The Experts below are selected from a list of 3990 Experts worldwide ranked by ideXlab platform
Xiao-nong Zhou - One of the best experts on this subject based on the ideXlab platform.
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Initial temperature for the development of Schistosoma japonicum larvae in Oncomelania hupensis
Chinese Journal of Parasitology and Parasitic Diseases, 2020Co-Authors: Xiao-nong Zhou, Qing-biao Hong, Yi-xin Huang, Guo-jing Yang, Wei-ping Xi, Yu-ji JiangAbstract:OBJECTIVE: To study the impact of environmental temperature on the development of Schistosoma japonicum larvae within the Oncomelania hupensis. METHODS: Oncomelania snails, collected from the field and free of S. japonicum infection, were exposed to miracidiae of S. japonicum in a ratio of 1:20 and raised at 30 degrees C, 27 degrees C, 24 degrees C, 21 degrees C and 18 degrees C, respectively. The prepatent period of larvae within the Oncomelania hupensis and the developmental velocity were determined, of which the relationship with the temperature was analysed. RESULTS: The average prepatent period of cercariae in snail was (128.89 +/- 16.05) d, (95.00 +/- 21.03) d, (71.93 +/- 12.74) d and (62.74 +/- 14.19) d at 21 degrees C, 24 degrees C, 27 degrees C, 30 degrees C, respectively. The regression formulation between prepatent period and temperature was y = 730.68x(-0.8918) (r = 0.9976, P < 0.01). And the regression formulation between developmental velocity of S. japonicum larvae in snail and temperature was y = 0.0235ln(x) -0.0639 (r = 0.9973, P < 0.01). It was derived that the unitial temperature for the development of S. japonicum within the snails was 15.17 degrees C +/- 0.43 degree C. CONCLUSION: The development of S. japonicum larvae within the Oncomelania snails declines with the decrease of temperature.
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the genetic diversity and geographical separation study of Oncomelania hupensis populations in mainland china using microsatellite loci
Parasites & Vectors, 2016Co-Authors: Wei Guan, Shi-zhu Li, Bonnie L Webster, David Rollinson, Xiao-nong ZhouAbstract:Background Oncomelania hupensis is the unique intermediate host of Schistosoma japonicum, which plays a crucial role in the transmission of schistosomiasis. The endemic area of S. japonicum is strictly consistent with the geographical distribution of O. hupensis.
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Prediction of on comelania hupensis (vector of schistosomiasis) distribution based on remote sensing data and fuzzy information theory
2015 IEEE International Geoscience and Remote Sensing Symposium (IGARSS), 2015Co-Authors: Chuanrong Li, Lingli Tang, Xiao-nong ZhouAbstract:Schistosomiasis is a parasitic disease that menaces human health. In terms of impact, this disease is second only to malaria as the most devastating parasitic disease. Oncomelania hupensis (snail) is the unique intermediate host of schistosoma, so monitoring and controlling of the number of snail is key to reduce the risk of schistosomiasis transmission. Remote sensing technology can real-timely access the large-scale environmental factors related to snail breeding and reproduction, then can also provide the efficient information to determine the location, area, and spread tendency of snail. But the complex relationship between snail and various environmental factors limit its development. To solve above problem, in this study, the fuzzy information theory was employed to analyze the relationship between snail density and environmental factors. A model for predicting snail distribution and density was developed and validated with field data of Dongting Lake. The validation results demonstrated the success of the developed model in predicting the distribution of Oncomelania hupensis.
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Advances on genetics and biological characteristics of Oncomelania hupensis
Chinese Journal of Parasitology and Parasitic Diseases, 2009Co-Authors: Xiao-nong Zhou, Shi-zhu Li, Yi ZhangAbstract:: This review focused on the research progress in genetic features of Oncomelania hupensis, including its relation to the snail distribution, susceptibility to Schistosoma japonicum. Series studies were done on genetic characteristics for snail distribution and its infectivity with S. japonicum by using population genetics and molecular biology approaches to explore the new avenue to block the transmission of schistosomiasis. However, limited progress has been achieved in this field inside in China comparing with global achievements. It is therefore recommended that future studies have to be focused on genetic features related to schistosome infections by referencing the study model of Biomphalaria glabrata/S. mansoni, and with assistance of modern technology on bionics, in order to improve investigations on genetics of Oncomelania hupensis in the country.
