Implementing a Geospatial Health Data Infrastructure for Control of Asian Schistosomiasis in the People's Republic of China and the Philippines

Challenges and way forward

Schistosomiasis, helminthic zoonoses and NTDs constitute a considerable majority of the diseases of poverty in the world. The RNAS⁺ targeted zoonoses are not only problems to human and animal health, but also cause poverty in 1 billion poor livestock keepers as well as result in 2.3 billion cases of human illness and 1.7 million human deaths a year. The gaps in research of those targeted zoonoses are urgently addressed by identifying the research priority, fulfilled by improving the multisectoral cooperation and strengthening the interventions in the control programme.

Use of Geospatial Surveillance and Response Systems for Vector-Borne Diseases in the Elimination Phase

The distribution of diseases caused by vector-borne viruses and parasites are restricted by the environmental requirements of their vectors, but also by the ambient temperature inside the host as it influences the speed of maturation of the infectious agent transferred. The launch of the Soil Moisture Active Passive (SMAP) satellite in 2015, and the new ECOSTRESS instrument onboard the International Space Station (ISS) in 2018, established the leadership of the National Aeronautics Space Administration (NASA) in ecology and climate research by allowing the structural and functional classification of ecosystems that govern vector sustainability. These advances, and the availability of sub-meter resolution data from commercial satellites, contribute to seamless mapping and modelling of diseases, not only at continental scales (1 km²) and local community or agricultural field scales (15⁻30 m²), but for the first time, also at the habitat⁻household scale (<1 m²). This communication presents current capabilities that are related to data collection by Earth-observing satellites, and draws attention to the usefulness of geographical information systems (GIS) and modelling for the study of important parasitic diseases.

Reaching the Surveillance-Response Stage of Schistosomiasis Control in The People's Republic of China: A Modelling Approach

With the goal set to eliminate schistosomiasis nationwide by 2020, The People's Republic of China has initiated the surveillance-response stage to identify remaining sources of infection and potential pockets from where the disease could reemerge. Shifting the focus from classical monitoring and evaluation to rapid detection and immediate response, this approach requires modelling to bridge the surveillance and response components. We review here studies relevant to schistosomiasis modelling in a Chinese surveillance-response system with the expectation to achieve a practically useful understanding of the current situation and potential future study directions. We also present useful experience that could tentatively be applied in other endemic regions in the world. Modelling is discussed at length as it plays an essential role, both with regard to the intermediate snail host and in the definitive, mammal hosts. Research gaps with respect to snail infection, animal hosts and sectoral research cooperation are identified and examined against the prevailing background of ecosystem and socioeconomic changes with a focus on coexisting challenges and opportunities in a situation with increasing financial constraints.

Spatial Modelling Tools to Integrate Public Health and Environmental Science, Illustrated with Infectious Cryptosporidiosis

Contemporary spatial modelling tools can help examine how environmental exposures such as climate and land use together with socio-economic factors sustain infectious disease transmission in humans. Spatial methods can account for interactions across global and local scales, geographic clustering and continuity of the exposure surface, key characteristics of many environmental influences. Using cryptosporidiosis as an example, this review illustrates how, in resource rich settings, spatial tools have been used to inform targeted intervention strategies and forecast future disease risk with scenarios of environmental change. When used in conjunction with molecular studies, they have helped determine location-specific infection sources and environmental transmission pathways. There is considerable scope for such methods to be used to identify data/infrastructure gaps and establish a baseline of disease burden in resource-limited settings. Spatial methods can help integrate public health and environmental science by identifying the linkages between the physical and socio-economic environment and health outcomes. Understanding the environmental and social context for disease spread is important for assessing the public health implications of projected environmental change.

