Globalization and disease Spanish soldiers introduced smallpox by contact with natives of the Aztec capital Tenochtitlan. A devastating epidemic broke out among the indigenous people, killing thousands. In 1617, smallpox reached Massachusetts, probably brought by earlier explorers to Nova Scotia, Canada.” By 1638 the disease had broken out among people in Boston, Massachusetts. In 1721 people fled the city after an outbreak, but the residents spread the disease to others throughout the thirteen colonies. Smallpox broke out in six separate epidemics in the United States through 1968. The smallpox vaccine was developed in 1798 by Edward Jenner. By 1979 the disease had been
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