Study On The Prevalence And Population Structure Of Cryptosporidium And Giardia Lamblia In Yaks From Qinghai Province

Cryptosporidium and Giardia lamblia are two important opportunistic zoonotic intestinal parasite with widely host range,which have been prevalent all over the world.Both of them are threat to human health,and also have harmful effect on the production performance of animals.Since yaks are the dominant species of livestock in Qinghai province,it is necessary to master the epidemic trends and the population structure of Cryptosporidium and G.lamblia in yaks in Qinghai province in order to provide basic data for the prevention and control of cryptosporidiosis and giardiasis.The prevalence of Cryptosporidium and G.lamblia of yaks in Qinghai province was investigated using nested PCR,and the population structure was analyzed.The results were obtained as follows:1.The PCR amplification based on 18 S rRNA and HSP70 genes of Cryptosporidium was used to detect and analyze 1,027 feces samples of yaks collected from 7 regions of Qinghai province.The overall infection rate of Cryptosporidium was 2.53%(26/1027),with no significant difference in infection rates among 7 regions as well as seasons.There was also no significant difference in infection rates of Cryptosporidium between the yaks within 6 months and over 6 months,which were 6.25% and 2.35% respectively.Phylogenetic analysis showed that C.ryanae and C.bovis were found in Qinghai province,and C.ryanae was dominant species of Cryptosporidium that infected yaks in Qinghai province.2.The PCR amplification based on TPI gene of G.lamblia was used to detect and analyze 1,027 feces samples of yaks collected from 7 regions of Qinghai province.The overall infection rate of G.lamblia was 2.04%(21/1207),with no significant difference in infection rates among 7 regions as well as seasons.However,there was significant difference in infection rates of Cryptosporidium between the yaks within 6 months and over 6 months,which were 8.33% and 1.73% respectively.Sequence alignment showed that assemblages E(18/21)and assemblages A(3/21)of G.lamblia were identified.Four assemblages E subtypes(E1-E4)and 1 assemblages A subtype A1 were found,among which E2-E4 were novel assemblages subtypes.The results of multilocus sequence typing based on TPI,BG and GDH genes showed that 3 G.lamblia isolates were amplified at 3 loci successfully,forming 3different MLGs.Among others,2 assemblages E MLGs were found in yaks in Yushu and 1assemblages A MLG was found in yaks in Xining.