Integrated control programmes for schistosomiasis and other helminth infections in P.R. China

The cultural policies of schistosomiasis control in China: a historical analysis

China has a history of using cultural policies to control infectious diseases, including schistosomiasis, which was once hyperendemic in the country. Since the founding of the People's Republic of China, significant achievements have been made in schistosomiasis control, with a decrease in the number of cases and infection rates. This study provides a historical analysis of cultural policies in schistosomiasis control in China. During the Mao era (1949-1976), socialist ideology shaped cultural policies that included mass mobilization campaigns, propaganda, and cultural education to promote health practices, and community participation and empowerment. During the Reform era (1978-2012), there was a shift towards market-oriented policies and individual responsibility, and cultural policies promoted behavioral change, but there were challenges in implementing them in a rapidly changing society. In the "New Era" of socialism (2012-now), cultural policies are focused on promoting comprehensive schistosomiasis control strategies, technological advancements and innovation, and international cooperation. The Chinese experience in schistosomiasis control provides valuable lessons for other countries facing similar challenges and underscores the importance of cultural policies in promoting health and well-being.

Molecular Techniques as Alternatives of Diagnostic Tools in China as Schistosomiasis Moving towards Elimination

Schistosomiasis japonica caused by the trematode flukes of Schistosoma japonicum was one of the most grievous infectious diseases in China in the mid-20th century, while its elimination has been placed on the agenda of the national strategic plan of healthy China 2030 after 70 years of continuous control campaigns. Diagnostic tools play a pivotal role in warfare against schistosomiasis but must adapt to the endemic status and objectives of activities. With the decrease of prevalence and infection intensity of schistosomiasis in human beings and livestock, optimal methodologies with high sensitivity and absolute specificity are needed for the detection of asymptomatic cases or light infections, as well as disease surveillance to verify elimination. In comparison with the parasitological methods with relatively low sensitivity and serological techniques lacking specificity, which both had been widely used in previous control stages, the molecular detection methods based on the amplification of promising genes of the schistosome genome may pick up the baton to assist the eventual aim of elimination. In this article, we reviewed the developed molecular methods for detecting S. japonicum infection and their application in schistosomiasis japonica diagnosis. Concurrently, we also analyzed the chances and challenges of molecular tools to the field application process in China.

The Dynamics of Hepatic Fibrosis Related to Schistosomiasis and Its Risk Factors in a Cohort of China

China has had a long history against schistosomiasis japonica. The most serious prognosis of chronic schistosome infection is hepatic fibrosis, which develops into advanced schistosomiasis if the process is not effectively controlled. After a more than seven decades endeavor, China has gained remarkable achievements in schistosomiasis control and achieved transmission control nationwide (infection rate of schistosomes in residents and domestic animals both less than 1%) by 2015. However, new advanced schistosomiasis cases emerge annually in China, even in areas where the transmission of schistosomiasis had been interrupted. In the present study, the residents (>5 years old) in a schistosomiasis endemic village were examined for schistosomiasis every year during 1995-2019 by the modified Kato-Katz thick smear method and/or miracidium hatching technique. Residents who were identified to have an active infection method were treated with praziquantel at a dose of 40 mg/kg body weight. Ultrasonography was carried out to assess the liver morbidity related to schistosomiasis in 1995 and 2019, respectively. The prevalence of schistosomiasis among residents presented a downward trend annually, from 17.89% (175/978) in 1995 to 0 (0/475) in 2019. Among 292 residents who received ultrasound scan both in 1995 and 2019, 141 (48.29%) presented stable liver damage, while liver fibrosis was developed severely in 86 (29.45%) and reversed in 65 (22.26%) residents. Univariate and multivariate analysis showed that anti-fibrosis treatment was the protective factor against schistosomiasis hepatic fibrosis. Males, residents aged 38 and above, fishermen, and people who did not receive anti-fibrosis treatment were groups with higher risk of liver fibrosis development. Our results revealed that although the infection rate of schistosome dropped significantly in endemic areas, liver fibrosis was still developing among some residents, even though they had received deworming treatment. Liver protection/anti-fibrosis treatment should be administered in endemic regions and regions with historically uncontrolled transmission to slow down the deterioration of hepatic fibrosis among patients in schistosomiasis endemic areas.

In vivo praziquantel efficacy of Schistosoma japonicum over time: A systematic review and meta-analysis

Praziquantel (PZQ), the only choice of chemotherapy for schistosomiasis recommended by World Health Organization (WHO), has been widely used over 40 years. The long-term, and rapid expansion of, PZQ use for disease control across a large populations continues to raise concern regarding the potential for emergence and establishment of drug resistance. Recent research has also proposed that the long survival and low sensitivity of unpaired worms, derived from either incomplete treatment cure rates or single-sex schistosome infections within final hosts, could exacerbate the risk of PZQ resistance (PZQ-R) emerging. With the aim of assessing whether PZQ efficacy amongst S. japonicum may have changed over time in China, we performed a unique systematic review and meta-analyses on datasets which evaluated the efficacy of PZQ via laboratory assays of field S. japonicum isolates on experimental mice over time. Relevant published literatures from four electronic bibliographic databases and lists of article references were searched. Two indexes, d, a measure used in meta-analyses for worm burden difference between two groups, and r, a traditional measure for worm reduction percentage after treatment but without considering sample size were calculated for each study. A total of 25 papers including 127 experimental studies with eligible data on 2230 mice were retrieved. The pooled d (D) was 3.91 (3.56-4.25) and pooled r (R) was 54.52% (52.55%-56.52%). D significantly increased over time, whereas R non-significantly decreased; both estimates were significantly associated with the total drug dose. Such findings suggested no evidence of PZQ-R emergence S. japonicum to date. However, we consider the potential role of parasite origins, PZQ dosage, and single versus mixed gender infections of the results published to date, and the avenues now needed for further research.

Assessment of China's contributions to the Regional Network for Asian Schistosomiasis and Other Helminth Zoonoses: a questionnaire survey

Background

The Regional Network for Asian Schistosomiasis and Other Helminth Zoonoses (RNAS⁺) was established in 1998, which has developed close partnerships with Asian countries endemic for schistosomiasis and other helminthiasis in Asia. RNAS⁺ has provided an ideal regional platform for policy-makers, practitioners and researchers on the prevention, control and research of parasitic diseases in Asian countries. China, one of the initiating countries, has provided significant technical and financial support to the regional network. However, its roles and contributions have not been explored so far. The purpose of this study was to assess China's contributions on the supporting of RNAS⁺ development.

