Feasible intervention combinations for achieving a safe exit of the Zero-COVID policy in China and its determinants: an individual-based model study.

Background: Although several pathways have been proposed as the prerequisite for a safe phase-out in China, it is not clear which of them are the most important for keeping the mortality rate low, what thresholds should be achieved for these most important interventions, and how the thresholds change with the assumed key epidemiological parameters and population characteristics.

Methods: We developed an individual-based model (IBM) to simulate the transmission of the Omicron variant in the synthetic population, accounting for the age-dependent probabilities of severe clinical outcomes, waning vaccine-induced immunity, increased mortality rates when hospitals are overburdened, and reduced transmission when self-isolated at home after testing positive. We applied machine learning algorithms on the simulation outputs to examine the importance of each intervention parameter and the feasible intervention parameter combinations for safe exits, which is defined as having mortality rates lower than that of influenza in China (14.

Exploring the Local Determinants of SARS-CoV-2 Transmission and Control via an Exposure-Based Model.

A simulation model was developed aimed at assisting local public health authorities in exploring strategies for the suppression of SARS-CoV-2 transmission. A mechanistic modeling framework is utilized based on the daily airborne exposure of individuals defined in terms of inhaled viruses. Comparison of model outputs and observed data confirms that the model can generate realistic patterns of secondary cases.

Modeling liver fluke transmission in northeast Thailand: Impacts of development, hydrology, and control.

Human infection with the Southeast Asian liver fluke Opisthorchis viverrini and liver fluke-associated cholangiocarcinoma cause significant disease burden in Southeast Asia. While there has been considerable work to understand liver fluke pathology and to reduce infection prevalence, there remains a limited understanding of the environmental determinants of parasite transmission dynamics to inform treatment and control programs. A particular setting where targeted control efforts have taken place is the Lawa Lake complex in northeast Thailand.

Low Transmission to Elimination: Rural Development as a Key Determinant of the End-Game Dynamics of Schistosoma japonicum in China.

Rural development has been a critical component of China's economic miracle since the start of economic reform in the early 1980s, both benefiting from and contributing to the nation's rapid economic growth. This development has yielded substantial improvements of public health relevance, including contributing to major reductions in schistosomiasis prevalence. The history of schistosomiasis elimination in Japan suggests that development played a dominant causal role in that nation.

The interplay of climate, intervention and imported cases as determinants of the 2014 dengue outbreak in Guangzhou.

Dengue is a fast spreading mosquito-borne disease that affects more than half of the population worldwide. An unprecedented outbreak happened in Guangzhou, China in 2014, which contributed 52 percent of all dengue cases that occurred in mainland China between 1990 and 2015. Our previous analysis, based on a deterministic model, concluded that the early timing of the first imported case that triggered local transmission and the excessive rainfall thereafter were the most important determinants of the large final epidemic size in 2014.

Preliminary genetic evidence of two different populations of Opisthorchis viverrini in Lao PDR.

Opisthorchis viverrini is a major public health concern in Southeast Asia. Various reports have suggested that this parasite may represent a species complex, with genetic structure in the region perhaps being dictated by geographical factors and different species of intermediate hosts. We used four microsatellite loci to analyze O.

Experimental and modelling investigations of Opisthorchis viverrini miracidia transmission over time and across temperatures: implications for control.

Transmissibility is a significant factor in parasite fitness. The rate and magnitude of parasite transmission affect prevalence and infection intensity in individual hosts and are influenced by environmental factors. In this context, the objectives of this study were: (i) to experimentally assess Opisthorchis viverrini miracidia survival and infectivity over time and across temperatures; and (ii) to combine these experimental results with environmental data to build a key component of a transmission model, identifying seasonal windows of transmission risk in hyper-endemic northeastern Thailand.

Review of "Mathematical Models for Neglected Tropical Diseases: Essential Tools for Control and Elimination, Part B" Edited by Maria-Gloria Basáñez and Roy M. Anderson.

Basáñez MG, Anderson RM, Editors: Mathematical Models for Neglected Tropical Diseases: Essential Tools for Control and Elimination, Part B, Volume 94, Advances in Parasitology, Academic Press; 2016, 430 pages. ISBN: 978-0-12-809971-1.

Exposure versus Susceptibility as Alternative Bases for New Approaches to Surveillance for Schistosoma japonicum in Low Transmission Environments.

