Extensive disseminated cysticercosis: a case report in Yunnan province, China.

BACKGROUND: Cysticercosis is spreading all over the world and it is a major health problem in most countries of Latin America, Africa, and Asia. Extensive disseminated cysticercosis is relatively rare and fewer than 120 case have been reported in the worldwide. We reported a rare case of extensive disseminated cysticercosis in Yunan province, China. CASE PRESENTATION: A rare case of extensive disseminated cysticercosis, in a 61-year-old male Chinese was detected from Yunnan province in 2018. Clinical and etiological examination was performed, as well as the epidemiological investigation. CONCLUSION: The life cycle of T. solium in the area where the case came from is complete. We expect this case could raise the attentions to the control of Taenia solium infection and subsequent cysticercosis there.

[Gaps in Clonorchiasis Control in China].

Clonorchiasis is currently the most important food-borne parasitic disease in China. In this review, gaps in the control of clonorchiasis in China are explored through problem tree analysis. From the perspective of disease control, clonorchiasis hyper-endemicity is associated with the implicit disease burden, incomplete epidemiological map, unclear epidemiological determinants, and a lack of surveillance and report system. Thus, studies are needed to overcome these problems, to promote clonorchiasis control and elimination in China.

Inducible nitric oxide synthase response and associated cytokine gene expression in the spleen of mice infected with Clonorchis sinensis.

Clonorchis sinensis is a food-borne parasite that induces a permanent increase of nitrosation in the body upon infection. The spleen is an important secondary lymphoid organ for the regulation of immune responses locally and in the whole body. However, the functions and mechanisms of the spleen in nitric oxide (NO) responses after C. sinensis infection remain unknown. In this study, BALB/c mice were infected with 20, 40, and 80 C. sinensis metacercariae to simulate mild, moderate, and severe infections, respectively. We examined the expression of inducible nitric oxide synthase (iNOS) in the spleen and the relevant cytokine transcription in splenocytes from the mice infected with different amounts of metacercariae. The iNOS of the mice infected with 80 metacercariae was expressed in the spleen as early as 10 days post-infection (dpi) and gradually increased until 90 dpi. The iNOS expression in the mice infected with 40 metacercariae was detected only at 45 and 90 dpi, but not in the mice infected with 20 metacercariae. The level of interferon (IFN)-γ messenger RNA (mRNA) transcription in splenocytes significantly increased at 10 and 20 dpi (P < 0.05) in response to mild/moderate infection but gradually decreased to normal levels after 45 dpi. The level of IL-12p35 mRNA transcription did not change at 10 and 20 dpi but significantly decreased after 45 dpi under moderate/severe infection (P < 0.05/0.01/0.001). The level of IL-18 mRNA transcription significantly increased at 10 dpi (P < 0.05/0.01) but significantly decreased after 20 dpi (P < 0.05/0.01/0.001). These results suggest that spleen is an important organ for iNOS/NO responses, which correspond to the severity of C. sinensis infection, but cannot be attributed to the expression of the Th1 cytokines.

Pathological Lesions and Inducible Nitric Oxide Synthase Expressions in the Liver of Mice Experimentally Infected with Clonorchis sinensis.

The nitric oxide (NO) formation and intrinsic nitrosation may be involved in the possible mechanisms of liver fluke-associated carcinogenesis. We still do not know much about the responses of inducible NO synthase (iNOS) induced by Clonorchis sinensis infection. This study was conducted to explore the pathological lesions and iNOS expressions in the liver of mice with different infection intensity levels of C. sinensis. Extensive periductal inflammatory cell infiltration, bile duct hyperplasia, and fibrosis were commonly observed during the infection. The different pathological responses in liver tissues strongly correlated with the infection intensity of C. sinensis. Massive acute spotty necrosis occurred in the liver parenchyma after a severe infection. The iNOS activity in liver tissues increased, and iNOS-expressing cells with morphological differences were observed after a moderate or severe infection. The iNOS-expressing cells in liver tissues had multiple origins.

[Effect of Excretory-secretory Products of Clonorchis sinensis on Nitric Oxide Production and NF-κB Activation in RAW264.7 Mouse Macrophages].

