Risk of exposure to Coxiella burnetii from ruminant livestock exhibited at Iowa agricultural fairs

O'Connor, Annette
Still Brooks, Kelly
Stensland, Wendy
Harmon, Karen
Plummer, Paul
O'Connor, Annette
Plummer, Paul
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Veterinary Diagnostic and Production Animal Medicine

Coxiella burnetii is a zoonotic pathogen typically associated with clinical and asymptomatic infection in ruminant livestock. A re‐emerging pathogen of significant public health importance, C. burnetii has caused recent epidemics in the U.S. and Europe and public livestock exhibitions are increasingly scrutinized as a potential source of C. burnetii exposure. Although C. burnetii prevalence data among North American domestic ruminants is extremely limited, contemporary studies suggest that this pathogen is both geographically widespread and highly prevalent on a herd basis, especially in dairy cattle and goat populations. We utilized a real‐time PCR assay to detect Coxiella burnetii fecal shedding by clinically normal, non‐periparturient beef cattle, meat goats, and sheep exhibited at Iowa agricultural fairs. Individual fecal samples were collected from beef cattle, meat goats, and sheep exhibited at twelve Iowa county fairs during the summer of 2009. The sample pool was blocked by species and fair, ten samples from each block were randomly selected for the diagnostic assay; this test pool is considered sufficient to identify with 95% confidence a shedding animal in a population prevalence of 2.85% (cattle and sheep) and 6.25% (goats). Detection of Coxiella burnetii DNA was determined through use of a real time PCR assay validated for use in bovine, ovine, and caprine feces; threshold of detection is one DNA copy per PCR (sensitivity 95.8%, specificity 100%). All tested samples were negative for Coxiella burnetii DNA. We conclude that non‐dairy, non‐periparturient ruminants exhibited at Iowa fairs are unlikely to shed Coxiella burnetii in their feces and that this population should not be considered to be a significant exposure risk to other livestock or fair attendees.


This is the peer reviewed version of the following article: Still Brooks KM, Stensland WR, Harmon KM, O'Connor AM, Plummer PJ. Risk of exposure to Coxiella burnetii from ruminant livestock exhibited at Iowa agricultural fairs. Zoonoses Public Health. (2017), which has been published in final form at doi: 10.1111/zph.12439. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Self-Archiving.