Survey Of Epidemiology And Primary Study On Molecular Biology Of Cyclopora Cayetanensis In Zhengzhou And Kaifeng, Henan Province

The prevalences of Cyclospora cayetanensis infection were studied in two cities in Henan province, China. Stool specimens were collected from June 2007 through December 2008. Single stool specimens were collected from 9150 individuals (age range=1 month to 107 years),5454 males and 3696 females. Each specimen was processed and examined by direct wet smear, modified acid fast stain, formalin-ethyl acetate sedimentation concentration technique, and molecular biology technique. For other pathogenic parasites formalin-ether concentrates and iodine wet mount smears were examined. Overall the main infection rate was 0.62%(61/9150). The infection rate for male was 0.68%(37/5454) and 0.54%(20/3696) for female with no significant difference (P>0.05). The infection rate C. cayetanensis infection in persons aged≤6 years old,7-17 years old,18-28 years old,29-44 years old,> 45 years old were 0.63% (5/788),0.87%(5/572),0.81%(9/1105),0.70%(13/1859),0.52%(25/4826) respectively with no significant difference (P>0.05). The positive rates of population in Zhengzhou and Kaifeng were 0.29%(9/3057) and 0.79%(48/6093) respectively with significant difference (P<0.01). The infection appears to have marked seasonality, with highest proportion of C. cayetanensis occurred during the rainy season (July-September). Then we used a nested PCR assay to amplify a 501-bp region of the small subunit rRNA gene and a single round PCR assay to amplify a 500bp region of ITS-1 gene, followed by DNA sequence analysis, then, Blast or Fasta was used to search homological sequences in NCBI, DDBJ and EMBL. After that, homological sequences were alignmented. Phylogenetic tree and homological analysis were made by some biological softwares such as Clustal X 1.81 and DNAstar4.0. Compare with the available C. cayetanensis species sequences for 18S rRNA gene there were two hypervariable sites at 687bp and 696bp. Based on the genotyping analysis, the thirty-five were identified as·C. cayetanensis. The sequence alignments and phylogenetic analyses showed that there are no significant difference in isolates from different geographic area over the world. The sequence alignments and phylogenetic analyses of ITS-1 gene showed that the sequences in the same geographic area are highly homophylic and the sequences from different geographic areas are significant difference.