Guinea pigs and llamas seem to be it for the new world. Whereas the Europeans had a vast list of animals available. They'd live in tight confines with pigs and chickens and cows during long cold winters - fabulous creatures and circumstances for cultivating new strains of disease.
It could be that Euro-african civilisations were more effective at cultivating new diseases thanks to the crossover between animals and humans.
http://en.wikipedia.org/wiki/Domestic_animals
Guinea pigs and llamas seem to be it for the new world. Whereas the Europeans had a vast list of animals available. They'd live in tight confines with pigs and chickens and cows during long cold winters - fabulous creatures and circumstances for cultivating new strains of disease.