Impact of water body environments on the microbial community of Oncomelania hupensis snails in marshlands around the eastern Dongting Lake / 中国血吸虫病防治杂志

Objective To evaluate the effects of water body environments on the microbial community of Oncomelania hupensis snails in marshlands of the eastern Dongting Lake where natural extinction of O. hupensis snails are found, so as to explore the correlation between the natural extinction of O. hupensis snails and the microbial community in snails. Methods Snails were caged water bodies in the Qianliang Lake marshland (Qianliang Lake regions) where natural extinction of snails was found and in the Junshan Park marshland (Junshan Park regions) in the eastern Dongting Lake for 30 days, and then all snails were collected and identified for survival or death. DNA sequencing of the fungi and bacteria was performed in snails before and after immersion in waters, and the biodiversity and abundance were analyzed. Results The survival rates of O. hupensis snails were 28.0% (70/250) and 64.8% (162/250) in Qianliang Lake regions and Junshan Park regions 30 days after immersion in waters, respectively (χ2 = 81.365, P < 0.01). The number of the fungal community and the biodiversity of the bacterial community were both greater in snails caged in Qianliang Lake regions post-immersion than pre-immersion, and there was a significant difference in the structure of the fungal and bacterial communities. The microbial community with a significant difference included Flavobacteriaceae,which was harmful to O. hupensis snails. Conclusion The water body environment affects the composition of the microbial community in O. hupensis snails in marshlands with natural snail distinction around the eastern Dongting Lake; however, further studies are required to investigate whether the natural distinction of snails is caused by water body environments-induced changes of the microbial spectrum in O. hupensis snails.

Relationship between natural extinction of Oncomelania hupensis snails and water chemical properties in Eastern Dongting Lake areas / 中国血吸虫病防治杂志

Objective To investigate the reasons of natural extinction of Oncomelania hupensis snails by comparing the difference of the water chemical properties between the snail-breeding marshland and non-snail marshland in Eastern Dongting Lake areas. Methods Three adjoining marshlands in Eastern Dongting Lake areas were selected, one was a snail-breeding marshland, the second was a non-snail marshland, and the third was a boundary zone between them. During the periods of water-rising season, wet season and water-falling season, the water samples from the bottom of 0.5 m were collected by the systematic random sampling method (200 m × 200 m grid method). In addition, the water samples below the surface of 0.5 m were also collected in the wet season. The physicochemical indexes of the sampling water were detected. Results According to the Surface Water Environmental Quality Standard (GB 3838–2002), the water quality indicators which were less than the detection limit were Cr, Cd, Zn, Hg, Cu, S－ and CN－ during the three sampling seasons. The pollutants which were slightly higher than Grade III but lower than Grade IV (Hg ≤ 1 μg/L, TP ≤ 0.1 mg/L) were Hg and TP. The pollutants below the Grade III included As and F－. The temperature and pH values were within the Grade III. The oxygen consumption indicators covering DO, COD and BOD in the water-rising season and wet season were within the Grade III, while the value of BOD was beyond the scope of Grade III but was between Grade Ⅳ (≤ 6 mg/L) and Grade V (≤ 10 mg/L) in the water-falling season. The differences of the water pollution indexes between the snail-breeding marshland and non-snail marshland were statistically significant, and these indexes included F－, As and pH in the water-rising season (P < 0.05); pH, BOD and Fat the surface layer in the wet season (P < 0.05); F－ at the bottom in the wet season (P < 0.05); TP and F－ in the water-falling season. Moreover, the above-mentioned indexes in the non-snail marshland of Qianliang Lake were higher than those in the snail-breeding marshland of Junshan Park. Thus, F－ was the only index which had statistical differences in every sampling season, and the concentration of F－ at the non-snail marshland was also higher than that at the snail-breeding marshland. In the water-rising season, the pH value at the non-snail marshland exceeded the suitable range for the growth of snails (6.8 to 7.8). Conclusion In the Eastern Dongting Lake area, the high concentration of F－ and pH of water may be responsible for the natural extinction of O. hupensis snails.

