Seroprevalence of bovine adenovirus and enterovirus antibodies reveals different infection dynamics in cattle herds

ABSTRACT

Background: Bovine enterovirus (BEV) and bovine adenovirus (BAV) are widely distributed in cattle population, and are among possible causes of gastroenteritis and respiratory disease, respectively, although the infection is more often subclinical. BAV infection may be also related to conjunctivitis, and may lead to severe infections and death in immunosuppressive calves. BEV infections have been associated with disorders of respiratory and reproductive tracts, and diarrhea. There is little available information about BAV and BEV in Brazil; however the main of the present study was to investigate the presence of antibodies against these viruses in cattle from some counties of the Rio Grande do Sul (RS), Brazil. Material, Methods & Results: A total of 415 bovine serum samples collected in 2015 year to detect neutralizing antibodies against BEV and BAV by Virus neutralization (VN) assay were performed. The serum samples were gently provided from Setor de Virologia da Universidade Federal de Santa Maria (SV-UFSM). The samples came from bovine with a history or report of clinical cases of diarrhea, respiratory and reproducible disorders and/or abortion suggestive of Leucosis, Bovine Viral Diarrhea Virus (BVDV) and/or Bovine herpesvirus type 1 and 5 (BoHV-1 and 5) infections. The samples are originated as from dairy and beef herd cattle in the following regions from RS State Southwest, Northeast, Northwest, West, Southeast, Midwest and Metropolitan regions; and were classified according to the origin, gender and age. The serum samples were tested against 100 TCID50/mL of (tissue cellular infection dose 50/mL) of previously characterized BEV and BAV-3 isolates. Serial dilution of the serum was performed in duplicate, starting at 15 up to > 1640 for BEV and at 12 to > 1256 for BAV in 96 wells plates. The serum and virus mixture was incubated in 37ºC for 4-6 h and then a suspension of CRIB cells was added to each well. [...]