Many diseases have a chicken and egg
situation; it is hard to say which existed first and which caused the other. They have been around for so long that they start feeling more like
a circle that has no beginning. But fortunately, this does not hold true for all diseases. According to a new study published in the journal Nature, scientists have now
figured out the mystery starting origin of the infectious disease tuberculosis
and how it spread to the New World.
According to New York Times article “Tuberculosisis Newer than Thought, Study Says”, scientists analyzed bacterial DNA from 1000
year old mummies to propose a new hypothesis for how tuberculosis originated. When
their search was expanded, they found that the bacterial DNA found in affected
mummies was most closely related to tuberculosis strains found only in seals. The
results were truly shocking. Who could have thought that an animal that everyone loves could be the cause of spreading such a deadly disease around the
world.
Tuberculosis is an infectious disease
caused by bacterium Mycobacterium tuberculosis. This bacteria attacks the lungs of the host where it causes extreme scarring. Different strands of this bacterium can also
affect the bones but the most common form of bacterium attacks the lungs. TB is one
of the leading cause of deaths in both children and adults worldwide which
makes it such a widely studied topic by different scientists.
To better understand the disease,
many ancient DNA experts and biomolecular archaeologists have dedicated studies
in trying to reconstruct the history of the bacterium that causes TB.
There had been many theories for the
origin of Mycobacterium tuberculosis, some dating back to as long as 10,000
years ago. But there has not been much consent among the genetic and
archaeological scientists until recently. Some hypothesized that this disease might have transferred
from cows to humans, but no one gave aquatic life much thought until the recent
study with mummies.
One of the fascinating aspects of
finding that seals might have brought this bacterium to the New World and around the globe is that
now it can be known exactly how old this bacterium is and what route might have
led to its spread throughout the world. According to scientists, the first strand of bacteria originated in Africa about 6000 years ago, from where it transferred to seals on the African shore. The affected seals spread the bacterium to other seals and the cycle continued til it reached North
America where it transferred from seals to other animals and eventually to humans.
It is hard to believe that such an adorable animal could be the source for spreading such a deadly disease in the world, but like they say- it is a disease with no borders.
It is hard to believe that such an adorable animal could be the source for spreading such a deadly disease in the world, but like they say- it is a disease with no borders.
Zimmer, Carl. (2014). “Tuberculosis
Is Newer Than Thought, Study Says.” The
New York Times. The New York Times. Web 16 Nov. 2014.
I really enjoyed reading this post. I'm really glad you took the time to explain what exactly tuberculosis is because I really didn't know what it was other than another disease that I got a shot for. I found it very interesting that tuberculosis came from seals but I don't believe I'm all too surprised at the fact. Animals carry lots of germs and bacteria, especially wild ones, because of the environment they live in. However I am really curious to know how exactly the transfer happened and if scientists were able to pinpoint that (i.e. hunting and eating seals, accidental transfer of blood, or a bite). You mentioned "affected seals" and I wonder if this means that they were infected with a disease or they just happened to carry the bacteria. If they were infected, are they still infected today?
ReplyDeleteYou would actually be surprised at how many diseases there are out there that they do not know the origins of. My topic is pertussis and I actually did my research proposal on finding the origin of pertussis because although there are ideas floating around out there, nothing is definitely known. I am currently taking biodiversity, which is why I chose this proposal because finding origins can be so useful in combating disease. Not only that, but it allows us to look at times when very similar diseases were prevalent allowing us to predict trends. Bacteria have in fact been around longer than we have so it makes sense that they are so resilient and deadly. I like how you bolded important points, I may definitely have to borrow that for my next posts. Well done.
ReplyDeleteHi Rimsha,
ReplyDeleteI enjoyed reading your blog post. I am shocked that TB originated from seals. They seem like such amazing creatures. It was nice how you added a picture, it helped make your blog post more enjoyable. I'm also wondering how TB was able to spread to humans, and if seals still carry the bacteria or disease today. Also, it was nice to add what exactly TB is and how it harmed the body. I wasn't sure of that before but all I knew is that TB was a disease.
Tuberculosis has always fascinated me. In my opinion, the origin of tuberculosis is a very controversial topic, and I noticed that you pointed that out too in your blog post. Last year, I remember reading an article that claimed the origin of TB from humans 70,000 years ago. Here’s the link to the article if you are interested in reading more about it: http://www.bbc.com/news/health-23897670
ReplyDeleteUntil now, I wasn’t even aware that tuberculosis was so prominent in seals as well, and they could have possibly spread the disease to humans. It does make sense that seals could have spread the disease since they can easily travel to other continents through water. Your topic is certainly very interesting, and it made me even more curious.
This article is extremely interesting since it can compare DNA strains of infected mummies to the tuberculosis. That alone will grab the reader’s attention to want to read more about your article. It’s also a great technique to bold print the catchy material, that way the reader is drawn directly to the point you are trying to make to your audience. It is an extremely interesting theory to say that infected seals from Africa 6,000 years ago could be the cause of the infectious disease since they eventually made their way into North America. Building off this article would be pretty cool, I am interested in hearing more about it!
ReplyDeleteFirst, great post. The content is extremely interesting, and does a good job of keeping the reader engaged. The fact that scientist has found that the tuberculosis disease strain found in the 1000 year old mummy, an interesting study in itself, but this is found in seals alone. Very interesting that scientist came to the conclusion that TB was originated 6,000 years ago. I am almost surprised at this date, it seems to be young, but I am very interested to see your next posts.
ReplyDeleteThe picture of the cute seals grabbed my attention, good job. The enboldened words helped me skim and understand the blog post without reading the whole thing intently. Your blogging techniques are working well.
ReplyDeleteIt's an interesting subject, I never really thought about the history of diseases (save for maybe the black plague), and until reading the blog thought of them either as temporary or independent of time.
It is so interesting to know the history of the disease and how unusual that it came from seals of all animals! I really liked how you explained everything really well in this post. I think that it is crazy that they tested mummies. What other things did they test the mummies for? I wonder how long it took the seals to cross the ocean and spread the disease and what the timeline of the disease looks like. I’m also curious to know if seals experience similar symptoms as humans do. Great blog post! I am excited to read the next installment.
ReplyDeleteRobert Koch had made one of the most ground breaking discoveries in the field of microbiology for finding tuberculosis. He discovered that the disease occurs in the tissues of both animals and humans which was an extreme ground breaking discovery in itself. He was able to discover that the disease was airborne which helped create isolation and health plans to save many lives. His ground breaking discovery got doctors moving quickly in search for a clear and immediate cure. I believe guys like this man are easily forgotten and not remembered enough for things they’ve done for society. I believe without Koch thousands/millions of people more would have died.
ReplyDeleteRimsha, this is a really interesting development in the study of TB. I had no idea that seals were the first contractors of the illness and I am very interested to know more specifics on the actual spreading of the illness and what organism was the actual bridge to humans. I would not have considered aquatic life as a starting point at all and wonder, does the illness manifest the same way in seals as it does in humans? Do a significant number of seals have TB or are susceptible to it today? I remember my first time hearing about the disease was when I applied for a job at a senior center and had to get tested. This occured with many jobs afterwards, and that was when I realized how widespread and serious TB is. Its great that scientists are learning more about the disease's origins and hopefully it will allow for more insight into transmission and totally eliminating the threat of TB.
ReplyDelete