Effect of integrated control intervention on soil-transmitted helminth infections in Jiangxi province in southeast China.

Soil transmitted helminths (STHs) burden was enormous in China several decades ago, however, rigorous control efforts have been successful with appreciable reduction in diseases burden. Here, we assessed provincial-level data derived from cross sectional surveys, executed in 1989, 2002 and 2014, on the prevalence of STHs among populations in Jiangxi province, China. This study, also, reported STHs integrated control intervention aimed at reducing STHs transmission and worm burden among population at county-level. The intervention strategies included mass drug administration (MDA), health education, improved water supply for drinking, improved sanitary facilities and environmental modification in Guixi municipality. The overall infection rate of STHs in Jiangxi province decreased from 77.7% (1989) to 6.3% (2014), while Ascaris lumbricoides, hookworm and Trichuris trichiura decreased from 71.1%, 17.6% and 17.0% (1989) to 0.9%, 4.7% and 1.0% (2014), respectively. STHs infection rates in female population were higher than male in the three surveys. Reduction in STHs prevalence was observed in all age groups, but the decline was less in higher age group. STHs prevalence in Guixi intervention region indicated remarkable reduction from 31.8% (2006) to 6.1% (2009) (χ2＝255.22, P＜0.01). A. lumbricoides, hookworm and T. trichiura infection rates decreased from 10.4%, 17.0% and 7.1% (2006) to 0.1%, 4.1% and 2.2%, respectively (2009) (X2A.l = 110.23, P<0.01; X2hk = 103.57, P < 0.01; X2T.t = 32.0, P < 0.01). A. lumbricoides infection rate declined the most of all STHs. Following control efforts with integrated control intervention strategies, STHs prevalence in Jiangxi province experienced remarkable trend in decline between 1989 and 2014. Consolidating control efforts with sustained integrated control strategies is, therefore, important to achieving STHs elimination in China.

[Evaluation on molluscicidal effect of chlorosalicylicamide on Oncomelania hupensis in schistosomiaisis endemic areas of eight provinces in China].

OBJECTIVE: To evaluate the effects of a novel molluscicide, the salt quinoid-2', 5-dichloro-4'-nitrosalicylanilide from niclosamide (LDS), with 10% wettable powder, in main schistosomiasis epidemic areas of China, including Hunan, Jiangxi, Hubei, Anhui, Jiangsu, Sichuan, Yunnan and Zhejiang Province. METHODS: In the immersion test, 6 effective concentrations of 10% LDS were tested respectively: 0.1, 0.2, 0.4, 0.6, 0.8, 1.0 g/m3 in the field; at the same time, 50% wettable powder of niclosamide ethanolamine salt (WPN) with effective concentrations of 1.0 g/m was used as the molluscicide control, and the fresh water as the blank control, then the mortality rates of 0. hupensis snails were recorded at 24 h, 48 h and 72 h after the immersion. In the spraying test and powder-spraying test, 5 effective dosages of 10% LDS were tested respectively: 0.2, 0.4, 0.6, 0.8, 1.0 g/m2, while 50% WPN 1.0 g/m2 was used as the molluscicide control, and the fresh water as the blank control in the field for 1 d, 3 d and 7 d, then the mortality rates of O. hupensis snails were recorded at 1 d, 3 d and 7 d after the spraying and powder-spraying. RESULTS: The snail mortality rates of LDS using the immersion test for 72 h were more than 95% in the field of eight provinces (0.1 g/m in Sichuan, Jiangxi, Jiangsu and Zhejiang provinces, 0.2 g/m3 in Yunnan, Hunan and Hubei provinces, and 0.4 g/min Anhui Province); the snail mortality rates of LDS using the spraying test for 7 d were more than 85% (0.2 g/m2 in Hunan, Hubei, Jiangxi and Zhejiang provinces, 0.4 g/m2 in Sichuan and Anhui provinces, 0.6 g/m2 in Yunnan and Jiangsu provinces). The snail mortality rates of LDS the powder-spraying test for 7 d were more than 85% (0.6 g/m2 in Yunnan, Sichuan, Hubei, Jiangxi, Anhui, Jiangsu and Zhejiang provinces). According to the standards of "Efficacy test methods and evaluation of molluscicide for pesticide registration (NY/T 1617-2008)", LDS is a qualified molluscicide. CONCLUSIONS: LDS has good molluscicidal effects through the immersion, spraying and powder-spraying test in the fields. It is suitable for a variety of environments to control O. hupensis snails of schistosomiasis endemic areas in China. The recommended dosages of LDS are 0.1-0.2 g/m3 by the immersion method, 0.2-0.4 g/m2 by the spraying method, and 0.4-0.6 g/m2 by the powder-spraying method in the fields.