Interplay between environment, agriculture and infectious diseases of poverty: case studies in China

Changes in the natural environment and agricultural systems induced by economic and industrial development, including population dynamics (growth, urbanization, migration), are major causes resulting in the persistence, emergence and re-emergence of infectious diseases in developing countries. In the face of rapid demographic, economic and social transformations, the People's Republic of China (P.R. China) is undergoing unprecedented environmental and agricultural change. We review emerging and re-emerging diseases such as schistosomiasis, dengue, avian influenza, angiostrongyliasis and soil-transmitted helminthiasis that have occurred in P.R. China due to environmental and agricultural change. This commentary highlights the research priorities and the response strategies, namely mitigation and adaptation, undertaken to eliminate the resurgence of those infectious diseases.

From gap analysis to solution and action: the RNAS⁺ model

The overall aim of the Regional Network for Asian Schistosomiasis and other Helminth Zoonoses (RNAS(+)) is to strengthen collaboration between control authorities in the regional, endemic countries. The network has provided critical research input during its 12 years of existence developing gradually from a small forum for information exchange. RNAS(+) now provides advice on regional strategies regularly and contributes to the mobilization of resources with respect to multi-country projects on several parasitic diseases in Southeast Asia, primarily schistosomiasis but also other helminth infections including polyparasitism. To make progress towards these goals, RNAS(+) has focused on platform design and technical standardization aiming at fostering research capacity and the development of networking capacities with easy access to information databases. This administrative body is largely virtual connecting RNAS(+) members via the Internet, providing database and administrative back-up. This strategy, aiming at boosting research on the target diseases, strongly emphasizes ways and means to alleviate the spectre of disease and poverty from the endemic areas.

Surveillance and response: Tools and approaches for the elimination stage of neglected tropical diseases

The presentation of the World Health Organization (WHO)'s roadmap for neglected tropical diseases (NTDs) in January 2012 raised optimism that many NTDs can indeed be eliminated. To make this happen, the endemic, often low-income countries with still heavy NTD burdens must substantially strengthen their health systems. In particular, they need not only to apply validated, highly sensitive diagnostic tools and sustainable effective control approaches for treatment and transmission control, but also to participate in the development and use of surveillance-response schemes to ensure that progress made also is consolidated and sustained. Surveillance followed-up by public health actions consisting of response packages tailored to interruption of transmission in different settings will help to effectively achieve the disease control/elimination goals by 2020, as anticipated by the WHO roadmap. Risk-mapping geared at detection of transmission hotspots by means of geospatial and other dynamic approaches facilitates decision-making at the technical as well as the political level. Surveillance should thus be conceived and developed as an intervention approach and at the same time function as an early warning system for the potential re-emergence of endemic infections as well as for new, rapidly spread epidemics and pandemics.

Spatio-temporal analysis to identify determinants of Oncomelania hupensis infection with Schistosoma japonicum in Jiangsu province, China

Background

With the successful implementation of integrated measures for schistosomiasis japonica control, Jiangsu province has reached low-endemicity status. However, infected Oncomelania hupensis snails could still be found in certain locations along the Yangtze river until 2009, and there is concern that they might spread again, resulting in the possible re-emergence of infections among people and domestic animals alike. In order to establish a robust surveillance system that is able to detect the spread of infected snails at an early stage, sensitive and reliable methods to identify risk factors for the establishment of infected snails need to be developed.

Methods

A total of 107 villages reporting the persistent presence of infected snails were selected. Relevant data on the distribution of infected snails, and human and livestock infection status information for the years 2003 to 2008 were collected. Spatio-temporal pattern analysis including spatial autocorrelation, directional distribution and spatial error models were carried out to explore spatial correlations between infected snails and selected explanatory factors.

Results

The area where infected snails were found, as well as their density, decreased significantly between 2003 and 2008. Changes in human and livestock prevalences were less pronounced. Three statistically significant spatial autocorrelations for infected snails were identified. (i) The Moran’s I of infected snails increased from 2004 to 2007, with the snail density increasing and the area with infected snails decreasing. (ii) The standard deviations of ellipses around infected snails were decreasing and the central points of the ellipses moved from West to East. (iii) The spatial error models indicated no significant correlation between the density of infected snails and selected risk factors.

