The Evolution of Tuberculosis and Biological Organisms
The definition of evolution according to the oxford dictionary is, “The process by which different kinds of living organism are believed to have developed from earlier forms during the history of the earth.” Mycobacterium tuberculosis is a pathogen which belongs to the ‘Mycobacteriaceae‘ family it is commonly known to cause tuberculosis. The question is how exactly did Mycobacterium manifest into the bacterium it is today? Did it evolve in humans and only humans or did it first emerge from another biological organism? Hence did factors of the environment such as climate/temperature change engage in the evolution of Mycobacterium Tuberculosis?
The following will be evaluated and investigated through: the history of the development of mycobacterium tuberculosis throughout the world, the relationships between Mycobacterium tuberculosis and humankind (also other organisms such as animals), how technology has provided perspicacity towards the evolution of Mycobacterium tuberculosis and the state of the bacterium from the present proceeding towards the future. The following facets will provide necessary knowledge required to devise a response for the constructed question related to origin and climate change in relation to Mycobacterium tuberculosis.
The origin and analogy between humans and other biological organisms in relation to Mycobacterium tuberculosis plays a cardinal role in the understanding of how to potentially ” control and eliminate the lethal disease”. As a result to Dr Robert Koch’s1 (1882) discovery of Mycobacterium tuberculosis many thereafter have evaluated ways on eliminating the Mycobacterium tuberculosis. In order to record and devise information on a topic one needs to deduce its relationships (past and present) and origin in order to evaluate its development and reduce its effects.
History of disease Tuberculosis and spread of Mycobacterium tuberculosis throughout the world
Approximately 70 000 years ago it is presumed that the tuberculosis bacteria originated through early humans of that period in the African region. Sarah Pruitt 2 (2018, p3)provides information in a History article of how scientist have accumulated research that stipulates how Mycobacterium Tuberculosis originated during the Neolithic Revolution 3. The article further explains that the findings led these scientists to believe that due to the Neolithic revolution Mycobacterium Tuberculosis ‘originated in animals and was then passed down to humans’(Pruitt,2018,p3). They deduced this due to the increasing phase of domestication of animals during the specific Neolithic period. Although Sebastien Gagneux 4 and the Swiss Tropical and Public Health Institute (2018)and other international researchers stated a more alternate conclusion with the research they obtained.
They collected 259 tuberculosis bacteria in different parts of the world and formulated an evolutionary genetic link which enabled them to study human history with the bacteria. This helped them deduce that the bacteria originated approximately 70 000 years ago in early humans in the African region and not in animals. The bacteria then spread due to the observed migration of the early human and increased due to the increase of the population. In order for the bacteria to survive this long Sebastien Gagneux (2018, p5)and many other researchers have deduced that the bacterium stayed dorment in its hosts for approximately 20 000 – 30 000 (years ago) and re-emerged later as means of survival. The proof of migration and re-emerging is evident in some of the suggested later findings in Ancient Egypt. Elizabeth A. Talbot and Brittany J. Raffa 5 (2015, p1) (in an article 6 stated that it was discovered that in Ancient Egypt numerous mummies were found to have Tuberculosis approximately 5000 BCE. This shows the possible evidence to how the spread of tuberculosis occurred due to migration. The internal and external spread of tuberculosis7 can occur through the air. An infected host can spread the bacterium through coughs or sneezes. This is because the particles emitted contain infectious bacterium resulting in another host who inhales those particles to become infected.
Relationship between Mycobacterium tuberculosis and humankind
Mycobacterium Tuberculosis is the cause of Tuberculosis in humans which occurs/develops in the lungs of a living host. The bacterium needs a living host because it is a pathogen8. Tuberculosis occurs in the human body in two ways such as: Latent TB or Active TB. Latent TB is when the host contracts Mycobacterium Tuberculosis although the bacteria remains alive while being dormant. This type of TB cannot be spread to other individuals (a result of a stronger immune system). Active TB occurs when the host is infected with Mycobacterium Tuberculosis and the bacteria settles in their lungs and starts to multiply and spread (a result of a weaker immune system). Therefore the bacterium is able to spread to other individuals. Zoonotic tuberculosis occurs in animals and according to the International Union Against Tuberculosis and Lung Disease (2018,p10)research has been formulated which stipulates that the bacteria can be spread into food supplies (such as cheese, milk etc.). The bacteria can also be spread through direct contact between animals and humans ( such as domestic livestock).