Methods

An assessment research framework was developed to evaluate China’s contributions to RNAS⁺ in four aspects, including capacity building, funding support, coordination, and cooperation. An anonymous web-based questionnaire was designed to acquire respondents’ basic information, and information on China’s contributions, challenges and recommendations for RNAS⁺development. Each participant scored from 0 to 10 to assess China’s contribution: “0” represents no contribution, and “10” represents 100% contribution. Participants who included their e-mail address in the 2017–2019 RNAS⁺ annual workshops were invited to participate in the assessment.

Results

Of 71 participants enrolled, 41 responded to the survey. 37 (37/41, 90.24%) of them were from RNAS⁺ member countries, while the other 4 (4/41, 9.76%) were international observers. Most of the respondents (38/41, 92.68%) were familiar with RNAS⁺. Respondents reported that China’s contributions mainly focused on improving capacity building, providing funding support, coordination responsibility, and joint application of cooperation programs on RNAS⁺ development. The average scores of China’s contributions in the above four fields were 8.92, 8.64, 8.75, and 8.67, respectively, with an overall assessment score of 8.81 (10 for a maximum score). The challenge of RNAS⁺ included the lack of sustainable funding, skills, etc. and most participants expressed their continual need of China’s support.

Conclusions

This survey showed that China has played an important role in the development of RNAS⁺ since its establishment. This network-type organization for disease control and research can yet be regarded as a great potential pattern for China to enhance regional cooperation. These findings can be used to promote future cooperation between China and other RNAS⁺ member countries.

Core components, concepts and strategies for parasitic and vector-borne disease elimination with a focus on schistosomiasis: A landscape analysis

Efforts to control and eliminate human schistosomiasis have accelerated over the past decade. In a number of endemic countries and settings, interruption of schistosome transmission has been achieved. In others, Schistosoma infections continue to challenge program managers at different levels, from the complexity of the transmission cycle, over limited treatment options and lack of field-friendly accurate diagnostics, to controversy around adequate intervention strategies. We conducted a landscape analysis on parasitic and vector-borne disease elimination approaches with the aim to identify evidence-based strategies, core components and key concepts for achieving and sustaining schistosomiasis control and for progressing elimination efforts towards interruption of transmission in sub-Saharan Africa. A total of 118 relevant publications were identified from Web of Science, Pubmed and the grey literature and reviewed for their content. In addition, we conducted in-depth interviews with 23 epidemiologists, program managers, policymakers, donors and field researchers. Available evidence emphasizes the need for comprehensive, multipronged and long-term strategies consisting of multiple complementary interventions that must be sustained over time by political commitment and adequate funding in order to reach interruption of transmission. Based on the findings of this landscape analysis, we propose a comprehensive set of intervention strategies for schistosomiasis control and elimination. Before deployment, the proposed interventions will require review, evaluation and validation in the frame of an expert consultation as a step towards adaptation to specific contexts, conditions and settings. Field testing to ensure local relevance and effectiveness is paramount given the diversity of socio-ecological and epidemiological contexts.

This landscape analysis explored successful concepts, approaches and interventions of past and ongoing parasitic and vector-borne disease elimination efforts and programs with regard to relevance for progress in the elimination of human schistosome infections. Schistosomiasis is a disabling, water borne parasitic disease of public health concern with an estimated 250 million people infected worldwide. The long-term morbidity of this neglected tropical disease significantly impacts growth, cognition and socioeconomic development at all ages. Despite increased global efforts to control morbidity and advance elimination, challenges in view of the complex life cycle which involves freshwater sources, intermediate snail hosts and humans, remain. This calls for targeted interventions and concerted programs. According to the evidence from the literature and as proposed by a wide range of key informants, comprehensive, multipronged and long-term strategies supported by strong political commitment and adequate funding are required in order to achieve and sustain the set goals. Based on the findings, we propose here a comprehensive set of intervention strategies for schistosomiasis control and elimination for review and evaluation to inform implementation research needs and elimination program design.

Construction and application of surveillance and response systems for parasitic diseases in China, led by NIPD-CTDR

Parasitic diseases have been widely epidemic in China with a long history. Great endeavours made in past 70 years led to significant decrease in morbidity and mortablity caused by several major parasitic diseases, while challenges existed to eliminate parasitic diseases. Surveillance-response system has play a crucial role in identifying public health problems, ascertaining the distribution and epidemic dynamics, discovering outbreaks and epidemic anomalies, evaluating the effects of on-site intervention activities and identifying risk factors. In this article, we reviewed the progress of the surveillance system for parasitic diseases, analysed the role of NIPD in the construction and application of surveillance-response system of parasitic diseases through elaborating the surveillance activities and typical surveillance-response events led by NIPD. Suggestion and comments for improve the surveillance-response system were put forward for further control or elimination of parasitic diseases.

Surveillance-based evidence: elimination of schistosomiasis as a public health problem in the Peoples' Republic of China

BACKGROUND

A steady progress on schistosomiasis control in the Peoples' Republic of China (P.R. China) was achieved and broadened into the twelve-year medium and long term national plan (MLNP) which marled the implementation of an integrated control strategy across all endemic areas in P.R. China in 2004. To understand the endemic trends of schistosomiasis to assess the effectiveness of an integrated strategy, we conducted an analysis of schistosomiasis surveillance data spanned from 2005 to 2015.

METHODS

The schistosomiasis sentinel surveillance data from sentinel sites were collected and analyzed from 2005 to 2015. In these sentinel sites, residents aged 6 years or above were screened annually by indirect hemagglutination assay (IHA), while only antibody positives were followed by stool examination either Kato-katz method (KK) and/or hatching technique (HT). Domestic animals raised in sentinel sites were examined by HT for confirming the infection of schistosomes. Snail investigation was conducted each year through systematic sampling method combined with environmental sampling method. The snails collected from field were tested by microscopic dissection method. The infection rates of schistosomes in residents, domestic animals and snails, as well as the indicators reflecting the snails' distribution were calculated and analyzed. ANOVA analysis was used to examine the changes of the number of eggs per gram feces in population and Chi-square test was used to examine any change in proportions among groups.