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retrieving eco environment factors relevant to Oncomelania snail distribution based on quickbird image
Chinese Journal of Parasitology and Parasitic Diseases, 2007Co-Authors: Qingni Huang, Lingli Tang, Xiaoguang Jiang, Zhao Chen, Xiao-nong ZhouAbstract:OBJECTIVE: To estimate snail distribution by using high spatial resolution QuickBird image on the basis of retrieving the eco-environment factors relevant to snail distribution. METHODS: Combined with the well-positioned ground data of Oncomelania snails, the meter-level high spatial resolution QuickBird image was used to retrieve the eco-environment factors related to snail distribution in Jiangxin village of Dangtu county, Anhui Province. The factors included vegetation (vegetation index and vegetation cover ratio) and soil (soil texture, soil cover type and humidity). A qualitative analysis was made by using principle component analysis, K-T transformation and supervision classification methods to retrieve the eco-environment factors. The vegetation index NDVI (Normalized Difference Vegetation Index) and MSAVI (Modified Soil Adjustment Vegetation Index) were calculated, and LAI (Leaf area index) and F (vegetation cover ratio) were retrieved. Information from QuickBird data and corresponding ground data were then used to analyze the relationship between snail distribution and environmental factors by using ArcGIS and statistical software. RESULTS: Snail data were received from 153 ground distribution spots and a GIS database on spacial distribution of snails was established. This database covered snail density, NDVI, MSAVI, LAI(NDVI), LAI(MSAVI), F(NDVI), F(MSAVI), PCA-1, PCA-2, PCA-3, KT-1, KT-2 and KT-3. Statistical analysis showed that the snail density could be estimated by LAINDVI and FMSAVI quantitatively based on the following regression model: Y = -3.919 + 1.22 LAI(MSVI) + 16.076 F(MSAVI). Decision index of the regression model was 0.2. CONCLUSIONS: A quantitative regression model between Oncomelania snail distribution and environmental variables retrieved from QuickBird images has been established, which may have a wide application prospect. KT-1, KT-2 and KT-3. Statistical analysis showed that the snail density could be estimated by LAINDVI and FMSAVI quantitatively based on the following regression model: Y = -3.919 + 1.22 LAI(MSAVI) + 16.076 F(MSAVI). Decision index of the regression model was 0.2. CONCLUSIONS: A quantitative regression model between Oncomelania snail distribution and environmental variables retrieved from QuickBird images has been established, which may have a wide application prospect.
Qingwu Jiang - One of the best experts on this subject based on the ideXlab platform.
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multi host model and threshold of intermediate host Oncomelania snail density for eliminating schistosomiasis transmission in china
Scientific Reports, 2016Co-Authors: Yi-biao Zhou, Yue Chen, Song Liang, Xiuxia Song, Gengxin Chen, Zhong He, Wuli Yihuo, Zonggui He, Qingwu JiangAbstract:Schistosomiasis remains a serious public health issue in many tropical countries, with more than 700 million people at risk of infection. In China, a national integrated control strategy, aiming at blocking its transmission, has been carried out throughout endemic areas since 2005. A longitudinal study was conducted to determine the effects of different intervention measures on the transmission dynamics of S. japonicum in three study areas and the data were analyzed using a multi-host model. The multi-host model was also used to estimate the threshold of Oncomelania snail density for interrupting schistosomiasis transmission based on the longitudinal data as well as data from the national surveillance system for schistosomiasis. The data showed a continuous decline in the risk of human infection and the multi-host model fit the data well. The 25th, 50th and 75th percentiles, and the mean of estimated thresholds of Oncomelania snail density below which the schistosomiasis transmission cannot be sustained were 0.006, 0.009, 0.028 and 0.020 snails/0.11 m2, respectively. The study results could help develop specific strategies of schistosomiasis control and elimination tailored to the local situation for each endemic area.