Pilot Study on Interferon-γ-producing T Cell Subsets after the Protective Vaccination with Radiation-attenuated Cercaria of Schistosoma japonicum in the Miniature Pig Model.

CLAWN miniature pig has been shown to serve as a suitable host for the experimental infection of Schistosoma japonicum. In this study, we found that radiation-attenuated cercaria (RAC) vaccine gave CLAWN miniature pigs protective immunity against subsequent challenge infection with S. japonicum cercaria. To characterize the protective immune response of the pig model vaccinated by attenuated cercaria, flow cytometric analysis of the reactive T cell subsets was performed. The intracellular interferon (IFN)-γ and the cell surface markers revealed the peripheral blood CD3+ T-lymphocytes produced significant amounts of IFN-γ during the immunization period and after the challenge infection. CD4+ αß-T cells as well as CD4+/CD8α(mid) double positive and/or CD8α(high) αß-T cells were the major IFN-γ-producing CD3+ T cells. On the contrary, γδ T cells did not produce intracellular IFN-γ. Our results suggested that RAC-vaccinated miniature pigs showed effective protective immunity through the activation of αß T cells bearing antigen specific T-cell receptors but not through the activation of γδ T cells.

[Analysis of characteristics of schistosome cercarial infested water contacts of residents in Poyang Lake endemic areas after operation of Three Gorges Project].

OBJECTIVE: To understand the characteristics of schistosome cercarial infested water contact of residents in Poyang Lake endemic areas after the operation of Three Gorges Project, so as to provide the evidence for formulating a well-directed control strategy. METHODS: The residents in two villages in schistosomiasis endemic areas were selected and surveyed for their activities of infested water contacts by questionnaire. RESULTS: The proportion and frequency of infested water contacts of residents in Poyang Lake region were high and the average rate of infested water contacts was 69.77%, and 98.96% of infested water contacts occurred in spring, summer and autumn. The main ways of infested water contacts were fishing/swimming/playing for adult men, washing clothes/fishing for adult women, and swimming/playing for school children, respectively. The rates of infested water contacts were 73.33%, 71.63% and 61.87% in adult men, women and school children, respectively. The frequencies of infested water contacts > 1 time/week, 1 time/week-1 time/month, and < 1 time/month were 62.61%, 23.74% and 13.66% respectively. CONCLUSIONS: The infested water contacts mainly occurs in spring, summer and autumn, and the main way of infested water contacts was fishing. Farming and mowing grass, which had been the primary way, now become the secondary way for the adult residents.

[Studies on changes of vegetation and Oncomelania hupensis snails in Poyang Lake after impoundment of Three Gorges Project].

OBJECTIVE: To explore the impact and change regularity of Oncomelania hupensis snails and vegetation in the marshlands of Poyang Lake caused by the impoundment of the Three Gorges Project. METHODS: By using the methods of stratified systematic sampling and pinpoint navigation, the succession of vegetation was observed and the distribution of O. hupensis snails was investigated in a period of 8 years on 4 typical marshlands in Poyang Lake. The regularity of changes in vegetation and 0. hupensis snails was analyzed on the marshlands at high, medium and low elevations, respectively. RESULTS: After the impoundment of Three Gorges Project, the average flooding days of these 4 marshlands in 2004 and in 2008 were reduced of 74.8 and 65.8 days compared with those in 2002, the year just before the impoundment of the project, respectively. The change of spatial distribution pattern and the succession of dominant species of vegetation on the marshlands of Poyang Lake have taken place since 2005, and several vegetations showed a trend of moving toward the center of the lake. The hygrophilous vegetation has degenerated and gradually been replaced by mesophily meadow in the marshland area above 14 m elevation. Carex, Phalaris arundinacea and Polygonum appeared in large area and expanded slowly towards the center of the lake on the marshland below 14 m elevation. O. hupensis snails were mostly found under the Carex association. The tendency of decreasing in density of snails and of migration of snail habitats towards low terrain was observed. CONCLUSIONS: The impoundment of Three Gorges Project has had a significant impact on hydrological regimes, and a new succession of vegetation has taken place in the marshlands of Poyang Lake. O. hupensis snails and the mesophily vegetation show a trend of migrating slowly to the areas of low elevation in the marshlands.

