Tools for the Toolbox: Going Viral

“Tools for the Toolbox” is a series of posts that describe disease types and organ systems. Eventually I hope to include enough information that a writer might be able to do some creative mixing and matching to produce the symptoms they want to give a character. Because it’s really frustrating to throw darts in the dark and hope something lands near the bull’s-eye. Hope it helps!

I’ll start this discussion of viruses by saying that Virology is a field of study in and of itself. So there’s no way that this blog post is going to come even close to being comprehensive or even extensive. I’m doing highlights only, and I may post further information at a later date.

Viruses act in a huge variety of different ways. So instead of talking about individual viruses and what they do, let’s talk about HOW they do what they do.

Viruses don’t have much of a life. As a matter of fact, they aren’t really alive. They’re just tiny organic machines that exist to make copies of themselves. If that doesn’t get your sci-fi juices flowing by itself, check your pulse. Or your level of consciousness.

Let’s build a virus!

So. In order to make copies of a thing, you need an original. In the case of viruses, the “original” copy is a strand of genetic material. It will be DNA or RNA, but not both. Regardless, the genetic material contains instructions for making a new virus, just like human DNA contains the instructions for making a human being. This picture shows DNA and RNA, side-by-side for comparison.

So, now we have a strand of genetic material. Let’s roll it up into a ball, and stuff it into a pouch made of proteins. This pouch or coat is called a “capsid”.

The genetic material (DNA or RNA) would be contained inside. Some capsids carry structural proteins and enzymes within the coat. Pretty handy, since there’s not much room inside. (Viruses are small! Like, really small!)

And for some viruses, that’s all they bother with. They’re called naked viruses.

OoooooooOOOOooooooooh!

Settle down. (Rhinoviruses are such teases.)

Other viruses are a little more modest. In addition to their capsid/coat of proteins, they also like to give themselves an extra layer. This is known as an “envelope”, and is made of a “lipid bilayer”, which is what the cell membranes of our cells are made of. It looks like this:

You can see the genetic material, coated by the capsid, enveloped by the envelope.

So, now we have a virus.

The driving purpose of a virus… THE VERY REASON FOR ITS EXISTENCE… is to make copies of itself. But it can’t! It’s a strand of genetic fluff wrapped in one or two layers. It doesn’t carry the proper materials or machinery to make copies. Doesn’t that suck?

Um…I’m not really worried about the existential satisfaction of the common cold.

Me either, to be honest. But it does really suck. Because instead of throwing up its non-existent hands at its complete and utter lack of purpose-fulfilling-equipment, it decides to hijack someone else’s.

Namely, yours.

I have viral-purpose-fulfilling-equipment?

Yup. The cells in your body contain the equipment for replicating genetic material. And the virus wants it!

So, here’s the virus’s rather overdramatic modus operandi. It drifts around, aimless and without propulsion, until it lands by chance on a cell. Then, it injects its genetic material into the cell! It’s like hijacking a factory and replacing its blueprints with your own. (Not, I feel I should point out, that I’ve ever hijacked a factory or replaced its blueprints with my own.)

Particularly not this factory. Or its blueprints.

Anyway, the cell then turns into a virus-producing factory! It’s forced to use its own machinery and resources to make hundreds and hundreds of viruses! As a matter of fact, the cell-factory is pushed into overdrive by its hijackers, and eventually so many viruses are created that there’s just no room in the cell anymore. So the cell EXPLODES, spraying new, copied viruses everywhere!

And then it all begins again.

A little diabolical, no?

Aren’t there any defenses built into the cell? Viruses have been around for a long time, after all.

Well, kinda. Once infected, the cell is pretty much a goner. But that doesn’t mean it gives up. During the hijacking/infection process, the hijacked cell displays some of the viral proteins on the outside of its membrane. It’s like sending up a panic flag. This alerts the rest of the body that the cell has been infected. The flag also gives information about the infecting agent to other cells nearby so they can get their defenses up, and sends a message to the immune system that there’s an attack going on.

It’s a really nifty process, and its ingeniousness blows me away. (I love the immune system, though learning it the first time really sucked monkey balls! I blame the naming scheme. Everything and its brother was named CD28 or CD32 or whatever. Almost impossible to keep straight.)

Who gets viruses?

Everyone.

Different people get exposed to different viruses, though. As with any other illness (besides genetic and autoimmune diseases), the types of viruses you’re exposed to depends on your surroundings and your lifestyle. A few examples:

- Human Papillomavirus (HPV) is spread through sexual contact.
- Cruise ships, dormitories, and nursing homes are great places to catch the Norwalk virus.
- Poliovirus is more likely found in areas of poor sanitation.
- Drug abusers who inject substances into their bloodstream are at risk for Human Immunodeficiency Virus (HIV) and Hepatitis B and C.

Different people also have different ways of responding to viruses. Some people might catch it and pass it along without developing any symptoms at all, while other people may be laid up for days or even die from the infection.