Currently, schistosomiasis in China provides an excellent example of many of the challenges of moving from low transmission to the elimination of transmission for infectious diseases generally. In response to the surveillance dimension of these challenges, we here explore two strategic approaches to inform priorities for the development of improved methods addressed specifically to schistosomiasis in the low transmission environment. We utilize an individually-based model and the exposure data used earlier to explore surveillance strategies, one focused on exposure assessment and the second on our estimates of variability in individual susceptibility in the practical context of the current situation in China and the theoretical context of the behavior of transmission dynamics near the zero state.

Climate and the Timing of Imported Cases as Determinants of the Dengue Outbreak in Guangzhou, 2014: Evidence from a Mathematical Model.

As the world's fastest spreading vector-borne disease, dengue was estimated to infect more than 390 million people in 2010, a 30-fold increase in the past half century. Although considered to be a non-endemic country, mainland China had 55,114 reported dengue cases from 2005 to 2014, of which 47,056 occurred in 2014. Furthermore, 94% of the indigenous cases in this time period were reported in Guangdong Province, 83% of which were in Guangzhou City.

Exploring the contribution of host susceptibility to epidemiological patterns of Schistosoma japonicum infection using an individual-based model.

We recently reported the analysis of epidemiological data suggesting variability in individual susceptibility to infection by Schistosoma japonicum among rural villagers who reside in Sichuan Province of southwestern China. By supplementing the data used in the earlier analysis from other studies we have reported from this region, we presented improved estimates of cercarial exposure, which in turn, result in stronger evidence of susceptibility. This analysis was conducted using an individual-based mathematical model (IBM) whose use was motivated by the nature and extent of field data from the low-transmission environments exemplified by one of our datasets and typical of the current situation in most endemic areas of China.

Associations between schistosomiasis and the use of human waste as an agricultural fertilizer in China.

Background: Human waste is used as an agricultural fertilizer in China and elsewhere. Because the eggs of many helminth species can survive in environmental media, reuse of untreated or partially treated human waste, commonly called night soil, may promote transmission of human helminthiases.

Methodology/principal Findings: We conducted an open cohort study in 36 villages to evaluate the association between night soil use and schistosomiasis in a region of China where schistosomiasis has reemerged and persisted despite control activities.

Exploring the impact of infection-induced immunity on the transmission of Schistosoma japonicum in hilly and mountainous environments in China.

Schistosomiasis has long been a threat to villagers in hilly and mountainous areas of southwestern China where the intermediate snail host is abundant. In recent years our group has focused on the development and parameterization of a community-level mathematical model of S. japonicum transmission that accounts for the role of environmental determinants of transmission intensity in Sichuan Province.

Evaluation of an educational intervention on villagers' knowledge, attitude and behaviour regarding transmission of Schistosoma japonicum in Sichuan province, China.

Health education is an important component of efforts to control schistosomiasis. In China, while education programmes have been implemented intensively, few articles in recent years in either the Chinese or English literature report randomised, controlled interventions of the impacts on knowledge, attitudes and behaviours. Thus, we designed and carried out a cluster-randomised controlled education intervention trial that targeted 706 adults from rural areas in 28 villages in Sichuan, China.

Repeated Schistosoma japonicum infection following treatment in two cohorts: evidence for host susceptibility to helminthiasis?

Background: In light of multinational efforts to reduce helminthiasis, we evaluated whether there exist high-risk subpopulations for helminth infection. Such individuals are not only at risk of morbidity, but may be important parasite reservoirs and appropriate targets for disease control interventions.

Methods/principal Findings: We followed two longitudinal cohorts in Sichuan, China to determine whether there exist persistent human reservoirs for the water-borne helminth, Schistosoma japonicum, in areas where treatment is ongoing.

Obesity hypertension: pathophysiological role of leptin in neuroendocrine dysregulation.

Leptin is a 16-kDa peptide hormone that is primarily synthesized and secreted by adipose tissue. One of the major actions of this hormone is the control of energy balance by binding to receptors in the hypothalamus, leading to reduction in food intake, elevation in temperature and energy expenditure. In addition, increasing evidence suggests that leptin, through both direct and indirect mechanisms, may play an important role in cardiovascular and renal regulation.

Modeling the combined influence of host dispersal and waterborne fate and transport on pathogen spread in complex landscapes.

