What do we know so far? We know that there are a few strain of Ebola viruses which are fatal to the human race. We know that viruses need some kind of medium to thrive and infect as they can't survive in the open environment. We know that Ebola can be traced in a significant amount throughout the digestive tract of bats. We know that Ebola is not the only virus which thrives inside the gut of a bat. Last but not least, we know that bats weren't even sick from owning all that kind of microbes.
Recently, a group of scientists from the United State Agency for International Development (USAID) published a paper in the Journal of Nature Microbiology regarding a discovery of a new strain of Ebola virus from bats which was subsequently named after the place the bat was discovered; the Bombali strain of Ebola virus. It's quite impressive don't you think? How all this time this creature can house some of the most fatal viruses in the human history but not affected by it? Is there any specific genetic constituent that will allow bats to increase its odds of surviving those viruses?
One of the most important things about bats in the past is they were an important clue in the medical history whether or not, people were infected with rabies after getting bitten; it's a common occurrence in Brazil. In 2005 if you were living in that particular country, living your windows or doors open while you were sleeping will not only predispose you of getting robbed but also getting bitten by a small, blind, quite intelligent, blood-sucking creature that has been killing 23 out of 1300 victims by September 2005.
Biting and sucking blood from its victim is probably one of the most effective routes of infection for blood-borne viruses. In the prehistoric era, bats are never a blood-sucking animal. They thrive on fruits, insects and any crap other than blood. We can safely assume that they develop an affinity to blood when some of them accidentally engulfed prehistoric animals blood while eating mosquito or other blood-sucking insects. Mutation is a bitch and sometimes it leads to some physical changes that would suit them to their new "lifestyle".
Even though some people didn't make too much fuss about being bitten by bats since people hardly noticed the wound (they rarely leave people with gaping wounds after a blood meal), it is medically significant since the bloodborne virus which is being housed by bats are quite fatal if they were to infect humans. If in some ways, we were able to duplicate the bat ability to retain those viruses without any consequence, we can be regards as medically-invulnerable. A virus does need a host to survive but in some, they are not particularly a great guest and often took over the house, claiming the life of their host.
There are several projects which have been created in the past to duplicate the genetic superiority of bats DNA and hoping, someday, we would be able to find any kind of cure which relate to viral diseases. I mean, we can eat antibiotics or anti-fungal to treat both bacterial and fungal infection respectively but for viral infection, some of the most effective anti-virals on the market aren't even treated by killing the virus responsible for a particular disease; they slow the progression of the disease and eventually people will succumb.
How Do Bats Tolerate Blood As Their Meal?
Blood can be seen as one of the most challenging food sources as it contains less nutrient while harbouring a variety of infectious agents that can potentially implicate the host in a negative way. I'm not sure how a vampire has an eternal life when they were prone to get all kind of bloodborne viral infection that would have made eternal life seems ridiculous. If vampires do exist, they may have adopted the same superior qualities presented among bats' digestive system that would have allowed them to drink blood while getting almost negligible consequence from such action.
If we regarded a vampire as a creature which is filled with numerous type of blood-borne viral infection then sexual intercourse with a vampire can be thought of as dangerous since we could get infected. Nevertheless, people do enjoy seeing those creature humping our own; try to watch True Blood TV series and you would understand what I mean, maybe. So back to the main topic, how do bats tolerate blood as their primary food source after their ancestors accidentally engulfed the blood of prehistoric creatures?
There are currently two quite fascinating reasons regarding bats capability to hold viruses without being affected by them and how they were able to nourish themselves while making one of the least nutritious food items available on the earth. If we think about it there are probably more than two but these certainly are the most fascinating one.
- The number of jumping genes available in the bat DNA
- The role of the bat's gut microbiome which might have been the most important surviving factors for blood-sucking bats
Jumping genes which are usually known as transposon to the scientific community can be an important surviving factor which has made withstanding certain harsh condition possible for a particular species. How adaptable an organism is to a new environment would usually be determined by how flexible their genes are and mind you, apart from owning 2.6 times more transposon than the human DNA, bats DNA are highly changeable (easily mutated).