RESULTS

A total of 148 902 residents from sentinel sites attended this study and 631 676 blood samples were examined by IHA test during the 11 covered years. The annual average antibody positive rates presented a significant decrease trends, from 17.48% (95% CI: 17.20-17.75%) in 2005 to 5.93% (95% CI: 5.71-6.15%) (χ2 = 8890.47, P < 0.001) in 2015. During 2005-2015, the average infection rate of schistosomes in residents declined from 2.07% (95% CI: 1.96-2.17%) to 0.13% (95% CI: 0.09-0.16%), accompanied by significant decrease of infection intensity in population. In 2015, the stool positives were only found in farmers, fishermen and boatmen with infection rate of 0.16% (95% CI: 0.11-0.20%), 0.17% (95% CI: 0-0.50%) respectively. The infection rate of schistosomes in domestic animals dropped from 9.42% (538/5711, 95% CI: 8.66-10.18%) to 0.08% (2/2360, 95% CI: 0-0.20%) from 2005 to 2015. Infections were found in eight species of domestic animals at the beginning of surveillance while only two cattle were infected in 2015. Totally 98 ha of new snail habitats were found, while 94.90% (93/98) distributed in lake and marshland regions. The percentage of frames with snails decreased from 16.96% (56 884/33 5391, 95% CI: 16.83-17.09%) in 2005 to 4.28% (18 121/423 755, 95% CI: 4.22-4.34%) in 2014, with a slightly increase in 2015. Meanwhile, the infection rate of schistosomes in snails was decreased from 0.26% (663/256 531, 95% CI: 0.24-0.28%) to zero during 2005-2015.

CONCLUSIONS

The infection rate of schistosomes declined significantly, providing evidence that the goal of the MLNP was achieved. Elimination of schistosomiasis as a public health problem defined as WHO was also reached in P.R. China nationwide. Surveillance-response system should be improved and strengthened to realize the final goal of schistosomiasis elimination.

Collaborative RNAS+ research: Priorities and outcomes

Over the past 20 years, RNAS⁺ has been generating research results from highly collaborative projects meant to promote and advance understanding in various aspects of schistosomiasis. Epidemiological studies in endemic countries like the Philippines, the People's Republic of China (PR China), the Lao People's Democratic Republic (Lao PDR) and Cambodia clarified the role of reservoir hosts in transmission and the use of spatio-temporal methods such as remote sensing and geographical information systems (GIS) in surveillance of schistosomiasis. Morbidity studies proposed factors that might influence development of fibrosis, anaemia and malnutrition in schistosomiasis. Immune responses in schistosomiasis continue to be an interesting focus in research to explain possible development of resistance with age. Results of evaluation of candidate vaccine molecules are also presented. New diagnostics are continually being developed in response to the call for more sensitive and field applicable techniques that will be used for surveillance in areas nearing elimination of the disease. Several studies presented here show the insufficiency of mass drug administration (MDA) with praziquantel in eliminating the disease. Emphasis is given to an integrated control approach that can be accomplished through intensive and extensive intersectoral collaboration.

From country control programmes to translational research

From the time it was conceptualized in 1998 to the present, RNAS⁺ has largely concentrated on research that will generate results to facilitate control, prevention and elimination of its target diseases. Diagnostics has remained an active field of research in order to develop tools that are appropriate for each stage from the first efforts until attempts to block transmission. For example, with regard to schistosomiasis, chemotherapy has excellent impact on morbidity, while better diagnostics and vaccine research have been promoted to complement the other components of the control programme. The need for surveillance in areas where the prevalence has been brought down to very low levels necessitated development of spatio-temporal tools and ecological models based on geographical information systems (GIS) to produce risk and distribution maps for monitoring and evaluation of programme success. New knowledge and experiences in management of the diseases contribute to the formulation of new schemes in management and treatment. Ways of drawing attention to the disease, such as determining disability weights for use in computation of burden of disease, updating epidemiological profile and unravelling new aspects of the disease provide bases for modifying the operation of control programmes as we move forward. Programme evaluation based on reports of actual implementation of activities brought to the fore problems related to the distribution of chemotherapy as well as social, cultural and behavioural aspects of endemic communities. Importantly, this highlighted the necessity of adapting control activities to specific situations of the endemic areas. New models evolving from reviews of this kind and success stories, such us the elimination of lymphatic filariasis (LF) in PR China and Cambodia are presented.

A Call for Systems Epidemiology to Tackle the Complexity of Schistosomiasis, Its Control, and Its Elimination

Ever since the first known written report of schistosomiasis in the mid-19th century, researchers have aimed to increase knowledge of the parasites, their hosts, and the mechanisms contributing to infection and disease. This knowledge generation has been paramount for the development of improved intervention strategies. Yet, despite a broad knowledge base of direct risk factors for schistosomiasis, there remains a paucity of information related to more complex, interconnected, and often hidden drivers of transmission that hamper intervention successes and sustainability. Such complex, multidirectional, non-linear, and synergistic interdependencies are best understood by looking at the integrated system as a whole. A research approach able to address this complexity and find previously neglected causal mechanisms for transmission, which include a wide variety of influencing factors, is needed. Systems epidemiology, as a holistic research approach, can integrate knowledge from classical epidemiology, with that of biology, ecology, social sciences, and other disciplines, and link this with informal, tacit knowledge from experts and affected populations. It can help to uncover wider-reaching but difficult-to-identify processes that directly or indirectly influence exposure, infection, transmission, and disease development, as well as how these interrelate and impact one another. Drawing on systems epidemiology to address persisting disease hotspots, failed intervention programmes, and systematically neglected population groups in mass drug administration programmes and research studies, can help overcome barriers in the progress towards schistosomiasis elimination. Generating a comprehensive view of the schistosomiasis system as a whole should thus be a priority research agenda towards the strategic goal of morbidity control and transmission elimination.

Effectiveness of the new integrated strategy to control the transmission of Schistosoma japonicum in China: a systematic review and meta-analysis

Since 2004, the national schistosomiasis control strategy in China has shifted from the morbidity control strategy (conventional strategy) to an integrated strategy (new strategy). We investigated the effectiveness of the new strategy and compared it against the conventional strategy. We retrieved from electronic databases the literature regarding the new strategy published from 2000 to 2017. The effect of the new or conventional strategy on infection by Schistosoma japonicum of humans and snails (Oncomelania hupensis) was evaluated with pooled log relative risk (logRR). A total of only eight eligible publications were included in the final meta-analysis. The results showed that implementation of the new strategy reduced the infection risk by 3–4 times relative to the conventional strategy. More specifically, the conventional strategy caused a reduction in both human (logRR = 0.56, 95% CI: 0.12–0.99) and snail infections (logRR = 0.34, 95% CI: −0.69–1.37), while the new strategy also significantly reduced both human (logRR = 1.89, 95% CI: 1.33–2.46) and snail infections (logRR = 1.61, 95% CI: 1.06–2.15). In contrast to the conventional strategy, the new strategy appeared more effective to control both human (logRR difference = 1.32, 95% CI: 0.78–1.86) and snail infections (logRR difference = 1.53, 95% CI: 0.76–2.31). Our data demonstrate that the new integrated strategy is highly effective to control the transmission of S. japonicum in China, and this strategy is recommended for schistosomiasis elimination in other affected regions across the world, with adaptation to local conditions.