OBJECTIVE: To study the role of excretory-secretory products (ESPs) from Clonorchis sinensis in the production of nitric oxide (NO) and the activation of nuclear transcription factor kappa B (NF-κB) in the macrophages of RAW264.7 mouse. METHODS: 20 µg/ml of C. sinensis EPSs, the organic solvent extracts of EPSs (ESP-ex), and 0.1 µg/ml of lipopolysaccharide from Salmonella minnesota (LPS-SM) were used as stimulators in co-culture with RAW264.7 mouse macrophages as experimental groups. The Hank's balanced salt solution (HBSS) served as control. At the same time the RAW264.7 macrophages were stimulated with EPSs, ESP-ex, and LPS-SM, and then added 0.3 mmol/L of SMT, a specific inhibitor of iNOS as the interference groups. After co-culture for 18 days, the concentrations of NO2- in the culture supernatants were detected with Griess regents, and the activation of NF-κB was determined by transfection with a NF-κB-inducible reporter plasmid, pNiFty2-SEAP. The activities of secreted embryonic alkaline phosphatase (SEAP) in culture supernatants were quantified by using HEK-Blue™ detection medium and expressed as the value of optical density at 620 nm (A620 value). The intercellular activities of SEAP were determined by microscopic observation. RESULTS: After stimulation with both ESPs-ex and LPS-SM, the concentrations of NO2- in culture supernatants were (14.30 ± 1.62) and (14.10 ± 2.17) µmol/L, respectively, which were significantly higher than that of the control [(7.70 ± 0.95) µmol/L] (P < 0.05), and significantly decreased to (8.97 ± 0.81) and (4.96 ± 1.36) µmol/L after adding SMT, respectively (P < 0.05). However, the concentration of NO2- in ESPs stimulation group [(4.06 ± 0.62) µmol/L] was lower than that of the control (P < 0.05), and almost unchanged [(3.99 ± 0.87) µmol/L] after adding SMT (P > 0.05). SEAP activity in ESP group (0.836 ± 0.005) was significantly higher than that of the control [(0.097 ± 0.009) µmol/L] (P < 0.05). A strong blue color reaction was observed in cells of ESP group. SEAP activity of ESPs-ex and LPS groups [(0.112 ± 0.004), (0.116 ± 0.009) µmol/L] was slightly higher than that of the control (P > 0.05), and blue color reaction was observed in some cells. CONCLUSION: ESPs from C. sinensis can stimulate NF-κB activation in RAW264.7 cells. The water-soluble components of ESPs can inhibit the NO production, while ESPs-ex and LPS-SM can promote the NO production.

[SWOT Analysis of the National Survey on Current Status of Major Human Parasitic Diseases in China].

The National Survey on Current Status of Major Human Parasitic Diseases in China has been carried out since 2014 under the organization of the National Health and Family Planning Commission of the People's Republic of China. The National Institute of Parasitic Diseases, Chinese Center for Disease Control and Prevention (NIPD, China CDC) provided technical support and was responsible for quality control in this survey. This study used SWOT method to analyze the strengths, weaknesses, opportunities and threats that were encountered by he NIPD, China CDC during the completion of the survey. Accordingly, working strategies were proposed to facilitate the future field work.

Increasing prevalence and intensity of foodborne clonorchiasis, Hengxian County, China, 1989-2011.

During 1989-2011, three parasitic disease surveys were conducted in Hengxian County, China, where soil-transmitted helminthiases and foodborne clonorchiasis are endemic. We compared the data and found that the prevalence of helminthiases decreased and the prevalence and intensity of clonorchiasis increased over time, especially among men. Clonorchiasis control/intervention measures are urgently needed in this area.

[From recognition to practice: The 140th anniversary of the discovery of Clonorchis sinensis].

It has been the 140th anniversary since the discovery of Clonorchis sinensis, of which adult worms were found by McConnell in an oversea Chinese in Calcutta, India, September of 1874. Then, Japanese scholar Kobayashi proved that freshwater fish served as the second intermediate hosts in 1910, while another Japanese parasitologist Muto found that the first intermediate hosts were freshwater snails in 1918. However, the perniciousness has not been recognized until recently. C. sinensis infection was classified as definite carcinogen (group 1) in cholangiocarcinoma in 2009 by the International Agency for Research on Cancer, WHO, and listed as one of the 17 diseases in WHO's first report on neglected tropical diseases in 2010, while its disease burden was published on line in an international journal in 2011. Nevertheless, our awareness on and practices in the control of clonorchiasis still lag behind the reality. Great efforts on research and control of clonorchiasis are especially required in China, since China takes the biggest share in global disease burden of clonorchiasis.

