|Santin, Monica - ARS VISITING SCIENTIST|
Submitted to: Meeting Abstract
Publication Type: Abstract Only
Publication Acceptance Date: April 8, 2004
Publication Date: July 24, 2004
Citation: Trout, J.M., Santin, M.D., Fayer, R. 2004. Giardia genotypes in post-weaned dairy calves in the Eastern United States. [Abstract]. ASP/AAVP Joint Meeting, July 24, 2003, Philadelphia, PA. p. 112. Technical Abstract: Fecal samples were collected from 3-11 month-old dairy calves from two farms in each of the following states: VT, NY, PA, MD, VA, NC, and FL. For analysis by immunofluorescent microscopy and PCR, fifteen gram portions of each sample were mixed with water, passed through a 45 micron screen, mixed with CsCl, and centrifuged. The top 4 ml of suspension from the tubes was collected, pelleted by centrifugation, washed with distilled water, and resuspended in 100 ul of distilled water. Fifty ul was stained with a commercial Giardia specific mAb. The remianing 50 ul was subjected to DNA extraction using a commercial tissue DNA extraction kit. PCR amplification was done for the TPI, 16S, and -giardin genes, using a nested PCR for TPI and 16S. PCR products were sequenced and the Giardia gene sequences obtained from animals in this survey were compared to each other and to previously sequenced Giardia isolates. Prevalence of Giardia as detected by PCR ranged from a low of 26% in MD to a high of 79% in FL, with an average prevalence across all farms of 52%. PCR and DNA sequence analysis revealed on average 87% of the isolates belonged to the hoofed-livestock genotype, Assemblage E, while 13% of the isolates were Assemblage A. This indicates that post-weaned calves are a source of Giardia duodenalis cysts potentially infectious for humans.