An emerging infection newly appears in a population or is spread in a new geographic area (Morens et al., 2004). The zoonotic transmission of pathogens from animals to humans is a pivotal mechanism by which emerging infections have af:licted humans throughout history (Wolfe et al., 2007). The probability of cross-species transmission of pathogens was dramatically enhanced with increased interactions with animals through hunting, animal farming, trade of animal-based foods, wet markets or exotic pet trade (Bengis et al., 2004).