Background:Biomphalaria straminea is an invasive vector in China,posing a significant threat to public health.Understanding the factors affecting the establishment of this snail is crucial to improve our ability to ma...Background:Biomphalaria straminea is an invasive vector in China,posing a significant threat to public health.Understanding the factors affecting the establishment of this snail is crucial to improve our ability to manage its dispersal and potential risk of schistosomiasis transmission.This study sought to determine the spatial distribution of B.straminea in China's Mainland and whether environmental factors were divergent between places with and without B.straminea.Methods:A malacological survey of B.straminea was conducted in Guangdong Province,China.Snails were identified using anatomical keys.Water and sediment samples were taken,and their physicochemical properties were analyzed using national standard methods.Landscape and climatic variables were also collected for each site.We compared the environmental characteristics between sites with and without B.straminea using Mann-Whitney U test.We further used generalized linear mixed models to account for seasonal effects.Results:B.straminea was found at six sites,including one in Dongguan and five in Shenzhen.Probability map found a hot spot of B.straminea distribution at Shenzhen and Hong Kong.Sites occupied by B.straminea were characterized by higher median altitude,mean annual precipitation and moderate temperature.Water with snails had higher median concentrations of total nitrogen,nitrate and nitrites,ammoniacal nitrogen,calcium,zinc and manganese but lower dissolved oxygen and magnesium.Sediments with snails had higher median copper,zinc and manganese.B.straminea was associated with maximum temperature of the warmest month(pMCMC<0.001)and sediment zinc(pMCMC<0.001).Conclusions:B.straminea is distributed in Shenzhen and its surrounding areas in Guangdong,China.Sites with and without B.straminea differed in the maximum temperature of the warmest month and sediment zinc.Surveillance should be continued to monitor the dispersal of this snail in China.展开更多
Background:Schistosomiasis is a common parasitic disease designated as a neglected tropical disease by the World Health Organization.Schistosomiasis mansoni is a form of the disease that is caused by the digenean trem...Background:Schistosomiasis is a common parasitic disease designated as a neglected tropical disease by the World Health Organization.Schistosomiasis mansoni is a form of the disease that is caused by the digenean trematode Schistosoma mansoni,transmitted through Biomphalaria spp.as an intermediate host.Biomphalaria was introduced to Hong Kong,China in aquatic plants shipments coming from Brazil and the snail rapidly established its habitats in southern China.Earlier studies of Biomphalaria spp.introduced to southern China identified the snails as Biomphalaria straminea,one of the susceptible species implicated in S.mansoni transmission in South America.However,recent molecular investigations also indicated the presence of another South American species,B.kuhniana,which is refractory to infection.As such,it is important to identify accurately the species currently distributed in southern China,especially with emerging reports of active S.mansoni infections in Chinese workers returning from Africa.Methods:We combined morphological and molecular taxonomy tools to precisely identify Biomphalaria spp.distributed in Guangdong Province,southern China.In order to clearly understand the molecular profile of the species,we constructed a phylogeny using mtDNA data(COI and 16S rRNA sequences)from six populations of Biomphalaria spp.from Shenzhen City in Guangdong Province.In addition,we examined the external morphology of the shell and internal anatomy of the reproductive organs.Results:Both morphological and molecular evidences indicated a close affinity between Biomphalaria spp.populations from Guangdong and B.straminea from Brazil.The shell morphology was roughly identical in all the populations collected with rounded whorls on one side and subangulated on the other,a smooth periphery,an egg-shaped aperture bowed to one side,and a deep umbilicus.The shape and number of prostate diverticula(ranged from 11.67 to 17.67)in Guangdong populations supports its close affinity to B.straminea rather than B.kuhniana.Molecular analysis did not conflict with morphological analysis.Little genetic differentiation was observed within Biomphalaria populations collected.Phylogenetic analysis of COI and 16S rRNA haplotypes from snails collected and B.straminea sequences from Brazil and China using Bayesian inference revealed that Guangdong populations were clustered in one clade with B.straminea from Hong Kong of China and B.straminea from Brazil indicating their close affinity to each other.Conclusions:Data obtained in the current study clearly show that the populations of Biomphalaria spp.investigated are B.straminea,and we assume that those snails were either introduced via passive dispersal from Hong Kong of China or as a result of multiple introduction routes from Brazil.展开更多