Relationship between natural extinction of Oncomelania hupensis snails and water chemical properties in Eastern Dongting Lake areas / 中国血吸虫病防治杂志

Objective To investigate the reasons of natural extinction of Oncomelania hupensis snails by comparing the difference of the water chemical properties between the snail-breeding marshland and non-snail marshland in Eastern Dongting Lake areas. Methods Three adjoining marshlands in Eastern Dongting Lake areas were selected, one was a snail-breeding marshland, the second was a non-snail marshland, and the third was a boundary zone between them. During the periods of water-rising season, wet season and water-falling season, the water samples from the bottom of 0.5 m were collected by the systematic random sampling method (200 m × 200 m grid method). In addition, the water samples below the surface of 0.5 m were also collected in the wet season. The physicochemical indexes of the sampling water were detected. Results According to the Surface Water Environmental Quality Standard (GB 3838–2002), the water quality indicators which were less than the detection limit were Cr, Cd, Zn, Hg, Cu, S－ and CN－ during the three sampling seasons. The pollutants which were slightly higher than Grade III but lower than Grade IV (Hg ≤ 1 μg/L, TP ≤ 0.1 mg/L) were Hg and TP. The pollutants below the Grade III included As and F－. The temperature and pH values were within the Grade III. The oxygen consumption indicators covering DO, COD and BOD in the water-rising season and wet season were within the Grade III, while the value of BOD was beyond the scope of Grade III but was between Grade Ⅳ (≤ 6 mg/L) and Grade V (≤ 10 mg/L) in the water-falling season. The differences of the water pollution indexes between the snail-breeding marshland and non-snail marshland were statistically significant, and these indexes included F－, As and pH in the water-rising season (P < 0.05); pH, BOD and Fat the surface layer in the wet season (P < 0.05); F－ at the bottom in the wet season (P < 0.05); TP and F－ in the water-falling season. Moreover, the above-mentioned indexes in the non-snail marshland of Qianliang Lake were higher than those in the snail-breeding marshland of Junshan Park. Thus, F－ was the only index which had statistical differences in every sampling season, and the concentration of F－ at the non-snail marshland was also higher than that at the snail-breeding marshland. In the water-rising season, the pH value at the non-snail marshland exceeded the suitable range for the growth of snails (6.8 to 7.8). Conclusion In the Eastern Dongting Lake area, the high concentration of F－ and pH of water may be responsible for the natural extinction of O. hupensis snails.

Knowledge of schistosomiasis in traditional Chinese medicine / 中国血吸虫病防治杂志

Schistosomiasis is a modern disease name, but it has been widespread in ancient China and exists in a specific form in traditional Chinese medicine (TCM) . The purpose of the paper is to make clear the existing form of schistosomiasis in TCM and infer the prevalence of schistosomiasis in ancient China. The paper focuses on the period when great progress was made on schistosomiasis by TCM, and sums up the understanding of TCM toward schistosomiasis in this period. By studying and analyzing the literature of schistosomiasis in this period, the paper tries to find out the representative Chinese medicine symptom description and TCM "other name" of schistosomiasis, so as to accurately judge whether the relevant description in ancient TCM books and historical documents can provide scientific basis for schistosomiasis. It is important to understand the prevalence and cognition of schistosomiasis in ancient China.

Knowledge of schistosomiasis in traditional Chinese medicine / 中国血吸虫病防治杂志

Schistosomiasis is a modern disease name, but it has been widespread in ancient China and exists in a specific form in traditional Chinese medicine (TCM) . The purpose of the paper is to make clear the existing form of schistosomiasis in TCM and infer the prevalence of schistosomiasis in ancient China. The paper focuses on the period when great progress was made on schistosomiasis by TCM, and sums up the understanding of TCM toward schistosomiasis in this period. By studying and analyzing the literature of schistosomiasis in this period, the paper tries to find out the representative Chinese medicine symptom description and TCM "other name" of schistosomiasis, so as to accurately judge whether the relevant description in ancient TCM books and historical documents can provide scientific basis for schistosomiasis. It is important to understand the prevalence and cognition of schistosomiasis in ancient China.

