Trypsin treatment of bovine embryos after in vitro exposure to infectious bovine rhinotracheitis virus or bovine herpesvirus-4

Abstract

The influence of relative humidity (R.H.) on the survival of the following viruses has been examined; feline herpesvirus (FHV); feline calicivirus (FCV); vesicular exanthema virus (VEV); infectious bovine rhinotracheitis virus (IBRV); parainfluenza 3 virus (PI-3 virus); vesicular stomatitis virus (VSV); equine herpesvirus type 1 (EHV-1), equine arteritis virus (EAV); equine rhinovirus (ERV-1), and African swine fever virus (ASFV). ASFV and PI-3 viruses survived well at all relative humidities when sampled 1 s after formation of an aerosol, but after storage of aerosols for 5 min both viruses were found to be sensitive to high R.H. The other lipid-containing viruses (EAV, VSV, FHV, EHV-1 and IBRV) were unstable when stored as aerosols in moist conditions. The picornavirus ERV-1 was the only virus which survived well at high R.H. but poorly on exposure to dry conditions. The caliciviruses VEV and FCV were sensitive to R.H. in the 30–70% range. When subjected to aeration, all of the lipid-containing viruses which were examined lost infectivity but non-lipid viruses, including bovine adenovirus type 1 (BAdV-1), were stable. The addition of 0.1% peptone reduced losses, probably by protecting against surface inactivation. The significance of these findings in relation to possible control measures for viral respiratory disease is discussed.