Immune responses result in misdiagnosis of Schistosoma japonicum by immunodiagnosis kits in egg-positive patients living in a low schistosomiasis transmission area of China.

BACKGROUND: In recent field surveys, we failed to detect the presence of specific antibody against Schistosoma japonicum in some egg-positive patients by commonly used immunodiagnostic kits. To find out whether low levels of specific antibody truly exist among egg-positive individuals and elucidate the underlying immune mechanisms, we carried out a cross-sectional epidemiologic study in a S. japonicum low transmission endemic area of Poyang Lake region, China and compared the humoral and cellular immune characteristics between S. japonicum high and low antibody responders. METHODS: Kato-Katz thick smear assay was used to determine the schistosomiasis status of 3,384 participants residing in two Poyang Lake region villages, Jiangxi, China. Among the 142 stool egg-positive participants, we identified low and high S. japonicum antibody responders with soluble egg antigen (SEA) and adult worm antigen (AWA) specific IgG levels by adopting ROC curve analysis. To compare the humoral and cellular immune responses between high and low S. japonicum antibody responders, serum specific antibody levels as well as the percentage of T lymphocyte subpopulation in PMBC, and cell stimulated cytokines (IFN- gamma and interlukin-10) were detected. RESULTS: Eight S. japonicum egg-positive participants were defined as low antibody responders. Although the percentage of CD3⁺T cells in low responders was slightly higher and the percentage of CD4⁺ T cells, CD8⁺ T cells, the ratio of CD4⁺/CD8⁺ and CD4⁺ CD25⁺ Treg cells were lower than those in high responders, the differences between the two groups were not significant (P > 0.05). AWA -stimulated interlukin-10 level was significantly higher in high responders, while other cytokines did not show differences between two groups. For antibody profiles, except AWA specific IgA, significant differences of each antibody isotype between low and high responders were detected (P < 0.05). CONCLUSIONS: Our study confirmed that there are S. japonicum antibody low responders among schistosome egg-positive residents in S. japonicum low-transmission areas in China. Thus, mis-diagnosis using immune-diagnosis kits do exist. Significant differences of responding antibody levels between low and high responders were detected, while no major cellular response changes were observed.

[Studies on impact of Water Conservancy Project of Poyang Lake on schistosomiasis transmission I: impact of water level regulation schemes of project on Oncomelania hupensis snail habitats].

OBJECTIVE: To investigate the impact of the Water Conservancy Project of Poyang Lake after operation on Oncomelania hupensis snail habitats in 10 counties (cities or districts) around Poyang Lake. METHODS: The data of the distribution, numbers, areas, elevation and slope, etc. of snail infested marshlands on upstream of the project site in Poyang Lake were investigated and collected. Accordingly, the status of the submerged and flooding areas of the marshlands were analyzed and calculated respectively in the case that the project ran by different water regulation schemes at 14, 13, 12 m and 11 m levels. RESULTS: In accordance with the regulation and storage preset programs at 14, 13, 12 and 11 m water levels, the number and its areas of submerged marshlands, from downstream to upstream in Poyang Lake, in turn decreased. Under the condition of the regulation at the 14 m water level, the numbers of completely submerged and partially submerged marshlands as well as the submerged areas were accounted for 32.9%, 51.4% and 60.3% of the whole marshlands, respectively. At the 13 m water level regulation, they were 9.8%, 46.8% and 1.9% respectively. At the 11 m level, only part of 4 marshlands were flooded, which were accounted for only 0.5% of the total number of marshlands and 0.2% of whole areas of the marshlands. CONCLUSIONS: The Water Conservancy Project of Poyang Lake may create a condition for eliminating snails through water flooding. If implementing regulation at the 14 m level for two or three consecutive years, 60.3% of snail habits could realize the snail-free objective. However, if implementing the 11 m or 10 m water level regulation, there will be little impact on areas of snail habitats and the snail distribution in the Poyang Lake region from the point of view of "marshlands flooding". The impacts on marshlands in different counties might differ due to the location and elevation.

