ARS | Publication request: IDENTIFICATION OF ASSEMBLAGE A GIARDIA IN WHITE-TAILED DEER

Submitted to: Journal of Parasitology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: August 7, 2003
Publication Date: December 1, 2003
Citation: TROUT, J.M., SANTIN, M.D., FAYER, R. IDENTIFICATION OF ASSEMBLAGE A GIARDIA IN WHITE-TAILED DEER. JOURNAL OF PARASITOLOGY. 2003. Vol. 89: 1254-1255.

Interpretive Summary: Environmental sources of Giardia that may be infectious for humans and cattle are not well defined. Tens of millions of white tailed deer share pastureland with cattle and suburban environments with humans. Although Giardia has been previously reported in white tailed deer, it was not know if these Giardia were infectious for cattle and humans. Fecal samples were collected during a managed deer hunt. The samples were cleaned and concentrated by density gradient centrifugation and analyzed for the presence of Giardia by immunofluorescent microscopy and PCR. Twenty-six samples were collected and analyzed over a 45 day period. One of these samples was positive by both microscopy and PCR. Gene sequencing of two genes revealed that the Giardia found in the deer belonged to Assemblage A, a genotype often found in human infections, and recently reported on a small percentage of cattle infections. These results indicate that white tailed deer are a potential reservoir of Giardia that are potentially infectious for both humans and cattle.

Technical Abstract: Fecal samples were collected from hunter killed white-tailed deer (Odocoileus virginianus) during a managed hunt in a central Maryland county. Fecal samples were cleaned of debris and concentrated by CsCl density gradient centrifugation and stained with MerIFluor reagents. Stained samples were examined by fluorescent microscopy for the presence of Giardia cysts. One of 26 samples was found to be positive for Giardia. PCR amplification using primers to directed to the $-giardin and TPI genes identified the same sample as the only positive. Sequencing of the $-giardin and TPI genes revealed that the Giardia belonged to Assemblage A, a genotype infectious for humans. This is the first report of Assemblage A Giardia in deer and suggests that deer could be a potential source of human infections and cattle.