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Oncomelania hupensis gastropoda rissooidea intermediate host of schistosoma japonicum in china genetics and molecular phylogeny based on amplified fragment length polymorphisms
Malacologia, 2007Co-Authors: Yi-biao Zhou, Genming Zhao, Meixia Yang, Qingwu JiangAbstract:Schistosomiasis japonica is one of the most serious parasitic diseases in China. Subspecies of the pomatiopsid snail species Oncomelania hupensis transmit the human blood fluke Schistosoma japonicum, the parasite causing the disease. In at least one study involving the subspecies Oncomelania hupensis robertsoni, there was no clear phylogenetic concordance between the mitochondrial and nuclear data, and it was strongly recommended that future studies incorporate more data from nuclear loci in order to better understand phylogeography and host-parasite coevolution (Wilke et al., 2006). In this paper, we explore genetic diversity based AFLP data involving 25 populations throughout mainland China. AFLP is a DNA fingerprinting technique that detects the polymorphism of the whole genome without prior knowledge of the nucleotide sequence, with the high degree of reproducibility and small amount of template DNA needed. Our AFLP data show that: (1) the genetic diversity within an O. hupensis population increases g...
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Study on the genetic diversity among populations of schistosome intermediate hosts within Oncomelania hupensis (Gastropoda: Rissooidea) in Mainland China
Chinese journal of epidemiology, 2006Co-Authors: Yi-biao Zhou, Genming Zhao, Qingwu JiangAbstract:OBJECTIVE: To explore the genetic diversity among populations of Oncomelania hupensis. METHODS: Amplified fragment length polymorphism method was used to amplify the genomic DNA pools of twenty five snail populations from ten provinces, and the genetic diversities among these snail populations were analyzed. RESULTS: The coefficient rates of similarity (GS(DICE)) among twenty five snail populations were ranged was from 0.694 to 0.831 while Nei's unbiased genetic identity was from 0.635 to 0.799. Genetic distance D from 0.169 to 0.306, and Nei's unbiased genetic distance from 0.225 to 0.452. Genetic variation among smooth-shell snail populations was higher than that of ribbed shell snail populations. Twenty five snail populations were divided into three groups: group A including smooth-shell snail from Fuqing of Fujian province and Yizhou of Guangxi province while group B consisted of smooth-shell snail from Dali of Yunnan province and Xichang, Puge, Danleng, Pujiang, Guanghan of Sichuan. Group C was composed of other seventeen snail populations from the Yangtze River drainage below the Three Gorges. CONCLUSION: Big genetic variation was found among these populations of Oncomelania hupensis. The clustering result of snail populations in genomic level was consistent basically with geographical distribution.
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Appropriate sample size and molecular marker loci in the study of genetic diversity of Ocomelania hupensis
Chinese journal of epidemiology, 2005Co-Authors: Yi-biao Zhou, Qingwu Jiang, Genming ZhaoAbstract:OBJECTIVE: To explore the reasonable sample size and the number of molecular marker loci in the study of amplified fragment length polymorphism (AFLP) being used to analyze the genetic diversity of Ocomelania hupensis. METHODS: The ribbed-shelled snails coming from Yueyang, Hunan province, were selected to analyze the relationship of the number of AFLP molecular marker loci and sample size with the reliability of information on genetic variation for Ocomelania hupensis by AFLP method. RESULTS: Correlations found among the numbers of AFLP molecular marker loci and the sample size with reliable information on genetic variation for Ocomelania hupensis. When sample size was less than 7 individuals, the total number of AFLP loci, the number of polymorphic loci, Nei's gene diversity and Shannon's information index appeared great changes. However, when sample size was bigger than 30 individuals, the values of these indices tended to be stabilized. When the number of AFLP loci was less than 128, the frequency of polymorphic loci, Nei's gene diversity, Shannon's information index and the standard deviation of these two indices changed greatly. Again, when the number of loci was bigger than 338, the values of these indices tended to be stabilized. CONCLUSION: When the genetic diversity of Ocomelania hupensis were analyzed by AFLP method, the sample size coming from each snail population should not be less than 30 individuals and the number of molecular loci analyzed not less than 338.
