Seroprevalence and risk factors associated with Brucella seropositivity in dairy and mixed cattle herds from Ecuador
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An extensive cross-sectional study to determine the seroprevalence of and associated risk factors for Brucella infection was performed in dairy and mixed (dairy-beef) cattle herds in Ecuador. A total of 2666 serum samples from 386 farms were analyzed using Rose Bengal test and a blocking ELISA test. In addition, a questionnaire with 57 variables related to management, feeding, facilities, biosecurity, and animal health was filled in every cattle farm. A Generalized Estimating Equations model was used to determine the factors associated with Brucella seropositivity. The true prevalence of Brucella seropositivity in dairy and mixed cattle from Ecuador reached 17.0% (CI95% 15.6–18.4%). The herd prevalence was 45.1% (174/386) (CI95% 40.1–50.1%), and the within-herd prevalence ranged from 10 to 100% (mean 38.9%; Q1 14.3%, Q2 26.8%, Q3 52.5%). Seven factors were included in the GEE model for Brucella seropositivity: the nominal variables sex (OR 2.03; CI95% 1.32–3.13), herd type (dairy) (OR 1.79; CI95% 1.11–2.87), closed facilities in the farm (OR 1.80; CI95% 1.19–2.74), and ad libitum feeding (OR: 0.32; CI95%: 0.19–0.54), and the quantitative variables age (OR 1.005; CI95% 1.001–1.009), average slope in the farm (%) (OR 1.013; CI95% 1.002–1.024), and annual abortion rate (OR 1.016; CI95% 1.002–1.031). This study remarks the high spread of Brucella infection in cattle farms from Ecuador. In addition, it reports the risk factors associated to this infection in the predominant extensive system existent in this country.
KeywordsBrucella Cattle Dairy Seropositivity Risk factors Ecuador
The authors thank all the farmers who participated in the present study as well as the staff of the Animal Health and Zoonotic Diseases Laboratory, belonging to Biotechnology and Production section.
This study was financed by the Universidad Técnica Particular de Loja (Ecuador).
Compliance with ethical standards
Ethical statement and animal rights
Permission and licenses from the Ecuadorian Ministry of Agriculture and Ethics Committee of the Universidad Técnica Particular de Loja to sample herds was obtained before the start of the study. In addition, consent to extract the samples was obtained from the owners at each farm. The study was performed among domestic animals from rural areas only. According to the Convention on Biological Diversity and CITES, no damage to endangered species of wild fauna and flora occurred during the study.
Conflict of interest
The authors declare that they have no conflict of interest.
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