[Assessment and analysis of risks of realizing schistosomiasis transmission control in Jiangxi Province].

OBJECTIVE: To evaluate the situation of realizing schistosomiasis transmission control in Jiangxi Province. METHODS: The situation of reaching the criteria of schistosomiasis transmission control was evaluated by using the method of field surveys combined with retrospective investigations. RESULTS: The schistosome infection in human was kept at a stable low level, and the infection rate in residents was below 1% in 90.24% (536/594) of whole epidemic controlled villages. There were 45 spots with schistosome infected Oncomelania hupensis snails in 38 pieces of marshland. The epidemic situation in livestock showed less optimistic than that in human, and the infection rate in bovine was higher than 1% in 19.87% (118/594) of the whole epidemic controlled villages. CONCLUSIONS: Currently, the prevalence of schistosomiasis is at a low level in 9 infection-controlled counties of Jiangxi Province. More favorable situation has emerged to the realization of schistosomiasis transmission control. However, it is necessary to strengthen the infectious sources control with emphasis on bovine so as to achieve the goal of transmission control in whole province in 2015.

A mathematical model for the transmission of Schistosoma japonicum in consideration of seasonal water level fluctuations of Poyang Lake in Jiangxi, China.

BACKGROUND: Poyang Lake, the largest fresh water lake in China, is the major transmission site of Schistosoma japonicum in China. Epidemics of schistosomiasis japonica have threatened the health of residents and stunted social-economic development there. OBJECTIVE: This article aims at evaluating the effect of various control measures against schistosomiasis: selective mass treatment (ST), targeted mass treatment (TT), mass treatment for animal reservoirs (MT), and health education (HE), on reduction of the prevalence through simulations based on a mathematical model. METHODS: We proposed a mathematical model, which is a system of ordinary differential equations for the transmission of S. japonicum among humans, bovines, and snails. The model takes into account the seasonal variation of the water level of Poyang Lake that is caused by the backflow of the Yangtze River and inflow from five small rivers, which influences the transmission of S. japonicum. For the purpose of dealing with the age-specific prevalence and intensity of infection, the human population was classified into four age categories in the model. We carried out several simulations resulting from the execution of ST and TT for elementary school children (E Sch), and combinations of ST, MT, and HE. RESULTS: The simulations indicated that all of the control measures only for humans had a trend of revival after interruption, and a combination of ST and MT has a significant effect on reducing human infection. Although TT and HE had a significant effect on the prevalence in the E Sch group, it had little effect on the overall human population. CONCLUSION: The simulations indicate that measures targeted to bovines such as chemotherapy besides humans will be vital to eliminate the transmission of S. japonicum in the Poyang Lake region. Moreover, it is desirable to improve health education for fishermen and herdsmen.

[Prevalence and control of schistosomiasis in Jiangxi Province during 2002-2012].