Shi-zhu Li - One of the best experts on this subject based on the ideXlab platform.
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identification of high risk habitats of Oncomelania hupensis the intermediate host of schistosoma japonium in the poyang lake region china a spatial and ecological analysis
PLOS Neglected Tropical Diseases, 2019Co-Authors: Yi Hu, Shi-zhu Li, Michael P Ward, Henry Lynn, Si Li, Jun Zhang, Jian Hu, Shuang Xiao, Chengfang Lu, Zhijie ZhangAbstract:Background Identifying and eliminating snail habitats is the key measure for schistosomiasis control, critical for the nationwide strategy of eliminating schistosomiasis in China. Here, our aim was to construct a new analytical framework to predict high-risk snail habitats based on a large sample field survey for Oncomelania hupensis, providing guidance for schistosomiasis control and prevention. Methodology/Principal findings Ten ecological models were constructed based on the occurrence data of Oncomelania hupensis and a range of variables in the Poyang Lake region of China, including four presence-only models (Maximum Entropy Models, Genetic Algorithm for rule-set Production, Bioclim and Domain) and six presence-absence models (Generalized Linear Models, Multivariate Adaptive Regression Splines, Flexible Discriminant Analysis, as well as machine algorithmic models–Random Forest, Classification Tree Analysis, Generalized Boosted Model), to predict high-risk snail habitats. Based on overall predictive performance, we found Presence-absence models outperformed the presence-only models and the models based on machine learning algorithms of classification trees showed the highest accuracy. The highest risk was located in the watershed of the River Fu in Yugan County, as well as the watershed of the River Gan and the River Xiu in Xingzi County, covering an area of 52.3 km2. The other high-risk areas for both snail habitats and schistosomiasis were mainly concentrated at the confluence of Poyang Lake and its five main tributaries. Conclusions/Significance This study developed a new distribution map of snail habitats in the Poyang Lake region, and demonstrated the critical role of ecological models in risk assessment to directing local field investigation of Oncomelania hupensis. Moreover, this study could also contribute to the development of effective strategies to prevent further spread of schistosomiasis from endemic areas to non-endemic areas.
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field evaluation of a novel molluscicide niclosamidate against Oncomelania hupensis intermediate host of schistosoma japonicum
Parasitology Research, 2017Co-Authors: Weisi Wang, Shi-zhu Li, Xia Zhang, Huaming Zhang, Hehua Hu, Liping DuanAbstract:The molluscicidal activity of a novel molluscicide (niclosamidate) was evaluated in field trials against Oncomelania hupensis, the intermediate host of Schistosoma japonicum. The environmental safety of niclosamidate for local fishes was also studied under field conditions. The results showed that, at the dosages of 8.0 g/m2 and 4.0 g/m3, niclosamidate exhibits highly potent molluscicidal activity in the spraying and immersion trials, resulting in mortality rates of up to 81.8 and 72.7%, respectively. Its performance seems to be target-specific, with good molluscicidal ability observed for Oncomelania hupensis snails, but very low toxicity for local fishes and other aquatic organisms. The results suggest that niclosamidate can be used as an alternative molluscicide for snail control, which would be particularly applicable in semi-commercial or commercial aquaculture ponds.
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the genetic diversity and geographical separation study of Oncomelania hupensis populations in mainland china using microsatellite loci
Parasites & Vectors, 2016Co-Authors: Wei Guan, Shi-zhu Li, Bonnie L Webster, David Rollinson, Xiao-nong ZhouAbstract:Background Oncomelania hupensis is the unique intermediate host of Schistosoma japonicum, which plays a crucial role in the transmission of schistosomiasis. The endemic area of S. japonicum is strictly consistent with the geographical distribution of O. hupensis.
