Synonyms and introduction

SYNONYMS AND INTRODUCTION

Synonyms : Sore mouth or sore muzzle, ovine catarrhal fever.

Introduction

  • Blue tongue (BT) is an infectious, non-contagious acute arthropod borne virus, primarily affecting sheep characterized by catarrhal inflammation of the mucous membrane of buccal mucosa and gastro intestinal tract.
  • This disease frequently involves the udder, coronary band of the foot and sensitive laminae of the hoof. There is epithelial desquamation but no vesicle formation occurs.
  • Blue tongue virus (BTV) is the double stranded RNA virus, species of the Orbi virus genus, family Reoviridae.
  • The disease first recognized in Africa and reported from Canada, Japan, Australia, Brazil, West Indies, USA, Egypt, Israel, Cyprus, and in some other countries.
  • This disease first reported in India in 1964.
  • The distribution of the disease is dependent on the presences of reservoir and amplifying host such as cattle and on suitable species of Culicoides being present in large numbers to effect transmission to sheep.
  • It is basically a disease of sheep but amongst sheep susceptibility varies in different age groups.
  • Young sheep within the age group of one year are more prone to infection.
  • Goats, cattle and wild ruminants exhibit milder symptoms and may act as non-clinical carriers.
  • Horses, dogs, cats, ferrets, rabbits and guinea pigs are not susceptible to natural infection.
  • The disease spread through blood sucking midges of the genus Culicoides.
  • Besides mosquitoes and other ectoparasites like sheep ked, Melophagus ovinus, may transmit the disease mechanically.
  • Wild animal reservoirs play an important role in maintaining the infection during the interepizootic period.
  • Stress factors like lower plane of nutrition, worm burden, inclement weather, and fatigue due to transportation are predisposing factors for the disease.
  • Blue tongue virus can most readily be identified isolated by inoculating into a 10-12 days old embryonated chicken eggs.
  • Primary isolation can only achieved by inoculating the suspected materials into intracerebral inoculation of new-born mice or in monolayer cell cultures such as BHK-21, mouse L cells, vero cells.
Last modified: Sunday, 3 June 2012, 8:14 AM