For example, Respiratory Syncytial Virus (RSV) causes a slight head-cold in adults…but can cause a life-threatening bronchiolitis (infection of the bronchioles in the lungs) in infants.

What are typical symptoms?

Depends on the virus.

You got your “flu-like symptoms” for your respiratory viruses: Fever, cough, sore throat, runny nose, headache, body aches, chills, fatigue, etc.

You got your fun vomiting-and-diarrhea pattern for your gastrointestinal viruses.

You got your lymphadenopathy-plus-sore-throat-and-fever pattern for Epstein-Barr virus (mononucleosis, or just “mono”) and the initial stage of HIV infection. (lymphadenopathy = swollen lymph nodes)

There are others as well.

And then the virus can kinda do its own thing from there. HIV attacks the T cells of the immune system. Mumps also likes the T cells for an initial replication site, then heads over to other tissues like the salivary glands and the testes. Herpes viruses (which include everything from cold sores to chicken pox/shingles to painful genital rashes) like to camp out in nerve ganglia when they’re done with their initial infection. Then they flare up in the distribution of the nerves they’re hiding in whenever the fluctuations of the body’s immune system give it a chance. (ganglia = collections of nerve cell bodies)

Basically, you can model your virus on any of the above patterns, and then let it attack your character in any way you want it to. But remember that it’s more plausible to start with a few, easily explained symptoms within the same body system (neurological, gastrointestinal, respiratory, etc.) than it is to justify a total, multi-system shutdown immediately on infection. The multi-system shutdown can happen, certainly…but let it build up.

Note: Sometimes a virus’s symptoms will correlate with the method of spread. For example, the rhinovirus (common cold) is spread through the air and causes respiratory symptoms. Norwalk virus is spread through the fecal-oral route (that’s exactly what it sounds like…) and causes gastrointestinal symptoms. HIV is spread through blood and fluid contact, and it attacks white blood cells. Many viruses don’t follow these kinds of patterns, but it’s something to think about when you’re world-building.

How do you cure them?

Well, that’s a tough one. There are antiviral medications that interfere with the life cycle of a virus and minimize the damage an infection can cause, but viruses themselves aren’t really cooperative when it comes to general medical treatment.

Usually, medical personnel defer to “supportive treatment” when dealing with viruses. That is, keeping the symptoms of infection under control while the body’s immune system mounts its own defense and fights off the infection itself. If a baby has severe diarrhea and vomiting during his bout of viral gastroenteritis, he should be hospitalized so his fluids can be replaced. If a college student develops respiratory distress from an influenza infection, his breathing can be supported with a ventilator. And so on.

Antibiotics have absolutely no effect on viruses.

But Good Housekeeping told me that…

Antibiotics have absolutely no effect on viruses.

But I took penicillin once for…

ANTIBIOTICS HAVE ABSOLUTELY NO EFFECT ON VIRUSES.

Do we have any questions about antibiotics and whether or not they have any effect on viruses?

. . .

Good. Please don’t come into my office and demand I give you antibiotics for your viral infection. Please don’t come into my office and demand I give your child antibiotics for her viral infection. This happens way too often, and it really pisses me off. It’s actually one of the reasons I decided not to go into Pediatrics as a specialty, and why I hope to avoid outpatient medicine as much as possible.

Some ways to use viruses in fiction.

-Use a virus if you need an epidemic that spreads quickly, like Captain Trips in The Stand.

-Use a gentled virus as a tool for altering genetic material, like they do with gene therapy.

-Use a virus if you want to create superbacteria in a population, since a population that incorrectly takes antibiotics for viral infections will teach its bacteria how to resist any medicine it’s exposed to. Like with MRSA. Or A. Baumannii, which killed my grandfather. (Yes, this is NOT some science fictional concept, and this is NOT some fuzzy problem that we’re just passing off to our children to solve later. This is killing people RIGHT NOW. Really, really IMPORTANT people. Is your grandfather next?)

-Use a virus if you need a disease that quickly mutates. This could prevent even your genius protagonist from coming up with a cure, or could make any treatments that she cooks up completely ineffective, just in time for your exciting climax. Like with HIV or influenza.

So, viruses are pretty diabolical little buggers. Versatile diabolical little buggers. And let’s be honest: what story doesn’t need a good bit of diabolical in it? Or a good bit of versatility?

The contents of this site, such as text, graphics, images, and other material contained on the Site (“Content”) are for informational purposes only. The Content is not intended to be a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your physician or other qualified health provider with any questions you may have regarding a medical condition. Never disregard professional medical advice or delay in seeking it because of something you have read on this Site!

If you think you may have a medical emergency, call your doctor or 911 immediately. This blog does not recommend or endorse any specific tests, physicians, products, procedures, opinions, or other information that may be mentioned on the Site. Reliance on any information provided by this blog, or other visitors to the Site is solely at your own risk.

