Resumen de Epizootiological investigation of a Q fever outbreak and implications for future control strategies
Alicia D. Anderson, Gilbert J. Kersh, Tahnee J. Szymanski, Michelle P. Emery, Paul H. Kohrs, Adam C. Bjork, Randall J. Nett, Nicola Haug, Dana M. Woodhall, Rachael A. Priestley, Joshua S. Self, Kelly A. Fitzpatrick
Objective—To describe the epizootiological investigation of an outbreak of Q fever (Coxiella burnetii infection).
Design—Epidemiological study.
Animals—17 goat herds in Washington, Montana, and Oregon.
Procedures—In April 2011, an abortion storm at a commercial goat farm in Washington was determined to be caused by C burnetii. A joint epidemiological investigation by public health and veterinary professionals was subsequently performed to assess the extent of the outbreak by performing a trace-forward of goats sold from the index farm, to determine risk factors associated with infection, and to implement control measures. A herd management plan was developed to control the outbreak and reduce risk of human exposure. Quarantine and temporary holds preventing the sale or movement of goats allowed time for trace-forward investigation, education of farmers regarding disease risk, and testing to determine the scope of the outbreak.
Results—17 farms were affected; 21 human Q fever cases were identified. Bacterial shedding in feces, vaginal fluid, or milk was confirmed in 156 of 629 (25%) goats tested by PCR assay. Seroprevalence of antibodies against C burnetii in goats, determined by ELISA, was 12%. The risk for C burnetii infection in goats was highest among females, those on farms associated with human Q fever, and those on Washington farms. A protective effect was observed for goats at farms where the primary form of goat carcass disposal was burial.
Conclusions and Clinical Relevance—This outbreak illustrated the importance of a joint investigation for zoonotic pathogens and the need to expand and strengthen relationships between medical, public health, and veterinary partners. Heightened awareness and enhanced veterinary diagnostic capabilities for C burnetii are needed to identify and control outbreaks expediently.