OBJECTIVE: To analyze the status of prevalence and control of schistosomiasis in Jiangxi Province from 2002 to 2012. METHODS: Endemic status and control effectiveness during the period from 2002 to 2012 was analyzed by using a combination of field survey, data collection and retrospective investigation. RESULTS: From 2002 to 2012, schistosomiasis control made significant achievements in Jiangxi Province. The number of counties which have reached the criteria of transmission interruption of schistosomiasis increased from 19 in 2002 to 22 in 2012. The number of patients with schistosome infection decreased from 128 331 in 2002 to 73 102 in 2012. The positive rate of serological test and fecal examination in residents decreased from 12.2% and 4.2% in 2002 to 5.2% and 0.4% in 2012, respectively. Acute infection reduced from 146 cases in 2002 to 3 cases in 2012, but advanced cases increased by 42.4%. The positive rate of fecal examination in cattle reduced from 4.7% in 2002 to 1.3% in 2012. The density of living snails and infected snails significantly decreased to 0.083 5/0.1 a? and 0.000 037/0.1 m2 in 2012, respectively. However, the snail-ridden areas slightly increased. Jiangxi Province reached the criteria of endemic control for schistosomiasis in 2008. During 2002-2012, control activities were intensified. Examination and chemotherapy for human increased by 65.2% and 65.5%, while 23.4% and 251.1% for cattle. Mean while, area with snail control activities increased by 617.8%. An integrated strategy of infection source control was implemented in the Province. CONCLUSION: During 2002 to 2012, endemic index of schistosomiasis in Jiangxi showed a steady decline after 2005. Currently, schistosomiasis prevalence shows a low level. The endemic indicators of infection in human and livestock as well as Oncomelania snails have been kept stable at low level.

[The changes of hydrological regime in Poyang Lake after runs of Three Gorges Project and its impact on prevalence of schistosomiasis in the lake region].

OBJECTIVE: To clarify new features of hydrological regime in the Poyang Lake after runs of the Three Gorges Project and its impact on the prevalence of schistosomiasis in this region. METHODS: It is collected information of Three Gorges Project, average daily water level from 2002 to 2012 at Duchang hydrological station in Poyang Lake and the data of prevalence and control of schistosomiasis in 12 endemic counties along the lake. It was analyzed the trends of prevalence of schistosomiasis under the changed condition of hydrologic situation. RESULTS: Effects of impoundment of Three Gorges reservoir running on water level of Poyang Lake are mainly shown in: Water levels of the lake are suppressed throughout the year which was characterized by high water level in flood season dropped, lower water level appeared in the spring, water withdrew earlier and quicker in the fall and to an even lower level in dry season. After impoundment of Three Gorges Project, infection rate of Schistosomajaponica in human and in bovine decreased by 92.65% and 76.37% respectively in endemic areas around the lake. The density of Oncomelania snails decreased by 94.21%. Prevalent of schistosomiasis in this region showed a significant downward trend. CONCLUSIONS: After runs of the Three Gorges Project, regularized changes hydrologic conditions has taken place in Poyang Lake which is characterized by lower water level and thus might lead to lower density of Oncomelania snails on marshlands and reducing of prevalence of schistosomiasis. Significant strengthening of schistosomiasis control efforts might also contributed to the stable and low level of prevalence of schistosomiasis in the region.

[Retrospective investigation on changes of endemic situation before and after reaching criteria of schistosomiasis transmission controlled or interrupted in hilly endemic areas of Jiangxi Province].

OBJECTIVE: To investigate the changing rules of schistosomiasis endemic situation before and after reaching the criteria of schistosomiasis transmission controlled or interrupted in hilly endemic areas of Jiangxi Province, so as to provide the evidence for reformulating the criteria of schistosomiasis control and eradication in the future. METHODS: In the hilly areas of schistosomiasis endemic in Jiangxi Province, 2 counties where the transmission has been interrupted and 1 county where the transmission has been controlled were selected and investigated with the retrospective research method. The endemic detailed data were collected and recorded 10 years before reaching the criteria of transmission interrupted/controlled, and several years after reaching the criteria (ending in 2008), and then a database was established. The changing rules of endemic situation before and after reaching the criteria of transmission interrupted/controlled were analyzed and compared. RESULTS: After reaching the criteria of transmission controlled, in the 3 counties, Guangfen, Shangrao and Dean, the declined rates of areas with Oncomelania hupensis snails were 96.79%, 98.99%, and 99.77% respectively. The snail density maintained a lower level, and 95% of infected persons and cattle were cured. The average time from transmission controlled to the transmission interrupted was 17 years in Guangfen County and 26 years in Dean County. However, in Shangrao County, the snail situation rebounded due to the snail re-found and spread although the schistosomiasis morbidity of population/animals maintained stably. CONCLUSIONS: After reaching the criteria of transmission interrupted/controlled, the remained snails were easy to re-find and spread under some certain condition, which is one of main obstacles for reaching the criteria of transmission interrupted. In an isolated snail unit, if the snail area and snail density are controlled in a very low level, it is still difficult to transmit and spread schistosomiasis even if there exist infectious sources.

