Population history of indigenous peoples of the Americas scope of the epidemics over the years was tremendous, killing millions of people—possibly in excess of 90% of the population in the hardest hit areas—and creating one of "the greatest human catastrophe in history, far exceeding even the disaster of the Black Death of medieval Europe", which had killed up to one-third of the people in Europe and Asia between 1347 and 1351. One of the most devastating diseases was smallpox, but other deadly diseases included typhus, measles, influenza, bubonic plague, cholera, malaria, tuberculosis, mumps, yellow fever and pertussis, which were chronic in Eurasia. This transfer of disease between the
Fish disease and parasites Fish can limit the impacts of pathogens and parasites with behavioural or biochemical means, and such fish have reproductive advantages. Interacting factors result in low grade infection becoming fatal diseases. In particular, things that causes stress, such as natural droughts or pollution or predators, can precipitate outbreak of disease. Disease can also be particularly problematic when pathogens and parasites carried by introduced species affect native species. An introduced species may find invading easier if potential predators and competitors have been decimated by disease. Pathogens which can cause fish diseases comprise: Parasites in fish are a common natural occurrence. Parasites can