Prevalence and Risk Factors of Ascaris lumbricoides, Trichuris trichiura and Cryptosporidium Infections in Elementary School Children in Southwestern China: A School-Based Cross-Sectional Study

Background: Intestinal parasitic infections pose great public health challenges in school children in developing countries. The aim of this study was to assess the prevalence of A. lumbricoides, T. trichiura and Cryptosporidium among elementary school children in rural southwestern China. Methods: A school-based cross-sectional study involving 321 elementary school children was conducted in 2014 in the southwest of China. They were invited to provide a stool sample and interviewed about the sanitary situation and hygiene behavior. Stool specimens were examined for A. lumbricoides and T. trichiura using the Kato-Katz fecal thick-smear technique. The presence of Cryptosporidium was determined using a modified acid-fast staining method. Results: The prevalence of infection was 10.0% (95% CI: 6.9–13.8%) for A. lumbricoides, 25.2% (95% CI: 20.6–30.4%) for T. trichiura and 2.4% for (95% CI: 1.1–4.9%) Cryptosporidium. The prevalence of co-infection was 3.7% (95% CI: 1.9–6.4%) for A. lumbricoides/T. trichiura, 0.3% (95% CI: 0–1.7%) for A. lumbricoides/Cryptosporidium and 0.9% (95% CI: 0.2–2.7%) for T. trichiura/Cryptosporidium. Children from households using well or river water were associated with a greater odds of A. lumbricoides infection (aOR = 2.61, 95% CI: 1.12–6.05). Having a household lavatory was associated with a lower odds of T. trichiura infection (aOR = 0.50, 95% CI: 0.30–0.84). Children who had three meals at the school canteen on week days were at a lower risk of Cryptosporidium infection. The use of spring water as a water source was associated with lower odds of any intestinal infection (aOR = 0.56, 95% CI: 0.35–0.91). Conclusions: Our study calls for an intervention program of school-based deworming combined with health education, hygiene promotion and provision of safe water and improved sanitation.

The effects of subcurative praziquantel treatment on life-history traits and trade-offs in drug-resistant Schistosoma mansoni

Natural selection acts on all organisms, including parasites, to maximize reproductive fitness. Drug resistance traits are often associated with life-history costs in the absence of treatment. Schistosomiasis control programmes rely on mass drug administration to reduce human morbidity and mortality. Although hotspots of reduced drug efficacy have been reported, resistance is not widespread. Using Bayesian state-space models (SSMs) fitted to data from an in vivo laboratory system, we tested the hypothesis that the spread of resistant Schistosoma mansoni may be limited by life-history costs not present in susceptible counterparts. S. mansoni parasites from a praziquantel-susceptible (S), a praziquantel-resistant (R) or a mixed line of originally resistant and susceptible parasites (RS) were exposed to a range of praziquantel doses. Parasite numbers at each life stage were quantified in their molluscan intermediate and murine definitive hosts across four generations, and SSMs were used to estimate key life-history parameters for each experimental group over time. Model outputs illustrated that parasite adult survival and fecundity in the murine host decreased across all lines, including R, with increasing drug pressure. Trade-offs between adult survival and fecundity were observed in all untreated lines, and these remained strong in S with praziquantel pressure. In contrast, trade-offs between adult survival and fecundity were lost under praziquantel pressure in R. As expected, parasite life-history traits within the molluscan host were complex, but trade-offs were demonstrated between parasite establishment and cercarial output. The observed trade-offs between generations within hosts, which were modified by praziquantel treatment in the R line, could limit the spread of R parasites under praziquantel pressure. Whilst such complex life-history costs may be difficult to detect using standard empirical methods, we demonstrate that SSMs provide robust estimates of life-history parameters, aiding our understanding of costs and trade-offs of resistant parasites within this system and beyond.

Environmental risk factors and changing spatial patterns of human seropositivity for Echinococcus spp. in Xiji County, Ningxia Hui Autonomous Region, China

Background

Human echinococcoses are parasitic helminth infections that constitute a serious public health concern in several regions across the world. Cystic (CE) and alveolar echinococcosis (AE) in China represent a high proportion of the total global burden of these infections. This study was conducted to predict the spatial distribution of human seropositivity for Echinococcus species in Xiji County, Ningxia Hui Autonomous Region (NHAR), with the aim of identifying communities where targeted prevention and control efforts are required.

Methods

Bayesian geostatistical models with environmental and demographic covariates were developed to predict spatial variation in the risk of human seropositivity for Echinococcus granulosus (the cause of CE) and E. multilocularis (the cause of AE). Data were collected from three cross-sectional surveys of school children conducted in Xiji County in 2002–2003, 2006–2007 and 2012–2013. Environmental data were derived from high-resolution satellite images and meteorological data.

Results

The overall seroprevalence of E. granulosus and E. multilocularis was 33.4 and 12.2%, respectively, across the three surveys. Seropositivity for E. granulosus was significantly associated with summer and winter precipitation, landscape fragmentation variables and the extent of areas covered by forest, shrubland, water and bareland/artificial surfaces. Seropositivity for E. multilocularis was significantly associated with summer and winter precipitations, landscape fragmentation variables and the extent of shrubland and water bodies. Spatial correlation occurred over greater distances for E. granulosus than for E. multilocularis. The predictive maps showed that the risk of seropositivity for E. granulosus expanded across Xiji during the three surveys, while the risk of seropositivity for E. multilocularis became more confined in communities located in the south.

Conclusions

The identification of high-risk areas for seropositivity for these parasites, and a better understanding of the role of the environment in determining the transmission dynamics of Echinococcus spp. may help to guide and monitor improvements in human echinococcosis control strategies by allowing targeted allocation of resources.

The Spatial-Temporal Trend Analysis of Schistosomiasis from 1997 to 2010 in Anhui Province, Eastern China

Schistosomiasis is still prevalent in some parts of China. A shift in strategy from morbidity control to elimination has led to great strides in the past several decades. The objective of this study was to explore the spatial and temporal characteristics of schistosomiasis in Anhui, an eastern province of China. In this study, township-based parasitological data were collected from annual cross-sectional surveys during 1997-2010. The kernel k-means method was used to identify spatial clusters of schistosomiasis, and an empirical mode decomposition technique was used to analyze the temporal trend for Schistosoma japonicum in each clustered region. Overall, the prevalence of schistosomiasis remained at a low level except for the resurgence in 2005. According to the Caliński-Harabas index, all the townships were classified into three different clusters (median prevalence: 3.6 per 10,100, 1.8 per 10,000 and 1.7 per 10,000), respectively representing high-, median-, and low-risk clusters. There was an increasing tendency observed for the disease over time. The prevalence increased rapidly from 2003 to 2005, peaked in 2006, and then decreased afterward in the high-risk cluster. A moderate increase was observed in the median-risk cluster from 1998 to 2006, but there was an obvious decreasing tendency in the low-risk cluster after the year 2000. The spatial and temporal patterns of schistosomiasis were nonsynchronous across the three clusters. Disease interventions may be adjusted according to the risk levels of the clusters.

