Study On Prevalence Of Helminths And Molecule Genetics Of Taenias In Dog Of Hunan Province

The species of helminths were about 120 in dogs,while about 50 in human and animals.These parasites caused dogs diarrhea,weight loss,anemia.Especially,it not only affected the growth and development of puppies,leaded to reduce disease resistance,infected by other diseases,but also badly harmed human health.In partâ… of the study,The prevalence of helminths in adult dogs was firstly investigated in Hunan Province.A total of 438 adult farm dogs slaughtered in local abattoirs from 9 representative administrative regions in Hunan Province were examined for the presence of helminths using a helminthological approach.All collected worms were counted and identified to species according to existing keys and descriptions.It resulted that infection rate was cestode 42.68%,toxocara 45.43%, trematode 21.92%,ancylostoma 7.3%,respectively.Mixed infection rate was cestode and toxocara 23.06%,cestode and trematode 19.18%,trematode and toxocara 21.92 %.At the same time,the distribution law of cestodes of the Hunan dog was discovered. Dipylidium caninum of dog was mainly distributed in Yueyang,Zhangjiajie and Huaihua.The infection rate was 60-100%.Diphyllobothrium latum of dog was mainly distributed in Xiangxi and it's infection intensity was a little.The highest infection rate of Spirometra mansoni was 60%,mainly distributed in Zhangjiajie and Xiangxi of mountain area.The infection of Taenia hydatigena was common in mountain area,especially in Zhangjiajie,and the infection rate was 30%.Taenia multiceps and Taenia taeniaformis were mainly distributed in Xiangxi and Huaihua of mountain area and the infection rate was 20%～25%.Overall infection rate of Taenia pisiformis was not high,only 3.42%.The distribution law of other dog' s helminth in Hunan was that the highest infection rate of ancylostoma was in Chen Zhou,amounts to 29.03%;the toxocara was distributed widely,mainly including Toxocara canis and Toxascaris leonine,which the highest infection rates were in Yiyang,and were up 58%and 41%respectively;the trematode was distributed widely,mainly being Clonorchis sinensis,which the highest infection rates were in Chenzhou,51.61%.It provided important data in order to control worm disease of dog.In partâ…¡of the study,the internal transcribed spacer(ITS) sequences of ribosomal DNA(rDNA) of dog cestodes were cloned and sequenced.The ITS sequences of Spirometra mansoni,Taenia hydatigena and Taenia multiceps were obtained firstly.There were ITS sequences of seven cestodes samples.The total length of those ITS sequence was 1200bp～1300bp(ITS-1 720bp,ITS-2 572bp).The content of G + C was 59.33%～53.99%.The seven ITS sequences(DM4XX,DM6YY, DM15ZJ,MM11JT,TH5XX,TH28CS,TPW2XX) were compared.It showed that ITS-1 and ITS-2 sequences of those samples were basically inconsistency.They separated into four population.The similarity of four ITS-1 and ITS-2 sequences were only 41.6%and 7.4%.Even if they were same population from different area,there were differences.The most inter-species similarity was 98.3%and 97.4%.It showed that there were apparent differences between population and there were certain inter-species differences.So ITS sequence could be used for genetic marker of cestodes,which have filled in the research gaps of ITS sequence of dog cestodes.In partâ…¢of the study,mitochondria DNA(mtDNA) nad4 of the dog cestodes have been studied.The mtDNA nad4 were cloned and sequenced.The nad4 sequences of six cestodes samples(MM11JT,TH29CS,TPW32CZ,TPW33CZ, TH45XX,TPW45) were obtained and their sequence length was 523bp.The six nad4 sequences comparison revealed that they separated into three population.The difference among three population were 2.1%～30.1%,more than the inter-species differences(2.2%).So nad4 could be used as genetic marker for population genetic studies of cestodes.In partâ…£of the study,mitochondria DNA(mtDNA) coxl of the dog cestodes have been studied.The mtDNA cox1 were cloned and sequenced.The cox1nad4 sequences of eight cestodes samples(TPW2XX,DM4XX,TH5XX,DM6YY, MM11JT,DM15ZJ,TH28XX,DM31CZ) were obtained and their sequence length was 341bp.The eight cox1 sequences comparison revealed that they separated into four population.The difference among four population were bigger,12.9%～30.3%, 7～85bp.The inter-species differences of Spirometra mansoni were 0.0%～1.8%,and that the inter-species differences of other population were 1～4bp.It showed that cox1 gene sequence were a section of very conservative gene sequence.So it was very suitable that cox1 was used for genetic marker of cestodes classification.In this experiment,nad4 and cox1 genetic variation of cestodes were firstly studied.Genetic variation and DNA polymorphism of mitochondria were carried out from mitochondrial gene.So the effective genetic markers were found which studied molecular taxonomy and Phylogenetic relationship of cestodes.This study have filled in the blank space of research that was related to China's cestodes mitochondrial genome research.In partâ…¤of the study,the specific PCR detection method of dog cestodes was firstly established in China.When done specific PCR detection of dog cestodes,the best annealing temperature was 65℃and the best MgCl₂ concentration was 3.0 mM. When the DNA samples were diluted 640 times,strip still clearly appeared.This was the molecular biology methods of cestodes diagnosis and epidemiological investigation.The researching results has founded the basis of cestodes for further research.