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Progress on molecular phylogeography and its application in Oncomelania hupensis research
2013Co-Authors: Li Zhang, Kun Yang, Shi-zhu LiAbstract:Objective Molecular phylogeography is a new discipline emerging with the development of mitochondrial DNA in the middle 1970's,providing a new method and idea for the study on population genetic differentiation of Oncomelania hupensis.The history and research methods of molecular phylogeography were introduced,and the application in population genetic differentiation of Oncomelania hupensis was analyzed,as well as the future research direction was addressed in this paper. Key words: Molecular phylogeography; Oncomelania hupensis; Population genetic differentiation
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Advances on genetics and biological characteristics of Oncomelania hupensis
Chinese Journal of Parasitology and Parasitic Diseases, 2009Co-Authors: Xiao-nong Zhou, Shi-zhu Li, Yi ZhangAbstract:: This review focused on the research progress in genetic features of Oncomelania hupensis, including its relation to the snail distribution, susceptibility to Schistosoma japonicum. Series studies were done on genetic characteristics for snail distribution and its infectivity with S. japonicum by using population genetics and molecular biology approaches to explore the new avenue to block the transmission of schistosomiasis. However, limited progress has been achieved in this field inside in China comparing with global achievements. It is therefore recommended that future studies have to be focused on genetic features related to schistosome infections by referencing the study model of Biomphalaria glabrata/S. mansoni, and with assistance of modern technology on bionics, in order to improve investigations on genetics of Oncomelania hupensis in the country.
Liping Duan - One of the best experts on this subject based on the ideXlab platform.
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field evaluation of a novel molluscicide niclosamidate against Oncomelania hupensis intermediate host of schistosoma japonicum
Parasitology Research, 2017Co-Authors: Weisi Wang, Shi-zhu Li, Xia Zhang, Huaming Zhang, Hehua Hu, Liping DuanAbstract:The molluscicidal activity of a novel molluscicide (niclosamidate) was evaluated in field trials against Oncomelania hupensis, the intermediate host of Schistosoma japonicum. The environmental safety of niclosamidate for local fishes was also studied under field conditions. The results showed that, at the dosages of 8.0 g/m2 and 4.0 g/m3, niclosamidate exhibits highly potent molluscicidal activity in the spraying and immersion trials, resulting in mortality rates of up to 81.8 and 72.7%, respectively. Its performance seems to be target-specific, with good molluscicidal ability observed for Oncomelania hupensis snails, but very low toxicity for local fishes and other aquatic organisms. The results suggest that niclosamidate can be used as an alternative molluscicide for snail control, which would be particularly applicable in semi-commercial or commercial aquaculture ponds.
Yi-biao Zhou - One of the best experts on this subject based on the ideXlab platform.
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multi host model and threshold of intermediate host Oncomelania snail density for eliminating schistosomiasis transmission in china
Scientific Reports, 2016Co-Authors: Yi-biao Zhou, Yue Chen, Song Liang, Xiuxia Song, Gengxin Chen, Zhong He, Wuli Yihuo, Zonggui He, Qingwu JiangAbstract:Schistosomiasis remains a serious public health issue in many tropical countries, with more than 700 million people at risk of infection. In China, a national integrated control strategy, aiming at blocking its transmission, has been carried out throughout endemic areas since 2005. A longitudinal study was conducted to determine the effects of different intervention measures on the transmission dynamics of S. japonicum in three study areas and the data were analyzed using a multi-host model. The multi-host model was also used to estimate the threshold of Oncomelania snail density for interrupting schistosomiasis transmission based on the longitudinal data as well as data from the national surveillance system for schistosomiasis. The data showed a continuous decline in the risk of human infection and the multi-host model fit the data well. The 25th, 50th and 75th percentiles, and the mean of estimated thresholds of Oncomelania snail density below which the schistosomiasis transmission cannot be sustained were 0.006, 0.009, 0.028 and 0.020 snails/0.11 m2, respectively. The study results could help develop specific strategies of schistosomiasis control and elimination tailored to the local situation for each endemic area.
