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Orf — SCE Infectious Diseases MCQ

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EasyInfection Prevention & ControlOrfSCE Infectious Diseases

A 55-year-old pig farmer develops a vesicular rash on his hands after handling pigs with a similar rash. The vesicles are on an erythematous base confined to his hands. He is systemically well. A dermatology opinion suggests orf. What is the causative agent?

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Correct answer: B — Parapoxvirus (Orf virus)

Orf is caused by Parapoxvirus, transmitted from infected sheep and goats (and occasionally pigs) to humans through direct contact. It presents as papulo-vesicular or nodular lesions (typically solitary but can be multiple) on the hands and fingers. It is self-limiting over 6–8 weeks. No specific treatment is required. It can be confused with anthrax, HSV, or Milker's nodules (caused by Pseudocowpox virus from cattle). PCR or electron microscopy can confirm the diagnosis.

Reference: UKHSA 2023 – Zoonotic infections; PHE 2018 – Orf guidance