It's common for us to assume that the same 300 letters sequence of DNA might have been in a fix position for every single cell in an organism, after all, they could have acted as a template to others but in the 1940s, Barbara McClintock who received Nobel prize for her work regarding transposon realised that, other than the fact that these 300 letters seem to be copied and pasted all around, they were highly mobile.
The position for the 300 letters sequence of DNA for a single cell might have been different from others even if they were from a single species of organism. This could have been implicated by mutations as a result of reactions to the harsh environment signifying that the presence of transposon indicate how likely for a single organism to survive a changing environment.
The fact that bats have more transposon than humans might have implicated that they have been adapting to every single bloodborne virus which might have the potential to infect them only being hindered by the bat's improved immune system, thanks to the flexibility of its own DNA. The evolution took time and I'm sure one time, there were bats who were affected by malnutrition as a result of sucking blood instead of eating insects or fruits which can be highly nutritious, at least, more than a blood can ever be. How many transposons could a vampire have in your opinion?
Gut's microbiome has been one of the most important factors that could determine how healthy you are or how prone you are to develop certain diseases. Animal and human studies have proved that a healthy individual/animal comprises of an adequate amount (either in number or species of bacteria) of gut microbiomes that could help in a multitude of physiological processes.
Think about it, one of the reasons why people can get sick is they were over treated with antibiotics. Antibiotics have the capability to wipe out not only the bad bacteria but also the good one. This would allow certain bad bacteria to latch itself onto the gut's surface and cause some pathological changes which would manifest itself mostly as signs and symptoms of specific diseases.
The most interesting thing about the bat's immune system is they were aided physiologically by the available microbiome which makes the effect of an anti-viral protein called interferon to be less inflammatory thus reducing the chances of autoimmunity. Interferons are activated by a specific cascade of reaction that would allow them to combat viral infection while causing a minimal anti-inflammatory reaction to the host cells.
In humans, to avoid autoimmunity, interferons were usually activated after a viral infection by a specific gene that would determine either the secretion is "on" or "off"; it's like flipping a switch. That would mean we can get infected and the interferons might have been secreted in the middle of the pathological changes caused by viral infections; it could go either good or bad depending on how early on the protein is secreted.
In bats, there is no "off" switch. It seems rather advantageous for them as the effect of the interferon on the host cell is dampened by the microbiomes in the gut. There were few to none anti-inflammatory effect and the interferon act as a preventative measure that disallows a specific infection to happen in the first place; they won't get sick by the virus. It's fascinating to see how microbiomes can be the key to optimise our health thus giving us a shot at longevity. Pretty neat, no?
The Bombali Strain Of Ebola Virus
Even thought Bombali strain seems like a big deal, scientists are unsure whether this new strain of Ebola virus can cause severe diseases in humans. Analysing the other 5 species of Ebola viruses, 4 of them can induce fatal consequences which mean there is a tiny possibility that the Bombali virus might have been non-consequential to humans.
One of the Ebola strains called Zaire is the one which is responsible for most of the kills, causing disease outbreaks in a few countries that killed over 10,000 people in 3 years. According to the information provided by the World Health Organisation on their website, the Ebola outbreak which seems to start in August this year was caused by Zaire strain of Ebola virus after much genetic sequencing and analyses.
We can't be too careful but we can't afford the luxury to be easy-going either. It's tricky especially if we want to determine the source of infection of which the Ebola virus originated from. Up to this point, after reading a few kinds of literature and do some research on that topic, the assumption of where do Ebola virus came from (the definitive host) have been inconsistent. Obviously, to test various kind of hypothesis, we need to test various kind of animals to trace the source.
Although scientists seem to find Ebola virus in the guts of 4 bats, all of them exhibit a different genome sequencing results from the previously found strain; they found a new strain of Ebola virus! Like all 5 of the previously found strain, Bombali strain of Ebola virus does have binding proteins which can be a crucial indication of its virility. We do need to take a few extra precautionary measures to avoid unforeseen consequences that might implicate us severely in the future.
References: [1], [2], [3], [4], [5]
All images were taken from Pixabay
Images: [1], [2], [3], [4], [5], [6]
