Submitted to: International Congress of Parasitologists
Publication Type: Abstract Only
Publication Acceptance Date: 6/7/2002
Publication Date: 8/7/2002
Citation: FAYER, R., TROUT, J.M., SULAIMAN, I.M., LAL, A.A., XIAO, L., SCHAEFER, F. THE FIRST REPORT OF ENTEROCYTOZOON BIENEUSI PARASITES IN WILDLIFE: IMPLICATIONS FOR PUBLIC HEALTH AND TRANSMISSION TO LIVESTOCK. International Congress of Parasitologists. 2002. Interpretive Summary:
Technical Abstract: Microsporidia are tiny, obligate, intracellular, parasites consisting of more than 1200 species in 143 genera infecting invertebrate and vertebrate hosts. Six genera including 14 species have been found to infect humans. The most common microsporidian parasite infecting mammals including humans is Enterocytozoon bieneusi. The most common sign of infection is diarrhea. It has been recently shown that E. bieneusi isolates from humans are genetically related to some isolates from farm and companion animals, suggesting that zoonotic infection can be a source of human infection. To address possible sources of human infection and public health importance of the parasites from animal origins, 465 fecal specimens from foxes, beavers, muskrats, raccoons, and otters trapped in Maryland were examined. After cesium chloride density gradient centrifugation to remove most fecal debris, fluorescence microscopy of Calcofluor white stained supernatent yielded unconfirmed results. A nested PCR protocol was developed to amplify a 428 base pair fragment of the internal transcribed spacer (ITS) region of the SSU rRNA gene from various E. bieneusi isolates. Primers complementary to the conserved regions of published E. bieneusi nucleotide sequences were used. Thirty eight E. bieneusi positive PCR products from these samples were sequenced on an ABI3100 automated sequencer using Big DyeTM. Multiple alignments of the sequences from this study identified 7 new genotypes of E. bieneusi. Most genotypes were found in multiple species of wildlife. One genotype of E. bieneusi, identical to a genotype described in humans, was found in a fox and 2 beaver. These findings suggest that certain wildlife can source as a reservoir of microsporidia known to infect humans and livestock. Because they live in and around water, a waterborne route of transmission is considered likely.