Horse Poll Evil: Causes and Prevention

Poll evil is a serious and painful condition in horses involving infection of the bursa at the top of the head, requiring prompt treatment to prevent chronic suffering.

Key Facts

Poll evil involves infection and inflammation of the atlantal bursa near the poll
Causes include trauma, ill-fitting headgear, and bacterial infection including Brucella
The condition can progress to fistulous tracts and severe tissue destruction
Brucella abortus is implicated in many chronic poll evil cases in horses
Treatment typically requires surgical drainage, long-term antibiotics, and wound management

Welfare Considerations

Poll evil causes intense chronic pain and can severely compromise a horse's ability to hold its head normally, eat, and move comfortably. The infection can progress insidiously before signs become obvious, meaning horses may suffer for extended periods before diagnosis. Zoonotic risk from Brucella adds complexity to management. Prevention through properly fitted tack, avoiding head trauma, and prompt treatment of any poll swelling represents the highest welfare priority for horse caretakers.

What You Can Do

Ensure all headgear fits properly and does not create pressure points at the poll
Inspect horses regularly for poll swelling or sensitivity
Consult a veterinarian promptly if any swelling or fistula appears near the poll
Test for Brucella infection in horses with chronic poll lesions
Follow proper biosafety protocols when handling discharge from infected horses