Conclusions

We conclude that the contribution of local infection sources including humans and livestock to the distribution of infected snails might be relatively small and that snail control may limit infected snails to increasingly small areas ecologically most suitable for transmission. We provide a method to identify these areas and risk factors for persistent infected snail presence through spatio-temporal analysis, and a suggested framework, which could assist in designing evidence based control strategies for schistosomiasis japonica elimination.

Awareness and knowledge of schistosomiasis infection and prevention in the "Three Gorges Dam" reservoir area: a cross-sectional study on local residents and health personnel

BACKGROUND

Schistosomiasis is a severe public health problem in China. It has been predicted that the ecological changes caused by the "Three Gorges Dam", the world's largest hydropower project, could potentially aggravate the spread of schistosomiasis in the area. This study focused on investigating (a) local residents' knowledge on the potential risks of schistosomiasis and (b) the capability of local health personnel in preventing schistosomiasis.

MATERIALS AND METHODS

A quantitative survey combined with qualitative interviews was conducted in three counties of the reservoir area during November and December 2008. A total of 1386 inhabitants and 180 local health personals participated in questionnaire survey; 18 inhabitants, 21 health professionals, and 8 local government officials were interviewed.

RESULTS

Of the surveyed inhabitants, 66.3% had no access to safe drinking water; 47.9% had water-contact regularly through farming or swimming; 58.7% did not have hygienic toilets; and only 13.7% used methane for energy. Besides, only 3.8% of the inhabitants had knowledge scores higher than 6 points within the range 0-10. Educational level, occupation and income were significant predictors of knowledge score (P<0.05). Only about 5% of the inhabitants had some knowledge on schistosomiasis. Among health professionals surveyed, 6.7% had college or higher education; 26.7% had prior schistosomiasis control experience; 75.6% did not receive any relevant training in the past year; and only 52.2% had basic knowledge of schistosomiasis. The logistic regression analysis identified occupation and time at work as significant factors to their knowledge level (P<0.05). Moreover, the surveillance work was often severely hindered by a shortage of funding, and challenged by monitoring of migrant population. There were very limited training opportunities for the health workers, and almost no health education for inhabitants, if any, neither efficient nor effective.

CONCLUSION

Although there were multiple risks for potential Schistosoma japonicum infections in the study area, the knowledge level on schistosomiasis and surveillance was relatively low both in local residents and health personnel. Thus, more health education and professional training are urgently required to local residents and health personnel, respectively. By considering limited activities in surveillance and health education been implemented, a strategy plan on intervention to ensure a stronger inter-sectoral cooperation is recommended in order to reduce schistosomiasis transmission risks in this area.

A Google Earth-based surveillance system for schistosomiasis japonica implemented in the lower reaches of the Yangtze River, China

BACKGROUND

Due to the success of the national schistosomiasis control programme in China, transmission has been sufficiently reduced in many areas to severely limit identification of areas at risk by conventional snail surveys only. In this study, we imported Google Earth technology and a Global Positioning System (GPS) into the monitoring system for schistosomiasis surveillance of the banks of the Yangtze River in Jiangsu Province, China.

METHODS

A total of 45 sites were selected and the risk was assessed monthly by water exposure of sentinel mice at these sites from May to September in 2009 and 2010. The results were assembled and broadcast via the Google Earth platform.

RESULTS

The intensity of schistosomiasis transmission showed peaks of risk in June and September of 2009, while there was only one small peak in June in 2010 as the number of detected positive transmission sites dropped dramatically that year thanks to improved mollusciciding. River ports were found to be areas of particular risk, but ferry terminals and other centres of river-related activities were also problematic.

CONCLUSIONS

The results confirm that the surveillance system can be rapidly updated and easily maintained, which proves the Google Earth approach to be a user-friendly, inexpensive warning system for schistosomiasis risk.