Establishment of first engineering specifications for environmental modification to eliminate schistosomiasis epidemic foci in urban areas

Snail control is a key link in schistosomiasis control, but no unified methods for eliminating snails have been produced to date. This study was conducted to explore an engineering method for eliminating Oncomelania hupensis applicable to urban areas. The engineering specifications were established using the Delphi method. An engineering project based on these specifications was conducted in Hankou marshland to eliminate snails, including the transformation of the beach surface and ditches. Molluscicide was used as a supplement. The snail control effect was evaluated by field investigation. The engineering results fulfilled the requirements of the design. The snail density decreased to 0/0.11m², and the snail area dropped to 0m² after the project. There was a statistically significant difference in the number of frames with snails before and after the project (P<0.05). Snails were completely eliminated through one year of continuous monitoring, and no new snails were found after a flood disaster. This study demonstrates that engineering specifications for environmental modification were successfully established. Environmental modification, mainly through beach and ditch remediation, can completely change the environment of Oncomelania breeding. This method of environmental modification combined with mollusciciding was highly effective at eliminating snails.

Interruption of schistosomiasis transmission in mountainous and hilly regions with an integrated strategy: a longitudinal case study in Sichuan, China

Background

Schistosomiasis remains a major public health concern in China. Since 2004, an integrated strategy was developed to control the transmission of Schistosoma japonicum in China. However, the long-term effectiveness of this integrated strategy for the interruption of schistosomiasis transmission remains unknown in the mountainous and hilly regions of China until now. This longitudinal study aims to evaluate the effectiveness of the integrated strategy on transmission interruption of schistosomiasis in Sichuan Province from 2005 through 2014.

Methods

The data regarding replacement of bovines with machines, improved sanitation, access to clean water, construction of public toilets and household latrines, snail control, chemotherapy, and health education were captured from the annual report of the schistosomiasis control programmes in Sichuan Province from 2005 to 2014, and S. japonicum infection in humans, bovines and snails were estimated to evaluate the effectiveness of the integrated strategy.

Results

During the 10-year period from 2005 through 2014, a total of 536 568 machines were used to replace bovines, and 3 284 333 household lavatories and 15 523 public latrines were built. Tap water was supplied to 19 116 344 residents living in the endemic villages. A total of 230 098 hm² snail habitats were given molluscicide treatment, and 357 233 hm² snail habitats received environmental improvements. There were 7 268 138 humans and 840 845 bovines given praziquantel chemotherapy. During the 10-year study period, information, education and communication (IEC) materials were provided to village officers, teachers and schoolchildren. The 10-year implementation of the integrated strategy resulted in a great reduction in S. japonicum infection in humans, bovines and snails. Since 2007, no acute infection was detected, and no schistosomiasis cases or infected bovines were identified since 2012. In addition, the snail habitats reduced by 62.39% in 2014 as compared to that in 2005, and no S. japonicum infection was identified in snails since 2007. By 2014, 88.9% of the endemic counties achieved the transmission interruption of schistosomiasis and transmission control of schistosmiasis was achieved in the whole province in 2008.

Conclusion

The government-directed and multi-department integrated strategy is effective for interrupting the transmission of schistosomiasis in the mountainous and hilly regions of China.

An integrated environmental improvement of marshlands: impact on control and elimination of schistosomiasis in marshland regions along the Yangtze River, China

BACKGROUND

Schistosomiasis is a global snail-transmitted infectious disease of poverty. Transmission control had been achieved in China in 2015 after the control efforts for over 60 years. Currently, the remaining core regions endemic for Schistosoma japonicum are mainly located in the marshland and lake regions along the Yangtze River basin.

METHODS

During the period from 2001 through 2015, an integrated environmental improvement of the marshlands was carried out through the implementation of industrial, agricultural and resources development projects in Yizheng County along the Yangtze River. S. japonicum infection in humans, livestock and snails was estimated by serology, stool examination, hatching technique and microscopy during the 15-year study period to evaluate the effect of the integrated environmental improvement on control and elimination of schistosomiasis.

RESULTS

A 0.05% overall rate of S. japonicum infection was observed in snails during the 15-year study period, and no infected snails were detected since 2012. The overall prevalence of S. japonicum infection was 0.09% in humans during the study period, and no human infection was found since 2012. In addition, only 13 bovines were identified with S. japonicum infection in 2003 during the 15-year study period, and since 2004, no infection was found in livestock.

CONCLUSION

The results of the present study demonstrate that the implementation of industrial, agricultural and water resources development projects, not only alters snail habitats in marshland regions, and promotes local economic development, which appears a win-to-win strategy to block the transmission of S. japonicum and accelerate socio-economic development along the Yangtze River.

Schistosoma mansoni infection and related knowledge among schoolchildren in an endemic area of Minas Gerais, Brazil, prior to educational actions

As a signatory to World Health Assembly Resolution WHA65.21 on eliminating schistosomiasis, the Brazilian Ministry of Health (MoH) recommends early identification and timely treatment of the infection carriers for morbidity control, plus complementary preventive measures, such as health education, for transmission control. This study reports infection and awareness of schistosomiasis among schoolchildren before the implementation of school-based educational actions in an endemic municipality with persisting moderate prevalence levels despite successive control campaigns since the late 1990s. A questionnaire was applied in April 2013 to schoolchildren in the middle years of schooling (6th to 8th year) of Malacacheta municipality to assess baseline knowledge and risk behaviour related to schistosomiasis. A stool survey was conducted in May/June 2013 in 2519 schoolchildren from all years of fundamental education (first to 9th year) to identify the infection carriers, as well as to assess baseline prevalence and intensity of infection using the Kato-Katz method (one sample, two slides). The infected schoolchildren were treated promptly with single-dose praziquantel 60mg/kg and followed up after 45days for treatment efficacy. Relevant outcomes from baseline stool survey, treatment and follow-up were statistically evaluated in relation to area of residence (rural/urban), gender, age group (<11/≥years) and infection. Adherence to baseline survey was 81.2%, and prevalence of infection was 21.4%. Of the 539 positives, 60 (11.1%) had ≥400 eggs per gram of faeces (heavy-intensity infection). Prevalence of infection was significantly higher among rural residents and≥11year olds, whereas intensity of infection was higher among rural residents,≥11year olds and boys. Adherence by the positives to treatment was 93.3% and adherence by the treated children to 45-day follow-up was 72.2%. At 45days after treatment, 97.0% of the 363 children surveyed were egg-negative; the egg reduction rate was 99.4%. Of the 924 children who responded to the questionnaire, 95.5% showed awareness of schistosomiasis, although 76.2% reported contact with natural, unsafe bodies of water. Reported contact with water was significantly more frequent among infected than non-infected, and boys than girls. The results show persisting infection and risk behaviour among schoolchildren, regardless of their basic knowledge about schistosomiasis. These are grounds for implementing specific educational actions to improve awareness and behavioural change, jointly with other control measures, to attain the MoH goals.

