Frontiers of parasitology research in the People's Republic of China : infection, diagnosis, protection and surveillance

ABSTRACT: Control and eventual elimination of human parasitic diseases in the People's Republic of China (P.R. China) requires novel approaches, particularly in the areas of diagnostics, mathematical modelling, monitoring, evaluation, surveillance and public health response. A comprehensive effort, involving the collaboration of 188 scientists (<85% from P.R. China) from 48 different institutions and universities (80% from P.R. China), covers this collection of 29 articles published in Parasites & Vectors. The research mainly stems from a research project entitled 'Surveillance and diagnostic tools for major parasitic diseases in P.R. China' (grant no. 2008ZX10004-011) and highlights the frontiers of research in parasitology. The majority of articles in this thematic series deals with the most important parasitic diseases in P.R. China, emphasizing Schistosoma japonicum, Plasmodium vivax and Clonorchis sinensis plus some parasites of emerging importance such as Angiostrongylus cantonensis. Significant achievements have been made through the collaborative research programme in the following three fields: (i) development of control strategies for the national control programme; (ii) updating the surveillance data of parasitic infections both in human and animals; and (iii) improvement of existing, and development of novel, diagnostic tools to detect parasitic infections. The progress is considerable and warrants broad validation efforts. Combined with the development of improved tools for diagnosis and surveillance, integrated and multi-pronged control strategies now pave the way for elimination of parasitic diseases in P.R. China. Experiences and lessons learned can stimulate control and elimination efforts of parasitic diseases in other parts of the world

The use of morbidity questionnaires to identify communities with high prevalences of schistosome or geohelminth infections in Tanzania

Parasitic infections were investigated in Morogoro Rural District, Tanzania, between October 1992 and June 1993. A total of 4589 schoolchildren (aged 7-17 years) from 30 primary schools was screened for infection with Ascaris lumbricoides, Trichuris trichiura, hookworms (3456 children only), Schistosoma mansoni and S. haematobium. The children were also asked about their recent experiences of the following: diarrhoea, abdominal pain, blood in stool, perception of suffering from schistosomiasis, and worm infection and examined for spleen and liver enlargement. Among schools, there were correlations between the prevalence of S. mansoni infection and bloody stools, spleen enlargement and liver enlargement, and between S. haematobium infection and the presence of blood in urine. To exclude ecological explanations for the correlations, logistic regression was used to estimate the adjusted odds ratio (OR) for each infection and each sign or symptom. No sign or symptom was significantly associated with any geohelminth infection. Reported blood in stool was significantly associated with S. mansoni infection (OR = 1·62, P = 0·045). Reported blood in urine was significantly associated with S. haematobium infection (OR = 7·71, P < 0·001), as was reported blood in stool (OR = 11·52, P < 0·001), indicating that presence of blood in either form of excreta was related to the local term for schistosomiasis. These results support the possibility of using reported blood in stool as a means of rapid assessment for identifying communities with a high prevalence of S. mansoni infectio

Health impact assessment of industrial development projects: a spatio-temporal visualization

Development and implementation of large-scale industrial projects in complex eco-epidemiological settings typically require combined environmental, social and health impact assessments. We present a generic, spatio-temporal health impact assessment (HIA) visualization, which can be readily adapted to specific projects and key stakeholders, including poorly literate communities that might be affected by consequences of a project. We illustrate how the occurrence of a variety of complex events can be utilized for stakeholder communication, awareness creation, interactive learning as well as formulating HIA research and implementation questions. Methodological features are highlighted in the context of an iron ore development in a rural part of Afric

Blood gene transcript signature profiling in pregnancies resulting in preterm birth: a systematic review

To pursue a systematic review and summarise the current evidence for the potential of transcriptome molecular profiling in investigating the preterm phenotype.; We systematically reviewed the literature, using readily available electronic databases (i.e. PubMed/Medline, Embase, Scopus and Web of Science) from inception until March 2020 to identify investigations of maternal blood-derived RNA profiling in preterm birth (PTB). Studies were included if circulating coding or non-coding RNA was analysed in maternal blood during pregnancy and/or at delivery. Interventional trials were not included. The primary outcome was the availability of whole genome expression patterns evaluated in pregnancies resulting in preterm deliveries.; A total of 35 articles were included in the final analysis. Most of the studies were conducted in high-income countries and published in the last decade. Apart from spontaneous PTB, a variety of phenotypes leading to preterm delivery were reported. Differences in sampling methods, target gene selection and laboratory protocols severely limited any quantitative comparisons. Most of the studies revealed that gene expression profiling during pregnancy has high potential for identifying women at risk of spontaneous and/or non-spontaneous PTB as early as in the first trimester.; Assessing maternal blood-derived transcriptional signatures for PTB risk in pregnant women holds promise as a screening approach. However, longitudinally followed, prospective pregnancy cohorts are lacking. These are relevant for identifying causes leading to PTB and whether prediction of spontaneous PTB or co-morbidities associated with PTB is achievable. More emphasis on widely employed standardised protocols is required to ensure comparability of results

Improved detection of intestinal helminth infections with a formalin ethyl-acetate-based concentration technique compared to a crude formalin concentration technique

