The Appearance of Plagues:
Throughout history many examples of plagues, and epidemics are found. Many of these illnesses have changed throughout history, leaving many questions about the beginning of plagues a mystery. That is why it is important for scientist and historians to look into the beginning of plagues, and try to pin point essentially where it all went wrong. Before 8000 BCE, people were still hunter-gatherers. Because of the fact that people were constantly moving, populations remained small and free of many human waists found in a more crowded environment. Hunter-gatherers would occasionally fall ill from things carried by animals, or in nature, but these occurrences were scarce, and it was rare for it to affect a large group. By the year 8000 BCE domestication of animals and agriculture started to take place. Because of this, populations increased significantly. By 1750 CE the world population had increased approximately 160 times.
This agricultural revolution brought about many changes to society, including societies susceptibility to illness. With the onset of domestication and agriculture came humans living among animals, and humans sharing a water supply with these animals. People were also not as sanitary as we are today, due to a lack of education and experience with communal living. Because of this, these new communities created perfect conditions for rats, mice, ticks, flies, and mosquitos. A deterioration of the human diet began to take place, due to the fact that people were relying on as little as one crop to make up their diet. This degradation in nutrition provided a weakening in people’s health and immune system. At the same time, these new animals, the accumulation of rodents and insects, and over crowding created a perfect breeding ground for pathogens and vector born illnesses.
Current Effects of Technology and Human Activity on Health:
Medicine has come a long way sense the emergence of plagues and epidemics. Society has developed new sanitation and agricultural habits, as well as become more educated on the spread of diseases and pathogens. Unfortunately pathogens and diseases continue to evolve and change with us. Diseases are constantly emerging for the first time, as well as re emerging after a long period of time, sometimes stronger then they were before. Our population is also continuing to rise, causing more problems in the field of epidemiology. In the Morbidity and Mortality Weekly Report, Scientist from the CDC describes “New Modes of Disease Transmission Created by 20th-Century Technology”. One 20th century problem created was a bacterium that causes legionnaires disease being spread through modern ventilation systems. With our infinitely rising population comes new technology and practices. As history has shown, with new technology and practices comes an unknown that opens a door for things such as bacteria and pathogens. People have also been contracting human immunodeficiency virus and hepatitis C virus through transfusions of unscreened blood. Foodborne diseases are also on a rise, as food is continuously processed and shipped in mass numbers throughout the world. Additionally, airplanes have taken ships to a new level when it comes to major vehicles of international disease spread. Unlike before, airplanes have made it possible for any person to get anywhere in the world in 24 hours; which is less then the incubation period for most diseases. With travel becoming more effortless, more people are traveling to different wilderness habitats that harbor many insects and animals carrying infectious agents that are unknown to us. Suburbanization as well as the reversion of agricultural land and secondary growth forests have also increased, putting people in contact with deer carrying ticks infected with Borrelia burgdorferi, and has brought household pets into contact with rabies-infected animals. Lastly, the increase of antibiotics has brought about drug resistance in many people. People’s immune systems have become impaired by many modern medical practices, making them more susceptible to opportunistic infections. (Crane et al. 1999)
Globalization, as well as climate change, has also impacted infectious diseases throughout the 20th century. In the article Impact of climate change on human infectious diseases: Empirical evidence and human adaptation, from Environment International, scientist talk about the impact climate change has had on infectious diseases. The article states that the impacts of global climate change can be examined through three disease components; pathogen, host, and transmission environment. The change in temperature is one agent responsible for effecting infectious diseases. Pathogens are greatly affected by temperature, and dramatic changes in temperature can increase the amount of pathogens found in an area. For example, “the EIP for P. falciparum reduces from 26 days at 20 °C to 13 days at 25 °C” Bunyavanich’s article as sited in (Wu et al. 2016). Also, as temperature start to rise, insects carrying pathogens may start to increase to higher altitudes, spreading vector born illnesses. Precipitation and humidity have also had an effect on infectious diseases. Humidity has been found to be a respondent for air-borne pathogens such as influenza. Mosquitos, and other insects, have also been found to thrive in humid conditions, due to the fact that many of their reproductive periods occur in standing water. Because of this, humidity and precipitation may affect the prevalence of vector born illness. Wind has also been found to move dust particles, which helps the spread of many infectious diseases. (Wu et al. 2016)
As society changes many infectious diseases and pathogens change, and re emerge. Because of this, it is important for scientist to look into the history of infectious diseases, as well as look into warning signs, and impacts these changes can have on the environment. Although it is impossible to be prepared for the unknown, scientist can look into these things in order to be better prepared for the next disease or epidemic, as well as to be better prepared to catch emerging pathogens before the spread.
References
Achievements in Public Health, 1900-1999: Control of Infectious Diseases. (n.d.). Retrieved February 15, 2018, from https://www.cdc.gov/mmwr/preview/mmwrhtml/mm4829a1.htm
Mcmichael, A. (2013). Impediments to Comprehensive Research on Climate Change and Health. International Journal of Environmental Research and Public Health, 10(12), 6096-6105. doi:10.3390/ijerph10116096
Wu, X., Lu, Y., Zhou, S., Chen, L., & Xu, B. (2016). Impact of climate change on human infectious diseases: Empirical evidence and human adaptation. Environment International, 86, 14-23. doi:10.1016/j.envint.2015.09.007
[All facts other then the ones listed above where found using The Price of Being Sedentary PowerPoint, and lecture notes]