[Evaluation on medium-term effect of schistosomiasis comprehensive control strategy based on infectious source control in Poyang Lake area].

OBJECTIVE: To evaluate the medium-term effect and stability of the schistosomiasis comprehensive control strategy based on infectious source control after its popularization and application in marshland endemic areas. METHODS: The schistosomiasis comprehensive control strategy based on infectious source control including "replacing buffalo with machine", "marshlands isolation and grazing forbidden", etc. was implemented in all villages of Sanli Township, a heavy endemic area with schistosomiasis in Jianxian County. The infection situation of schistosomiasis in population and Oncomelania snails in 4 villages around the lake were monitored regularly for 6 consecutive years. RESULTS: The infection rate of schistosomiasis in population significantly decreased after the comprehensive control measures were carried out. Two years later, the infection rate in Huangjia Village was 0, and was sustained at zero for 5 consecutive years; the infection rate in Fengfu Village decreased by 77.24% and stabilized to zero for the next three years; the population infection rates in Fanrong Village and Caomen Village decreased by 82.33% and 82.53%, respectively, then the infection rates of the two villages kept under 1% and were 0 for 2 years and 1 year, respectively. The number of spots with infected snails in two marshlands in pilot areas decreased yearly from 10 before the intervention to 0, in which, the infection rate of snails and the number of spots with infected snails in Huangjiaoniu Marshland and Goulian Marshland decreased to zero 1 year and 3 years after the strategy was implemented, respectively, and the infected snails were not found in these marshlands in following years. CONCLUSION: Strengthening the management of buffaloes in surrounding areas and utilizing marshland resources is the main measure that can consolidate and expand the medium-term and long-term effect of the schistosomiasis 2.2 comprehensive strategy based on infectious source control.

Immunoproteomics Identification of Major IgE and IgG4 Reactive Schistosoma japonicum Adult Worm Antigens Using Chronically Infected Human Plasma.

Immunoepidemiological studies from endemic areas have revealed age-dependent resistance correlation with increased level of IgE and decreased level of IgG4 antibodies in responses to schistosomes' soluble worm antigen. However, there have been limited studies on analyses of major antigens that provoke IgE and IgG4 immune response during chronic stage of schistosomiasis. In this study, for the first time, immunoproteomics approach has been applied to identify S. japonicum worm antigens in liquid fractions that are recognized by IgE and IgG4 antibody using plasma from chronically infected population. ProteomeLabPF 2D fractionated 1-D and 2-D fractions of SWA antigens were screened using pooled high IgE/IgG4 reactive plasma samples by dot-blot technique. In 1-D fractions, IgE isotype was detected by fewer antigenic fractions (43.2%). The most recognized isotype was IgG3 (79.5%) followed by IgG1 (75.0%) and IgG4 (61.4%). Liquid chromatography MS/MS protein sequencing of reactive 2-D fractions revealed 18 proteins that were identified, characterized and gene ontology categories determined. 2-D fractions containing proteins such as zinc finger, RanBP2-type, domain-containing protein were strongly recognized by IgE and moderately by IgG4 whereas fractions containing proteins such as ubiquitin-conjugating enzyme and cytosolic II 5'-nucleotidase strongly recognizing by IgG subclasses (IgG1, IgG3 and IgG4) but not IgE. By this study, a simple and reproducible proteomic method has been established to identify major immunoreactive S. japonicum antigens. It is anticipated that this will stimulate further research on the immunogenicity and protective potential of proteins identified as well as discovery of novel compounds that have therapeutic importance.

A novel procedure for precise quantification of Schistosoma japonicum eggs in bovine feces.