Intestinal helminth infections are the most prevalent neglected tropical diseases, predominantly affecting rural and marginalised populations. The mainstay of diagnosis is the microscopic examination of faecal samples to detect parasites in the form of eggs, larvae and cysts. In an effort to improve the standard of care, the comparative accuracy in detecting helminth infections of the hitherto used formalin-based concentration method (FC) was compared to a previously developed formalin ethyl-acetate-based concentration technique (FECT), prior to the systematic deployment of the latter at a research and humanitarian unit operating on the Thailand-Myanmar border. A total of 693 faecal samples were available for the comparison of the two diagnostic methods. The FECT was superior in detecting hookworm, Trichuris trichiura and small liver flukes. Interestingly, there was no significant difference for Ascaris lumbricoides, possibly due to the high observed egg density. Despite the minor increase in material cost and the fact that the FECT is somewhat more time consuming, this method was implemented as the new routine technique

Environmental determinants of access to shared sanitation in informal settlements: a cross-sectional study in Abidjan and Nairobi

BACKGROUND: Universal access to basic sanitation remains a global challenge, particularly in low- and middle-income countries. Efforts are underway to improve access to sanitation in informal settlements, often through shared facilities. However, access to these facilities and their potential health gains-notably, the prevention of diarrheal diseases-may be hampered by contextual aspects related to the physical environment. This study explored associations between the built environment and perceived safety to access toilets, and associations between the latter and diarrheal infections. METHODS: A cross-sectional study was carried out between July 2021 and February 2022, including 1714 households in two informal settlements in Abidjan (Cote d'Ivoire) and two in Nairobi (Kenya). We employed adjusted odds ratios (aORs) obtained from multiple logistic regressions (MLRs) to test whether the location of the most frequently used toilet was associated with a perceived lack of safety to use the facility at any time, and whether this perceived insecurity was associated with a higher risk of diarrhea. The MLRs included several exposure and control variables, being stratified by city and age groups. We employed bivariate logistic regressions to test whether the perceived insecurity was associated with settlement morphology indicators derived from the built environment. RESULTS: Using a toilet outside the premises was associated with a perceived insecurity both in Abidjan [aOR = 3.14, 95% confidence interval (CI): 1.13-8.70] and in Nairobi (aOR = 57.97, 95% CI: 35.93-93.53). Perceived insecurity to access toilets was associated with diarrheal infections in the general population (aOR = 1.90, 95% CI: 1.29-2.79 in Abidjan, aOR = 1.69, 95% CI: 1.22-2.34 in Nairobi), but not in children below the age of 5 years. Several settlement morphology features were associated with perceived insecurity, namely, buildings' compactness, the proportion of occupied land, and angular deviation between neighboring structures. CONCLUSIONS: Toilet location was a critical determinant of perceived security, and hence, must be adequately addressed when building new facilities. The sole availability of facilities may be insufficient to prevent diarrheal infections. People must also be safe to use them. Further attention should be directed toward how the built environment affects safety

Non-optimal apparent temperature and cardiovascular mortality: the association in Puducherry, India between 2011 and 2020

BACKGROUND: Cardiovascular diseases (CVDs), the leading cause of death worldwide, are sensitive to temperature. In light of the reported climate change trends, it is important to understand the burden of CVDs attributable to temperature, both hot and cold. The association between CVDs and temperature is region-specific, with relatively few studies focusing on low-and middle-income countries. This study investigates this association in Puducherry, a district in southern India lying on the Bay of Bengal, for the first time. METHODS: Using in-hospital CVD mortality data and climate data from the Indian Meteorological Department, we analyzed the association between apparent temperature (T(app)) and in-hospital CVD mortalities in Puducherry between 2011 and 2020. We used a case-crossover model with a binomial likelihood distribution combined with a distributed lag non-linear model to capture the delayed and non-linear trends over a 21-day lag period to identify the optimal temperature range for Puducherry. The results are expressed as the fraction of CVD mortalities attributable to heat and cold, defined relative to the optimal temperature. We also performed stratified analyses to explore the associations between T(app) and age-and-sex, grouped and considered together, and different types of CVDs. Sensitivity analyses were performed, including using a quasi-Poisson time-series approach. RESULTS: We found that the optimal temperature range for Puducherry is between 30 degrees C and 36 degrees C with respect to CVDs. Both cold and hot non-optimal T(app) were associated with an increased risk of overall in-hospital CVD mortalities, resulting in a U-shaped association curve. Cumulatively, up to 17% of the CVD deaths could be attributable to non-optimal temperatures, with a slightly higher burden attributable to heat (9.1%) than cold (8.3%). We also found that males were more vulnerable to colder temperature; females above 60 years were more vulnerable to heat while females below 60 years were affected by both heat and cold. Mortality with cerebrovascular accidents was associated more with heat compared to cold, while ischemic heart diseases did not seem to be affected by temperature. CONCLUSION: Both heat and cold contribute to the burden of CVDs attributable to non-optimal temperatures in the tropical Puducherry. Our study also identified the age-and-sex and CVD type differences in temperature attributable CVD mortalities. Further studies from India could identify regional associations, inform our understanding of the health implications of climate change in India and enhance the development of regional and contextual climate-health action-plans