Bovine coronaviruses from the respiratory tract

antigenic and genetic diversity

Abstract

Bovine coronaviruses (BoCV) have been associated with bovine respiratory diseases (BRD) in cattle pulled for treatment in feedlots and from healthy cattle in the US with BoCV identified by virus isolation from nasal swab and bronchoalveolar lavage (BAL) samples, and also by seroconversions for the detection of active infections. Bovine coronaviruses have been identified in pneumonic lungs from field cases, often in combination with other viruses and bacteria including Mycoplasma spp. Experimentally, BoCV infections have caused respiratory tract lesions. It has been suggested there is a dual tropism of BoCV for the respiratory and enteric tracts. Historically, BoCV was associated with neonatal enteric disease and adult winter dysentery. Respiratory isolates were identified later and focused on post-weaning cattle entering feedlots. Control measures are limited. There are USDA-licensed killed and modified live virus (MLV) vaccines for BoCV; however, these are for control of the enteric disease in cattle. There are no USDA-licensed vaccines for control of BoCV associated BRD in cattle. The purpose of the study was to compare BoCVisolates from the respiratory tract of cattle in Oklahoma to reference respiratory tract and enteric strains via antigenic and genetic procedures.