The Site may contain health- or medical-related materials that are sexually explicit. If you find these materials offensive, you may not want to use our Site. The Site and the Content are provided on an “as is” basis.

If you use this as if it were real medical information, I will hijack your factory, and replace its blueprints with my own. Because I’m diabolical like that. And rather versatile.

Sources:

http://www.flu.gov/

Robbins and Cotran. Pathologic Basis of Disease. 7th edition. Elsevier, 2005

Pictures:

About these ads
Published in: on February 20, 2010 at 8:53 pm  Comments (11)  
Tags: , ,

The URI to TrackBack this entry is: http://doctorgrasshopper.wordpress.com/2010/02/20/tools-for-the-toolbox-going-viral/trackback/

RSS feed for comments on this post.

11 CommentsLeave a comment

  1. So much fun here — not to experience personally, but to inflict on my unsuspecting characters. I think someone in the chapter I’m currently writing needs to spontaneously bleed out their eyeballs…

  2. Thanks! While I usually know the basics of what you talk about, you often give more detailed information than I’ve heard elsewhere. Never realized viruses ‘hijack’ a cell and ‘replace its blueprints with its own’.

    And I’m sorry about your grandfather. I can see why you’d be pissed off at folks who use antibiotics for viruses.

    • Thanks for the kind words, BJ. I’m glad you’re enjoying the blog!

  3. I have a related question now. Do viruses die? I mean if they don’t find appropriate cells to hijack, if an airborne virus floats into an empty room, if a bloodborne virus is spilled on the floor, do they die eventually? How long does that take on average? Many people like to clean doorknobs and toilets in fear of cathcing whatever the previous person might have left there, but is that really something to worry about?

    • Hi, Nathreee!

      Viruses certainly can’t replicate outside of a host. Some viruses can’t even survive for very long outside of a host. And some can, in a dormant phase. It really depends on the virus; there are hundreds and hundreds of them, and they all act in different ways.

      I’m all for hand-washing, in general; it’s the best way to prevent the spread of stuff from person to person. But I can’t really speak to whether the toilet-and-doorknob-cleaning thing is effective. I don’t do it myself. I also periodically get sick. Just like anyone else, I guess. So I don’t think I can advise you on that issue.

      • Thanks for your answer. I was just looking for ways to make a virus that’s really dangerous but doesn’t cause a worldwide epidemic, because its living conditions are very specific.

        I love your blog here, you’re being very helpful and easy to follow.

        • Hi, Nathreee

          Whether or not a virus becomes an epidemic will really depend on its method of spread: its vector. Some vectors result in more widespread epidemics than others. For example, an airborne virus will travel pretty far and wide, since people sneeze on airplanes, and sneezes can spread viral particles to a number of different people at the same time. In contrast, HIV is passed through contact with blood and fluids; during normal passage, only one-to-a-few people can be infected at a time.

          Vectors include: airborne (can be widespread), waterborne (can give you an extensive epidemic localized to a water source distribution), foodborne (similar), sexually transmitted (can spread far and wide even in a situation where only a few people are infected at a time, due to cultural taboos, as we’ve seen with HIV), bloodborne (often people who inject themselves with substances through potentially dirty needles, or hospital workers who get needle-sticks at work), and a number of others.

          Living conditions for the virus can also modify its spread, so it sounds like you have a reasonable setup going, there.

          Thanks for reading, and I’m glad you like the blog!

          Dr. G

  4. Thank you, that was fascinating reading, especially while I am in the throes of my own viral cultivation. Turns out, spending a weekly total of 24 hours in airports during a snowstorm is a really good way to get sick. (Overheard a woman talking to her toddler, “Oh honey, don’t put your mouth on that, it’s covered with germs. International germs.”)

  5. Yay, viruses! Well, I mean not yay. I hate them too. But they’re such fascinating little replicants, more writers should use them!Thank you especially for mentioning the use of viruses in genetic engineering, so much more subtle and practical than one-off superspiders or atomic blasts.

    And just this once, I think people *should* use your blog as medical advice– to never ever ever use antibiotics for viruses!

    • Hey, glad you liked it!

      And yes, I do accidentally allow some reality to seep in sometimes. But I try my darnedest not to….. :D

  6. This helped me a whole bunch with my story, I’m especially glad that it is possible to have a gentle virus that alters your genes. It was my original idea for my story. And if I’m not mistaken, it is likely for a bloodborne virus to also be sexually transmitted? AIDS, for example.


Leave a Reply

Fill in your details below or click an icon to log in:

WordPress.com Logo

You are commenting using your WordPress.com account. Log Out / Change )

Twitter picture

You are commenting using your Twitter account. Log Out / Change )

Facebook photo

You are commenting using your Facebook account. Log Out / Change )

Google+ photo

You are commenting using your Google+ account. Log Out / Change )

Connecting to %s

Follow

Get every new post delivered to your Inbox.

Join 125 other followers

%d bloggers like this: