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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 O. hu-pensis 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 The hygrophilous vegetation has degenerated and gradu-ally been replaced by mesophily meadow in the marshland area above 14 m elevation. Carex,Phalaris arundinacea and Polygo-num 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 habi-tats towards low terrain was observed. Conclusions The impoundment of Three Gorges Project has had a significant impact on hy-drological 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.
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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 con-trol strategy. Methods The residents in two villages in schistosomiasis endemic areas were selected and surveyed for their activi-ties 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 con-tacts 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. Conclu-sions 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.
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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 <i>S. japonicum</i> 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 <i>S. japonicum</i> 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.
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Objective To explore the relationship between the vegetation and space distribution of Oncomelania snails in Poyang Lake region,so as to get better understanding of the habitats of Oncomelania snails by using remote sensing technology.Methods The marshlands close to schistosomiasis endemic villages in Poyang Lake region were selected,and the traditional methods were used to investigate the situation of vegetation and Oncomelania snails.The longitude and latitude of investigation spots were recorded by GPS,and the field survey data were vectored by using ArcGIS software.The geometric calibration and unsupervised classification were made on TM satellite images of low-flow period of spring by using PCI 9.0.And then,the relationship between space distribution of snail habitats and vegetation was analyzed through superposing the filed data and satellite images.Results The vegetation in marshlands of Poyang Lake region can be differentiated as three types,in which the single dominant vegetation area was mainly breeding place of Oncomelania snails,and wet vegetation type and hybrid weed type were snail seldom breeding areas.Conclusions The distribution roles of vegetation in marshland are closely related to the habitats of snails,presenting a flaky and bandy distribution.The habitats of Oncomelania snails can be quickly understood by remote sensing technology.
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According to the requirement of the national assessment for achieving the infection control criteria, 42 villages (among them,25 villages belonged to the first stratum, and 17 villages belonged to the second stratum) in 14 counties from 5 provinces, including Hunnan, Hubei, Jiangxi, Anhui and Yunnan, were selected as sampling villages for the assessment.The results from the field assessment showed that 154 out of 9 067 people were found infected with Sckistosoma japonicum, with an average infection rate of 1.7% ranged from 0.31 % to 4.10% , and only Yongping Village from Weishan County and Tenglong Village from Eryuan County were not found any case. A total of 46 out of 3 323 head of cattle were infected with S. japonicum, with an average infection rate of 1.38% ranged from 0.26% to 3.79% , and no any infected individual detected in Nanling County. No outbreak occurred in those sampling villages. Therefore, it is indicated that the five sampling provinces have reached the national criteria on infection control of schistosomiasis.
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GPS was used in the snail survey of Nuanhuping marshland in Poyang Lake region and its application value was discussed. The results suggest that GPS which can measure the marshland area and survey area at real-time and draw electronic maps of snail situation rapidly, could realize the electronic and image management of the data from snail survey and provide more accurate information to the department in charge of schistosomiasis control.
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To determine the diagnostic efficiency of parallel detection of the circulating antigens and antibodies in schistosomiasis, sandwich ELISA and indirect ELISA by using the labeled McAb JPG3 were used to detect the presence of the circulating antigens and the circulating IgG antibodies in serum samples from different kinds of population. and then the sensitivity and specificity of this method of testing as well as the efficiency of the application of this method in heavy endemic area. were determined in comparison with serial test. It was found that the sensitivity and specificity of the parallel test were 97.9% and 92.2% , however, those of the serial test were 76.0% and 99.2% respectively. The positive rates of parallel test and serial test to detect the stool examination-positive for schistosoma eggs in population of the endemic area were 94.6% (35/37) and 67.6% (25/37), while those to detect the stool examination-negative for schitosoma eggs were 69.8% (97/139) and 39.6% (55/139) respectively. It is apparent the parallel test for the detection circulating antigens and antibodies in schistosomiasis shows its high diagnostic efficiency, especially in the heavy endemic area of schitosomiasis.
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Objective To explore the relationship between vegetation and the distribution of Oncomelania snails inside and outside the embankments of Poyang Lake region. Methods The plantation and Oncomelania snails were surveyed at 4 villages and their related marshlands in Yugan, Nanchang and Jinxian counties by the stratified systematic sampling method. The investigation was targeted to the vegetation species,height,coverage and frequency of plantation and synchronously to the distribution of snails and infection of snails in marshland of high, middle and low altitudes,adjacent beaches as well in cultivated and waste land inside embankment. The relationship between vegetation dominant association and the distribution of snails in those area was analyzed. Results The vegetation inside and outside the embankment were remarkably diverse. Inside the embankment, the species of vegetation varied greatly and distributed randomly,and no snail was found. While outside the embankment,the distribution of vegetation characterized an unregulated annulus or patch. Plant's association types were distinct on marshlands. The snails mainly distributed in areas at 15-17 m altitude,closely related to the species of vegetation. The coverage of dominant plants,Carex cinerascen and Miscanthus sacchariflorus showed a quadratic curve correlation with the density of snails. Conclusions In the Poyang Lake region,plants and snails are impacted by common environmental factors,which then lead to their close association in distribution. It might be attributed to integrated impacts of changes in ecological factors that Oncomelania snails disappear gradually in areas inside embankment after construction of embankment.
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Objective To understand the effect of the three-cell latrine and B-type tilted ellipsoid methane tank for eliminating eggs of schistosome in different seasons and temperatures in order to evaluate their values for popularization and application in schistosomiasis endemic areas.Methods The eggs of schistosome collected from infected rabbits were put into the three-cell latrines and methane tanks in different seasons.The miracidia were observed and counted after collecting the eggs for hatching experiments on the 5th,10th,15th,20th,25th,30th,40th,50th,and 60th day,respectively.Results In the three-cell latrine,the time of eliminating eggs completely in the fecal residue in winter,spring(autumn),and summer was 50,30,15 days,respectively,and the time of completely eliminating 100 eggs of schistosome was 40,20,10 days,respectively.Correspondingly,in the methane tank,the time of eliminating eggs completely in the fecal residue in winter,spring(autumn),and summer was 30,15,10 days,respectively,and the time of completely eliminating 100 eggs of schistosome was 20,15,5 days,respectively.Conclusions The three-cell latrine and B-type tilted ellipsoid methane tank could effectively eliminate schistosome eggs in human and animal excreta and achieve the national hygienic standard on night soil in the endemic areas of Jiangxi Province.
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Objective To observe the effect of artemether in the control of prevalence and acute infection of Schistosoma japonicum in humans in high endemic areas. Methods During the transmission season (May-October), the residents in the pilot village took artemether with a 15- day interval to prevent the infection of S. japonicum. Results By the end of the transmission season, the egg positive rate was 0.83% and no acute case occurred in the artemether group, while 15.01% and 3 acute cases were observed in the placebo group. Conclusions Oral administration of artemether at a 15-day interval shows an effective protection from infection of S. japonicum, with a protection rate of 94.47% in residents of a high endemic area and it also shows marked effect to prevent acute schistosomiasis.