Bluetongue Disease in Sheep: Welfare Impacts and Prevention

Bluetongue is a viral disease transmitted by midges that causes severe suffering in sheep, with symptoms ranging from mouth ulcers to lameness and respiratory distress.

Key Facts

Bluetongue virus is transmitted by Culicoides biting midges, not direct contact
Sheep are most severely affected; cattle act as reservoir hosts with milder symptoms
Mortality in susceptible sheep populations can reach 70% during outbreaks
Symptoms include fever, swelling of face and tongue, ulcers, lameness, and breathing difficulty
The 2006 BTV-8 outbreak in northern Europe caused massive welfare and economic impacts
Climate change is expanding midge habitat, pushing bluetongue into new regions
Vaccination is the most effective prevention tool where vaccines are available

Welfare Considerations

Bluetongue causes intense suffering in affected sheep. The painful oral ulcers make eating extremely difficult, leading to rapid weight loss and dehydration. Lameness severely impairs movement and grazing. The respiratory distress that can accompany infection is acutely distressing. Animals may suffer for weeks before dying or recovering. The welfare burden is compounded when outbreaks occur in naive populations with no prior immunity, leading to rapid spread through flocks. Early vaccination and movement restrictions during outbreaks are essential welfare interventions.

What You Can Do

Vaccinate sheep in at-risk regions before midge season begins
Monitor for early bluetongue signs: fever, swollen face, drooling, lameness
Implement midge control around housing during high-risk periods
Follow movement restrictions during outbreaks to prevent spread
Support veterinary investigation of any suspected bluetongue cases
Advocate for research funding into new bluetongue vaccines covering emerging strains