In the new era of human disease human social habits and their various circumstances are noted as being one of the primary facilitators of the spread of infectious diseases. What must be understood is that humans are inherently social animals and as such they have a predilection towards gathering in groups, going to areas with large concentrations of people and other forms of social activity that involves close contact with a large number of people.
As a result this facilitates the spread of infectious diseases from one carrier to the next creating the possibility of an epidemic. It must also be noted that the current human living environment acts as an adjunct facilitator of the spread of disease which, when combined with humanity’s inherent need to socialize, become two of the main reasons behind the spread of modern day diseases.
An examination of modern day living conditions show that with the current trend of excessive population concentrations into increasingly smaller living spaces as noted by the development of modern day apartment complexes this has resulted in people becoming more vulnerable to catching a variety of infectious disease from various carriers.
The reason behind this is quite simple, increased population concentrations within a confined location raises the likelihood of catching an infection as compared to populations that are spread over a particularly large area.
For example, an examination of the spread of diseases within areas in India, particularly the city of Mumbai, show that the rate of catching disease is higher as compared to various suburbs located outside of the city. This trend is noticeable in cities such as Manila, New York, London and other global population centers where the rate of catching infectious diseases are far higher as compared to areas that are less densely populated.
It must also be noted that this change in human living conditions has also had a distinct impact on particular disease life cycles. Due to greater human population concentrations particular diseases no longer go into distinct phases of long term remission as seen in various historical records but instead continue to propagate among the general population. This of course is due to the greater likelihood of infection that concentrated population centers have.
As a result this creates the possibility of greater amounts of mutated disease strains that grow more resistant to modern medication due to their longer periods of activity. Evidence of this can be seen in strains of nasopharyngitis or more commonly know as the common cold. Greater population concentrations have resulted in prolonged activities of this particular type of disease resulting in a plethora of variants appearing on an almost yearly basis.
Various studies examining the prevalence of the common cold in human populations reveal that its disease life cycle has continued to grow lengthier as a direct result of concentrated populations which increased the likelihood of different variants evolving from a single strain.
It is due to this that the average person is infected nearly two to four times a year by differing variants of the common cold with certain strains being more resistant to standard treatments as a direct result of an apparent evolution of the strain itself.
Environmental Changes and Human Diseases
When examining the evolution and spread of diseases what must be understood is that all diseases mutate and spread within a specific environmental context with specific impacts to the environment caused by human activity also having a way of changing the way diseases spread and evolve.
For example, diseases rely on insects as carriers in order to spread from one location to the next, with the current issue of global warming and habitation alteration affecting many natural environments this has in effect changed the way in which certain insects proliferate in the natural world (Faulde et al., 71 – 73).
The mosquito for example has thrived as of late as a direct result of the current changes in habitations and global weather patterns, this has resulted in an increased area of effect of certain mosquito populations wherein the range of disease carrying mosquitoes has grown to encompass increasingly larger land masses (Faulde et al., 71 – 75). With this increased range comes the issue of certain diseases travelling outside of areas from which they were previously confined.
For example, people in various temperate regions of the world are increasingly finding themselves beset by various types of diseases that were historically confined to tropical climates and environments however due to the increased range of mosquito populations these diseases have now been brought into new environments that have little resistance to these new diseases (Faulde et al., 71 – 73).
Malaria for example has spread to various regions of the globe with increasingly virulent and treatment resistant strains as a direct result of its prevalence and spreadability in certain population centers diseases (Faulde et al., 71 – 73).
Even dengue fever that was previously isolated to South East Asia has found its way into the U.S. causing widespread cases in populations that have little experience in dealing with this particular type of disease.
What must be understood is the fact that with diseases spreading from where they were previously confined comes the possibility of new strains developing as a direct result of being introduced to populations that have had little resistance to the disease itself. Virus strains evolve as a direct result of environmental and carrier characteristics wherein the environment acts as a method of control and carriers act as a means of transmission (Selkirk et al., 51).
In most cases diseases find themselves in environments that have a distinct level of control as well as carriers that have a certain degree of resistance, this actually acts as a stopgap measure in preventing disease from evolving beyond a certain capacity.
In cases though where diseases are introduced into new environments that have lower levels of control with carriers that are less resistant to their effects this creates a literal explosion in the disease population which affects its evolutionary characteristics (Selkirk et al., 56).
With fewer limits on control and resistance this has the effect of creating strains that are more virulent, deadly and more resistant to methods of prevention.
Environmental Disruptions, Evolution, Anthropology and the Recurrence of Diseases
From an anthropological standpoint it can be stated that environmental disruptions and the subsequent influence they have on diseases has been one of the most influential factors in human evolution. When examining the history of humanity it can be seen that the prevalence of certain types of diseases has actually both limited and encouraged humanity’s growth throughout the years.
For example, the Black Death that wiped out nearly 50% of Europe’s population during the middle ages actually originated from the actions of the Mongols during this particular period of time. The disease was actually isolated within a particular desert near China at the time until it was encountered by the Mongol horde.
Seeing the potential this disease could have in decimating populations within fortified strongholds diseased corpses were often flung into fortified cities during invasions and from there the disease travelled via infected rats and people to various harbors in Europe spreading the Black Death (Benembarek, et al., 427).
There are also numerous instances where environmental disruptions have caused diseases to proliferate in particular populations as evidenced during the era of the Spanish invasion of South America by Cortez and the subsequent proliferation of European diseases which decimated local populations.
It was the introduction of unknown diseases into the local environment that caused such and occurrence to happen and as such is evidence of what happens when outside foreign elements are introduced to local populations.
Taking this into consideration it can be seen diseases have acted in numerous pivotal points throughout humanity’s history and such should be considered a vital stepping stone in understanding how history developed as a direct result of the destruction of particular populations.
When trying to understand how particular diseases keep on coming back it is important to take note of the fact that diseases have a way of going into periods of remission and then flare up once particular conditions are right for proliferation.
Diseases at times can remain dormant for years in particular areas due to their ability to survive in small population sets for prolonged period of time (BARRYS et al., 202) It is often the case that certain diseases will continue to remain isolated within a particular area until such a time that some outside method of interference causes the disease to once again expand (Todd et al, 437).
Such occurrences can happen naturally however increasingly it has been noted that continuous human expansion and the resulting environmental changes it causes is being considered as one of the main factors behind diseases coming back to threaten human populations (BARRYS et al., 206) As human population centers continuously expand into new areas local ecologies are disturbed to such an extent that dormant diseases often come into contact with new carriers.
It is in this particular instance that the disease starts to become virulent and expands within a particular population until it is either sufficiently eliminated or once again goes into dormancy. Unfortunately with increased human expansion the areas where diseases can go dormant are increasingly getting fewer which results in higher rates of disease outbreaks.
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