Horse Poll Evil and Fistulous Withers

Poll evil and fistulous withers are serious deep tissue infections in horses causing significant pain and often associated with Brucella bacterial infection.

Key Facts

Poll evil involves infection of the bursa at the top of the skull between the ears
Fistulous withers involves infection of the bursa over the shoulder blades (withers)
Brucella abortus is the most common causative bacterium
Both conditions create draining tracts oozing purulent material
Treatment requires long-term antibiotics and often surgical debridement
Brucellosis is a zoonotic disease transmissible to humans handling infected horses
Prevention includes vaccination against brucellosis and avoiding contact with infected cattle
Chronic cases can result in permanent deformity and long-term pain

Welfare Considerations

Poll evil and fistulous withers cause deep, persistent pain that significantly affects horses' ability to lower their heads, be bridled, and perform normal activities. The draining tracts cause ongoing discomfort and attract flies that worsen the situation. Treatment requires prolonged handling of painful areas which adds stress. Inadequately treated cases develop chronic pain and structural damage that permanently reduces quality of life. Prompt diagnosis and aggressive treatment are essential welfare measures.

What You Can Do

Vaccinate horses against brucellosis in endemic areas
Avoid housing horses with potentially Brucella-infected cattle
Seek prompt veterinary care for any swelling in poll or withers regions
Use appropriate personal protective equipment when handling horses with draining tracts
Support equine infectious disease research and surveillance programs