Environmental models, often applied to questions on the fate and transport of chemical hazards, have recently become important in tracing certain environmental pathogens to their upstream sources of contamination. These tools, such as first order decay models applied to contaminants in surface waters, offer promise for quantifying the fate and transport of pathogens with multiple environmental stages and/or multiple hosts, in addition to those pathogens whose environmental stages are entirely waterborne. Here we consider the fate and transport capabilities of the human schistosome Schistosoma japonicum, which exhibits two waterborne stages and is carried by an amphibious intermediate snail host.

[Mathematical modeling as an aid in understanding transmission and control of Schistosoma japonicum in hilly and mountainous regions of China].

Over the past years there has been an increasing trend in the application of mathematical models in the studies and control of infectious disease. With development of computing technologies and increasing access to them, it becomes appealing for public health professionals to use mathematical models in their work. In this paper based on our previous experience working on environmental determinants and control of schistosomiasis in the hilly and mountainous regions of Sichuan Province, we introduce principles and basic procedures in building a mathematical model for schistosomiasis transmission; we then illustrate the use of a mathematical model to integrate data from diverse sources and to aid in designing control strategies, assessing progress, and evaluating surveillance programs.

Toward sustainable and comprehensive control of schistosomiasis in China: lessons from Sichuan.

Triggered by a fascinating publication in the New England Journal of Medicine detailing China's new multi-pronged strategy to control and eventually interrupt the transmission of Schistosoma japonicum, this PLoS Neglected Tropical Diseases Debate critically examines the generalizability and financial costs of the studies presented from the marshlands of the lake region. Edmund Seto from the University of California and colleagues emphasize that the epidemiology and control of schistosomiasis varies according to the social-ecological context. They conjecture that the successful intervention packages piloted in the lake region is not fully fit for the hilly and mountainous environments in Sichuan and Yunnan provinces, and hence call for more flexible, setting-specific, and less expensive control strategies.

Near-infrared spectroscopy monitoring to predict postoperative renal insufficiency following repair of congenital heart disease.

Background: Infants undergoing repair or palliation of congenital heart disease are at risk of renal insufficiency. Development of renal insufficiency increases mortality. This project seeks to determine whether intra- and postoperative renal near-infrared spectroscopy (NIRS) monitoring can reliably predict renal insufficiency after cardiac surgery in infants.

Internal versus external determinants of Schistosoma japonicum transmission in irrigated agricultural villages.

Currently schistosomiasis transmission has been suppressed to low levels in many historically endemic areas of China by widespread use of praziquantel in human and bovine populations and application of niclosamide for snail control. However, re-emergent transmission has signalled the need for sustainable interventions beyond these repeated chemical interventions. To take advantage of ongoing investment in rural infrastructure, an index of schistosomiasis transmission potential is needed to identify villages where environmental modifications would be particularly effective.

Evaluation of mammalian and intermediate host surveillance methods for detecting schistosomiasis reemergence in southwest China.

Background: Schistosomiasis has reemerged in China, threatening schistosomiasis elimination efforts. Surveillance methods that can identify locations where schistosomiasis has reemerged are needed to prevent the further spread of infections.

Methods And Principal Findings: We tested humans, cows, water buffalo and the intermediate host snail, Oncomelania hupensis, for Schistosoma japonicum infection, assessed snail densities and extracted regional surveillance records in areas where schistosomiasis reemerged in Sichuan province.

Polymorphic microsatellites in the human bloodfluke, Schistosoma japonicum, identified using a genomic resource.

Re-emergence of schistosomiasis in regions of China where control programs have ceased requires development of molecular-genetic tools to track gene flow and assess genetic diversity of Schistosoma populations. We identified many microsatellite loci in the draft genome of Schistosoma japonicum using defined search criteria and selected a subset for further analysis. From an initial panel of 50 loci, 20 new microsatellites were selected for eventual optimization and application to a panel of worms from endemic areas.

Obesity hypertension: the regulatory role of leptin.

Leptin is a 16-kDa-peptide hormone that is primarily synthesized and secreted by adipose tissue. One of the major actions of this hormone is the control of energy balance by binding to receptors in the hypothalamus, leading to reduction in food intake and elevation in temperature and energy expenditure. In addition, increasing evidence suggests that leptin, through both direct and indirect mechanisms, may play an important role in cardiovascular and renal regulation.