Submitted to: American Society of Parasitologists
Publication Type: Abstract Only
Publication Acceptance Date: March 1, 2005
Publication Date: July 7, 2005
Citation: Trout, J.M., Santin, M., Greiner, E., Fayer, R. 2005. Prevalence of Giardia genotypes in dairy cows in seven eastern states [abstract]. American Society of Parasitologists. p. 44.
Fecal samples were collected from 571 dairy cattle, 12-24 months of age, 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 'l of distilled water. Fifty 'l was stained with a commercial Giardia specific mAb. The remaining 50 'l was subjected to DNA extraction using a commercial tissue DNA extraction kit. PCR amplification was done for the 16S genes, using a nested protocol. 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 11% in NY to a high of 75% in NC, with an average prevalence across all farms of 36%. PCR and DNA sequence analysis revealed on average 91% of the isolates belonged to the hoofed-livestock genotype, Assemblage E, while 9% of the isolates were Assemblage A, the zoonotic genotype. These findings demonstrate a high prevalence of Giardia duodenalis cysts in mature dairy cows, including both the genotype infectious for livestock and the genotype potentially infectious for humans.