Infection of Blastocystis and Cyclospora cayetanensis in residents in Eryuan County,Yunnan Province and their molecular characterization
Objective To investigate the prevalence and molecular characterizations of Blastocystis and Cy-clospora cayetanensis in residents in Eryuan County,Yunnan Province to provide reference for parasitic disease control and prevention.Methods From July to August 2022,permanent residents over the age of 1 were enrolled for the survey by simple random sampling from the five villages in Eryuan County,Yunnan Province.Fresh fecal samples and their social demographic information were collected.The fecal genomic DNA was extracted,and the ribosomal small subunit RNA(SSU rRNA)genes of Blastocystis and C.cayetanensis were amplified by PCR and nested PCR,re-spectively,in order to analyze the prevalence in the residents.The positive products were sequenced bidirectionally,the species and gene subtypes were identified by BLAST alignment in NCBI.The phylogenetic trees were constructed using the neighbor-Joining method by MEGA 11.0 software.SPSS 21.0 software was used for statistical analysis,and the infection rates were compared by x2 test or Fisher's exact probability method.Results A total of 100 fecal samples were obtained from residents,of which the Blastocystis infection rate was 14.0％(14/100).Among them,the Blastocystis infection rates in male and female were 14.6％(6/41)and 13.6％(8/59),respectively.Residents over 60 years old and the family size of 6 persons and above had the highest infection rate,which was 18.5％(5/27)and 3/15,respectively.The infection rates were 2/11 and 17.0％(8/47)for those with no education and only elementary school education,respectively.All the infected residents were farmers.There was no statistically significant difference in Blasto-cystis infection rate by gender,age,family size,education level and occupation(x2=0.023,2.730,2.235,1.404,1.668;all P＞0.05).The C.cayetanensis infection rate was 2.0％(2/100).All of the infected residents were female farmers.No mixed infection of Blastocystis and C.cayetanensis was detected.Both 7 ST1 and ST3 sequences were amplified from 14 Blastocystis-positive samples,of which 7 ST1 sequences had 25 nucleotide differences.Five sequences were 100％homology to the Blastocystis sequences(GenBank:ON932511,KU147348,MK801408,MW728079,OR754904);2 were new sequences(GenBank:PP439288-PP439289),with 99.8％homology to the Blastocystis sequences(GenBank:OP725964,KU 147333).There was 1 nucleotide difference within 7 ST3 sequences,with 100％homology to the Blastocys-tis sequences(GenBank:KU147372,MK801366).The 2 sequences of C.cayetanensis obtained were identical and showed 100％homology to the C.cayetanensis sequence(GenBank:KY770755).The phylogenetic trees showed that Blastocystis in this study clustered in large branches with gene subtype ST1 and ST3,respectively,and C.cayetanensis clustered in the same branch with C.cayetanensis of human origin.Conclusion Blastocystis and C.cayetanensis were detected in the residents of Eryuan County,Yunnan Province.The infection rate of Blastocystis was high,with the subtypes of ST1 and ST3,and the ST1 of Blastocystis reveals higher genetic variation.
BlastocystisCyclospora cayetanensisInfectionMolecular characterizationEryuan County
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NSTL
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