Definition. Rickets (in children) and osteomalacia (in adults) are two forms of a metabolic bone disease resulting from vitamin D deficiency. Both cause softening and weakening of bones because of defective or inadequate bone mineralization. Rickets. Copyright Â© Nucleus Medical Media, Inc.
The flow from west to east: Disease. In terms of diseases, the Columbian Exchange was a wildly unequal affair, and the Americas got the worst of it. The flow of disease from the Americas eastward into Eurasia and Africa was either trivial or consisted of a single important infection.
The 'Columbian Exchange' How Discovering the Americas Transformed the World Columbus' arrival in the Americas sparked the globalization of animals, plants and microbes. A recent book takes a closer look at how items from the New World, such as potatoes, guano and rubber, quickly and radically transformed the rest of the planet.