Cost-effectiveness of comprehensive schistosomiasis control strategy with fo-cus on cattle and sheep removal in Junshan District,Yueyang City / 中国血吸虫病防治杂志

Objective To evaluate the cost-effectiveness of comprehensive schistosomiasis control measures with focus on total removal of cattle and sheep in Juanshan District,Yueyang City.Methods The schistosome infection status of human,cat-tle,sheep and Oncomelania hupensis snails and costs of control measures were gathered during the period of 2006 to 2016.The costs for different periods and cost-effectiveness ratios were calculated.Results The prevalence of schistosome infection in resi-dents in the pilot villages decreased from 3.44% in 2006 to 0 in 2016.The annual costs of schistosomiasis prevention and control were 4 708 500 yuan from 2006 to 2008,5 094 700 yuan from 2009 to 2012 and 9 522 700 yuan from 2013 to 2016.The cost-ef-fectiveness analysis showed that the average annual cost of reduction in the residents'infection rate by 1% were 79 500 yuan from 2006 to 2008,101 200 yuan from 2009 to 2012,and 95 200 yuan from 2013 to 2016,respectively. Conclusion The comprehensive schistosomiasis control strategy with focus on cattle and sheep removal in Junshan District is cost effective, which could be extended to other lake and marshland schistosomiasis endemic areas.

Research on living status of Oncomelania hupensis in autumn and winter and its correlates in Eastern Dongting Lake area / 中国血吸虫病防治杂志

Objective To explore the dynamic changes of Oncomelania hupensis snail densities in autumn and winter and the relationship between hydrological and meteorological factors and snail growth and decline.Methods From Octobers to De-cembers of 2007 to 2014,a bottomland close to eastern Dongting Lake was selected as the study field.The snails and elevation of the points were surveyed,and the hydrological and meteorological data were collected.The snail densities and death rates of every month were calculated.The meteorological and hydrological data were described,and the relationship between the snail densities and associated factors were fitted by the multiple regression model.Results The snail density was highest in October 2012(41.88 per 0.1 m2)and lowest in November 2008(1.23 per 0.1 m2).The snail mortality was highest in November 2008 (73.72%)and lowest in October 2012(1.09%).The multiple regression model found a linear relationship between hydrological and meteorological factors and snail densities.The correlation coefficient between the prediction of ln(snail density)and its mea-surements by using this model was 0.927(P=0.001).Conclusion The average minimum temperature in January and time of starting flood have an obvious influence on the snail densities in autumn and winter.

Snail habitats detection in the marshland of Eastern Dongting Lake Area, based on China-Brazil Earth Resources Satellite-02B CCD data / 中华流行病学杂志

Objective To detect the snail habitats from the marshland of Eastern Dongting Lake Area, using the Remote Sensing (RS) and Geographic Information System (GIS) technology based on the China-Brazil Earth Resources Satellite-02B (CBERS-02B) CCD images. Methods According to the two typical traits of snail habitats in marshland including "water in summer and land in winter" and "no grass, no snails" , the "water in summer and land in winter" region and the vegetation coverage region were calculated by RS image processing respectively. The two regions mentioned above were then overlapped to confirm the snail habitats through comparing with the data from field survey under spatial overlapping of Arcgis as the last step. Results In Eastern Dongting Lake area, the "water in summer and land in winter" region and vegetation coverage region were predicted based on the formula normalized difference water index (NDWI) >0.01 and normalized difference vegetation index (NDVI) >0.36, respectively. The snail habitat was determined by theme overlay of the two regions said above.The agreement rate between the prediction and the geospatial data of field survey was 93.55% , which demonstrated the final results were credible and reliable. Conclusion CBERS-02B image could be used to detect the snail habitats and to monitor the changes of them, so as to find out the characteristics of distribution and the trends of diffusion. The snail index (discriminant 1 and 2) seemed to be suitable for the detection of snail habitats in the marshland of Lake area and used for the programs of snail control.