[Identification of Clonorchis sinensis metacercariae based on PCR targeting ribosomal DNA ITS regions and COX1 gene].

OBJECTIVE: To identify Clonorchis sinensis metacercariae using PCR targeting ribosomal DNA ITS region and COX1 gene. METHODS: Pseudorasbora parva were collected from Hengxian County of Guangxi at the end of May 2013. Single metacercaria of C. sinensis and other trematodes were separated from muscle tissue of P. parva by digestion method. Primers targeting ribosomal DNA ITS region and COX1 gene of C. sinensis were designed for PCR and the universal primers were used as control. The sensitivity and specificity of the PCR detection were analyzed. RESULTS: C. sinensis metacercariae at different stages were identified by PCR. DNA from single C. sinensis metacercaria was detected by PCR targeting ribosomal DNA ITS region and COX1 gene. The specific amplicans have sizes of 437/549, 156/249 and 195/166 bp, respectively. The ratio of the two positive numbers in PCR with universal primers and specific primers targeting C. sinensis ribosomal DNA ITS1 and ITS2 regions was 0.905 and 0.952, respectively. The target gene fragments were amplified by PCR using COX1 gene-specific primers. The PCR with specific primers did not show any non-specific amplification. However, the PCR with universal primers targeting ribosomal DNA ITS regions performed serious non-specific amplification. CONCLUSION: C. sinensis metacercariae at different stages are identified by morphological observation and PCR method. Species-specific primers targeting ribosomal DNA ITS region show higher sensitivity and specificity than the universal primers. PCR targeting COX1 gene shows similar sensitivity and specificity to PCR with specific primers targeting ribosomal DNA ITS regions.

[Research priorities for the control and elimination of major helminthiases].

In 2009, the Disease Reference Group on Helminth Infections (DRG4) was established by the Special Programme for Research and Training in Tropical Diseases (TDR) to comprehensively review recent advances, identify gaps and rank priorities in helminthiases research towards control and elimination. Six major human helminthiases are targeted, namely onchocerciasis, lymphatic filariasis, soil-transmitted helminthiases, schistosomiasis, food-borne trematodiasis and cysticercosis/taeniasis. Systematic reports made by the DRG4 from such aspects as the impact of helminthiases, control and elimination, interventions, diagnostics, social-ecology and health systems, modeling, basic research and capacity building in research was published in PLoS Neglected Tropical Diseases in 2012. Generalized introduction is presented here and further analysis of its influence on the research of the major helminthiases in China is done.

[Enterobius vermicularis infection status among children in 9 provinces/autonomous regions/municipalities of China].

OBJECTIVE: To investigate the infection status of Enterobius vermicularis among children in 9 Provinces/Autonomous regions/Municipalities (P/A/M) of China, and analyze its risk factors. METHOD: From April to December 2011, one provincial capital (prefecture-level city) and one county (city, district) were chosen as investigation spots from Guangdong, Guangxi, Hainan, Chongqing, Sichuan, Zhejiang, Fujian, Anhui and Guizhou, respectively. Children aged 2 to 12 were examined by using adhesive cellophane anal swab with round-bottom tube. Information of children's family condition, health behavior and school environment were collected by questionnairing. RESULTS: 14 964 children were examined, and 14 582 qualified questionnaires were collected. The total prevalence was 17.8% (2 659/14 964). Of the 9 P/A/M, the prevalence was highest in Hainan Province (51.1%, 869/1 701) and lowest in Anhui Province (0.8%, 13/1 589). The prevalence in urban areas (7.3%, 552/7 581) was lower than that of rural areas (28.5%, 2 107/7 383) (chi2 = 1156.73, P < 0.01). The highest prevalence in urban and rural areas was found in Haikou City(38.0%, 322/847) and Wanning City (64.1%, 547/854) of Hainan Province. The prevalence rate in males and females was 17.4% (1 410/8 128) and 18.3% (1249/6 834), respectively (chi2 = 2.192, P > 0.05). The highest prevalence in males (61.2%, 300/490) and females (67.9%, 247/364) was found in children of Wanning City. Multivariate logistic regression analysis showed that residence, education level of parents, occupation of parents, nail biting, types of classroom ground and type of boarding were the risk factors on E. vermicularis infection. CONCLUSION: The prevalence of enterobiasis in children is still high in many areas of China, and the prevention and control measures should be taken according to the risk factors.

