Coxiella burnetii seroprevalence and associated risk factors in dairy and mixed cattle farms from Ecuador.

Q fever is a zoonotic disease caused by Coxiella burnetii, a bacterial agent for which ruminants are the main reservoir. An extensive cross-sectional study to determine the seroprevalence of and associated risk factors for Q fever was performed in dairy and mixed (dairy-beef) cattle herds in Ecuador. A total of 2668 serum samples from 386 herds were analyzed using an ELISA. In addition, a questionnaire with 57 variables related to management, feeding, facilities, biosecurity and animal health was completed for every cattle farm. A Generalized Estimating Equations model was used to determine the factors associated with C. burnetii seropositivity. The true prevalence of C. burnetii seropositivity in dairy and mixed cattle from Ecuador reached 12.6% (CI95%: 11.3-13.9%). The herd prevalence was 46.9% (181/386) (CI95%: 41.9-51.9%), and the within herd prevalence ranged between 8% and 100% (mean: 25.0%; Q1: 12.5%, Q2: 25.0%, Q3: 37.5%). Four factors were included in the GEE model for C. burnetii seropositivity: age of the cattle (OR: 1.01; CI95%: 1.006-1.014), feeding of calves with milk replacers (OR: 1.94; CI95%: 1.1-3.3), bovine respiratory syncytial virus seropositivity (OR: 1.54; CI95%: 1.1-2.3), and disinfection of the umbilical cord (OR: 0.60; CI95%: 0.4-0.9).