Affiliation:
1. North Dakota State University, Fargo, North Dakota 58105
2. Wisconsin State Laboratory of Hygiene, Madison, Wisconsin 53706
Abstract
ABSTRACT
Cryptosporidium hominis
and
Cryptosporidium parvum
are the primary species of
Cryptosporidium
that infect humans.
C. hominis
has an anthroponotic transmission cycle, while
C. parvum
is zoonotic, infecting cattle and other ruminants, in addition to humans. Most cryptosporidiosis outbreaks in the United States have been caused by
C. hominis
, and this species is often reported as the primary cause of cryptosporidiosis in this country. However, outbreaks account for only 10% of the overall cryptosporidiosis cases, and there are few data on the species that cause sporadic cases. The present study identified the species/genotypes and subgenotypes of
Cryptosporidium
in 49 cases of sporadic cryptosporidiosis in Wisconsin during the period from 2003 to 2005. The species/genotype of isolates was determined by PCR restriction fragment length polymorphism analysis of the 18S rRNA and
Cryptosporidium
oocyst wall protein genes. The
C. parvum
and
C. hominis
isolates were subgenotyped by sequence analysis of the GP60 gene. Forty-four of 49 isolates were identified as
C. parvum
, and 1 was identified as
C. hominis
. Of the remaining isolates, one was identified as being of the cervine genotype, one was identified as being a cervine genotype variant, and two were identified as being of a novel human genotype, previously reported as W17. Nine different subgenotypes were identified within the
C. parvum
species, and two of these were responsible for 60% of the cases. In this study we found that most sporadic cases of cryptosporidiosis in Wisconsin are caused by zoonotic
Cryptosporidium
species, indicating that zoonotic transmission could be more frequently associated with sporadic cases in the United States.
Publisher
American Society for Microbiology
Cited by
183 articles.
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