Soil-transmitted helminthiasis in mainland China from 2016 to 2020: a population-based study.

Background: Soil-transmitted helminthiasis is epidemic in China and many other countries of the world, and has caused substantial burdens to human health. We conducted successive national monitoring in China from 2016 to 2020 to analyze the prevalence, changing trends, and factors influencing soil-transmitted helminthiasis, which provided a reference for future control strategies. Methods: Soil-transmitted helminth monitoring was carried out in 31 provinces (autonomous regions or municipalities, herein after referred to as "provinces") throughout China. Each province determined the number and location of monitoring sites (counties), and a unified sampling method was employed. At least 1,000 subjects were investigated in each monitoring county. Stool samples were collected and the modified Kato-Katz thick smear method was employed for stool examination. Infection data and the details of factors influencing soil-transmitted helminthiasis from 2016 to 2020 were collected from national monitoring sites. Additional influencing factors such as environment, climate and human activities were obtained from authoritative websites. Prevalence of soil-transmitted helminths was presented by species, province, sex, and age group. ArcGIS software was used to conduct spatial autocorrelation and hotspot analysis on the infection data. A Poisson distribution model and SaTScan software were used to analyze the infection data with retrospective spatiotemporal scan statistics. A database was built by matching village-level infection rate data with influencing factors. Subsequently, machine learning methods, including a Linear Regression (LR), a Random Forest (RF), a Gradient Boosted Machine (GBM), and an Extreme gradient boosting (XGBOOST) model was applied to construct a model to analyze the main influencing factors of soil-transmitted helminthiasis. Findings: The infection rates of soil-transmitted helminths at national monitoring sites from 2016 to 2020 were 2.46% (6,456/262,380), 1.78% (5,293/297,078), 1.29% (4,200/326,207), 1.40% (5,959/424,766), and 0.84% (3,485/415,672), respectively. The infection rate of soil-transmitted helminths in 2020 decreased by 65.85% compared to that in 2016. From 2016 to 2020, the infection rate of soil-transmitted helminthiasis was relatively high in southern and southwestern China, including Hainan, Yunnan, Sichuan, Guizhou, and Chongqing. In general, the infection rate was higher in females than in males, with the highest rate in the population aged 60 years and above, and the lowest in children aged 0-6 years. Global autocorrelation and hotspot analyses revealed spatial aggregation in both the national and local distribution of soil-transmitted helminthiasis in China from 2016 to 2020. The hotspots were concentrated in southwestern China. The spatiotemporal scanning analysis revealed aggregation years from 2016 to 2017 located in southwestern China, including Yunnan, Sichuan, Chongqing, Guizhou and Guangxi. The RF model was the best fit model for the infection rate of soil-transmitted helminths in China. The top six influencing factors of this disease in the model were landform, barefoot farming, isothermality, temperature seasonality, year, and the coverage of sanitary toilets. Interpretation: The overall infection rate of soil-transmitted helminths in China showed a decreasing trend from 2016-2020 due to the implementation of control measures and the economic boom in China. However, there are still areas with high infection rates and the distribution of such areas exhibit spatiotemporal aggregation. As a strategic next step, control measures should be adjusted to local conditions based on the main influencing factors and the prevalence of different sites to aid in the control and elimination of soil-transmitted helminthiasis. Funding: This research was funded by the National Key Research and Development Program of China (Grant Nos. 2021YFC2300800 and 2021YFC2300804) and the National Natural Science Foundation of China (Grant No. 32161143036).

Analysis of the results of two nationwide surveys on Clonorchis sinensis infection in China.

