Kamen Rider Ex-Aid: Insights into Virology

Author’s Note – this post was originally slapped out in about half an hour on a whim, and then posted to Twitter back in January of this year. I’ve edited it slightly, but there is quite a bit of the show that has aired in the meantime, and I may do a follow-up to take into account new information we’ve gained since I originally wrote this.

As my introduction states, or in case you missed it, I work as a science teacher. But before I did that for a living, I studied Biology in college, and focused heavily on cell biology and genetics. So I have a reasonably sturdy background regarding the mechanics of disease and how viruses operate within the human body and through other vectors. That being said, I am not a medical professional or a research scientist who keeps up with the latest technical information on this subject, so feel free to call me out if I’m mistaken in explaining something.

What the hell is a virus?

Whenever we talk about viruses, we first should define what viruses are. Viruses, strictly speaking, are not “living” things. They are packets of genetic information, as RNA or DNA, wrapped in proteins that are adapted specifically to infiltrate and hijack cells to produce more of themselves. They are not considered to be “living” because unlike other forms of life that are made up of cells, viruses instead have to use another cell’s own natural machinery to do so.

We can think of the Bugster virus, therefore, as viral “information” that seeks to override and replace a host’s own genetic information. With a successful infection of a human host, the Bugster can replace the original DNA entirely to attain real, physical existence.

There actually are viruses in real life that insert their own genomes into ours, these are “retroviruses” which splice that information into sections of DNA, then promote the cell’s natural process of reading that information. This has the effect of making the cell  EXCLUSIVELY read only those instructions to make the proteins that will build more viruses.

Other viral DNA or RNA sequences can be incorporated into our genes through other methods. It’s estimated that a significant portion of genes in our body originated from, or were influenced by, viral infection in this way. It’s a major driving cause of mutation and variation that can allow for evolution over time, not just in humans, but really all organisms.

Mutation and Natural Selection

Speaking of mutation, another thing that the Bugster virus has in common with a real epidemic is the fact that it has mutated into new, more virulent strains. It’s shown with episode 15 that the current form of the Bugster virus was unleashed after Dr. Pac-Man experimented with it on Emu in the past.

(There’s a sentence I’d never thought I would write in an article like this.)

This is pretty similar to how other dangerous viral outbreaks occur.

Since viruses make more of themselves within cells, just like with the ordinary process of transcription and translation (making more DNA and reading that DNA to make proteins) in cells, there’s going to be typos and mistakes. Sometimes these mistakes are fatal and prevent the virus from functioning, but because of the sheer numbers of viruses being produced, simple statistics means that some of the mutations are going to be beneficial and allow the viruses to infect more cells faster. Or allow them to “jump” and become able to infiltrate and infect new types of cells that it couldn’t before.

The “Bird Flu” scares that crop up happen when a strain of influenza (which already mutates insanely quickly, it’s why you need a new flu vaccine every year), crosses from an animal vector (like birds or pigs) and into humans. Other viruses originate from animal vectors, or carriers, like the Ebola virus, which normally is harbored in bats.

The catch is that this is a numbers game, like rolling dice, and so the more times a virus can roll their “dice”, i.e., the longer they can replicate in other hosts cells, the better the chance of it developing a positive mutation that helps it spread quicker.

Again, using Ebola as an example, one of the reasons why the 2014 outbreak was so dangerous was because the strain involved developed a mutation early on that made it easier to infect human cells. This either made it deadlier, or able to spread quicker between victims, or maybe both. Scientists are still studying it.

Either way, something happened with Dr. Pacman’s experiment on Emu that made it mutate and able to infect people through the lungs or other airborne contact.

We see it mutate again to become stronger with the leveled-up Bugsters that the Riders have fought the past few episodes. If they don’t wipe out the virus, there’s a real possibility it will get worse as the positive mutations begin to stack up against them.

In real-life though, viruses don’t always want to just be deadlier though. Remember, the longer they can replicate inside of a host, the more viruses they can produce, and the better the chance of spreading and surviving inside more hosts later.

