Risk factors associated with Bovine Viral Diarrhea Virus (BVDV) infection in the semiarid of the state of Paraíba, in the northeast region of Brazil

Abstract

Bovine viral diarrhea virus (BVDV) has become an important viral infectious agent in cows and is considered endemic in many regions. This study aimed to determine the epidemiological status of BVDV in bovine herds in the semiarid state of Paraíba, in northeastern Brazil, by determining the frequency of anti-BVDV antibodies and risk factors associated with the infection. We tested 359 cows from 20 farms. Three had a history of clinically suspected bovine viral diarrhea (BVD) or mucosal disease (MD), whereas the other 17 locations were randomly selected. Detection of anti-BVDV antibodies was performed by indirect ELISA using a commercial kit (IDEXX BVDV p80 Ab Test). Risk factor analysis was performed in two steps, univariate and multivariate analysis. Seven samples were considered suspicious and were excluded from the analysis of seropositive animals. Of 352 animals, 141 (40.1 %; CI 95 % = 34. 9% - 45.2 %) were seropositive. Of the 20 farms analyzed, 19 (95%) had seropositive animals and the frequency of seropositivity per farm varied between 4.5 % and 85.7 %. The risk factors identified were as follows: area ? 120 hectares (OR = 3.06; CI 9 5% = 1.43 - 6.53), high animal density (OR = 3.48; CI 95 % = 1.24-9.79), weaning age ? 60 days (OR = 10.99; CI 95 % = 1.31-91.9), exchange of animals (OR = 4.95; CI 95 % = 2.08-11.8), calf mortality > 5% (OR = 2.33; CI 95 % = 1.07-5.11), and use of natural breeding and artificial insemination (OR = 3.06; CI 95 % = 1.22 - 7.67). It was suggested that to avoid the transmission of BVDV infection in bovine herds in the Sertão of Paraíba, it is important to prevent identified associated risk factors and to perform further studies, identifying persistently infected animals.