OBJECTIVE: To examine Clonorchis sinensis infection in China and evaluate the effectiveness of efforts to prevent and control it, two nationwide surveys were undertaken in 31 provinces, autonomous regions, and municipalities (PAMs) during 1988-92 (the 1990 survey) and during 2001-04 (the 2003 survey). METHODS: During the period 2001-04, two sampling methods were applied. The first method repeated the stratified cluster random sampling used in the 1990 survey; the second method applied two-characteristic stratified cluster random sampling in 27 PAMs-the 2003 endemic area (EA) survey. The Kato-Katz thick smear method was used for the nationwide survey. RESULTS: The infection rates of Clonorchis sinensis in the 1990 and 2003 surveys were 0.311% and 0.579%, respectively. The infection rate was 2.40% in the 2003 EA survey, and it was estimated that 12.49 million people in China were infected with Clonorchis sinensis. CONCLUSION: The 2003 survey showed that the standardized infection rate of Clonorchis sinensis increased by 74.85% compared with the 1990 survey. The infection rate in males was higher than in females; the infection rate among people eating raw fish or eating out frequently was higher than among those who did not.

Chemotherapy-based control of ascariasis and hookworm in highly endemic areas of China: field observations and a modeling analysis.

OBJECTIVE: Our objective was to systematically evaluate chemotherapy-based control of ascariasis and hookworm infection and make predictions of the effectiveness of repeated mass treatment at different levels of coverage in highly endemic areas of China. METHODS: Field surveys were carried out to acquire the ascariasis and hookworm prevalence and intensity (mean worm burden) at baseline, one month and one year later. We calculated model parameters based on the survey data, then incorporated them into a quantitative framework to predict the prevalence and intensity one year later. Sensitivity analyses were performed to assess the influence of the chemotherapy measures on prevalence and intensity, and model simulations were performed to evaluate the feasibility of achieving the proposed transmission control criteria under different chemotherapy measures. RESULTS: The predicted prevalence and intensity one year from baseline were within the 95% confidence interval of actual values. As treatment frequency or coverage increased, the prevalence and intensity decreased. Model simulations show that many rounds of treatment are needed to maintain the prevalence at a low level in highly endemic areas of China. CONCLUSION: We should select different combinations of treatment frequency, coverage and drug efficacy according to available resources and practical attainable conditions. Mathematical modeling could be used to help optimize the chemotherapeutic scheme aiming at specific parasitic species and areas, and to direct the establishment of soil-transmitted helminthiasis control criteria in China.

[A cross analysis on the capability of examining helminths: national technique competition for parasitic disease diagnosis in 2011].

OBJECTIVE: To understand the comprehensive capability of helminth detection among professionals at different level of parasitic disease control institutions and promote the overall strength of diagnosis. METHODS: Four professionals from each parasitic diseases control institutions were selected as contestant (age < 45 and at least two contestant from county-level institution). The content of contest included making stool slides with Kato-Katz method (five slides in thirty minutes, a total score of 15 and 9 as passing score) and identification of eleven common helminth eggs with microscopy (ten slides, five minutes per slide, a total score of 60, 36 as passing score). RESULTS: The average score of making slides in 119 contestants from 30 provinces was 11.4, and 119 contestants passed accounted for 93.3%. The average score of film-reading was 22.0, and 20 contestants passed accounted for 16.8%. There were no statistically significant differences between the results in different gender, age (< or = 30, 31-40, > 40), job title (the junior, intermediate, and senior), institution level (provincial, municipal, and county level) (P > 0.05). By Kato-Katz slide-making and film-reading, the scores in contestants from provinces with schistosomiasis control task (12.1 +/- 1.7, 32.1 +/- 11.5, respectively) were better than contestants from other provinces (11.1 +/- 1.8, 18.1 +/- 10.5, respectively). The scores in contestants from western (18.4 +/- 11.4) were lower than those from eastern (25.2 +/- 12.4) and central (24.1 +/- 13.1) for film-reading. CONCLUSION: The overall capability of parasitic disease examination is unbalanced among regions, and evidently there is a need to strengthen the capacity of pathogen detection in the disease control programs.

[A cross analysis on the theoretical testing results on diagnosis of common parasitic diseases: national technique competition China].

