Epidemiological characterization and risk factors associated with Brucella ovis infection in sheep from the states of Rio Grande do Norte, Paraíba, and Sergipe

Abstract

Prevalence of 5.37% (70/1304) for ovine brucellosis in the three northeastern states. Higher positivity of adults compared to youth (p <0.001-odds ratio = 3.41). Females are significantly more infected than males. (p <0.01-odds ratio = 0.41). Mothers sheep more infected than young animals (p <0.001-odds ratio = 3.64). Lack of worker training is an associated risk factor (odds ratio = 3.68).

First study of Brucella ovis antibodies in purebred sheep flocks in the State of Parana, Brazil

“…In Brazil, the flock seroprevalence of B. ovis in the studied populations was between 0% (Marinho and Mathias, 1996;Chiebao, 2011) and 34% (Silva et al, 2003). Our study seroprevalence estimate, based on serologic testing, is much lower than other prevalence estimates published in Brazil with commercial non-mechanized sheep flocks (Magalhães Neto and Gil-Turnes, 1996;Schafer et al, 1997;Coleto et al, 2003;Pinheiro Junior et al, 2009;Rizzo et al, 2009;Silva et al, 2009;Alves et al, 2010;Souza et al, 2012;Araujo et al, 2013;Martins et al, 2013;Azevedo et al, 2014;Rizzo et al, 2014;Manhezzo et al, 2015;Lima et al, 2020;Teixeira et al, 2021), including 1.40% (Cunha Filho et al, 2007) and 18.26% of AGID seropositive sheep (Oliveira et al, 2016) (Magalhães Neto and Gil-Turnes, 1996), and 2.89% (Machado et al, 2015) in Rio Grande do Sul, but both studies analyzed intensive half-bred herds, not purebred animals, maybe justifying the higher occurrence when compared to this study, as more intensive systems can contribute to the introduction and persistence of B. ovis infection in sheep flocks (Elderbrook et al, 2019) and rams from large flocks were 14 times more likely to become infected than rams from small flocks (Chávez et al, 2013). It is also important to stress that molecular characterization showed a high genetic diversity among B. ovis field isolates from Rio Grande do Sul State, Brazil (Dorneles et al, 2014), reinforcing the importance of studies on B. ovis survey.…”

“…The low occurrence observed in this study can be explained by the fact that purebred sheep with genealogical record are constantly undergoing clinical exams, health management and are kept in low demographic concentrations. According to Lone et al (2013), the prevalence of brucellosis was higher in farms without zootechnical bookkeeping and sanitary controlling (14.14%) than those who carry out the zootechnical and sanitary management of the herd (3.23%), and this may be due to the good management practices of organized farms, such as the selection of healthy animals for reproduction, which could justify the result obtained in the present study.…”