This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: Virology, Subject name: Microbiology
Mad Cow disease (Spongiform disease) occurs due to - 
Select and explain. 
A. CJ virus, B. Arena virus, C. Kuru virus, D. Parvo virus
A: CJ virus
Answer: A: CJ virus 
Explanation: prion disease in animals include scrapie,mink encephalopathy,BSE madcow disease.These are caused by slow virus group B. REF:ANANTHANARAYAN AND PANIKER'S TEXTBOOK OF MICROBIOLOGY 9TH EDITION PAGE NO:556,557