The native people had never been exposed to European diseases and had no immunity.
If by people in America you mean "Native Americans", they had not developed the immunities to European diseases, over the centuries that Europeans had developed. Diseases such as measles, diphtheria, even chicken pox, not to mention smallpox were devastating to the American Indian. It is probable that more Native Americans died of European diseases than died in the many battles with the white man.
It introduced deadly new diseases to native communities. (july 20222) Apex
European exploration caused Native Americans to lose much of their land and exposed them to new weapons, beliefs and lifestyles. It also exposed them to European diseases that their bodies weren't accustomed to, leading to the deaths of millions of Native Americans from disease.
The spread of the diseases (such as Small Pox)
There are no diseases unique to Australia, and in fact Australia is free of many diseases, such as rabies, that are prevalent in other parts of the world.
Australia's native inhabitant people Aborigins lost "control" over the continent (if there ever was any unified control) and it became populated by europeans.
diseases
The population of Native Americans in Australia is quite small. However, they would still be called Native Americans. The indigenous people of Australia are called Aborigines.
Cholera.
The British are responsible for the death toll of the Native American people. Not only were many killed during battles but the British also gave the Native Americans blankets infected with smallpox.
because the native Americans did not have any contact with outside continent germs, and viruses. When the Europeans came into america, they brought with them all foreign germs and diseases.
Aborigines.