title: Coxiella burnetii (Q Fever) Seropositivity and Associated Risk Factors in Sheep and Goat Farm Workers in Ontario, Canada.
abstract: Coxiella burnetii is a zoonotic bacterium that causes Q fever, a potentially severe disease of humans. The objectives of this study were to determine the seroprevalence and risk factors for C. burnetii exposure in sheep and goat farm workers in Ontario, Canada. Between August 2010 and March 2012, 172 farm workers from 78 sheep and goat farms were surveyed regarding demographics, lifestyle, farm practices, and medical history. Sera from these people were collected and analyzed for Q fever titers using the immunofluorescence assay. A mixed multivariable logistic regression model was constructed to identify risk factors for seropositivity. Individual-level and farm-level seroprevalence for C. burnetii were 64.5% (111/172, 95% CI = 57.2-71.4) and 74.4% (58/78, 95% CI = 63.2-83.6), respectively. Farm worker seropositivity was positively associated with an increasing proportion of seropositivity of sheep/goats on farm (odds ratio [OR] = 1.04; 95% CI 1.02-1.07). A higher odds of seropositivity was also observed for people working on dairy goat farms compared to the odds on dairy sheep (OR = 0.04; 95% CI 0.003-0.53) or meat goat (OR = 0.09; 95% CI 0.01-0.67) farms. Coxiella burnetii seropositivity was common in workers on sheep and goat farms in Ontario. Given the significant risk of morbidity associated with this infection, early recognition and treatment of Q fever are important. The risk factors identified provide insight into disease transmission between animals and people, which is particularly important for farmers, researchers, medical doctors, veterinarians, and public health professionals. Physicians practicing in rural areas should consider Q fever infection when patients present with atypical pneumonia and suggestive risk factors.
authors: 1 Department of Population Medicine, University of Guelph , Ontario, Canada .
authors: Shannon
authors: S
authors: Meadows
authors: 1 Department of Population Medicine, University of Guelph , Ontario, Canada .
authors: Andria
authors: A
authors: Jones-Bitton
authors: 1 Department of Population Medicine, University of Guelph , Ontario, Canada .
authors: Scott A
authors: SA
authors: McEwen
authors: 2 Veterinary Science and Policy, Ontario Ministry of Agriculture, Food and Rural Affairs, Elora, Canada .
authors: Jocelyn
authors: J
authors: Jansen
authors: 3 Public Health Ontario , Toronto, Canada .|4 Department of Laboratory Medicine and Pathobiology, University of Toronto , Toronto, Canada .
authors: Samir N
authors: SN
authors: Patel
authors: 5 Ontario Ministry of Health and Long-Term Care , Toronto, Canada .
authors: Catherine
authors: C
authors: Filejski
authors: 1 Department of Population Medicine, University of Guelph , Ontario, Canada .
authors: Paula
authors: P
authors: Menzies
mesh_terms: D000818:Animals; D000067565:Farmers; D006041:Goats; D006801:Humans; D016015:Logistic Models; D016273:Occupational Exposure; D009864:Ontario / Q000453:epidemiology; D011778:Q Fever / Q000276:immunology*; D012307:Risk Factors; D012756:Sheep; D011795:Surveys and Questionnaires
keywords: Coxiella burnetii; Ontario; Q fever; farm worker; risk factor; seroprevalence