Epidemiology originates from Hippocrates observation more than 2 decades ago that environmental factors influence the occurrence of disease. However, it was not until nineteenth century that the distribution of disease in specific human population groups was measured to any large extent. Some of the spectacular achieves include the work of John Snow, the risk of cholera was related to the drinking of water supplied by a particular company. John Snow located the homes of each individual who died from cholera in London during 1848-49 and 1853-54, and noted an apparent association between the source of drinking water and the deaths. He compared cholera deaths in districts with different water supplies and showed that both the number of deaths and threat of deaths were higher among people supplied water by a specific company. Snow constructed a theory about the communication of infectious diseases and suggested that cholera was spread by contaminated water (Bauch et al., 2013).

Epidemiology therefore in its modern form is a relatively new discipline and uses quantitative methods to study disease in human populations, to prevent and control efforts, Richard Doll and Andrew Hill, studied the relationship between tobacco use and lung cancer, there work was precede by experimental studies on the carcinogenicity of tobacco tars and by clinical observations.

Therefore success in epidemiology has played a great role in eradication of small pox; its elimination has contributed greatly to the health and well-being of millions of people, particularly in many of the poorest populations (Kostyrka, G, 2015). Smallpox illustrates both achievements and frustrations of modern public health. In the 1970s, it was shown that cowpox infection conferred protection against the smallpox virus, yet it took almost 200 years for the benefits of this discovery to be accepted and applied throughout the world (Kostyrka, G , 2015). The fact that there was no animal host was of critical importance together with the low average number of secondary cases infected by a primary case. In England a farmer by the name Benjamin Jest, noticed that his milk maids were not contacting the smallpox disease but they did develop cow pox, he therefore believed there was a link between the two, hence he had to infect his family with cowpox to be immune from the smallpox which worked but little was publicized about his observations (Bauch et al., 2013).

By 1700, servants were often the ones who milked the cows. Servants were also required to tend to the heels of horses affected with cowpox. This led to spread of the disease from horses to cows during milking; Jenner observed that when a person had cowpox this same person would not get smallpox if exposed (Bauch et al., 2013). Jenner came to the conclusion and invented smallpox vaccine with this knowledge. The vaccine proved a vital role in preventing infection from this disease.

References

Bauch, C., d'Onofrio, A., & Manfredi, P. (2013). Behavioral epidemiology of infectious diseases: an overview. In Modeling the Interplay Between Human Behavior and the Spread of Infectious Diseases (pp. 1-19). Springer New York.

Kostyrka, G. (2015). Disease ecology and the concept of emerging infectious disease: its impact on the epidemiology of rabies virus, 1990s-2010s.

Epidemiological studies conducted detailing the spread, risks, prevention and control of the diseases listed in this study envisioned the health of population a couple of years later. The quest to understand how these variables influence various diseases among humans and animals is a precursor to goals and objectives that are on course for the eventual realization of how crucial preventive and control measures can be adopted as illustrated below.

First, the events within the epidemiological study given have contributed to a greater understanding of the etiology of and development of prevention methods for dietary deficiency diseases. Life style diseases, the most common ailments in the world today particularly among the developed countries have seen more efforts to link the types of foods and the likely diseases related to them (Dellit et al, 2007). For instance, tobacco use and lung cancer was vital for study conducted by John Lind on the relationship between Scurvy and Citrus fruits which is largely down to life style. Also the study of cigarettes smoking and lung cancer has heralded the advent into chronic disease epistemology in the 21st century (Dellit et al, 2007). This has instead displaced the infectious diseases as the mainstay in the public health across the world.

Secondly, significant awareness has been realized and continues being the dominant theme in the fight to find cure for the diseases deemed to danger to humanity. More efforts have been focused on campaigns both on local, national and global level to sensitive people on the importance of keeping healthy and avoiding instances that increases chances of contracting certain diseases. Broad awareness has been vital in the fight against contagious diseases. More so, today we have a broader factual knowledge base with regard to the aforementioned tenets of studying diseases. Major public health problems have been allayed as well through extensive public sensitization.

Thirdly, alternative cure and preventive measures have been advanced as a result of epidemiological studies. For instance, vaccination has emerged as a key method that can be used to enhance temporary ‘cure' while research scientists delve more into research. New discoveries being made about the various diseases have received more confidence from the public.

Fourthly, the events illustrated in the study have laid the foundation for a stronger interest in the public health profession. Today, the health profession is the most vital organ of any nation. A collective action has been tailored on the discovery, causes and prevention of these diseases (Dellit et al, 2007). Communicable and acute diseases have ended being prototypical for entire public health. In essence, they have had a widespread influence in terms of mortality and morbidity. They have been discovered to be highly contagious and inherently social diseases