Helicobacter pylori strains that share ancestry with their human hosts are less likely to cause severe disease
Author: Jef AkstSource: http://www.the-scientist.com/?articles.view/articleNo/38845/title/Human-Pathogen-Coevolution/
Summary:
Helicobacter pylori is a bacterium that colonizes in the gut mucosa in nearly half the human population, causing gastric inflammation and sometimes stomach cancer. This is one of the second-leading causes of death by cancer in the world! The study of this bacterium shows that patients who contain this strain possess fewer severity of diseases compared to the distinct ancestor who had the bacterium in their body. Scientists and doctors say that this issue should be seen with both the host and microbe, or population and pathogen. After collecting samples from a Columbian Hospital with gastric cancer patients, doctors found out that the severity of the H. pylori is less severe compared to the distinct ancestors due to the evolutionary adaptation and change of humans. The idea was that if one coevolved with the bacterium, the strain becomes les and less virulent.
Connection:
This article talks about the idea of evolution and how coevolution or convergent evolution is something species, including bacterium, undergo. In this article, it shows how the bacterium Helicobacter pylori underwent coevolution with humans in different environments, causing the severity of its affects to be dampened. Another connection to the evolution unit is the idea of adaptive radiation. Due to humans adapting in various environmental conditions, humans on the African coast had a less virulent strain of the bacterium similar to humans living in the mountains. As a result, the bacterium adapted and varied itself to the environment as it was in the host, causing the severity to decrease.
Why would coevolution make the strain less severe?
ReplyDeleteCoevolution would make the stress less severe because as we saw from the example from the Biology book, the strain mutates itself to other impacts that could have on it. As a result, the strain becomes less sever over time
DeleteIf the bacteria adapted to the environment as it was in the host, why would the severity of the stain decrease?
ReplyDeleteAs I've noted in the previous question, the strain doesn't expose itself to environmental disruption. As a result, it adapts to its natural environment. When it encounters new environments, the strain begins to increase in severity but when it is in the same or non-changing environment there is no severity in the stain
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