A few individuals with intermediate morphology always appeared in the sympatric distributions of Gentiana straminea and G.siphonantha.These intermediate individuals were hypothesized to be the hybrids of two species a...A few individuals with intermediate morphology always appeared in the sympatric distributions of Gentiana straminea and G.siphonantha.These intermediate individuals were hypothesized to be the hybrids of two species after a careful evaluation of their morphological characteristics.To test this hypothesis,sequence comparison of the internal transcribed spacer(ITS)regions of the nuclear ribosomal and trnS(GCU)-trnG(UCC)intergenic spacer region of the chloroplast DNA from Gentiana straminea,G.siphonantha and the putative hybrids was performed.The results suggest that most intermediate individuals were the natural hybrids between G.straminea and G.siphonantha.In addition,we examined the sequence variation among the individuals of both parent species and analyzed the possibility leading to the incongruent identification in some individuals based on morphologic and molecular evidences,respectively.The intraspecific diversification of DNA fragments within both parent species and their high variability in hybrid swarms probably resulted from chloroplast genome recombination and incomplete lineage sorting during the early stages of speciation origin of the parent species.展开更多
目的:本研究旨在开发无人机影像与深度学习结合技术,实现对野外大范围两种秦艽组植物的快速识别与资源量评估。方法:本研究选用具有较高精度的You Only Look Once(YOLO)系列模型用于识别麻花艽和粗茎秦艽,并分别探究输入图像尺寸、模型...目的:本研究旨在开发无人机影像与深度学习结合技术,实现对野外大范围两种秦艽组植物的快速识别与资源量评估。方法:本研究选用具有较高精度的You Only Look Once(YOLO)系列模型用于识别麻花艽和粗茎秦艽,并分别探究输入图像尺寸、模型结构及数据增强方法对训练过程及模型性能的影响。结果:640×640图像尺寸下YOLOv5s模型综合性能最优,平均mAP_(0.5)达93.2%(粗茎秦艽0.919,麻花艽0.944),较160×160图像尺寸提升22.1%。混合数据增强显著提升模型鲁棒性,使粗茎秦艽与麻花艽的跨尺度检测指标(mAP_(0.5)∶0.95)分别提升20.3%和28.5%,其中云雾模糊增强对麻花艽识别效果突出(mAP_(0.5)∶0.95+9.6%)。在样本量占比29.7%的麻花艽识别中,模型仍保持91.2%的mAP_(0.5),F1-score达0.906。结论:本研究提出的“无人机影像+图像增强+深度学习”技术方案,实现了自然生长区域中药用植物的高效识别(训练耗时0.629小时,综合精度>93%),不同的图像增强技术在对不同生长区域和不同特征植物的识别中能产生明显影响,利用图像增强可以有效提高光照不足或者云雾遮挡下获取图像的识别精度。该成果为野外大范围粗茎秦艽和麻花艽资源蕴藏量的动态监测提供了可推广的技术,对实现资源可持续利用具有重要实践价值。展开更多
基金This work was supported by the National Research and Development Plan of China(No.2016YFC1200500).
文摘Background:Biomphalaria straminea is an invasive vector in China,posing a significant threat to public health.Understanding the factors affecting the establishment of this snail is crucial to improve our ability to manage its dispersal and potential risk of schistosomiasis transmission.This study sought to determine the spatial distribution of B.straminea in China's Mainland and whether environmental factors were divergent between places with and without B.straminea.Methods:A malacological survey of B.straminea was conducted in Guangdong Province,China.Snails were identified using anatomical keys.Water and sediment samples were taken,and their physicochemical properties were analyzed using national standard methods.Landscape and climatic variables were also collected for each site.We compared the environmental characteristics between sites with and without B.straminea using Mann-Whitney U test.We further used generalized linear mixed models to account for seasonal effects.Results:B.straminea was found at six sites,including one in Dongguan and five in Shenzhen.Probability map found a hot spot of B.straminea distribution at Shenzhen and Hong Kong.Sites occupied by B.straminea were characterized by higher median altitude,mean annual precipitation and moderate temperature.Water with snails had higher median concentrations of total nitrogen,nitrate and nitrites,ammoniacal nitrogen,calcium,zinc and manganese but lower dissolved oxygen and magnesium.Sediments with snails had higher median copper,zinc and manganese.B.straminea was associated with maximum temperature of the warmest month(pMCMC<0.001)and sediment zinc(pMCMC<0.001).Conclusions:B.straminea is distributed in Shenzhen and its surrounding areas in Guangdong,China.Sites with and without B.straminea differed in the maximum temperature of the warmest month and sediment zinc.Surveillance should be continued to monitor the dispersal of this snail in China.
基金This work was supported by the National Key Research and Development Program of China(No.2016YFC1202001)Research Fund for the Technical Reserves,National Institute of Parasitic Diseases,Chinese CDC(No.CB-1603)+1 种基金Mohamed R.Habib was supported by a Post-doctoral Programme from the Ministry of Science and Technology of China and National Center for International Research on Tropical Diseases(Shanghai,China)Roberta L.Caldeira is supported by a fellowship from Conselho Nacional de Desenvolvimento Científico e Tecnologico/CNPq(No.304121/2014–2).
文摘Background:Schistosomiasis is a common parasitic disease designated as a neglected tropical disease by the World Health Organization.Schistosomiasis mansoni is a form of the disease that is caused by the digenean trematode Schistosoma mansoni,transmitted through Biomphalaria spp.as an intermediate host.Biomphalaria was introduced to Hong Kong,China in aquatic plants shipments coming from Brazil and the snail rapidly established its habitats in southern China.Earlier studies of Biomphalaria spp.introduced to southern China identified the snails as Biomphalaria straminea,one of the susceptible species implicated in S.mansoni transmission in South America.However,recent molecular investigations also indicated the presence of another South American species,B.kuhniana,which is refractory to infection.As such,it is important to identify accurately the species currently distributed in southern China,especially with emerging reports of active S.mansoni infections in Chinese workers returning from Africa.Methods:We combined morphological and molecular taxonomy tools to precisely identify Biomphalaria spp.distributed in Guangdong Province,southern China.In order to clearly understand the molecular profile of the species,we constructed a phylogeny using mtDNA data(COI and 16S rRNA sequences)from six populations of Biomphalaria spp.from Shenzhen City in Guangdong Province.In addition,we examined the external morphology of the shell and internal anatomy of the reproductive organs.Results:Both morphological and molecular evidences indicated a close affinity between Biomphalaria spp.populations from Guangdong and B.straminea from Brazil.The shell morphology was roughly identical in all the populations collected with rounded whorls on one side and subangulated on the other,a smooth periphery,an egg-shaped aperture bowed to one side,and a deep umbilicus.The shape and number of prostate diverticula(ranged from 11.67 to 17.67)in Guangdong populations supports its close affinity to B.straminea rather than B.kuhniana.Molecular analysis did not conflict with morphological analysis.Little genetic differentiation was observed within Biomphalaria populations collected.Phylogenetic analysis of COI and 16S rRNA haplotypes from snails collected and B.straminea sequences from Brazil and China using Bayesian inference revealed that Guangdong populations were clustered in one clade with B.straminea from Hong Kong of China and B.straminea from Brazil indicating their close affinity to each other.Conclusions:Data obtained in the current study clearly show that the populations of Biomphalaria spp.investigated are B.straminea,and we assume that those snails were either introduced via passive dispersal from Hong Kong of China or as a result of multiple introduction routes from Brazil.
基金The project was supported by the National Natural Science Foundation of China(Grant No.30572329).
文摘A few individuals with intermediate morphology always appeared in the sympatric distributions of Gentiana straminea and G.siphonantha.These intermediate individuals were hypothesized to be the hybrids of two species after a careful evaluation of their morphological characteristics.To test this hypothesis,sequence comparison of the internal transcribed spacer(ITS)regions of the nuclear ribosomal and trnS(GCU)-trnG(UCC)intergenic spacer region of the chloroplast DNA from Gentiana straminea,G.siphonantha and the putative hybrids was performed.The results suggest that most intermediate individuals were the natural hybrids between G.straminea and G.siphonantha.In addition,we examined the sequence variation among the individuals of both parent species and analyzed the possibility leading to the incongruent identification in some individuals based on morphologic and molecular evidences,respectively.The intraspecific diversification of DNA fragments within both parent species and their high variability in hybrid swarms probably resulted from chloroplast genome recombination and incomplete lineage sorting during the early stages of speciation origin of the parent species.
文摘目的:本研究旨在开发无人机影像与深度学习结合技术,实现对野外大范围两种秦艽组植物的快速识别与资源量评估。方法:本研究选用具有较高精度的You Only Look Once(YOLO)系列模型用于识别麻花艽和粗茎秦艽,并分别探究输入图像尺寸、模型结构及数据增强方法对训练过程及模型性能的影响。结果:640×640图像尺寸下YOLOv5s模型综合性能最优,平均mAP_(0.5)达93.2%(粗茎秦艽0.919,麻花艽0.944),较160×160图像尺寸提升22.1%。混合数据增强显著提升模型鲁棒性,使粗茎秦艽与麻花艽的跨尺度检测指标(mAP_(0.5)∶0.95)分别提升20.3%和28.5%,其中云雾模糊增强对麻花艽识别效果突出(mAP_(0.5)∶0.95+9.6%)。在样本量占比29.7%的麻花艽识别中,模型仍保持91.2%的mAP_(0.5),F1-score达0.906。结论:本研究提出的“无人机影像+图像增强+深度学习”技术方案,实现了自然生长区域中药用植物的高效识别(训练耗时0.629小时,综合精度>93%),不同的图像增强技术在对不同生长区域和不同特征植物的识别中能产生明显影响,利用图像增强可以有效提高光照不足或者云雾遮挡下获取图像的识别精度。该成果为野外大范围粗茎秦艽和麻花艽资源蕴藏量的动态监测提供了可推广的技术,对实现资源可持续利用具有重要实践价值。
