Africa is considered the cradle of humanity. The earliest evidence of our ancestors was found in Africa. The fossils found date to about4.2 to 3.8 million years and were known to be “apelike humans”. It is inferred from the fossils of their teeth that they ate things like fruits, seeds and plants – not meat. However, as humans evolved more and become more intelligent, they developed tools to hunt game and eat meat. This in turn exposed them to other infectious diseases and vectors of parasites. Thus, was the beginning of zoonosis- or animal infections being transmitted to humans. With evolution comes change in cultural and societal practices. We began as hunter-gatherers who roamed distances to find plants, hunt and find water. In other words, we were nomadic. As a result, humans were not exposed to rotting meat or feces and exposure to parasites was limited. Groups or tribes were small, isolated bands so “crowd” diseases requiring human-to-human contact transmission was absent or severely limited. Some of the infections these types of early humans were probably exposed to were intestinal worms, lice/fleas, malaria, yellow fever and tularemia. As time continued to pass, the human population in the world increased. Some major factors that contributed to this include tool making, the agricultural revolution, scientific-industrial revolution. This increase in in population led to an increase in disease. Agricultural technology and advancement, sedentary or stagnant lifestyle and globalization are responsible for the increase in variety and especially transmission of diseases. Finally, slavery played a large part in disease. The slave trade bringing over workers brought malaria and small pox with them.
Part 2
Globalization and technological advancements such as airplanes and other transportation technology has significantly changed infectious diseases. A good case study is the increase and spread of sexually transmitted diseases like chlamydia, genital herpes, and recently AIDS. The AIDS epidemic has been prevalent over the last 20 years. The increase in climate has also contributed to the spread of infectious diseases. Vectors such as malaria and bird flu (or diseases and infections of those variety) have also been allowed to survive and spread rapidly through animals and insects such as mosquitos.