Genetic and Antigenic Diversity of Ruminant Pestiviruses: Implications for Diagnosis and Control

Abstract

Pestiviruses are pathogens of major economic importance for the livestock industry worldwide and have significant influence in cattle, pig and sheep production. The genus Pestivirus in the family Flaviviridae contains four approved species, Bovine viral diarrhoea virus type 1 (BVDV-1), BVDV-2, Border disease virus (BDV) and Classical swine fever virus (CSFV) and one tentative species, giraffe pestivirus. The phylogenetic analysis of nucleotide sequences obtained from various region of genome has led to identification of 16 subtypes within BVDV-1, 2–4 subtypes within BVDV-2 and at least 7 subtypes within BDV species. Moreover, several new pestiviruses or new subtypes of pestiviruses have been identified recently both in domestic and wild ruminants thereby enhancing the genetic and antigenic diversity repertoire. This chapter will focus mainly on research involving genetic and antigenic diversity of ruminant pestiviruses since the wide genetic and antigenic differences between ruminant pestivirus isolates pose considerable challenges in diagnosis and control. Considering the large number of publications in recent years, it is possible to cite only selected reports. In the first part of the chapter I will provide an overview of pestivirus epidemiology, transmission, genome structure and current methods of diagnosis and control. In the following part of the chapter, critical analysis of genetic and antigenic diversity of existing and new ruminant pestiviruses will be carried out. Finally, I will discuss future perspectives in relation to ruminant pestivirus diversity vis-a-vis its implications for diagnosis and control.