Submitted to: Parasitology Research
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 11/1/2003
Publication Date: 3/1/2004
Citation: Sulaiman, I.M., Fayer, R., Yang, C., Santin, M., Matos, O., Xiao, L. 2004. Molecular characterization of enterocytozoon bieneusi in cattle indicates that only some isolates have zoonotic potentials. Parasitology Research. 92:328-334. Interpretive Summary: The most common microsporidian parasite infecting humans is Enterocytozoon bieneusi. ARS scientists recently found it in dairy calves, the first report of its presence in cattle in North America. Now, a molecularly based study of 338 fecal specimens from cattle from 7 states and Portugal reveals 5 distinct genetic variations of this parasite, most of which form a cluster of closely related organisms found only in cattle. One group, consisting of E. bieneusi from 6 animals was found identical or very closely related to genetic types found in humans and other domestic animals. These findings indicate that cattle throughout the United States become infected with and can serve as sources of microsporidia specific for other cattle as well as for microsporidia infectious for other domestic animals and humans.
Technical Abstract: In this study, 338 fecal samples were analyzed for Enterocytozoon bieneusi in cattle from farms located in Florida, Maryland, Michigan, New York, North Carolina, Pennsylvania, Virginia, and Portugal. The internal transcribed spacer (ITS) region (392 bp) of the rRNA gene of E. bieneusi was amplified using a nested PCR protocol and 32 E. bieneusi-PCR positive samples were sequenced. A high degree of genetic polymorphism was noticed in bovine E. bieneusi, and altogether 5 distinct genotypes of E. bieneusi (BEB1-BEB5) were found. Most of the bovine isolates formed a distinct cluster consisting of the 4 bovine genotypes, but 6 isolates of a genotype clustered together with E. bieneusi genotypes in humans and other domestic animals. Therefore, some but not all E. bieneusi isolates of cattle should be considered of public health importance.