Background:The prevalence of schistosomiasis japonica has decreased significantly,and the responses changing from control to elimination in Jiangsu Province,P.R.China.How to estimate the change in prevalence of schistosomiasis using only serological data will be important and useful.Methods:We collected serum samples from 2011 to 2015 to build a serum bank from Dantu County of Jiangsu,China.Serum samples were detected by enzyme-linked immunosorbent assay(ELISA),the positive rate and optical density(OD)value were obtained.The Bayesian model including the prior information of sensitivity and specificity of ELISA was established,and the estimated infection rates were obtained for different years,genders and age groups.Results:There was no significant difference in the mean OD between different years and genders,but there was a significant difference between the different age groups.There were statistically significant differences in the positive rate for different years and age groups,but no significant difference at different genders.The estimated infection rate for the five years was 1.288,1.456,1.032,1.485 and 1.358%,respectively.There was no significant difference between different years and between genders,but a significant difference between different age groups.Conclusions:The risk of schistosomiasis transmission in this area still exists,and risk monitoring of schistosomiasis should be strengthened.
Xin-Yao WangJing XuSong ZhaoWei LiJian-Feng ZhangJian HeAshley M.SwingKun Yang
Oncomelania hupensis is the unique intermediate host of Schistosomajaponicum, which plays a key role in the transmission of human blood fluke Schistosoma. The complete mitochondrial （mt） genome of O. hupensis has been characterized; however, the phylogenefic performance of mt protein-coding genes （PCGs） of the snail remain unclear. In this study, 11 whole mt genomes of snails collected from four different ecological settings in China and the Philippines were sequenced. The mt genome sizes ranged from 15 183 to 15 216 bp, with the G＋ C contents from 32.4% to 33.4%. A total of 15 251 characters were generated from the multiple sequence alignment. Of 2711 （17.8%） polymorphic sites, 56.22% （1524） were parsimony sites. The mt genomes＇ phylogenetic trees were reconstructed using minimum evolution, neighbor joining, maximum likelihood, maximum parsimony, and Bayesian tree estimate methods, and two main distinct clades were identified： （i） the isolate from mountainous regions; （ii） the remaining isolate which included three inner branches. All phylogenetic trees of the 13 PCGs were generated by running 1000 bootstrap replicates and compared with the complete mtDNA tree, the classification accuracy ranging from 21.23% to 87.87%, the topological distance of phylogenetic trees between PCGs ranging from 5 to 14. Therefore, the performance of PCGs can be divided into good condition （COI, ND2, ND5, and ND3）, medium （COII, ATP6, ND1, ND6, Cytb, ND4, and COIll）, poor （ATP8 and ND4L）. This study represents the first analysis ofmt genome diversity of the O. hupensis snail and phylogenetic performance of mt PCGs. It presents clear evidence that the snail populations can be separated into four landscape genetic populations in China's Mainland based on whole mt genomes. The identification of the phylogenetic performance of PCGs provides new insight into the intensive genetic diversity study using mtDNA markers for the snail.
