Changes

===Classification===

===Classification===

The  viral aetiology of BVD was first established over 60 years ago, but it was not until the 1960s that the agent was assigned to the newly penned "Pestivirus" genus. At this stage Pestiviruses were considered to be non-arthropod-borne togaviruses; later, sequencing of genomic RNA showed that they are taxonomically better suited to the Flaviviridae family, as they are classified today^{1, 2}. (Collett et al, 1988; Meyers et al, 1989)

The  viral aetiology of BVD was first established over 60 years ago, but it was not until the 1960s that the agent was assigned to the newly penned "Pestivirus" genus. At this stage Pestiviruses were considered to be non-arthropod-borne togaviruses; later, sequencing of genomic RNA showed that they are taxonomically better suited to the Flaviviridae family^{1, 2}. The Flaviviridae family contains several genera. The Flaviviruses, such as yellow fever virus and West Nile Virus, and the  typically spread by arthropod vectors, particularly mosquitoes and ticks. Genera within the family include the Flaviviruses, which cause disease in both man (such as yellow fever virus and West Nile virus) and animals (for example, louping ill), and Hepacivirus, which contains Hepatitis C virus only.  

 

The Flaviviridae are primarily spread via arthropod vectors, particularly mosquitoes and ticks. Genera within the family include the Flaviviruses, which cause disease in both man (such as yellow fever virus and West Nile virus) and animals (for example, louping ill), and Hepacivirus, which contains Hepatitis C virus only.  

Pestiviruses, however, are not arthropod-borne, and include pathogens of cattle (BVDV), sheep and pigs. The porcine Pestivirus, classical swine fever virus (CSFV), was first documented in 1833 in Ohio (quoted by Hanson, 1957). Acute disease (classical swine fever) typically includes a raised body temperature, inco-ordination of movement and hyperaemia of the skin followed by petechial or extensive haemorrhage (Dahle and Leiss, 1992).

Pestiviruses, however, are not arthropod-borne, and include pathogens of cattle (BVDV), sheep and pigs. The porcine Pestivirus, classical swine fever virus (CSFV), was first documented in 1833 in Ohio (quoted by Hanson, 1957). Acute disease (classical swine fever) typically includes a raised body temperature, inco-ordination of movement and hyperaemia of the skin followed by petechial or extensive haemorrhage (Dahle and Leiss, 1992).