Science Buddies: "Ask an Expert"

I was wondering if anyone could explain to me what happens when a virus (not HIV or other usual bloodborne viruses, but a common infectious virus such as enterovirus or rhinovirus) accesses the body through a break in the skin barrier and enters the bloodstream?

After learning about virally induced inflammation of the heart i.e. myocarditis, and how it is often triggered by a viral infection such as a stomach virus or even the common cold, I have become worried that a virus could enter the bloodstream through a cut in the gums or skin.

For instance, I have had an upper respiratory tract viral infection and during that infection, when brushing my teeth I noticed my gums were bleeding. In turn I became worried that said virus could enter my blood.

I spoke to a doctor who explained to me that the body is usually quick to recognise foreign pathogens or proteins and the immune response will react, target and destroy them using white blood cells. If anyone could give me a more in depth explanation of how this works I'd really appreciate it.

I mean, a lot of people have issues such as bleeding gums or broken skin such as a coldsore during flu, and viruses are able potentially able to enter their bloodstream too. So how does our immune system protect us from these pathogens entering our bloodstream where they can potentially access vital organs, and how efficient is the innate immune response in dealing with viruses that enter the blood through a cut or wound?

Hi,
Your observations and questions are all very good--however, this is not a forum for answering general science questions. The purpose of scibuddies is to provide K-12 students with specific help in doing science fair projects.

What your doctor said is correct. I am a biomedical researcher who studies the immune system and a virus called respiratory syncytial virus that causes respiratory disease, especially in infants and young children. In fact, you may have heard of RSV as it is a fairly common cause of respiratory illness along with rhinoviruses.

Bacteria and viruses are on your skin and in your mouth and in the air you breathe and when you have a cut they will certainly enter the blood. Your body has evolved complex and highly effective defenses against microbial invaders in the blood and there is no worry that an opportunistic organism is going to survive long enough to cause trouble. HIV was unusual in that the virus hid within the immune system's own cells, thus avoiding detection and annihilation.

Bacteria floating around in the blood are quickly identified, surrounded and devoured by your body's cellular immune system. It IS possible to get a microbial infection in the blood and it is very serious and often fatal, but it is usually associated with a deep wound, lack of immune system defenses and a large number of bacteria.

Viruses can be a little more problematic because they are much smaller than bacteria and can hide within cells only to emerge later and cause trouble--like herpes zoster.

So, the best advice is to do all the healthy things you have been told to do which will keep your immune defenses healthy and active against invading microbes. 99.9% of the bacteria and fungi are harmless or even beneficial. I'm sure you have been hearing about the potential benefits of pre-biotics and pro-biotics in the human gut microbiome. This collection of microbes in your intestines helps digest your food and provides a barrier between the lumen of the intestine and the body to protect you from pathogenic bacteria. This barrier is only one cell thick so it needs to be maintained pretty tightly and securely. Talk about a border wall--this is your own personal gut border wall that saves you from harmful gut bacteria like Clostridium.

Go to Youtube and type in several different topics that relate to this subject and watch some good lectures about it. You can learn a lot that way, if you choose reputable, academic lecturers. And, whenever you hear something that you don't understand you can pause the video and look it up on Wiki.

Good luck!

Sybee