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

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

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)

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. The reproduction number in the hospital was <1 (range: 0.16-0.46) for all scenarios. Outside the hospital, the reproduction number was >1 for nearly all scenarios without transmission from animal reservoirs (range: 1.0-1.34). However, the reproduction number for the human population was 3.5-26.0%) of human exposures originated from animal reservoirs. Symptomatic adults accounted for <10% transmission in the community. Under conservative assumptions, infants accounted for 17% of community transmission. An estimated 33-40% of community-acquired cases were reported but 28-39% of these reported cases were misclassified as hospital-acquired by recommended definitions. Transmission could be plausibly sustained by asymptomatically colonized adults and infants in the community or exposure to animal reservoirs, but not hospital transmission alone. Underreporting of community-onset cases and systematic misclassification underplays the role of community transmission

Malaria burden and costs of intensifi ed control in Bhutan, 2006–14: an observational study and situation analysis

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 intensifi ed control activities, the main donors of funding for the control activities, and the costs of diff erent 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 diff erent control and preventive measures were calculated, and the average numbers of long-lasting insecticidal nests per person were estimated. Findings A total of 5491 confi rmed 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 signifi cantly 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

Addressing hard-to-reach populations for achieving malaria elimination in the Asia Pacific Malaria Elimination Network countries

Member countries of the Asia Pacific Malaria Elimination Network are pursuing the regional goal of malaria elimination by 2030. The countries are in different phases of malaria elimination, but most have demonstrated success in shrinking the malaria map in the region. However, continued transmission in hard-to-reach populations, including border and forest malaria, remains an important challenge. In this article, we review strategies for improving intervention coverage in hard-to-reach populations. Currently available preventive measures, including long-lasting insecticidal nets and long-lasting insecticidal hammocks, and prompt diagnosis and treatment need to be expanded to hard-to-reach populations. This can be done through mobile malaria clinics, village volunteer malaria workers and screening posts. Malaria surveillance in the hard-to-reach areas can be enhanced through tools such as spatial decision support systems. Policy changes by the malaria programs will be required for implementing the strategies outlined in this article. However, strategies or tools may be suitable for some population groups but difficult to implement in other groups

Using internet search queries for infectious disease surveillance: screening diseases for suitability

Background: Internet-based surveillance systems provide a novel approach to monitoring infectious diseases. Surveillance systems built on internet data are economically, logistically and epidemiologically appealing and have shown significant promise. The potential for these systems has increased with increased internet availability and shifts in health-related information seeking behaviour. This approach to monitoring infectious diseases has, however, only been applied to single or small groups of select diseases. This study aims to systematically investigate the potential for developing surveillance and early warning systems using internet search data, for a wide range of infectious diseases. Methods: Official notifications for 64 infectious diseases in Australia were downloaded and correlated with frequencies for 164 internet search terms for the period 2009–13 using Spearman’s rank correlations. Time series cross correlations were performed to assess the potential for search terms to be used in construction of early warning systems. Results: Notifications for 17 infectious diseases (26.6%) were found to be significantly correlated with a selected search term. The use of internet metrics as a means of surveillance has not previously been described for 12 (70.6%) of these diseases. The majority of diseases identified were vaccine-preventable, vector-borne or sexually transmissible; cross correlations, however, indicated that vector-borne and vaccine preventable diseases are best suited for development of early warning systems. Conclusions: The findings of this study suggest that internet-based surveillance systems have broader applicability to monitoring infectious diseases than has previously been recognised. Furthermore, internet-based surveillance systems have a potential role in forecasting emerging infectious disease events, especially for vaccine-preventable and vector-borne diseases. Electronic supplementary material The online version of this article (doi:10.1186/s12879-014-0690-1) contains supplementary material, which is available to authorized users

Evaluation of the performance of a dengue outbreak detection tool for China

An outbreak detection and response system, using time series moving percentile method based on historical data, in China has been used for identifying dengue fever outbreaks since 2008. For dengue fever outbreaks reported from 2009 to 2012, this system achieved a sensitivity of 100%, a specificity of 99.8% and a median time to detection of 3 days, which indicated that the system was a useful decision tool for dengue fever control and risk-management programs in China.This work was supported by the grants from Research and Promotion of Key Technology on Health Emergency Preparation and Dispositions (201202006), the National Key Science and Technology Project on Infectious Disease Surveillance Technique Platform of China (2012ZX10004-201) and Development of Early Warning Systems for Dengue Fever Based on Socio-ecological Factors (NHMRC APP1002608)

Impact of anthropogenic and natural environmental changes on Echinococcus transmission in Ningxia Hui Autonomous Region, the People’s Republic of China

Echinococcus transmission is known to be affected by various environmental factors, which may be modified by human influence or natural events including global warming. Considerable population growth in the last fifty years in Ningxia Hui Autonomous Region (NHAR), the People's Republic of China (PRC), has led to dramatic increases in deforestation and modified agricultural practices. In turn, this has resulted in many changes in the habitats for the definitive and intermediate hosts of both Echinococcus granulosus and E. multilocularis, which have increased the risks for transmission of both parasites, affecting echinococcosis prevalence and human disease. Ecological environmental changes due to anthropogenic activities and natural events drive Echinococcus transmission and NHAR provides a notable example illustrating how human activity can impact on a parasitic infection of major public health significance. It is very important to continually monitor these environmental (including climatic) factors that drive the distribution of Echinococcus spp. and their impact on transmission to humans because such information is necessary to formulate reliable future public health policy for echinococcosis control programs and to prevent disease spread.We acknowledge financial support by the National Health and Medical Research Council (NHMRC) of Australia (APP1009539) and the Natural Science Foundation of China (NSFC) (30960339) for our studies on echinococcosis. DJG is an Australian Research Council Fellow (DECRA); DPM is a NHMRC Senior Principal Research Fellow; ACAC is a NHMRC Career Development Fellow