Long-term effectiveness of the integrated schistosomiasis control strategy with emphasis on infectious source control in China: a 10-year evaluation from 2005 to 2014

Schistosomiasis is a neglected tropical parasitic disease of great public health significance worldwide. Currently, mass drug administration with praziquantel remains the major strategy for global schistosomiasis control programs. Since 2005, an integrated strategy with emphasis on infectious source control was implemented for the control of schistosomiasis japonica, a major public health concern in China, and pilot studies have demonstrated that such a strategy is effective to reduce the prevalence of Schistosoma japonicum infection in both humans and bovines. However, there is little knowledge on the long-term effectiveness of this integrated strategy for controlling schistosomiasis japonica. The aim of this study was to evaluate the long-term effectiveness of the integrated strategy for schistosomiasis control following the 10-year implementation, based on the data from the national schistosomiasis control program released by the Ministry of Health, People's Republic of China. In 2014, there were 5 counties in which the transmission of schistosomiasis japonica had not been interrupted, which reduced by 95.2% as compared to that in 2005 (105 counties). The number of schistosomiasis patients and acute cases reduced by 85.5 and 99.7% in 2014 (115,614 cases and 2 cases) as compared to that in 2005 (798,762 cases and 564 cases), and the number of bovines and S. japonicum-infected bovines reduced by 47.9 and 98% in 2014 (919,579 bovines and 666 infected bovines) as compared to that in 2005 (1,764,472 bovines and 33,736 infected bovines), respectively. During the 10-year implementation of the integrated strategy, however, there was a minor fluctuation in the area of Oncomelania hupensis snail habitats, and there was only a 5.6% reduction in the area of snail habitats in 2014 relative to in 2005. The results of the current study demonstrate that the 10-year implementation of the integrated strategy with emphasis on infectious source has greatly reduced schistosomiasis-related morbidity in humans and bovines. It is concluded that the new integrated strategy has remarkable long-term effectiveness on the transmission of schistosomiasis japonica in China, which facilitates the shift of the national schistosomiasis control program from transmission control to transmission interruption and elimination. However, such a strategy seems to have little effect on the shrinking of areas of snail habitats.

Major parasitic diseases of poverty in mainland China: perspectives for better control

Significant progress has been made in the prevention, control, and elimination of human parasitic diseases in China in the past 60 years. However, parasitic diseases of poverty remain major causes of morbidity and mortality, and inflict enormous economic costs on societies.In this article, we review the prevalence rates, geographical distributions, epidemic characteristics, risk factors, and clinical manifestations of parasitic diseases of poverty listed in the first issue of the journal Infectious Diseases of Poverty on 25 October 2012. We also address the challenges facing control of parasitic diseases of poverty and provide suggestions for better control.

Current status and perspectives of Clonorchis sinensis and clonorchiasis: epidemiology, pathogenesis, omics, prevention and control

Clonorchiasis, caused by Clonorchis sinensis (C. sinensis), is an important food-borne parasitic disease and one of the most common zoonoses. Currently, it is estimated that more than 200 million people are at risk of C. sinensis infection, and over 15 million are infected worldwide. C. sinensis infection is closely related to cholangiocarcinoma (CCA), fibrosis and other human hepatobiliary diseases; thus, clonorchiasis is a serious public health problem in endemic areas. This article reviews the current knowledge regarding the epidemiology, disease burden and treatment of clonorchiasis as well as summarizes the techniques for detecting C. sinensis infection in humans and intermediate hosts and vaccine development against clonorchiasis. Newer data regarding the pathogenesis of clonorchiasis and the genome, transcriptome and secretome of C. sinensis are collected, thus providing perspectives for future studies. These advances in research will aid the development of innovative strategies for the prevention and control of clonorchiasis.

Surveillance and response systems for elimination of tropical diseases: summary of a thematic series in Infectious Diseases of Poverty

The peer-reviewed journal Infectious Diseases of Poverty provides a new platform to engage with, and disseminate in an open-access format, science outside traditional disciplinary boundaries. The current piece reviews a thematic series on surveillance-response systems for elimination of tropical diseases. Overall, 22 contributions covering a broad array of diseases are featured – i.e. clonorchiasis, dengue, hepatitis, human immunodeficiency virus/acquired immune deficiency syndrome (HIV/AIDS), H7N9 avian influenza, lymphatic filariasis, malaria, Middle East respiratory syndrome (MERS), rabies, schistosomiasis and tuberculosis (TB). There are five scoping reviews, a commentary, a letter to the editor, an opinion piece and an editorial pertaining to the theme “Elimination of tropical disease through surveillance and response”. The remaining 13 articles are original contributions mainly covering (i) drug resistance; (ii) innovation and validation in the field of mathematical modelling; (iii) elimination of infectious diseases; and (iv) social media reports on disease outbreak notifications released by national health authorities. Analysis of the authors’ affiliations reveals that scientists from the People’s Republic of China (P.R. China) are prominently represented. Possible explanations include the fact that the 2012 and 2014 international conferences pertaining to surveillance-response mechanisms were both hosted by the National Institute of Parasitic Diseases (NIPD) in Shanghai, coupled with P.R. China’s growing importance with regard to the control of infectious diseases. Within 4 to 22 months of publication, three of the 22 contributions were viewed more than 10 000 times each. With sustained efforts focusing on relevant and strategic information towards control and elimination of infectious diseases, Infectious Diseases of Poverty has become a leading journal in the field of surveillance and response systems in infectious diseases and beyond.

Evolution of the National Schistosomiasis Control Programmes in The People's Republic of China

Schistosomiasis japonica is caused by the parasitic trematode Schistosoma japonicum. It is endemic in The People's Republic of China and has significant impact on human health and socioeconomic development in certain regions. Over the last six decades, the national control programmes evolved in remarkable ways and brought schistosomiasis japonica largely under control. We describe the history and evolution of schistosomiasis control in The People's Republic of China, with an emphasis on shifts in control strategies that evolved with new insights into the biology of the parasite and its intermediate hosts, and the epidemiology of the disease in the country. We also highlight the achievements in controlling the disease in different socioecological settings, and identify persisting challenges to fully eliminate schistosomiasis japonica from the country. To reach the goal of schistosomiasis elimination, further integration of interventions, multisector collaboration, sensitive and effective surveillance are needed to strengthen.

