Epidemiologic and experimental studies on transmissible mink encephalopathy

Area of Science:

• Veterinary Medicine
• Neuroscience
• Foodborne Illness

Background:

• Transmissible mink encephalopathy (TME) is a rare foodborne disease affecting ranch-raised mink.
• The cause of TME has been elusive, with initial theories pointing to scrapie-infected sheep, but subsequent research has not supported this.
• Epidemiological investigations have failed to link TME outbreaks to specific feed ingredients.

Purpose of the Study:

• To investigate the potential role of cattle as the source of TME in a specific outbreak in Stetsonville, Wisconsin.
• To experimentally determine if cattle can be infected with the TME agent.
• To characterize strains of the TME agent.

Main Methods:

• Experimental intracerebral inoculation of mink brain material into Holstein steers.
• Observation of clinical signs and development of spongiform encephalopathies in inoculated cattle.
• Experimental inoculation of the Stetsonville TME agent into Syrian hamsters to identify and characterize strains.

Main Results:

• Both inoculated Holstein steers developed fatal spongiform encephalopathies 18 and 19 months post-inoculation.
• The findings suggest that cattle infected with a BSE-like disease could be the source of TME.
• Two distinct strains of the TME transmissible agent were identified in Syrian hamsters, differing in incubation period, clinical signs, and pathogenicity.

Conclusions:

• Cattle infected with an unrecognized BSE-like disease may be the source of Transmissible Mink Encephalopathy.
• The study provides evidence for a novel animal prion disease in the United States.
• Further research is needed to understand the prevalence and characteristics of this cattle-associated prion disease.