OBJECTIVE: To understand the theoretical level among technicians from disease control and prevention institutions on basic knowledge of parasitic disease diagnosis. METHODS: A national competition on basic knowledge of parasitic disease detection was organized in September, 2011, with 119 technicians participating from disease control and prevention institutions at province, prefecture or county level in 30 provinces. Database was constructed with the essential information of participants and scores of testing results. T-test or one-way Anova methods were used to analyze the scores by gender, age, professional title, institutions and places of participants. RESULTS: The scores of the competitors were in the range of 40-93 with an average value of 66.37 +/- 11.80 and a passing rate of 74.95%. No difference was shown by gender, age and professional tide (P > 0.05). Except the knowledge of helminth detection, the score on the knowledge in other aspects was higher among the technicians from provinces with control activities of schistosomiasis and other parasitic infections than those from provinces without the control activities (P < 0.05). The same was true in technicians from areas with or without malaria control activities (P < 0.05). CONCLUSION: The level of basic knowledge on parasite detection is low in general among technicians at the institutions of parasitic disease control, and therefore, training needs to be strengthened.

National surveillance of hookworm disease in China: A population study.

BACKGROUND: Hookworm disease is endemic in China and is widespread globally. The disease burden to humans is great. METHODS: The study described the national surveillance of hookworm implemented in 31 provinces/autonomous regions/municipalities (P/A/Ms) of China in 2019. Each P/A/M determined the number and location of surveillance spots (counties). A unified sampling method was employed, and at least 1000 subjects were investigated in each surveillance spot. The modified Kato-Katz thick smear method was employed for stool examination. Fifty samples positive with hookworm eggs were cultured in each surveillance spot to discriminate species between A. duodenale and N. americanus. Twenty-five soil samples were collected from each surveillance spot and examined for hookworm larva. The 2019 surveillance results were analyzed and compared with that of 2016-2018. RESULTS: A total of 424766 subjects were investigated in 31 P/A/Ms of China in 2019, and the overall hookworm infection rate was 0.85% (3580/424766). The weighted infection and standard infection rates were 0.66% (4288357/648063870) and 0.67% (4343844/648063870), respectively. Sichuan province had the highest standard infection rate (4.75%) in 2019, followed by Chongqing (2.54%) and Hainan (2.44%). The standard infection rates of other P/A/Ms were all below 1%, with no hookworm detected in 15 P/A/Ms. The standard hookworm infection rate in the males and the females were 0.61% (2021216/330728900) and 0.71% (2267141/317334970), respectively, with a significant difference between different genders ([Formula: see text] = 17.23, P<0.0001). The highest standard hookworm infection rate (1.97%) was among age ≥ 60 years, followed by 45~59 years (0.77%), 15~44 years (0.37%), and 7~14 years (0.20%). The lowest standard infection rate was among the 0~6 years age group (0.12%). A significant difference was observed among different age groups ([Formula: see text] = 2 305.17, P<0.0001). The constitute ratio for N. americanus, A. duodenale, and coinfection was 78.70% (1341/1704), 2.03% (346/1704), and 1.00% (17/1704), respectively. The detection rate of hookworm larva from soil was 3.45% (71/2056). CONCLUSION: The national surveillance showed that the hookworm infection rate has been decreasing annually from 2016 to 2019, and it is now below 1%. China has made significant progress in controlling hookworm. The national surveillance system is an important way to understand the endemic status and provide important information in this process and thus needs to be continually optimized.

[Strengthening the research on clonorchiasis in China].

Liver flukes mainly include Clonorchis sinensis, Opisthorchis viverrini, and Opisthorchis felineus. The international congress of liver flukes was held in Khon Kaen, Thailand, during 7-8th March, 2011. The congress assembled a wide array of studies and reflected the current status of research, control and prevention of liver flukes in the world. This paper summarizes basic information from the meeting. Meanwhile, based on the research status and needs for control and prevention, priorities of research on clonorchiasis in China are discussed.

Cost yield of different treatment strategies against Clonorchis sinensis infection.

