EPIDEMIOLOGY OF MYCOBACTERIUM-BOVIS INFECTION IN FERAL FERRETS (MUSTELA-FURO) IN NEW-ZEALAND .1. PATHOLOGY AND DIAGNOSIS

Necropsies of 228 ferrets captured from eight areas in the North and S outh Islands provided material for an investigation into the epidemiol ogy of tuberculosis in feral ferrets. Mycobacterial culture of pooled lymph nodes (retropharyngeal, respiratory and jejunal) identified the prevalence of infection to be much higher than that estimated from gro ss lesions only. Seventy-three of the 228 animals examined (32%) were diagnosed as tuberculous. Fifty-three culture-positive ferrets and 18 seemingly uninfected animals were subjected to detailed histopathologi cal examination. The outcomes of these investigations, including the c haracteristics of the disease. distribution of lesions and aids to dia gnosis, are presented. Of the feral carnivores found in New Zealand. t he disease persists at high prevalence only in ferrets, and is probabl y maintained principally by ingestion of tuberculous carrion. The cour se of the disease may be prolonged in some ferrets, but tuberculosis e ventually causes the death of many infected animals. Microscopic hepat ic granulomas may be considered pathognomonic of the disease, and have potential to be used as a rapid diagnostic tool in ferrets with no gr oss lesions.