How to cite this article: Vet. Res. (2008) 39:46
DOI: 10.1051/vetres:2008023

Review

Bluetongue virus: virology, pathogenesis and immunity

Isabelle Schwartz-Cornil¹, Peter P.C. Mertens², Vanessa Contreras¹, Behzad Hemati¹, Florentina Pascale¹, Emmanuel Bréard³, Philip S. Mellor², N. James MacLachlan⁴ and Stéphan Zientara<sup>3

1</sup>  Virologie et Immunologie Moléculaires, UR892 INRA, Domaine de Vilvert, 78352 Jouy-en-Josas Cedex, France
²  Department of Arbovirology, Institute for Animal Health, Ash Road, Pirbright, Woking, Surrey, GU24 0NF, UK
³  UMR 1161 Afssa/INRA/ENVA, 23 Avenue du Général de Gaulle, 94703 Maisons-Alfort, France
⁴  Department of Pathology, Microbiology and Immunology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA

Received 24 March 2008; accepted 19 May 2008; published online 22 May 2008

Abstract - Bluetongue (BT) virus, an orbivirus of the Reoviridae family encompassing 24 known serotypes, is transmitted to ruminants via certain species of biting midges (Culicoides spp.) and causes thrombo-hemorrhagic fevers mainly in sheep. During the 20th century, BTV was endemic in sub-tropical regions but in the last ten years, new strains of BTV (serotypes 1, 2, 4, 8, 9, 16) have appeared in Europe leading to a devastating disease in naive sheep and bovine herds (serotype 8). BTV enters into insect cells via the viral inner core VP7 protein and in mammalian cells via the external capsid VP2 haemagglutinin, which is the major determinant of BTV serotype and neutralization. BTV replicates in mononuclear phagocytes and endothelial cells where it induces expression of inflammatory cytokines as well as apoptosis. BTV can remain as nonreplicating entities concealed in erythrocytes for up to five months. Homologous protection against one BTV serotype involves neutralizing antibodies and T cell responses directed to the external VP2 and VP5 proteins, whereas heterologous protection is supported by T cells directed to the NS1 non structural protein and inner core proteins. Classical inactivated vaccines directed to a specific serotype generate protective immunity and may help control current epidemic situations. New recombinant vaccine strategies that allow differentiating infected from vaccinated animals and that generate cross protective immunity are urgently needed to efficiently combat this worldwide threatening disease.

Key words: bluetongue / orbivirus / arbovirus / viral haemorrhagic disease / ruminants

Corresponding author: isabelle.schwartz@jouy.inra.fr

© INRA, EDP Sciences 2008