Schistosomiasis japonica is a zoonosis with a number of mammalian species acting as reservoir hosts, including water buffaloes which can contribute up to 75% to human transmission in the People's Republic of China. Determining prevalence and intensity of Schistosoma japonicum in mammalian hosts is important for calculating transmission rates and determining environmental contamination. A new procedure, the formalin-ethyl acetate sedimentation-digestion (FEA-SD) technique, for increased visualization of S. japonicum eggs in bovine feces, is described that is an effective technique for identifying and quantifying S. japonicum eggs in fecal samples from naturally infected Chinese water buffaloes and from carabao (water buffalo) in the Philippines. The procedure involves filtration, sedimentation, potassium hydroxide digestion and centrifugation steps prior to microscopy. Bulk debris, including the dense cellulosic material present in bovine feces, often obscures schistosome eggs with the result that prevalence and infection intensity based on direct visualization cannot be made accurately. This technique removes nearly 70% of debris from the fecal samples and renders the remaining debris translucent. It allows improved microscopic visualization of S. japonicum eggs and provides an accurate quantitative method for the estimation of infection in bovines and other ruminant reservoir hosts. We show that the FEA-SD technique could be of considerable value if applied as a surveillance tool for animal reservoirs of S. japonicum, particularly in areas with low to high infection intensity, or where, following control efforts, there is suspected elimination of schistosomiasis japonica.

Five-year longitudinal assessment of the downstream impact on schistosomiasis transmission following closure of the Three Gorges Dam.

BACKGROUND: Schistosoma japonicum is a major public health concern in the Peoples' Republic of China (PRC), with about 800,000 people infected and another 50 million living in areas at risk of infection. Based on ecological, environmental, population genetic and molecular factors, schistosomiasis transmission in PRC can be categorised into four discrete ecosystems or transmission modes. It is predicted that, long-term, the Three Gorges Dam (TGD) will impact upon the transmission of schistosomiasis in the PRC, with varying degree across the four transmission modes. METHODOLOGY/PRINCIPAL FINDINGS: We undertook longitudinal surveillance from 2002 to 2006 in sentinel villages of the three transmission modes below the TGD across four provinces (Hunan, Jiangxi, Hubei and Anhui) to determine whether there was any immediate impact of the TGD on schistosomiasis transmission. Eight sentinel villages were selected to represent both province and transmission mode. The primary end point measured was human incidence. Here we present the results of this five-year longitudinal cohort study. Results showed that the incidence of human S. japonicum infection declined considerably within individual villages and overall mode over the course of the study. This is also reflected in the yearly odds ratios (adjusted) for infection risk that showed significant (P<0.01) downward trends in all modes over the follow-up period. CONCLUSIONS/SIGNIFICANCE: The decrease in human S. japonicum incidence observed across all transmission modes in this study can probably be attributed to the annual human and bovine PZQ chemotherapy. If an increase in schistosome transmission had occurred as a result of the TGD, it would be of negligible size compared to the treatment induced decline seen here. It appears therefore that there has been virtually no immediate impact of the TGD on schistosomiasis transmission downstream of the dam.

[Study on immune status of patients with schistosomiasis japonica in Poyang Lake region II characterization of cellular immune in schistosomiasis patients].

OBJECTIVE: To observe the characterization of cellular immune of schistosomiasis japonica patients in low endemic area of Poyang Lake region. METHODS: The schistosomiasis patients who were positive by stool detections were selected as study subjects, and the individuals who were negative by stool detections in three consecutive years were selected as negative controls. The CD4+T cell, CD8+T cell and CD4+CD25+Treg in venous blood of the study subjects were detected by using flow cytometry. In vitro, cytokine (IFN-gamma and IL-10) production of PBMC in response to soluble egg antigen (SEA) and soluble worm antigen preparation (SWA) were measured by ELISA. RESULTS: The levels of CD4+CD25+Treg in individuals who were positive by stool detections (5.99 +/- 1.60)% were higher than those of the negative (5.04 +/- 1.64)%, and the difference was significant (t = 3.261, P < 0.01). One year after the treatment, the levels of IFN-gamma were significantly higher (Stimulated by SEA before and after the treatment, the mean levels were 121.97 and 2 564.03 pg/ml, respectively; stimulated by SWA before and after treatment, the mean levels were 102.89 and 646.26 pg/ml, respectively) and IL-10 were significant lower in patients who were positive by stool detections (Stimulated by SEA before and after treatment, the mean level were 294.75 and 122.43 pg/ml, respectively; stimulated by SWAP before and after treatment, the mean cytokine levels were 110.10 and 31.85 pg/ml, respectively). CONCLUSION: The increase of induced CD4+CD25+Treg is one of causes that down-regulate cellular immune of human body after infection with Schistosoma japonicum.

