Difference between revisions of "Bluetongue Virus"
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*Characteristic of Bluetongue Virus, | *Characteristic of Bluetongue Virus, | ||
*Epithelium lost and haemorrhage produces blue / black discoloration of the [[Oral Cavity - Tongue - Anatomy & Physiology|tongue]], hence the name. | *Epithelium lost and haemorrhage produces blue / black discoloration of the [[Oral Cavity - Tongue - Anatomy & Physiology|tongue]], hence the name. | ||
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+ | *Caused by [[Reoviridae|bluetongue virus of family Reoviridae]] | ||
+ | *Non-contagious | ||
+ | *Insect-borne | ||
+ | *Causes vasculitis, especially in oral cavity | ||
+ | *Grossly: | ||
+ | **Infarctions -> necrosis | ||
+ | **Haemorrhage | ||
+ | *Histologically: | ||
+ | **Necrosis -> calcification or regeneration (depends on age of lesion) | ||
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[[Category:Orbiviruses]][[Category:Cattle]][[Category:Sheep]][[Category:Pig]] | [[Category:Orbiviruses]][[Category:Cattle]][[Category:Sheep]][[Category:Pig]] | ||
[[Category:Tongue_-_Pathology]][[Category:To_Do_-_Viruses]] | [[Category:Tongue_-_Pathology]][[Category:To_Do_-_Viruses]] |
Revision as of 10:43, 1 July 2010
This article is still under construction. |
Antigenicity
- 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
Current Relevance
- August 2006: suspicious Dutch sheep confirmed as serotype 8
- Serotype 8 found in Belgium, Luxembourg, Germany, and north-eastern France
- Previously BTV-8 only seen in sub-Saharan Africa
- August 2007: increased outbreaks in same regions
- September 2007: first UK outbreak in Suffolk
- 2008: Virus declared endemic and BTV-8 vaccine produced, voluntary vaccination strongly encouraged
Control
- 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.
Haemorrhagic Inflammation
- 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.
- Caused by bluetongue virus of family Reoviridae
- Non-contagious
- Insect-borne
- Causes vasculitis, especially in oral cavity
- Grossly:
- Infarctions -> necrosis
- Haemorrhage
- Histologically:
- Necrosis -> calcification or regeneration (depends on age of lesion)