To the Editor.—
We read with great interest the recent report by Gill et al1 concerning four cases of orf. We would agree with many of their comments and, in particular, it is our impression also that orf is considered too rarely in the differential diagnosis of inflammatory nodules. An awareness of the disease is important for urban as well as rural physicians, as a series of cases has been reported in meat workers in the heart of London, England.2 We do, however, wish to make two further points:The authors give the impression that electron microscopy of fluid from the lesion is the best means of establishing a diagnosis. This is probably not the case, as previous studies have shown that the crust from a lesion contains large amounts of orf virus and is the best tissue to examine electron microscopically.3 These authors report that vesicle