Leproid granulomas: a unique mycobacterial infection of dogs

Abstract

In 1973, a Rhodesian veterinarian, Richard Smith, documented a mycobacterial skin infection in a Doberman and a Rhodesian Ridgeback dog that was characterised by variably sized subcutaneous nodules. It was thought at first that these dogs may have had tuberculosis and, because of public health considerations, they were euthanased and subjected to postmortem examination. There was no internal organ involvement at necropsy and, although acid-fast bacilli (AFB) were abundant in the lesions, culture was negative for the tubercle bacillus. Similar cases were recorded soon thereafter in an Australian veterinary discussion forum, although the infection was not subjected to systematic investigation until the end of the 20th century. The disease was given the name ?canine leprosy? by some veterinary dermatologists, but the alternative name canine leproid granuloma syndrome (CLGS) was later suggested by an Australian veterinarian David Watson. It is now clear that leproid granulomas are not uncommon and indeed are by far the most frequently encountered mycobacterial disease of dogs in Australia.