding of uncertainties surrounding the geographical distribution of animal diseases, particularly where information is sparse, and encourage wider application of the decision science methodology in the field of animal health

Spatial and temporal patterns of diarrhoeain Bhutan 2003–2013

Background To describe spatiotemporal patterns of diarrhoea in Bhutan, and quantify the association between climatic factors and the distribution and dynamics of the disease. Methods Nationwide data on diarrhoea were obtained for 2003 to 2013 from the Health Information and Management System (HIMS), Ministry of Health, Bhutan. Climatic variables were obtained from the Department of Hydro Met Services, Ministry of Economic Affairs, Bhutan. Seasonal trend decomposition was used to examine secular trends and seasonal patterns of diarrhoea. A Bayesian conditional autoregressive (CAR) model was used to quantify the relationship between monthly diarrhoea, maximum temperature, rainfall, age and gender. Results The monthly average diarrhoea incidence was highly seasonal. Diarrhoea incidence increased by 0.6% (95% CrI: 0.5–0.6%) for every degree increase in maximum temperature; and 5% (95 Cr I: 4.9–5.1%) for a 1 mm increase in rainfall. Children aged <5 years were found to be 74.2% (95% CrI: 74.1–74.4) more likely to experience diarrhoea than children and adults aged ≥5 years and females were 4.9% (95% CrI: 4.4–5.3%) less likely to suffer from diarrhoea as compared to males. Significant residual spatial clustering was found after accounting for climate and demographic variables. Conclusions Diarrhoea incidence was highly seasonal, with positive associations with maximum temperature and rainfall and negative associations with age and being female. This calls for public health actions to reduce future risks of climate change with great consideration of local climatic conditions. In addition, protection of <5 years children should be prioritize through provision of rotavirus vaccination, safe and clean drinking water, and proper latrines

A Clinical, Pathological and Demographic Study of an Unusual Locomotor Disorder of Sheep

Kangaroo Gait is a locomotor disorder of sheep, which was first described in New Zealand in 1978, and was subsequently reported in the United Kingdom, initially in 1986. The reported features of the condition included acute onset bilateral forelimb paresis in adult female sheep occurring during lactation or late gestation, Wallerian degeneration of the radial nerves, subsequent regeneration, and, in most cases, clinical recovery. The aetiology of Kangaroo Gait remained obscure and there was little information regarding the incidence, the geographical distribution or the economic importance of this condition. This study was undertaken with the aims of characterising Kangaroo Gait in northern Britain in terms of its clinical, pathological and demographic features. Thirteen adult female sheep from six flocks in south west Scotland, which had presented with an abnormal forelimb gait, were subjected to a clinical investigation, and four of these adult female sheep, as well as two lambs from one adult female, were submitted for pathological examination. The anamnesis for each flock did not reveal consistent problems with general management, nutrition, disease occurrence, or the presence of toxic plants or chemicals. Apart from the abnormal locomotion, physical examinations and ancillary investigations did not detect any consistent abnormalities. Neurological examinations resulted consistently in findings of bilateral forelimb paresis and reduced muscle bulk of the proximal forelimbs. Variable findings included proprioceptive deficits in the forelimbs and normal pedal withdrawal reflexes in all four limbs. A clinical diagnosis of Kangaroo Gait was determined for the 13 sheep. Evidence of Wallerian degeneration was found in the radial nerves of one adult female (onset of clinical signs during lactation), and minor changes were found in the radial nerves of a second (onset of clinical signs during gestation) but no significant abnormalities were detected in the peripheral nerves of the remaining adult females or the lambs. Non-specific changes were detected in the spinal cord of two adult females and the brain of one adult female (onset of clinical signs during gestation). Results suggested that Kangaroo Gait could occur in adult female sheep of a number of breeds, between the ages of one and seven years, onset of clinical signs could occur during late gestation or early to mid lactation, and recovery from clinical signs was not dependent on cessation of lactation. It was suggested that a range of pathological changes were associated with this condition, and that close observation of animals around the time of onset of clinical signs, and recruitment of individuals for detailed pathological examinations at that time, would be essential for determining the aetiopathogenesis of Kangaroo Gait. In order to gain more information, two questionnaire studies were undertaken. The first survey was mailed to veterinary surgeons in all practices in Northern Britain which, according to the Directory of Veterinary Practices (Hall, 1997), provided veterinary care for sheep, and the second was mailed to sheep flock owners and managers located in the Scottish Borders, who were recruited via veterinary surgeons. Response rates of 84.7% and 30.7% were achieved. In total, 29.7% and 24.1% of respondents had identified one or more cases of Kangaroo Gait in their practice area or flocks at some time. Almost all respondents who had identified cases indicated that adult females were affected, most often during lactation, and less commonly during late gestation. Results suggested that Kangaroo Gait was more common among commercial cross breeds, and was less common on hill farms than upland or lowland farms. The annual number of affected individuals and flocks had increased since the condition was first identified. Comparing the results of the two surveys revealed that a majority of cases of Kangaroo Gait and other locomotor disorders were not reported to veterinary surgeons. Further epidemiological investigations could prove useful in determining risk factors for the occurrence of Kangaroo Gait. However, it was suggested that economic crises in the UK sheep industry, accompanied by a perception that Kangaroo Gait is of little economic importance, make it unlikely that detailed studies of this condition will be conducted in the foreseeable future

Major inpatient surgeries and in-hospital mortality in New South Wales public hospitals in Australia: A state-wide retrospective cohort study

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