Bethony J, Hotez PJ, Young ND, Gasser RB. Soil-transmitted helminths of humans in Southeast Asia--towards integrated control

Soil-transmitted helminths (STHs) pose significant public health challenges in many countries of Southeast Asia (SEA). Overall, approximately one-third of the world's cases of ascariasis, trichuriasis, and hookworm disease occur in the 11 major SEA countries. Various countries are at different stages in their response to controlling these diseases. For instance, in Malaysia and Thailand, the major burden of disease is confined to rural/remote, indigenous and/or refugee populations. In countries, such as Cambodia, Lao People's Democratic Republic and Vietnam, the burden remains high, although extensive deworming programmes are underway and are yielding encouraging results. The present chapter reviews the current status of STH infections in SEA, identifies knowledge gaps and offers a perspective on the development of improved, integrated surveillance and control in this geographical region. It indicates that advances in our understanding of the epidemiology of these parasites, through the strategic use of molecular and predictive (e.g. geographical information systems (GIS) and remote sensing (RS)) technologies, could readily underpin future research and control programmes. It is hoped that the gradual move towards integrated treatment/control programmes will assist substantially in decreasing the chronic disease burden linked to STHs, thus increasing human health and welfare, and supporting socio-economic growth and development in SEA countries.

Important helminth infections in Southeast Asia diversity, potential for control and prospects for elimination

Besides the 'big three'-HIV/AIDS, malaria and tuberculosis-there are a host of diseases that, by comparison, are truly neglected. These so-called neglected tropical diseases (NTDs), many of which caused by helminths, are intimately linked with poverty and are rampant where housing is poor; access to clean water and adequate sanitation is lacking; hygiene and nutrition is substandard and populations are marginalized and vulnerable. More than a billion people are affected by NTDs, mainly in remote rural and deprived urban settings of the developing world. An overview of papers published in two special thematic volumes of the Advances in Parasitology is provided here under the umbrella of current status of research and control of important helminth infections. A total of 25 comprehensive reviews are presented, which summarise the latest available data pertaining to the diagnosis, epidemiology, pathogenesis, prevention, treatment, control and eventual elimination of NTDs in Southeast Asia and neighbourhood countries. The focus of the first volume provides the current regional status of schistosomiasis, lymphatic filariasis, food-borne trematodiases, echinococcosis and cysticercosis/taeniasis, less common parasitic diseases that can cause epidemic outbreaks and helminth infections affecting the central nervous system. The second volume deals with the tools and strategies for control, including diagnostics, drugs, vaccines and cutting-edge basic research (e.g. the '-omics' sciences). Moreover, cross-cutting themes such as multiparasitism, social sciences, capacity strengthening, geospatial health technologies, health metrics and modelling the potential impact of climate change on helminthic diseases are discussed. Hopefully, these two volumes will become useful for researchers and, most importantly, disease control managers for integrated and sustainable control, rigorous monitoring and eventual elimination of NTDs in Southeast Asia and elsewhere.

Coordinating research on neglected parasitic diseases in Southeast Asia through networking

The new dialogue between stakeholders, that is, scientists, research administrators and donors as well as the populations victimized by endemic infections, is initiating a virtuous circle leading to lower disease-burdens, improved public health and the mitigation of poverty. There is now general agreement that control activities need research collaboration to advance, while surveillance plays an increasingly important role in sustaining long-term relief. On the part of the Regional Network on Asian Schistosomiasis and Other Helminth Zoonoses (RNAS(+)), this has led to a new vision not only focused on general strengthening of research capabilities but also on furthering efforts to close the gap between research and control and bridge different branches of science. From its original, exclusive focus on schistosomiasis, RNAS(+) has expanded to include food-borne and soil-transmitted helminth infections as well. Its current repository of data on the distribution, prevalence and severity of these diseases is increasingly utilised by decision makers charged with epidemiological control in the endemic countries. Thanks to a more rapid translation of research results into control applications and the dissemination of data and new technology through networking, the overall situation is improving. Working as a virtual organisation of researchers and control officers in the endemic countries of Southeast Asia, RNAS(+) is playing an important role in this conversion. Its responsibilities are divided along disease lines into five main areas, but no serious, endemic disease is considered to be outside the network's sphere of interest. This chapter recounts some of the more important RNAS(+) accomplishments, pinpoints potential directions for future operations and highlights areas where research is most needed.