Serological survey for bovine herpesvirus 1 in cattle from different regions in the state of Bahia, Brazil

Abstract

The presence of antibodies against BHV-1 was evaluated in young bovines from fifteen different counties distributed along North, South and Central regions of the state of Bahia. Bovines with age ranged from 1 to 4 years old, non-vaccinated against BHV-1 and without diagnostic of BHV-1 infection were chosen for blood collection. A total of 558 serum samples were collected equivalent to 10% of the population in each farm. The sera were submitted to ELISA (HerdCheck-IDDEX) and Microserum neutralization (MSN) tests. The MSN was performed in monolayers of MDBK cells in microplates using Los Angeles BHV-1 strain. The results of serum samples by ELISA showed that 56% (314/558) were positive and 44% (244/558) were negative. The sera assayed by MSN showed that 48% (269/558) were negative and 52% (289/558) were positive. These positive sera demonstrated that 54% had serumneutralization titer between 4-16, 35% between 32-64 and 11%  64. Our results suggest that the virus is circulating actively in herds. Furthermore, the high diffusion of the BHV-1 in young bovines could represent a constant source of viral infection in the herd.