Cowpox is found in both cattle and horses where it infects the udder and teats of the animals. When an infected animal is milked by hand it can be spread to the hand or fingers where it presents as a localized skin lesion.
Cowpox virus. This is a pox
virus that is antigenically similar to present vaccinia strains.
Human cowpox presents as
a papulovesiculogranulomatous skin lesion at the site of inoculation. There
is balooning degeneration of the keratinocytes and the presence of eosinophilic
inclusion bodies within the cytoplasm of the infected cell.
In the human cowpox presents
as a papulovesiculogranulomatous skin lesion at the inoculation site. It
does not spread to other body parts from the initial lesion, which is usually
located on the hand or fingers.
Diagnosis is accomplished
via presentation of the classic skin lesion in a patient who admits to
milking animals by hand, by the unique pathology and by the presence of
antibodies that cross-react with the smallpox virus and the vaccinia virus.
It is usually self limiting
and no treatment is indicated except in immunocompromised patients. Then
methisazone can be used.