> In late May 2003, studies were conducted using samples of wild animals sold as food in the local market in Guangdong, China. The results found that the SARS coronavirus could be isolated from masked palm civets (Paguma sp.)
and
> The SARS epidemic began in the Guangdong province of China in November 2002 ... Chinese government officials did not inform the World Health Organization of the outbreak until February 2003.
That's six months from the start of the outbreak, and less than four months from WHO being informed, not three years.
Where did you get your "three years" figure from?