Integrated Control Strategy of Schistosomiasis in The People's Republic of China: Projects Involving Agriculture, Water Conservancy, Forestry, Sanitation and Environmental Modification

Among the three major schistosome species infecting human beings, Schistosoma japonicum is the only endemic species in The People's Republic of China. Schistosomiasis is endemic in 78 countries and regions and poses a severe threat to public health and socioeconomic development. Through more than 60years of hard work and endeavour, The People's Republic of China has made considerable achievements and reduced the morbidity and prevalence of this disease to the lowest level ever recorded, especially since the introduction of the new integrated control strategy in 2004. This review illustrates the strategies implemented by giving successful examples of schistosomiasis control from the different types of remaining endemic areas. The challenge to control or eliminate S. japonicum is analysed in order to provide useful information to policy makers and scientists.

China-Africa and China-Asia Collaboration on Schistosomiasis Control: A SWOT Analysis

Schistosomiasis, a disease caused by a trematode, parasitic worm, is a worldwide public health problem. In spite of great progress with regard to morbidity control, even elimination of this infection in recent decades, there are still challenges to overcome in sub-Saharan Africa and endemic areas in Southeast Asia. Regarded as one of the most successful countries with respect to schistosomiasis control, The People's Republic of China has accumulated considerable experience and learnt important lessons in various local settings that could benefit schistosomiasis control in other endemic countries. Based on an analysis of conceived strengths, weaknesses, opportunities and threats (SWOT) of potential collaborative activities with regard to schistosomiasis in Africa and Asia, this article addresses the importance of collaborative efforts and explores the priorities that would be expected to facilitate the transfer of Chinese experience to low- and middle-income countries in Africa and Asia.

Enhancing collaboration between China and African countries for schistosomiasis control

Schistosomiasis remains an important public health issue, with a large number of cases reported across sub-Saharan Africa, and parts of Asia and Latin America. China was once highly endemic, but has made substantial progress and is moving towards elimination of schistosomiasis. Meanwhile, despite long-term, repeated, school-based chemotherapy in many African countries, more than 90% of all schistosomiasis cases are concentrated in Africa, and hence, this continent constitutes the key challenge for schistosomiasis control. Opportunities and issues for international collaboration in the fight against schistosomiasis are outlined with a focus on China's experiences, including the role of public health authorities and intersectoral collaboration, use of new and effective snail control approaches and diagnostic tools adapted to the specific stage of control, as well as the strengthening of risk mapping and surveillance-response mechanisms. Training courses targeting African governmental officials and professionals, coupled with field visits of African scientists and control programme managers to China, and vice versa, are considered important for improved schistosomiasis control and elimination. The crucial question remains whether the Chinese experience can be translated and applied in African countries to improve the effectiveness of health interventions and scale-up.

Integrated Schistosomiasis and Soil-Transmitted Helminthiasis Control over Five Years on Kome Island, Tanzania

Integrated control strategies are important for sustainable control of schistosomiasis and soil-transmitted helminthiasis, despite their challenges for their effective implementation. With the support of Good Neighbors International in collaboration with National Institute of Medical Research, Mwanza, Tanzania, integrated control applying mass drug administration (MDA), health education using PHAST, and improved safe water supply has been implemented on Kome Island over 5 years for controlling schistosomiasis and soil-transmitted helminths (STHs). Baseline surveys for schistosomiasis and STHs was conducted before implementation of any integrated control strategies, followed by 4 cross-sectional follow-up surveys on randomly selected samples of schoolchildren and adults in 10 primary schools and 8 villages, respectively, on Kome islands. Those follow-up surveys were conducted for impact evaluation after introduction of control strategies interventions in the study area. Five rounds of MDA have been implemented from 2009 along with PHAST and improved water supply with pumped wells as other control strategies for complementing MDA. A remarkable steady decline of schistosomiasis and STHs was observed from 2009 to 2012 with significant trends in their prevalence decline, and thereafter infection rate has remained at a low sustainable control. By the third follow-up survey in 2012, Schistosoma mansoni infection prevalence was reduced by 90.5% and hookworm by 93.3% among schoolchildren while in adults the corresponding reduction was 83.2% and 56.9%, respectively. Integrated control strategies have successfully reduced S. mansoni and STH infection status to a lower level. This study further suggests that monitoring and evaluation is a crucial component of any large-scale STH and schistosomiasis intervention.

Identifying Spatial Clusters of Schistosomiasis in Anhui Province of China: A Study from the Perspective of Application

With the strategy shifting from morbidity control to transmission interruption, the burden of schistosomiasis in China has been declining over the past decade. However, further controls of the epidemic in the lake and marshland regions remain a challenge. Prevalence data at county level were obtained from the provincial surveillance system in Anhui during 1997–2010. Spatial autocorrelation analysis and spatial scan statistics were combined to assess the spatial pattern of schistosomiasis. The spatial-temporal cluster analysis based on retrospective space-time scan statistics was further used to detect risk clusters. The Global Moran’s I coefficients were mostly statistically significant during 1997–2004 but not significant during 2005–2010. The clusters detected by two spatial cluster methods occurred in Nanling, Tongling, Qingyang and Wuhu during 1997–2004, and Guichi and Wuhu from 2005 to 2010, respectively. Spatial-temporal cluster analysis revealed 2 main clusters, namely Nanling (1999–2002) and Guichi (2005–2008). The clustering regions were significantly narrowed while the spatial extent became scattered during the study period. The high-risk areas shifted from the low reaches of the Yangtze River to the upper stream, suggesting the focus of schistosomiasis control should be shifted accordingly and priority should be given to the snail habitats within the high-risk areas of schistosomiasis.

Prevalence of Cystic Echinococcosis in Slaughtered Sheep as an Indicator to Assess Control Progress in Emin County, Xinjiang, China

Hydatid disease imposing serious threat on human health and great loss in live¬stock pastoralism remains a major public health problem in western China. To assess and monitor the effect of control program on transmission dynamics, we used the prevalence of cystic echinococcosis in slaughtered sheep at slaughterhouse as an indicator during the period of 2007 to 2013 in Emin County, Xinjiang Uygur Autonomous Region, China. The results showed a significant decline trend of prevalence in all age groups during the 7 years when the control program was implemented; particularly, the rate was reduced by 72% after first 3 years. Among the sheep slaughtered, the age distribution evidenced that the prevalence increased significantly as the sheep grew older. The baseline data indicated that the rate was 4.5% at the age <1, 6.7% at age 2~, and reached to the highest 17.9% at age ≥4 years. Earlier response to the intervention pressure was seen in the sheep at the younger age. Significant decline started from 2008 at the age <1, from 2009 at age of 1~, 2010 at 2~ to 3~, and the latest, in 2012 at age ≥4. This study demonstrated that the prevalence of cystic echinococcosis in slaughtered sheep may be used as an indicator to assess and monitor the transmission status during and after control program providing information for betterment of performance to sustain control strength.

