Submitted to: Parasitology Research
Publication Type: Peer reviewed journal
Publication Acceptance Date: 7/29/2005
Publication Date: 9/16/2005
Citation: Santin, M., Trout, J.M., Fayer, R. 2005. Enterocytozoon bieneusi genotypes in dairy cattle in Eastern United States. Parasitology Research. 97:535-538 Interpretive Summary: Enterocytozoon bieneusi, the most frequently reported species of Microsporidia that infects humans, is found in the small intestine and biliary tract and is shed as mature spores in the feces. Little is known about the routes of transmission, zoonotic potential, or possible sources of infectious organisms. The fact that E. bieneusi has been identified in different animals and water sources, has raised public health concerns about its potential as a zoonotic and waterborne pathogen. Enterocytozoon bieneusi has been reported from cattle in the United states but the extent to which E. bieneusi infected cattle might pose a risk of human infection is unknown. The current study was conducted using molecular techniques to determine the prevalence of E. bieneusi in 571 dairy heifers on 14 farms in 7 states and to determine whether they constitute a potential source of human infection. E. bieneusi was found in 23% of the animals but only 2 were infected with the same genetic types reported in humans.
Technical Abstract: Fecal specimens were obtained from 12-24 month-old dairy heifers on farms in Vermont, New York, Pennsylvania, Maryland, Virginia, North Carolina, and Florida. PCR positive specimens for Enterocytozoon bieneusi were found in 131 of 571 heifers examined (23%) and on all farms visited. The prevalence of E. bieneusi varied considerably across farms, with the lowest prevalence (4.7%) on MD-2 and the highest prevalence (37.8%) on NY-2. All PCR positive specimens that amplified the ITS region as well as a portion of the flanking large and small subunit ribosomal RNA genes were sequenced to determine the genotype(s) of E. bieneusi present and 6 genotypes were identified. Most were identified as cattle specific genotypes previously reported from cattle as BEB1, BEB2, BEB3 and BEB4. Two isolates were genetically identical or similar to E. bienesusi reported as the human pathogens Peru 6 and Peru 9 (or D) genotypes. Although our data demonstrate the presence of zoonotic genotypes in cattle, most genotypes found in cattle were host-specific.