Orf (contagious ecthyma) transmitted by a cat

Abstract

A 65-year-old woman presented with a 6-cm umbilicated lesion on the forearm (Figure 1), which was evolving for a few days. Orf was clinically diagnosed. There was no viral sample. The patient had not been in contact with any goats or sheep. However, she reported having been in contact with a cat presenting with scabbed sores around the right ear (Figure 2) 4 weeks earlier. This cat was leaving in a house next to a farm with ewes and lambs, that could have been in contact with this cat. Lesions spontaneously disappeared in the cat and in our patient in 4 weeks, with a very discrete scar. We concluded that orf was transmitted by this cat.

Orf is usually transmitted by sheep and goats.¹ We found only three cases of orf in cats² in the literature, all involving close contact of cats with sheep or goats. Only one case of cat-to-human transmission³ has been noted, linked to a cat scratch.

The main differential diagnosis would be cowpox/catpox'.^{4, 5} In this disease, the human patients present with large painful papules which progresses to ulceration and necrosis with thick, hard, black crusts and flu-like symptoms, which was not the case in our patient.

Victoire Laumondais and Laurent Misery have written the paper. Muriel Delhomme and Laurent Misery performed the diagnosis.

The authors declare no conflict of interest.

The patient has given written informed consent for participation in the study and the use of her deidentified, anonymized, aggregated data and her case details (including photographs) for publication. Ethical approval: not applicable.