An additional fact relating to the relationship between mycobacterium tuberculosis and humans according to the World Youth Organization (2018, p8)is that statics show that people with HIV/AIDS are 20 – 30 times more able to contract the bacterium more easily, children are also more likely to contract the bacterium (as in 2017, 1 million children contracted tuberculosis and 230 000 children died). This leads to the deduction that those with weaker immune systems are more likely to be infected by Mycobacterium Tuberculosis, which results in tuberculosis one of the top 10 causes of human deaths in the world.
How improved technology has provided insight to the evolution of Mycobacterium tuberculosis
The rate of the spread of tuberculosis according to the World Health Organization(2018, p1)has said to be decreasing worldwide by 2% each year. This decrease is due to better understanding of the bacterium, more resources and improved technology. Improved technology and better understanding can be shown through the development of genotyping9 (genotyping term was coined by Wilhelm Johannsen10). Genotyping according the National Center for Biotechnology Information (2018)has now developed more ways for researchers to identify strains that occur in the bacterium such as drug resistance. The genotype of Mycobacterium Tuberculosis is named ‘Beijing’ it is the group/family name for the genotype containing multiple strains. According to Centers for Disease Control and Prevention (National Center for Health statistics,2018) genotyping is essential to the in-depth detail of the evolution of Mycobacterium Tuberculosis. This information is fundamental as it provides more insight of the relationship between Mycobacterium tuberculosis and humans and their genetic similarity which enabled that bacterium to survive for generations thereafter its origination and dormant phase. Genotyping is important as it enables doctors to diagnose the host through their genotypes and find/create ways to alter the effects of the bacterium.
Another relation to technology and Mycobacterium Tuberculosis is CRISPR11 (Clusters of Regularly Interspaced Short Palindromic Repeats). CRISPR is technology used as a genome silencer or alternator. According to an article by Biomed Research International (Wolf.J,2019.) CRISPR in relation to Mycobacterium Tuberculosis is used to explore the adaption of drug resistance within the bacterium, many researches were accumulated which helped researchers understand the adaption of Mycobacterium Tuberculosis. Further studies are ongoing which is fundamental for the future of the bacterium.
The present and the future
According to medicinenet.com in simplified terms drug resistance is defined as “the ability of bacteria and other microorganisms to withstand a drug that once stalled them or killed them”. The present problem of Tuberculosis is that Mycobacterium tuberculosis has started to adapt and evolve which has resulted into drug-resistant TB. According a report by the UN Interagency Coordination Group (IACG) on Antimicrobial Resistance (Pai.M, 2019) globally drug-resistant tuberculosis contributes to 230,000 deaths per year. The current prevention strategies and treatments include the decrease of spreading the disease through respirators and masks, the BCG vaccine12 ,increase in education about tuberculosis, chemoprophylaxis13, isoniazid14. With more knowledge about prevention to tuberculosis more research is being used to eliminate the current problem of drug-resistant tuberculosis. This involves the improvement of technology through genotyping and CRISPR which can help explain and remove the genome which enables the bacterium to become drug resistant.
According to an article by the national center for biotechnology information (2018)mycobacterium tuberculosis does not die at temperatures below 100 degrees Celsius. According to the national Centers for environmental information (2019)global warming is indicated at an average temperature of 70 degrees Celsius which means there is no effect upon the bacterium. According to The Brazilian Journal of Infectious Diseases (2015)a research study showed that the bacterium was widely more spread during winter and people were more likely to contract tuberculosis during colder periods15.
The future goal for scientists when dealing with the bacterium and tuberculosis is to eliminate it. According to the national center for biotechnology information (2019)it is stated that current research was done to show a genome connection between mycobacterium tuberculosis and humans , this resulted in the development to study gene silencing16 the connective genome for the elimination of mycobacterium tuberculosis. The complete extinction of the Bacterium is not fully researched as the according to many sources it had largely spread and the extraction of it through the world according to an article by sahivsoc.org Richard E. Chaisson, MD Center for AIDS Research Center for TB Research Johns Hopkins University states that the eradication of tuberculosis by 2050 is probably not possible.
In summary and in relation to the question of environmental factors and bacterium relation to animals and humans ; the bacterium occurred through the development of early humans and later pasted on to animals through domestication. Although the able transfer between bacteria, animals and humans indicate a possible related genome which is currently being researched through genotyping, CRISPR and further technology. The external factors such as temperature/climate play a minimal role in the contraction of tuberculosis. As in colder climate /temperatures the contraction of the bacterium can occur more likely and the bacterium in warm heat still survives over temperatures of 50 degrees Celsius therefore global warming won’t necessarily have a drastic change in the bacterium. The elimination of the bacterium is not completely attainable but the development of more attainable treatments and silencing of resistance genes create a solution for the decrease of tuberculosis spread and better evolutionary success of the human population.
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