Sequence variability in the first internal transcribed spacer region within and among Cyclospora species is consistent with polyparasitism

• Published in: International journal for parasitology 2001-11, Vol.31 (13), p.1475-1487
• Main Authors: Olivier, C., van de Pas, S., Lepp, P.W., Yoder, K., Relman, D.A.
• Format: Article
• Language: English
• Subjects: Animals; Base Sequence; Biological and medical sciences; Coccidiosis; Cyclospora - chemistry; Cyclospora - classification; Cyclospora - genetics; Cyclospora cayetanensis; Cyclospora papionis; Cyclosporiasis - parasitology; DNA, Protozoan - chemistry; DNA, Protozoan - genetics; DNA, Protozoan - isolation & purification; DNA, Ribosomal - chemistry; DNA, Ribosomal - genetics; DNA, Ribosomal Spacer - chemistry; DNA, Ribosomal Spacer - genetics; Fundamental and applied biological sciences. Psychology; Genetic Variation; Human protozoal diseases; Humans; Infectious diseases; Internal transcribed spacer; Medical sciences; Molecular Sequence Data; Parasitic diseases; Phylogeny; Polymerase Chain Reaction - methods; Polymerase chain reaction-based diagnosis; Polyparasitism; Protozoa; Protozoal diseases; Ribosomal DNA; RNA, Ribosomal, 5.8S - genetics; rRNA 5.8S; rRNA Operon - genetics; Sequence Homology, Nucleic Acid; Species Specificity; Systematics. Geographical distribution. Morphology. Cytology
• ISSN: 0020-7519; 1879-0135
• DOI: 10.1016/S0020-7519(01)00283-1

Cyclospora cayetanensis is a coccidian parasite which causes severe gastroenteritis in humans. Molecular information on this newly emerging pathogen is scarce. Our objectives were to assess genetic variation within and between human-associated C. cayetanensis and baboon-associated Cyclospora papionis by examining the internal transcribed spacer (ITS) region of the ribosomal RNA operon, and to develop an efficient polymerase chain reaction- (PCR)-based method to distinguish C. cayetanensis from other closely related organisms. For these purposes, we studied C. cayetanensis ITS-1 nucleotide variability in 24 human faecal samples from five geographic locations and C. papionis ITS-1 variability in four baboon faecal samples from Tanzania. In addition, a continuous sequence encompassing ITS-1, 5.8S rDNA and ITS-2 was determined from two C. cayetanensis samples. The results indicate that C. cayetanensis and C. papionis have distinct ITS-1 sequences, but identical 5.8S rDNA sequences. ITS-1 is highly variable within and between samples, but variability does not correlate with geographic origin of the samples. Despite this variability, conserved species-specific ITS-1 sequences were identified and a single-round, C. cayetanensis-specific PCR-based assay with a sensitivity of one to ten oocysts was developed. This consistent and remarkable diversity among Cyclospora spp. ITS-1 sequences argues for polyparasitism and simultaneous transmission of multiple strains.