Difference between revisions of "Bluetongue Virus"
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==Description== | ==Description== | ||
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| − | + | Bluetongue is an infectious, noncontagious arthropodborne viral disease primarily of domestic and wild ruminants. Infection with bluetongue virus is common worldwide but is usually subclinical or mild in most infected ruminants. Bluetongue is almost exclusively a disease of sheep, particularly the fine-wool and mutton breeds, although white-tailed deer ( Odocoileus virginianus ), and pronghorn ( Antilocapra americana ) and desert bighorn sheep ( Ovis canadensis ) may develop severe clinical disease in North America. | |
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==Aetiology== | ==Aetiology== | ||
Revision as of 18:50, 19 August 2010
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This article is still under construction. |
Description
Bluetongue is an infectious, noncontagious arthropodborne viral disease primarily of domestic and wild ruminants. Infection with bluetongue virus is common worldwide but is usually subclinical or mild in most infected ruminants. Bluetongue is almost exclusively a disease of sheep, particularly the fine-wool and mutton breeds, although white-tailed deer ( Odocoileus virginianus ), and pronghorn ( Antilocapra americana ) and desert bighorn sheep ( Ovis canadensis ) may develop severe clinical disease in North America.
Aetiology
- 24 serotypes of BTV have been described
Hosts
- Ruminants, including sheep, cattle, deer, goats, and camelids
Pathogenesis
- Transfer occurs through blood from viremic animals via biting midges (Culicoides spp.)
- Replication in haematopoietic and endothelial cells of blood vessels
- Clinical signs vary between species, with sheep most severely affected
- Pyrexia
- Ocular and nasal discharge
- Drooling from mouth uclers
- Swelling of the mouth, head and neck
- Lameness
- Subdural hemorrhages
- Inflammation of the coronary band
- Cattle as the main reservoir
- A blue tongue is rarely seen as as a clinical sign of infection
- Resulting loss of condition, reduction in wool an meat production, which can be followed by death
Diagnosis
- Clinical signs can be confirmed through the lab:
- RT-PCR to detect viral RNA
- ELISA serology for Ab and rising Ab titres
Clinical Signs
Laboratory Tests
Pathology
Complete loss of integrity of epithelium. Uncommon.
- Characteristic of Bluetongue Virus,
- Epithelium lost and haemorrhage produces blue / black discoloration of the tongue, hence the name.
- Grossly:
- Infarctions -> necrosis
- Haemorrhage
- Histologically:
- Necrosis -> calcification or regeneration (depends on age of lesion)
Treatment
- BTV is NOTIFIABLE
- Vigilance in recognizing clinical signs
- Restriction of movement:
- Protection Zone: 100km radius around infected premises, movement within zone allowed but not in or out
- Vaccination within PZ using appropriate serotype is encouraged but still voluntary
- Surveillance Zone: 50km radius beyond PZ
- Protection Zone: 100km radius around infected premises, movement within zone allowed but not in or out
- Vector control: ectoparasiticides, etc.