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Oncomelania hupensis gastropoda rissooidea intermediate host of schistosoma japonicum in china genetics and molecular phylogeny based on amplified fragment length polymorphisms
Malacologia, 2007Co-Authors: Yi-biao Zhou, Genming Zhao, Meixia Yang, Qingwu JiangAbstract:Schistosomiasis japonica is one of the most serious parasitic diseases in China. Subspecies of the pomatiopsid snail species Oncomelania hupensis transmit the human blood fluke Schistosoma japonicum, the parasite causing the disease. In at least one study involving the subspecies Oncomelania hupensis robertsoni, there was no clear phylogenetic concordance between the mitochondrial and nuclear data, and it was strongly recommended that future studies incorporate more data from nuclear loci in order to better understand phylogeography and host-parasite coevolution (Wilke et al., 2006). In this paper, we explore genetic diversity based AFLP data involving 25 populations throughout mainland China. AFLP is a DNA fingerprinting technique that detects the polymorphism of the whole genome without prior knowledge of the nucleotide sequence, with the high degree of reproducibility and small amount of template DNA needed. Our AFLP data show that: (1) the genetic diversity within an O. hupensis population increases g...
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Study on the genetic diversity among populations of schistosome intermediate hosts within Oncomelania hupensis (Gastropoda: Rissooidea) in Mainland China
Chinese journal of epidemiology, 2006Co-Authors: Yi-biao Zhou, Genming Zhao, Qingwu JiangAbstract:OBJECTIVE: To explore the genetic diversity among populations of Oncomelania hupensis. METHODS: Amplified fragment length polymorphism method was used to amplify the genomic DNA pools of twenty five snail populations from ten provinces, and the genetic diversities among these snail populations were analyzed. RESULTS: The coefficient rates of similarity (GS(DICE)) among twenty five snail populations were ranged was from 0.694 to 0.831 while Nei's unbiased genetic identity was from 0.635 to 0.799. Genetic distance D from 0.169 to 0.306, and Nei's unbiased genetic distance from 0.225 to 0.452. Genetic variation among smooth-shell snail populations was higher than that of ribbed shell snail populations. Twenty five snail populations were divided into three groups: group A including smooth-shell snail from Fuqing of Fujian province and Yizhou of Guangxi province while group B consisted of smooth-shell snail from Dali of Yunnan province and Xichang, Puge, Danleng, Pujiang, Guanghan of Sichuan. Group C was composed of other seventeen snail populations from the Yangtze River drainage below the Three Gorges. CONCLUSION: Big genetic variation was found among these populations of Oncomelania hupensis. The clustering result of snail populations in genomic level was consistent basically with geographical distribution.
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Appropriate sample size and molecular marker loci in the study of genetic diversity of Ocomelania hupensis
Chinese journal of epidemiology, 2005Co-Authors: Yi-biao Zhou, Qingwu Jiang, Genming ZhaoAbstract:OBJECTIVE: To explore the reasonable sample size and the number of molecular marker loci in the study of amplified fragment length polymorphism (AFLP) being used to analyze the genetic diversity of Ocomelania hupensis. METHODS: The ribbed-shelled snails coming from Yueyang, Hunan province, were selected to analyze the relationship of the number of AFLP molecular marker loci and sample size with the reliability of information on genetic variation for Ocomelania hupensis by AFLP method. RESULTS: Correlations found among the numbers of AFLP molecular marker loci and the sample size with reliable information on genetic variation for Ocomelania hupensis. When sample size was less than 7 individuals, the total number of AFLP loci, the number of polymorphic loci, Nei's gene diversity and Shannon's information index appeared great changes. However, when sample size was bigger than 30 individuals, the values of these indices tended to be stabilized. When the number of AFLP loci was less than 128, the frequency of polymorphic loci, Nei's gene diversity, Shannon's information index and the standard deviation of these two indices changed greatly. Again, when the number of loci was bigger than 338, the values of these indices tended to be stabilized. CONCLUSION: When the genetic diversity of Ocomelania hupensis were analyzed by AFLP method, the sample size coming from each snail population should not be less than 30 individuals and the number of molecular loci analyzed not less than 338.
