Mini Microbiology Lesson

People should be required to take a microbiology course at some point in their life.  Perhaps it should be a requirement to graduate high school.

I find that people are vastly uneducated when it comes to microbiology.  Especially pertaining to hygiene and etiquette.

So in light of my frustration with general lack of knowledge and/or lack of etiquette and hygiene, I have decided to do a quick little microbiology lesson on my blog.

With regards to the spread of communicable diseases -- focusing on airborne transmission, let's talk a little bit about coughing and sneezing.

I don't understand why anyone would not cover their mouth when coughing or sneezing. It's common courtesy. It is something that every two-year-old should be taught.  I am appalled at the lack parenting nowadays when children are not taught common hygiene and etiquette practices. Everybody should know from the time they are able to understand language that they need to cover their mouth when they cough or sneeze and wash their hands!

I had an experience a couple of weeks ago where two elementary school age children sneezed and neither bothered to cover or even attempted to do so.  One of them sneezed in the kitchen after all the food was set out and just after the blessing was said and before people started dishing up. So not only were 20+ people exposed to airborne pathogens, all the food was also exposed.  Then, just a few minutes later the sibling of the guilty party sneezed 2 feet from me as she was conversing with me. Obviously these children were not taught simple hygiene etiquette. Apparently these children were raised by wolves.  At least they acted as though they were. But I digress.

Coughs and sneezes contain numerous bacteria and viruses in tiny water droplets that are propelled throughout the room.  Anyone in the room will breathe some of them in and potentially become ill. And those germs that aren't breathed in will settle onto surfaces.

Even though viruses are completely parasitic -- meaning they must be in a host to survive -- they can survive on hard surfaces anywhere from a few minutes to over a week.  Most, however, can't survive past 24 hours.  An unusual exception being the norovirus -- which causes diarrhea and vomiting -- which can survive over a week on hard surfaces.  Most cold and flu viruses can survive only hours on hard surfaces.  Even less on soft surfaces. But if you happen to touch a contaminated surface such as a door handle and then touch your face, you are infected.  Very common.  But if people would cover when they cough or sneeze, those surfaces are much less likely to be contaminated.

If you sneeze or cough into your hand the virus can remain on your skin for over an hour.  Something like 40% of the viruses are still on your skin after one hour. Unless you wash your hands of course.

Bacteria can survive even longer.  In fact, some bacteria such as Clostridium --which can cause such diseases as botulism (Clostridium botulinum) or tetanus (Clostridium tetani)-- can go dormant in spore form and can survive in soil for years. Clostridium difficile which causes intestinal illness can survive for up to five months.

Okay so back to coughing and sneezing.  I was taught in medical school nearly 2 decades ago that coughs and sneezes travel 15 to 20 feet. Certainly enough to contaminate an entire room.  I saw a study conducted by MIT that concluded that coughs and sneezes can travel 5 to 200 times farther than originally thought.  Due to each droplet traveling on a gas cloud.  All the more reason to cover your cough or sneeze!

Another thing to understand is that even though you are not sick -- "it's just allergies" -- doesn't mean you can't spread illness.  You could be carrying a pathogen that perhaps you are immune to that you can still spread to others who may not be immune to that specific pathogen.  For example, I was also taught in medical school that there are over 100 strains of the rhinovirus which causes the common cold. So once you get over a particular strain, your body produces antibodies to that particular rhinovirus and you become immune. But you can still keep getting the common cold because of the many different strains of rhinovirus to which you are not immune.  And you can certainly spread any of them to other people.  Even if it's one you are carrying but happen to be immune to because you had it before.

I also remember learning that for instance, the bacteria that causes strep throat -- Streptococcus pyogenes -- can be part of the normal flora for some people and it doesn't make them sick.  But they can certainly pass it on to others who will then come down with strep throat.

So, my point is, you can carry pathogens and spread them to others without actually being sick yourself.

I could go on and on but if I say much more this won't be a mini lesson anymore.  :-)

The moral of the story is the best way to prevent airborne communicable diseases is by covering your mouth when you cough and sneeze -- and washing your hands afterwards!

I didn't get into handwashing but that is the best way to prevent communicable disease.  Wash your hands!

And please teach your children to cover their mouths when they cough and sneeze and to wash their hands!  Simple hygiene.  Simple etiquette.

That's my two cents.