POTENTIAL ZOONOTIC TRANSMISSION OF GIARDIA: THE ROLE OF DAIRY CATTLE

Authors: Fayer, Ronald; Trout, James; Santin-Duran, Monica

Submitted to: Meeting, Center for Food Safety, University of Georgia
Publication Type: Abstract Only
Publication Acceptance Date: 1/23/2006
Publication Date: 2/27/2006
Citation: Fayer, R., Trout, J.M., Santin, M. 2006. Potential zoonotic transmission of Giardia: The role of dairy cattle [abstract]. Workshop, Center for Food Safety, University of Georgia, February 27-28, 2006, Atlanta, Georgia.

Interpretive Summary:

Technical Abstract: Approximately 2000 dairy cattle from 15 farms in 7 states were examined for the presence of Giardia. Feces collected from each animal were transported within 48 hours to the laboratory in Beltsville, Maryland where DNA was extracted from each specimen and Giardia-specific primers were used for detection using a nested PCR protocol. All PCR-positive specimens were sequenced using the 16S rRNA gene and the genotype of each positive specimen was determined. Zoonotic G. duodenalis are designated genotypes (also called assemblages) A and B. The cattle-specific genotype is designated E although some cattle also excrete cysts of genotype A. The overall prevalence of G. duodenalis for 1971 dairy cattle was 38%. In preweaned calves, from birth to 8 weeks of age (n = 480) the prevalence was 34%. In postweaned calves, 2 to 11 months-of-age, (n = 379) the prevalence was 62%. In heifers 1 to 2 years-of-age (n = 571) the prevalence was 36%. And in cows older than 2 years-of-age (n = 541) the prevalence was 27%. Overall 4.4% of dairy cattle harbored genotype A the remainder harbored genotype E. Within each of these 4 age-related groups the zoonotic genotype A was found in 5, 8, 3, and 1.5%, respectively. No geographic trend was found for the presence of genotype A on farms from Vermont to Florida and no animals of no specific age could be identified as sources for this zoonotic genotype.