Progress in research, control and elimination of helminth infections in Asia

Global health has substantially improved over the past 20 years. In low- and middle-income countries, in particular, great strives have been made in the control of communicable diseases, including helminth infections. Nevertheless, the most marginalised communities still suffer from infectious diseases that are intimately connected with poverty and lack of access to essential commodities and services, such as clean water, improved sanitation and sufficient food. A two-pronged approach is thus necessary: (i) intensifying control in remaining high-endemicity areas and pockets of high transmission; and (ii) moving from morbidity control to interruption of disease transmission in low-endemicity areas with the goal of local elimination. The latter will require new tools and strategies, going hand-in-hand with strong partnerships and new strategic alliances. In this special issue of Acta Tropica, 35 articles are featured that, together, provide an up-to-date overview of the latest progress made in research, control and elimination of helminth infections in East and Southeast Asia. The first 12 articles expound tools and approaches for improved detection, surveillance and monitoring of helminth infections. Control and elimination approaches for the most important helminth infections are revisited in the next 20 articles. The three remaining articles are cross-cutting pieces examining the interface of agriculture, environment and helminth infections and providing a rationale for integrated, multi-sectorial control approaches that are necessary for sustaining helminthiasis control and progressively moving towards elimination. An interesting aspect revealed through an in-depth analysis of the provenance of the 35 contributions is that the People's Republic of China emerges as a key player in global health, which is documented through its prominent role in research and control of helminth infection and networking throughout Asia. Policy implications are discussed and will hopefully shape the future agenda for the control and elimination of helminth infections the world over.

Evaluation of banked urine samples for the detection of circulating anodic and cathodic antigens in Schistosoma mekongi and S. japonicum infections: a proof-of-concept study

In Asia, Schistosoma japonicum is the predominant schistosome species, while Schistosoma mekongi is confined to limited foci in Cambodia and Lao People's Democratic Republic. While the People's Republic of China has been successful in controlling schistosomiasis, the disease remains a major public health issue in other areas. In order to prioritise intervention areas, not only accurate diagnosis is important but also other factors, such as practicality, time-efficiency and cost-effectiveness, since they strongly influence the success of control programmes. To evaluate the highly specific urine-based assays for the schistosome circulating cathodic antigen (CCA) and the circulating anodic antigen (CAA), banked urine samples from Cambodia (n=106) and the Philippines (n=43) were examined by the upconverted phosphor lateral flow (UCP-LF) CAA assay and the point-of-care (POC)-CCA urine assay. Based on 250 μl urine samples, UCP-LF CAA sensitivity outcomes surpassed a single stool examination by the Kato-Katz technique. The banked urine samples in the current study did not allow the evaluation of larger volumes, which conceivably should deliver considerably higher readings. The sensitivity of a single urine POC-CCA was in the same order as that of a single Kato-Katz thick smear examination, while the sensitivity approached that of triplicate Kato-Katz when a combination of both CAA and CCA assays was used. The promising results from the current proof-of-concept study call for larger investigations that will determine the accuracy of the urine-based CCA and CAA assays for S. mekongi and S. japonicum diagnosis.

A multi-component integrated approach for the elimination of schistosomiasis in the People's Republic of China: design and baseline results of a 4-year cluster-randomised intervention trial

Despite major successes in its control over the past 50years, schistosomiasis japonica continues to be a public health problem in the People's Republic of China (P.R. China). Historically, the major endemic foci occur in the lakes and marshlands along the Yangtze River, areas where transmission interruption has proven difficult. The current endemic situation may alter due to the closure of the Three Gorges Dam. Considerable environmental and ecological changes are anticipated that may result in new habitats for the oncomelanid intermediate snail host of Schistosoma japonicum (Sj), thereby increasing the risk of transmission. The current national control program for P.R. China involves a multi-component integrated strategy but, despite targeting multiple transmission pathways, certain challenges remain. As the Chinese government pushes towards elimination, there is a requirement for additional tools, such as vaccination, for long-term prevention. Whereas the zoonotic nature of schistosomiasis japonica adds to the complexity of control, it provides a unique opportunity to develop a transmission blocking vaccine targeting bovines to assist in the prevention of human infection and disease. Mathematical modelling has shown that control options targeting the various transmission pathways of schistosomiasis japonica and incorporating bovine vaccination, mass human chemotherapy and mollusciciding could lead to its elimination from P.R. China. Here we present the study design and baseline results of a four-year cluster randomised intervention trial we are undertaking around the schistosomiasis-endemic Dongting Lake in Hunan Province aimed at determining the impact on schistosome transmission of the multi-component integrated control strategy, including bovine vaccination using a heterologous "prime-boost" delivery platform based on the previously tested SjCTPI vaccine.

Surveillance-response systems: the key to elimination of tropical diseases

Tropical diseases remain a major cause of morbidity and mortality in developing countries. Although combined health efforts brought about significant improvements over the past 20 years, communities in resource-constrained settings lack the means of strengthening their environment in directions that would provide less favourable conditions for pathogens. Still, the impact of infectious diseases is declining worldwide along with progress made regarding responses to basic health problems and improving health services delivery to the most vulnerable populations. The London Declaration on Neglected Tropical Diseases (NTDs), initiated by the World Health Organization's NTD roadmap, set out the path towards control and eventual elimination of several tropical diseases by 2020, providing an impetus for local and regional disease elimination programmes. Tropical diseases are often patchy and erratic, and there are differing priorities in resources-limited and endemic countries at various levels of their public health systems. In order to identify and prioritize strategic research on elimination of tropical diseases, the 'First Forum on Surveillance-Response System Leading to Tropical Diseases Elimination' was convened in Shanghai in June 2012. Current strategies and the NTD roadmap were reviewed, followed by discussions on how to identify and critically examine prevailing challenges and opportunities, including inter-sectoral collaboration and approaches for elimination of several infectious, tropical diseases. A priority research agenda within a 'One Health-One World' frame of global health was developed, including (i) the establishment of a platform for resource-sharing and effective surveillance-response systems for Asia Pacific and Africa with an initial focus on elimination of lymphatic filariasis, malaria and schistosomiasis; (ii) development of new strategies, tools and approaches, such as improved diagnostics and antimalarial therapies; (iii) rigorous validation of surveillance-response systems; and (iv) designing pilot studies to transfer Chinese experiences of successful surveillance-response systems to endemic countries with limited resources.