Which clinical sign is most characteristic of pinworm infection in horses?

Which clinical sign is most characteristic of pinworm infection in horses?

• A. Pruritus at the Tail Base
• B. Chronic Coughing
• C. Persistent Diarrhea
• D. Facial Swelling

Answer: (A)

Pruritus at the tail base is the hallmark sign of pinworm infection in horses because the female worms migrate to and lay eggs around the perianal area, causing intense itching. This leads to rubbing, tail swishing, and irritation specifically at the base of the tail, which is the classic presentation for Oxyuris equi infection. The other signs—chronic coughing, persistent diarrhea, and facial swelling—are not typically associated with pinworms and point to respiratory disease or other GI or inflammatory processes rather than the characteristic perianal itch of pinworms.

Pruritus at the tail base is the hallmark sign of pinworm infection in horses because the female worms migrate to and lay eggs around the perianal area, causing intense itching. This leads to rubbing, tail swishing, and irritation specifically at the base of the tail, which is the classic presentation for Oxyuris equi infection. The other signs—chronic coughing, persistent diarrhea, and facial swelling—are not typically associated with pinworms and point to respiratory disease or other GI or inflammatory processes rather than the characteristic perianal itch of pinworms.