Viral Diseases: The Epidemics We All Hate


It’s that time of the year, when all high-schoolers fear missing even a single day of school and getting behind on tons of work — flu season.

Flu season is named for one of its most common viral illnesses: influenza. Influenza is a highly contagious infection, transmitted through the air. Symptoms usually appear in one to four days and include fevers, sore throats, congestions, and headaches.

Even though the human immune system can fight it off quickly, the most severe symptoms take about two to three days to go away even with proper medication and a healthy immune system.

Some background on viruses: viruses are simply protein shells containing DNA or RNA – they are not technically alive. All viruses follow one of two life cycles: lytic or lysogenic.

If a virus follows the lytic cycle, it injects its genetic material into a host cell, spurs said host to create more copies of itself, and destroys the host cell, spilling out viruses to take over surrounding cells. By contrast, in the lysogenic cycle, viruses inject their DNA and become dormant or inactive in a host cell for some time before they transition to the lytic cycle to spread the infection.

The influenza virus follows the lytic cycle, meaning that symptoms show up in an individual soon after exposure. One positive for lytic viruses is that they are typically much easier for the immune system to target and destroy.

The speed of the immune response depends on whether or not you have been exposed to this virus before. The immune system’s initial response to the foreign material is slow because it has never encountered the virus before. This allows for the immune response to be quicker and less stressful on the individual the next time the same strain of the flu is in the body.

This is why vaccinations are extremely important. A vaccine is a diluted or deactivated strain of a virus that is given to individuals so that their immune system can have its primary response to a weaker version, so it is not as difficult to fight off during the second exposure. For this reason, vaccines can make people feel a bit sick for a day or two after taking it. Read more about vaccinations here.

Last year’s flu season was one of the worst by far: it killed about 80,000 Americans and caused over 900,000 to be hospitalized. It is still too early in the flu season to make any predictions about the strength of this year’s strains, especially since influenza viruses become resistant to preventive drugs exceptionally quickly.

So far, this year’s trivalent vaccine will protect against two A-strains and one B-strain of influenza, and its quadrivalent vaccine will protect against an additional B strain.

Whether you are covered for the quadrivalent vaccine is up to your insurance provider; it costs almost double the price of the trivalent vaccine.

The main difference between A and B strains of the flu, both of which affect humans, is that the B strains tend to spread more slowly, are less likely to cause a pandemic, and only affect humans, where the A strains also affect other animals.

Another particular viral infection that was going around Harriton earlier this year and typically travels around high schools and colleges is mononucleosis, otherwise known as “the kissing disease” and “mono.” This infection is caused by the Epstein-Barr virus and is transmitted through saliva and other bodily fluids, hence its nickname.  

Symptoms of mono include fatigue, fever, rashes and swollen glands. It usually takes about two to four weeks for the immune system to recognize and fight this virus off, slower than the body’s response to the flu. However, similar to the flu, mono is a lytic virus, so symptoms are seen soon relatively after exposure.

Even though we don’t know the strength of this year’s flu, it is always better to be prepared and get a vaccination, even if you are a healthy individual. Being under the assumption that you are healthy enough to not need a vaccine can result in serious and maybe even fatal consequences.

With viral infections like the flu and mono, it is always important to remain sanitary. Washing your hands, not sharing drinks, and cleaning yourself and your living spaces, are very helpful preventative measures which can ensure a higher chance of being illness-free all year long!