[Study on immune status of patients with schistosomiasis japonica in Poyang Lake region I characterization of antigen-specific antibody isotype responses to Schistosoma japonicum].

OBJECTIVE: To understand the characterization and levels of antibody isotype responses to soluble egg antigen (SEA) and adult worm antigen (AWA) of Schistosoma japonicum in schistosomiasis patients in Poyang Lake region. METHODS: Antibody isotype IgG, IgG1, IgG2, IgG3, IgG4, IgE, IgM and IgA responses to SEA and AWA in the sera of individuals from endemic and non-endemic areas were determined by indirect ELISA. RESULTS: The levels of antigen-specific antibody isotypes in the sera of patients with egg positive were significantly higher than those of people with egg negative and normal control population from non-endemic area (P < 0.001), and except for anti-SEA IgG2 and anti-AWA IgG4 and IgE antibodies, the levels of antibody isotypes in the sera of people with egg negative in endemic area were significantly higher than those of normal control population from non-endemic area (P < 0.05). In the population with egg positive, children had higher levels of anti-SEA IgM and IgG1 and anti-AWA IgM antibody, and lower AWA specific IgG than adults. There was no significant difference between the male and female except for the male had higher levels of IgG (F = 4.677, P = 0.032) and IgG1 (F = 5.55, P = 0.020)against AWA. Three months post-treatment, the levels of IgG1, IgG3, IgG4 antibody responses to SEA deceased significantly (P < 0.001, P = 0.029, P = 0.044), and almost all the antibody levels decreased significantly (P < 0.05) twelve months post-treatment, except for SEA specific IgE and IgM and AWA specific IgG4 and IgM antibodies. CONCLUSIONS: The levels of antigen-specific antibody isotypes in the sera of patients with egg positive are significantly higher than those of people with egg negative and normal control population from non-endemic area. Almost all of antibody levels decrease significantly twelve months post-treatment. The levels of antibody isotypes in the sera of people with egg negative in endemic area are significantly higher than those of population from non-endemic area, giving a clue that the selection of negative control of schistosomiasis diagnostic kit should be noticed.

[Control strategy of schistosomiasis and key points in the 12th Five-Year Plan in China].

Based on the objective of long- and mid-term development program for schistosomiasis control in China, the paper presents an analysis of strategy for schistosomiasis control and its function in the 12th Five-Year Plan. Meanwhile, the strategy and key elements of schistosomiasis control for recent years are put forward for different endemic areas.

[Bioinformatics analysis of nicotinamide phosphoribosyl transferase of Schistosoma japonicum].

OBJECTIVE: To perform the bioinformatics analysis of nicotinamide phosphoribosyl transferase of Schistosoma japonicum so as to provide the evidence for the development and application of it. METHODS: Internet online procedures and the related software were exploited to analyze the open reading frame (ORF) of SjNAMPT gene, physical and chemical properties of SjNAMPT protein and the domains of the protein, and predict the space structure and functions of the protein. RESULTS: The SjNAMPT protein sequence was composed of 179 amino acids with 19.63 kDa of the molecular weight. The protein was stable and had no structures of transmembrane and helical coils. The protein belonged to the family of nicotinate phosphoribosyl transferase with multiple phosphorylation sites. The protein probably located in cytoplasm and dominated by random coils in second structure. The similarity of the SjNAMPT protein sequence was lower than that of other species of NAMPT. CONCLUSIONS: SjNAMPT is a specific protein of Schistosoma japonicum with a certain activity, and probably related to purine metabolism and glucose metabolism. It is worth for further study.