Zoonotic cryptosporidiosis

Authors

  • Lihua Xiao,

    1. Division of Parasitic Diseases, National Center for Zoonotic, Vector-borne, and Enteric Disease, Center for Disease Control and Prevention, Atlanta, GA, USA
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  • Yaoyu Feng

    1. Division of Parasitic Diseases, National Center for Zoonotic, Vector-borne, and Enteric Disease, Center for Disease Control and Prevention, Atlanta, GA, USA
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  • Present address: Yaoyu Feng, School of Resources and Environmental Engineering, East China University of Science and Technology, Shanghai 200237, China.

  • Editor: Willem van Leeuwen

Correspondence: Lihua Xiao, Division of Parasitic Disease, National Center for Zoonotic, Vector-borne, and Enteric Disease, Center for Disease Control and Prevention, Building 22, Mail Stop F-12, 4770 Buford Highway, Atlanta, GA 30341-3717, USA. Tel.:+1 770 488 4840; fax: +1 770 488 4454; e-mail: lxiao@cdc.gov

Abstract

The widespread usages of molecular epidemiological tools have improved the understanding of cryptosporidiosis transmission. Much attention on zoonotic cryptosporidiosis is centered on Cryptosporidium parvum. Results of genotype surveys indicate that calves are the only major reservoir for C. parvum infections in humans. The widespread presence of human-adapted C. parvum, especially in developing countries, is revealed by recent subtyping and multilocus typing studies, which have also demonstrated the anthroponotic transmission of C. parvum subtypes shared by humans and cattle. Developing and industrialized countries differ significantly in disease burdens caused by zoonotic species and in the source of these parasites, with the former having far fewer human infections caused by C. parvum and little zoonotic transmission of this species. Exclusive anthroponotic transmission of seemingly zoonotic C. parvum subtypes was seen in Mid-Eastern countries. Other zoonotic Cryptosporidium spp. are also responsible for substantial numbers of human infections in developing countries, many of which are probably transmitted by anthroponotic pathways. The lower pathogenicity of some zoonotic species in some populations supports the occurrence of different clinical spectra of Cryptosporidium spp. in humans. The use of a new generation of molecular diagnostic tools is likely to produce a more complete picture of zoonotic cryptosporidiosis.

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