One of the best examples of this selective pressure is the common cold. It’s not a life-threatening disease, you feel like crap for a few days, have a runny nose and a cough, and that’s about it.In this case, the virus is replicating at high enough levels that it has a good chance to spread to other victims, but it also isn’t debilitating the host to the point where they can’t go out to contact other individuals, and thus become unable to spread the virus.

Ebola epidemics are scary, but they burn themselves out quickly in usual cases (I explained why the most recent one was an unusual case) just because they kill and incapacitate so fast that there aren’t many opportunities for the infected individual to spread it to others who are not caretakers or health care workers.

We can think of Emu’s case in this way. For some reason, he harbors enough virus to allow him to use the Gamer Driver and the Gashats, but not so much that he’s symptomatic. This can be called a “subclinical” infection, where he still has the virus, but doesn’t show the “clinical” presentation of it. (Author’s note: at least, not until he starts using Mighty Bros. XX. See my comments below regarding “Viral load”)

Viral Load

This brings up another factor in describing how viruses spread, what we call the “viral load”.

Viral infections, like I mentioned, are a numbers game. The more viruses that can be produced inside of a host, the more viruses can spread to others to possibly infect them further. A healthy person’s immune system will stop an infection if there’s only a few viruses that make it to their body, to get around those defenses, you need a “viral load” above a certain point, or enough viruses to ensure that some will successfully infect cells to start the process of the disease.

When these infected cells die due to damage sustained by the virus hijacking their natural processes, and the body’s immune system mounts a response to attack the virus, then you start feeling “sick” with symptoms of the infection.

This is probably why Emu suddenly became symptomatic after using the Mighty Bros. XX Gashat, the huge viral load he was exposed to triggered an immune response, or caused the virus already present in his body to start replicating again.

Also note this is how real-life vaccines fail, when the viral load overwhelms the boosted immune response from inoculated individuals and they can get sick anyways. So between the possibility of a mutation to change the antigens that your immune system responds to against a virus, or just being overwhelmed by a huge amount of the virus (certainly didn’t help Kiriya when he tried to use Dangerous Zombie), there’s a very real possibility that Taiga or Hiiro could become infected themselves in the future.

Even Taiga thought initially that Emu suddenly exhibiting symptoms was a result from overuse of his Gamer Driver and Gashats, so that implies that they’re getting exposed to more virus each time they transform.

Some viruses can hide out in cells and remain inactive for long periods of time, and then resurface when conditions are right, and they can get around a body’s immune system. This is how the condition called “Shingles” works. It’s caused by the same Varicella virus that causes Chickenpox, but the virus will hide out in nerves along certain areas of the body. Then when the individual gets older, and their immune system weakens with age, the virus can replicate again, and it produces new symptoms.

Given episode 15 of Ex-Aid, it seems like Dan’s warning about the virus being all over the city is accurate. Many people have been exposed to this airborne virus, and it’s remaining dormant in most of them until conditions are correct for it to be activated. How the activation occurs is still unknown. There’s still a lot of other questions about the origin and mechanism of the virus that need to be answered as well, but this far into the series, I’m surprised at how closely all this tracks to real-life epidemiology and virology. I applaud the writers for doing their homework on the subject at least.


Post-Script notes:

The mechanism that triggers active symptoms appears to just be an increased exposure to the virus, given how Graphite created a massive outbreak with the viral particles from his proto-Drago Knight Hunter Z Gashat.

It seems that the Gamer Driver and the Gashats naturally expose the users to viral particles, which would explain why Nico suddenly got sick from trying to use Bang Bang Shooting, and why Taiga thought initially that Emu’s active infection was from transforming too many times.

Remember what I mentioned earlier about high viral loads preventing vaccinations from working? Hiiro’s side effects from using a Level 50 gashat with Taddle Fantasy are probably the result of a huge dose of the virus.

Lastly, the reveal that people can get infected by the virus multiple times with no change in severity of symptoms was interesting. It suggests that exposure to the virus doesn’t produce an immune response along my expectations, and there is another mechanism that governs how individuals react or defend against infection. As the show goes on, it will demand another look to see if these aspects of infection still line up with real-world pathology.


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