Population Based Epidemiology

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PopulationBased Epidemiology

PopulationBased Epidemiology

Question1: Significance of historical developments in epidemiology

Asuggestion that the occurrence of diseases was directly associatedwith the environment in which one lived in was a departure from thegeneral perception that illnesses resulted from the supernaturalpowers. Hippocrates held in 400 B.C that illnesses could be caused bythe physical environment (Friis &amp Sellers, 2013). This was asignificant breakthrough because it motivated the society to startsearching for the cure for diseases since it was now clear that thesupernatural powers had nothing to do with the sicknesses.

Theapplication of vital statistics helped earlier philosophers andscholars increase their understanding of different demographicfactors and problems affecting various groups of a given population.For example, the application of mortality counts in 1662 helped JohnGraunt study infant mortality, identify the relationship betweenbirth rate and seasons (Friis &amp Sellers, 2013). In essence, thestatistics makes it possible to study issues affecting the society indetail, thus increasing the possibility of finding viable solutions.

Theapplication of natural experiments allowed the scholars to conductobjective observational studies where individual members of a givenpopulation who were exposed to control as well as experimentalconditions were not influenced by investigators. This enabled theresearchers to investigate cases in which the application ofcontrolled experimental design could be possible. For example, JohnSnow had to conduct a natural experiment in the study of choleraepidemic in London, since it was not possible to apply a controlledexperiment (Friis &amp Sellers, 2013).

Thediscovery that diseases were caused by specific organisms is amongthe most significant breakthroughs that have been made in the historyof medicine. It resulted in the establishment of the germ theory anddetermination of drugs that could kill specific pathogens as a way oftreating illnesses (Friis &amp Sellers, 2013).

Question2: Meaning of different components of epidemiology

Theterm determinant is used to refer to events or factors that arecapable of bringing a significant change in health. Epidemiologistsare guided by an assumption that diseases occur when there is asufficient concentration of determinants, but they do not take placerandomly (Center for Disease Control (2016). The term “distribution”refers to the frequency as well as the pattern in which a givenhealth event affects the population. Frequency is the number of casesof a given illness, in relation to the population size, while patternrefers to dynamics of place, time, and place. Epidemiologists use theterm morbidity to refer to the state of being ill within a givenpopulation (Friis &amp Sellers, 2013). The term “mortality”refers to the number of people who have died in a given population.

Question3: A review of exhibit 1-2

Theflocculent particles that were observed in the water at the BroadStreet pump were indicators of the presence of organic contaminants(Friis &amp Sellers, 2013). The presence of these particles in thewater found in a particular pump and their absence in the rest of thewater helped Snow make a conclusion that the cholera outbreak couldbe attributed to consumption of water from the Broad Street pump.

Thelocation of deaths as indicated in Figure 1-12 suggests that most ofthe cases of infection occurred in areas surrounding the pump that islocated near the Broad Street. This suggests that the highconcentration of cases of death in the surrounding streets was causedby water from the pump.

Inaddition, the fact that some of the residents who died had avoidedfetching water from Marlborough Street and started getting it fromthe pump located in the Broad Street, acts a lead to conclusion thatthe outbreak of cholera was caused by contamination of water at BroadStreet. This is because people who consumed water from other pumpsdid not die, while all those who fetched water from the Broad Streetpump as well as those who shifted from their usual pumps were at ahigher risk of infection and death.

Thegreatest number of cases of attack on September 1 can be attributedto the fact that many people had consumed the contaminated water andthe incubation time for cholera for most of them elapsed on thatdate. In addition, September 1 appeared to be the climax because manypeople had just started fleeing after witnessing the spread of thediseases. The removal of the handle played a significant rolein reducing the spread of cholera, which is confirmed by an instantdecline in the number of daily attacks. However, a few cases werereported even after the removal of the handle because the water wasstill contaminated.

Question4: Pandemic and epidemic diseases

Epidemicdiseases are illnesses that are contagious and highly infectious andthey spread in a population that is located in a given geographicalregion. A pandemic is similar to epidemic in terms of infection, butit affects millions of people since its spread is not limited to aspecific region (Friis &amp Sellers, 2013). Endemic, on the otherhand, refers to a disease that affects people in a given place on aregular basis. Examples of the pandemic include HIV, the Black Death,the 7 Cholera Pandemics, and the 1918 Spanish Flue (Robert WoodJohnson Foundation, 2016). The Spanish Flue of 1918 qualified as apandemic because it spread quickly and affected millions of people indifferent geographical locations. It is estimated that the flu killedabout 50 million people across the globe, including some remoteareas, such as the Arctic and Pacific Islands.


Centerfor Disease Control (2016). Lesson 1: Introduction to epidemiology.CDC.Retrieved August 15, 2016, fromhttp://www.cdc.gov/ophss/csels/dsepd/ss1978/lesson1/section1.html

Friis,H. &amp Sellers, T. (2013). Epidemiologyfor public health practice.Burlington: Jones and Bartlett Publishers.

RobertWood Johnson Foundation (2016). The five deadliest outbreaks andpandemics in history. RWJF.Retrieved August 15, 2016, fromhttp://www.rwjf.org/en/culture-of-health/2013/12/the_five_deadliesto.html

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