Phylogenetic Analysis Of The Two Gastrointestinal Nematodes In Frogs

Anura distributes broadly on the earth. Most of them are natural enemy of insects. Some of them can be used as food and drugs, moreover used in teaching, scientific research and clinical medicine. Parasites in frogs cause frog parasitic diseases and even spread to human via mouth or other ways.This study was firstly reported the investigation of gastrointestinal nematodes in Frogs in Hunan province. Results showed that total infection rate of gastrointestinal nematode in Frogs was96.2%. Infection rate of Toxascaris leonine and Contracaecum osculatum was54.5%,41.7%respectively. This two parasites have typical structure features compared with that in other animal hosts.Based on conserved DNA sequence of mitochondria coxl, a pair of the primers for mitochondria coxl was designed. Part sequences of mitochondria coxl gene were cloned and sequenced and then analyses by bioinformatics. Results showed that: Intraspecific differences of the pcoxl sequences for Toxascaris leonine and Contracaecum osculatum were respectively6.6%-8.4%and6.6%-7.9%; Inter-species differences of the pcoxl sequences for Toxascaris leonine and Contracaecum osculatum were respectively72.7%-81.9%and46.8%-67.9%. The pcox1sequences homology of Toxascaris leonine in frogs was91.6%-93.4%compared with that in cats and dogs. And that of Contracaecum osculatum was92.1%-93.4%compared with that in seals.In conclusion, the gastrointestinal nematodes in frogs were Toxascaris leonina and Contracaecum osculatum in Hunan province. They have typical structure features of this two parasites and high infection rates in frogs. Their cox1sequences were greatly conservative and had some intraspecific differences. They can be used for their classification and identify as genetic markers.