Transplacental transmission of field and rescued strains of BTV-2 and BTV-8 in experimentally infected sheep

Rasmussen, L., Savini, G., Lorusso, A., Bellacicco, A., Palmarini, M. , Caporale, M., Rasmussen, T., Belsham, G.J. and Bøtner, A. (2013) Transplacental transmission of field and rescued strains of BTV-2 and BTV-8 in experimentally infected sheep. Veterinary Research, 44(75), (doi: 10.1186/1297-9716-44-75)

Abstract

Transplacental transmission of bluetongue virus has been shown previously for the North European strain of serotype 8 (BTV-8) and for tissue culture or chicken egg-adapted vaccine strains but not for field strains of other serotypes. In this study, pregnant ewes (6 per group) were inoculated with either field or rescued strains of BTV-2 and BTV-8 in order to determine the ability of these viruses to cross the placental barrier. The field BTV-2 and BTV-8 strains was passaged once in Culicoides KC cells and once in mammalian cells. All virus inoculated sheep became infected and seroconverted against the different BTV strains used in this study. BTV RNA was detectable in the blood of all but two ewes for over 28 days but infectious virus could only be detected in the blood for a much shorter period. Interestingly, transplacental transmission of BTV-2 (both field and rescued strains) was demonstrated at high efficiency (6 out of 13 lambs born to BTV-2 infected ewes) while only 1 lamb of 12 born to BTV-8 infected ewes showed evidence of in utero infection. In addition, evidence for horizontal transmission of BTV-2 between ewes was observed. As expected, the parental BTV-2 and BTV-8 viruses and the viruses rescued by reverse genetics showed very similar properties to each other. This study showed, for the first time, that transplacental transmission of BTV-2, which had been minimally passaged in cell culture, can occur; hence such transmission might be more frequent than previously thought.

• Item Type: Articles
• Status: Published
• Refereed: Yes
• Glasgow Author(s) Enlighten ID: Palmarini, Professor Massimo and Caporale, Dr Marco
• Authors: Rasmussen, L., Savini, G., Lorusso, A., Bellacicco, A., Palmarini, M., Caporale, M., Rasmussen, T., Belsham, G.J., and Bøtner, A.
• College/School: College of Medical Veterinary and Life Sciences > School of Infection & Immunity; College of Medical Veterinary and Life Sciences > School of Infection & Immunity > Centre for Virus Research
• Journal Name: Veterinary Research
• Publisher: BioMed Central
• ISSN: 0928-4249
• ISSN (Online): 1297-9716
• Copyright Holders: Copyright © 2013 The Authors
• First Published: First published in Veterinary Research 44(75)
• Publisher Policy: Reproduced under a Creative Commons License