BACKGROUND: Clonorchiasis is attributed to the ingestion of raw freshwater fish harboring Clonorchis sinensis. Morbidity control is targeted through the administration of antihelminthics. This study modelled the cost yield indicated by effectiveness and utility of different treatment strategies against clonorchiasis. METHODS: About 1000 participants were enrolled from each of 14 counties selected from four provincial-level administrative divisions namely Guangxi, Guangdong, Heilongjiang and Jilin in 2017. Fecal examination was adopted to detect C. sinensis infection, while behavior of ingesting raw freshwater fish was enquired. Counties were grouped into four categories based on prevalence, namely low prevalence group (< 1%), moderate prevalence group (1-9.9%), high prevalence group (10-19.9%) and very high prevalence group (≥ 20%), while population were divided into three subgroups, namely children aged below 14 years old, adult female and adult male both aged over 14 years old. The average of cost effectiveness indicated by the cost to treat single infected cases with C. sinensis and of cost utility indicated by the cost to avoid per disability-adjusted life years (DALYs) caused by C. sinensis infection was calculated. Comparisons were performed between three treatment schedules, namely individual treatment, massive and selective chemotherapy, in which different endemic levels and populations were considered. RESULTS: In selective chemotherapy strategy, the cost to treat single infected case in very high prevalence group was USD 10.6 in adult male, USD 11.6 in adult female, and USD 13.2 in children. The cost increased followed the decrease of endemic level. In massive chemotherapy strategy, the cost per infected case in very high prevalence group was USD 14.0 in adult male, USD 17.1 in adult female, USD 45.8 in children, which were also increased when the endemic level decreased. In individual treatment strategy, the cost was USD 12.2 in adult male, USD 15.0 in adult female and USD 41.5 in children in very high prevalence group; USD 19.2 in adult male, USD 34.0 in adult female, and USD 90.1 in children in high prevalence group; USD 30.4 in adult male, USD 50.5 in adult female and over USD 100 in children in moderate prevalence group; and over USD 400 in any population in low prevalence group. As to cost utility, the differences by treatment strategies, populations and endemic levels were similar to those in cost effectiveness. CONCLUSIONS: Both cost effectiveness and cost utility indicators are highly impacted by the prevalence and population, as well as the treatment schedules. Adults especially men in the areas with a prevalence over 10% should be prioritized, in which selective chemotherapy was best and massive chemotherapy was also cost effective. In moderate endemic areas, the yield is not ideal, but selective chemotherapy for adult male may also be adopted. In low endemic areas, all strategies were high costly and new strategies need to be developed.

Severe hepatobiliary morbidity is associated with Clonorchis sinensis infection: The evidence from a cross-sectional community study.

Clonorchis sinensis infection is highly prevalent in Asia. Diverse hepatobiliary morbidity has been documented for C. sinensis infection. This study aimed to assess the association between C. sinensis infection and hepatobiliary morbidity, taking into consideration of the control, confounders and infection intensity. A cross-sectional community survey was implemented in Hengxian county, southeastern China. Helminth infections were detected by fecal examination. Physical examination and abdominal ultrasonography were then conducted. After excluding confounding effects from gender, age and alcohol drinking, quantitative association between C. sinensis infection and hepatobiliary morbidity was assessed, and the effect from infection intensity was also evaluated, through adjusted odds ratio (aOR) and 95% confidence intervals (95% CI). 696 villagers older than 10 years were enrolled. The prevalence and infection intensity of C. sinensis were higher in male, elder people and the individuals consuming alcohol. Light C. sinensis infection was associated with the increase of diarrhoea (aOR: 2.2, 95% CI: 1.1-4.5). C. sinensis infection was associated with the increase of fatty liver (aOR: 2.7, 95% CI: 1.4-5.2), and the effect was similar in different infection intensities. Moderate C. sinensis infection was associated with the increase of gallbladder stone (aOR: 3.0, 95% CI: 1.1-8.6), while moderate and heavy infections with the increase of intrahepatic bile duct dilatation (aOR: 2.2, 95% CI: 1.0-4.9 and aOR: 4.3, 95% CI: 1.9-9.9, respectively). C. sinensis infection had an effect on the development of periductal fibrosis (aOR: 3.2, 95% CI: 2.1-4.9), which showed increasing trend by infection intensity. The length and width of gallbladder in those with C. sinensis infection were enlarged, especially in those over 30 years old. C. sinensis infection is significantly associated with hepatobiliary morbidity. The occurrence of some morbidity was strongly related to the infection intensity. Awareness on harm of clonorchiasis should be raised both for policy-makers and villagers to adopt effective interventions.