Disease.  Disease is quite a gloomy word.  No one wants to be infected yet so many people in our world are.

On our first day of class, Andrew said he studies infectious diseases.  I texted in to the comment wall and asked “how do diseases start”, but I didn’t get a response, so after four months of wondering I think it is time I figure it out.

Put simply, Merriam Webster  defines disease as a change in a living body that prevents it from functioning normally.  There are many more specific definitions and there are many different types of diseases.

According to Medline Plus infectious diseases are caused by germs and “kill more people worldwide than any other single cause.  They can be spread through touching, eating, kissing, sexual contact, insect/animal bites, and even breathing.

So how do these diseases start?  What caused the AIDS outbreak in the 80s?  How did herpes start?  What caused ebola?  How do these diseases seem to just come out of nowhere?

Infectious diseases are caused by pathogenic microorganisms that spread indirectly from person to person.  The World Health Organization explains that zoonotic diseases are diseases in animals that can infect humans.

A disease is a living organism.  It wants to survive just like you and me, but the only way the disease can survive is through a host cell.  This CBC article discusses the swine flu virus, but it does a good job of explaining the mutation process.  The virus wants to survive but it can only do so by attaching itself and reproducing through a host cell.  The disease “injects its genetic material into the cell” and that DNA or RNA “carries with it instructions” for the cell to make more viruses.  The virus than spreads “to other parts of the host organism.”

But the host organisms don’t just let it happen.  They do their best to fight it off, and eventually host organisms learn how to protect themselves and become immune to the virus.  So in order to survive the virus must mutate.

It reminds me of the fruit flies Andrew talked about in class.  The male fruit flies would inject their toxic sperm into the female so she couldn’t have anyone else’s offspring, but it would also kill her.  Evolution and natural selection are not concerned about health, happiness, or longevity; there is no long term goal.  As we learned in class:

“Adaptive evolution is about genetic representation in the next generation.”

Diseases are living organisms very similar to the fruit flies.  “They” are not concerned about the happiness and wellbeing of their hosts, the disease is simply trying to maximize its offspring and survive.

The Guardian explains that 60% of the infectious diseases since 1940 have been zoonotic.

“HIV originated in monkeys, ebola in bats, influenza in pigs and birds.”

The Bubonic Plague, or Black Death, took over Europe in the middle ages.  The disease was transmitted to humans through fleas on rats and killed over one-third of Europe’s entire population.  The Spanish influenza in the early 1900s killed 50 million people, and more than 30 million people have died from AIDS.

In our modern world people are constantly traveling and in contact with foreign species and people.  According to the World Health Organization the Ebola outbreak occurred in West Africa a year ago.  It left the world terrified as “many feared that the Ebola virus was the pathogen that would overwhelm humanity.”  Since then, the virus has been controlled and people are not as worried, but the question remains what’s next?

Infectious disease outbreaks are confusing, and it is nearly impossible to predict what is coming, but scientists are keeping a close eye on bats and birds.

As we learned in class, humans can get vaccinations.  According to The Medical Dictionary  vaccinations for any specific disease are medicine that contain a very small amount of the virus’ bacteria to get the body to produce antibodies.  If that person is ever exposed to the disease later in life the antibodies will keep them healthy.

It’s scary because diseases can mutate to protect themselves from vaccinations.  As Andrew mentioned in class, this is what he is currently working on with malaria.  Disease is scary because it is a part of life and there is only so much humans and science can do to stop it.  We try to protect ourselves from disease so that we don’t die, while the infectious pathogenic microorganisms try to protect themselves from us so that they don’t die.

Disease is a part of life because it is trying to live one.