An Application Study Of Sequential Sampling In The Investigaton Of Oncomelania Hupensis Snail In Schistosomiasis Epidemic Area Of Marshland And Lake

As the only intermediate host of schistosomiasis,oncomelania hupensis snail is a very important indicator of schistosomiasis,and was an important risk factor for the transmission and control of schistosomiasis.The identification,investigation,extirpation of snail;identification and demarcation of the epidemic areas of schistosomiasis;the use of these resources,are closely related with the spatial distribution of snails and sampling research questions,only has sufficient understanding about the spatial distribution of snails in epidemic areas and how to sampling in field investigation,the work of schistosomiasis control could reasonable and very fruitful.On November 2013,Upon comprehensive consideration,We set up a 50m×50m square snail spot as a survey area on the grass land of lakeshore.The area in Poyang Lake coastal areas were schistosomiasis endemic areas,the specific position in the Henghu farmland cayegang grassland,Xinjian District of Nanchang city,Jiangxi province.The selected sample,the snail survey methods push-broom for all sampling plots in the box(the size of standard was 1/3m×1/3m = 0.11m~2,and instituting the standard frame agreement)in Oncomelania were carefully investigated,seized all the sampling frame in continuous coverage of the screw nail,and statistics the number of snails.Get the snail data,using sequential analysis of insect population ecology theory,based on the use of mathematical statistics,spatial distribution type of snail populations in different scale sampling units under the access to the relevant letter of regional snail population spatial distribution pattern of information;based on the type of population spatial distribution of Oncomelania hupensis snail.The basic situation of the snail groups of individuals into the analysis;system will present technology at home and abroad for reference to the sequential sampling survey of snail sampling practice,comparison of the sequential sampling method to investigate the optimum sequential sampling model.The conclusions are as follows:(1)The spatial distribution pattern of Oncomelania hupensis snail was studied by used twelve cluster index and eight regression model of the spatial pattern.The results showed that in all indices of aggregation,experimental plots within snail populationsat all scales(within 17/3m×17/3m)sampling unit,the spatial distribution patterns are aggregated distribution;in the analysis of eight regression models,in addition to the La-m power regression model,in the rest of the seven regression model and the experimental plots within snail populations at all scales(within 17/3m × 17/3m)sampling unit,the spatial distribution patterns are aggregated distribution;for the La-m power regression model,the sampling unit scale of 1/3m×1/3m to 10/3m×10/3m scale,distribution of snail population space show aggregated distribution that in the sampling unit scale of 11/3m × 11/3m to 17/3m × 17/3m scale,the snail population spatial distribution pattern for uniform distribution.(2)The basic situation of individual groups of snail population was analyzed.The distribution pattern of experimental plots within the snail population space based on the gathered in the study: using Blacktich population aggregation mean lambda causes aggregation of snail populations may be due to the interaction of heterogeneous snail habitat aggregation behaviour factors and their own or one of factors used;Sylvesetr-cox zero frequency model formula to estimate the average density of snails was 4.2348/0.11m~2,the estimated results of the investigation and the 4.9465/0.11m~2have14.3893% relative errors,so it was not suitable for estimating the average density of the study area were the model of different scales;snail sampling unit average individual group size,by regression analysis,that can estimate the size of the average snail individual groups through the average density;combined with cluster index and La-m regression model,It concluded that the optimal scale of sampling unit was between 3m×3m to 10/3m×10/3m.(3)The optimal sampling model of snail population in the investigated area was studied.The distribution pattern of experimental plots within the snail population based on the spatial aggregation in the study: through seven sequential regression analysis,obtained the maximum amount of sample required sequential sampling analysis of Taylor based on s~2-m regression model are all regression model sequential sampling method in the least,in line with the sequential sampling analysis in a given probability ensure and control the sampling error,as far as possible to reduce the number of sampling is the core idea,model of snail sequential sampling analysis the most suitable test sample.