Genetic Polymorphism among Cryptosporidium parvum Isolates: Evidence of Two Distinct Human Transmission Cycles

Michael M. Peng, Lihua Xiao, Amanda R. Freeman, Michael J. Arrowood, Ananias A. Escalante, André C. Weltman, Corinne S L Ong, William R. Mac Kenzie, Altaf A. Lal, Charles B. Beard

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315 Scopus citations

Abstract

We report the results of molecular analysis of 39 isolates of Cryptosporidium parvum from human and bovine sources in nine human outbreaks and from bovine sources from a wide geographic distribution. All 39 isolates could be divided into either of two genotypes, on the basis of genetic polymorphism observed at the thrombospondin-related adhesion protein (TRAP-C2) locus. Genotype 1 was observed only in isolates from humans. Genotype 2, however, was seen in calf isolates and in isolates from a subset of human patients who reported direct exposure to infected cattle or consumed items thought to be contaminated with cattle feces. Furthermore, experimental infection studies showed that genotype 2 isolates were infective to mice or calves under routine laboratory conditions, whereas genotype 1 isolates were not. These results support the occurrence of two distinct transmission cycles of C. parvum in humans.

Original languageEnglish (US)
Pages (from-to)567-573
Number of pages7
JournalEmerging Infectious Diseases
Volume3
Issue number4
Publication statusPublished - 1997
Externally publishedYes

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ASJC Scopus subject areas

  • Microbiology (medical)

Cite this

Peng, M. M., Xiao, L., Freeman, A. R., Arrowood, M. J., Escalante, A. A., Weltman, A. C., ... Beard, C. B. (1997). Genetic Polymorphism among Cryptosporidium parvum Isolates: Evidence of Two Distinct Human Transmission Cycles. Emerging Infectious Diseases, 3(4), 567-573.