Bluetongue: history, global epidemiology, and pathogenesis

Area of Science:

• Veterinary Virology
• Epidemiology
• Pathology

Background:

• Bluetongong virus (BTV) is an arthropod-borne virus affecting ruminants globally.
• The disease has been known for over a century, endemic in tropical and temperate zones.

Observation:

• Significant recent shifts in BTV distribution have been observed globally.
• Novel BTV serotypes have emerged in Europe, the southeastern US, and Australia since 1998.
• Global climate change is a proposed, though unproven, factor in these distribution changes.

Findings:

• BTV infection is often asymptomatic but can cause severe disease outbreaks.
• Outbreaks are seasonal, occurring in late summer and autumn, particularly at the virus's global range limits.
• The disease mechanism involves vascular injury, endothelial permeability, and hypovolemic shock.

Implications:

• Understanding BTV's changing epidemiology is crucial for disease control.
• Further research is needed to confirm the role of climate change in BTV spread.
• The pathogenesis of BTV highlights similarities to human hemorrhagic viral fevers.