Studies On Prevalence And Genotypes Of G.lamblia,B.hominis And E.bieneusi In Humans In Dali

?Objective?Giardia lamblia,Blastocystis hominis and Enterocytozoon bieneusi are the most common parasitic protozoa existing in human intestines in China.They can infect a wide range of hosts,including humans and most vertebrates with a worldwide distribution.G.lamblia,E.bieneusi are opportunistic pathogenic protozoa,immunocompromised patients such as AIDS and malignant tumor can be easily infected,which can cause diarrhea,stomachache,vomit,even lead to death.This study aims to study the prevalence and genotypes of G.lamblia,B.hominis and E.bieneusi in humans in Dali,Yunnan province.?Methods?In this study,fecal DNA samples of undergraduates and inhabitants in Dali,Yunnan province were tested for the TPI and BG gene of G.lamblia,the SSU r RNA partial gene of B.hominis,and the ITS gene of E.bieneusi by PCR,respectively.Genotypes were identified by DNA sequencing and phylogenetic analysis.The risk factors were analyzed by chi-square test.?Results?In the first part,a total of 426 fecal samples were collected from healthy undergraduates in Dali University,18 samples were tested as G.lamblia positive,6 samples were B.hominis positive and 1 sample was E.bieneusi positive based on the TPI gene,SSU rRNA partial gene and ITS gene,respectively.The overall prevalence of G.lamblia infection was 4.23%(18/426,95%CI 2.32-6.14).The prevalence of G.lamblia infection for college students living in rural area was 5.57%(17/305,95%CI 2.99-8.14),while it was 5.57%(17/305,95%CI 2.99-8.14)for college students living in city,and the difference was statistically significant(P=0.028).The prevalence of G.lamblia infection was 6.37%(10/157,95%CI 2.55-10.19)in male,and was 2.97%(8/269,95%CI 0.94-4.99)in female.There is no statistically significant difference in G.lamblia prevalence between different genders and ethnic groups,(P > 0.05).Sequence analyses confirmed that the identified G.lamblia isolates as G.lamblia AI sub-genotype.The overall prevalence of B.hominis infection was 1.41%(6/426,95%CI 0.29-2.53).There is no statistically significant differencein B.hominis prevalence between different genders,ethnic groups,and regions(P>0.05).Sequence analyses confirmed that the identified B.hominis isolates as B.hominis ST1 sub-genotype.The overall prevalence of E.bieneusi infection was 0.23 %(1/426),and sequence analysis confirmed that the identified E.bieneusi isolate as E.bieneusi EbpC genotype.One case of co-infection of G.lamblia and B.hominis was found in this part.In the second part,a total of 596 fecalsamples were collected from healthy inhabitants in the Bai concentrated area,Dali,Yunnan province.Four samples were tested as G.lamblia positive based on the BG gene,but no B.hominis positive sample was detected.The overall prevalence of G.lamblia infection was 0.67%(4/596,96%CI 0.02-1.32),the G.lamblia prevalence in male was 0.66%(2/301,95%CI 0-0.016),and the prevalence in female was 0.67(2/295,95%CI 0-0.016);the prevalence in Bai nationality was 0.95%(3/317,95%CI 0-0.020),the prevalence in Han nationality was 0.36%(1/279,95%CI 0-0.011);the prevalence in farmer was 1.09%(4/364,95%CI 0-0.022),but no G.lamblia positive sample was detected in other vocations;the G.lamblia prevalence in the elderly group was 1.85%(3/162,95%CI 0-0.039),the prevalence in the middle-aged group was 0.29%(1/324,95%CI 0-0.009),but no G.lamblia positive samples was detected in other two age groups.The result indicated that there were no statistically differences in G.lamblia prevalence among different groups(P>0.05).Sequence analyses confirmed the identified G.lamblia strains as G.lamblia B and E genotypes.?Conclusion? 1.The prevalence of G.lamblia,B.hominis,E.bieneusi infection was 4.23%,1.41%,0.23%,respectively,in healthy undergraduates in Dali university.The prevalence of G.lamblia infection was 0.67% in healthy inhabitants in the Bai concentrated area.2.Sequence analyses confirmed the identified protozoans as G.lamblia AI sub-genotype,B genotype and E genotype,B.hominis ST1 sub-genotype,and E.bieneusi EbpC genotype.3.This is the first time that G.lamblia E genotype was found in human feces in China,indicating that G.lamblia E genotypehas zoonotic potential.One case of co-infection of G.lamblia and B.hominis was found.