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"Virus" is a word we hear thrown around a lot. But what exactly is a virus? Biologically speaking, viruses are tiny microorganisms, even smaller than bacteria, made up of DNA or RNA.

What that means for us is that the genetic material carried by the virus can cause a wide variety of diseases, ranging from the common cold to more serious longer-lasting diseases such as HIV and AIDS. 

Once a virus gets inside of an organism, like a human, it's genetic material allows it to damage or change cells in order to multiply rapidly. And if your immune system can't fight it off, the viral illness can prove fatal. In this article, we discuss how viruses spread and how you can protect yourself against infection.  

How transmission happens

Depending on the type of virus, it can be spread through sneezes, coughs, sexual contact, shared needles, or fecal-to-oral transmission, according to Jeffrey D. Klausner, MD, MPH, Professor of Medicine and Public Health at UCLA David Geffen School of Medicine and Fielding School of Public Health. 

"For this Coronavirus 19, we're specifically speaking about respiratory droplets that can be spread between three to six feet from sneezing or coughing, and from contaminated secretions that could be on people's hands, doorknobs, or [other] devices," he says. 

With other viruses, such as influenza (the flu), transmission is also mostly through respiratory droplets. The flu is most contagious within four days of first getting it. On the other hand, measles is more contagious because its primary mode of transmission is airborne, meaning that the virus particles can stay suspended in the air for up to two hours where an infected person has coughed or sneezed.

Viruses like Hepatitis B or HIV require direct sexual contact and either shared bodily fluids or blood. Generally speaking, this makes them harder to transmit compared to the common cold, says Klausner. 

Another way viruses can be transmitted is through skin-to-skin contact, like kissing, in the case of human papillomavirus (HPV) or herpes simplex virus (HSV), for example. HSV can also be transmitted from mother to baby during labor. 

A virus can also be transmitted by inanimate objects, if bodily fluids, mucus, or respiratory droplets are left on a surface, like a doorknob. Klausner says viruses can exist on a surface and potentially cause infection for up to a few hours. According to Mayo Clinic, viruses will exist longer on harder surfaces – like plastic or stainless steel – than on soft fabric surfaces like clothing or pillows. (Here's how to properly disinfect everyday objects.)

Animals can transmit viruses to humans, which is why it's extremely important to be cautious when cooking raw meat from any animal — exotic or wild animals are especially risky. "When we cook animals, whether it be steak or fish or chicken, we kill these viruses and bacteria. But it's by preparing raw animals and the products that we expose ourselves [to the viruses]," says Klausner. Also when preparing foods, it is important to remember that viruses and bacteria can be transmitted from the fecal-to-mouth route, meaning through the stool. Handwashing is of paramount importance.

Getting blood or infected tissue from an animal on your hands can transmit a virus to you, and then you can pass it on to others. Meats that are eaten raw or mostly raw (like sushi or steak tartare) do come along with some risk – but professional chefs at restaurants know how to prepare these meats in a way that kills the potential viruses and bacteria. So leave these kinds of dishes to the pros. 

While a virus can be transmitted anywhere, there are some places that have higher rates of transmission. According to Klausner, anywhere where people are "in close contact" is at high risk – including nursing homes, prisons, institutionalized settings, colleges, and boarding schools. After that, you have public and mass transportation, like trains, planes, and buses. 

How to prevent transmission

There are measures you can take to protect yourself from viruses. According to Klausner, the best way to avoid getting a viral infection is to stay away from sick people, regularly wash your hands (the right way), and avoid touching your nose, mouth, and face. 

You should also try to maintain general good health, which makes your body stronger and better equipped to fight off viruses. Stay healthy by eating a well balanced, nutrient-rich diet, taking vitamins (the right ones), and getting enough sleep. It's also a good idea to regularly disinfect surfaces in your home. Also, when it comes to influenza, you should get your flu shot every year.

If you catch a virus, there are ways to prevent spreading it. The best way is to keep away from others, which can mean staying home from school or work and keeping your distance from family members or roommates. Aside from that, here are other things you can do to prevent passing your virus on:

• Wash your hands routinely and use an alcohol-based hand sanitizer when soap and water isn't available.
• Wear a mask if you must go out while you're sick.
• Clean the surfaces of your home and frequently touched items (including cell phones) with disinfectants.
• Cough or sneeze into your elbow, not into your mouth.
• Throw out tissues immediately instead of leaving them around.
• Wash your hands after blowing your nose. 
• Do not share needles if your virus is bloodborne.
• Use protection during sex if your virus is sexually transmitted.
• Disclose your virus status to others so they can make informed decisions. 

Whether you're already sick and trying to not pass the virus on, or you're healthy and want to ward off germs, make sure you're removing viruses from surfaces the correct way. Klausner recommends using bleach-based wipes, hydrogen peroxide-based wipes, or general antiseptic wipes. Make sure you allow the surface to dry completely before touching it, as the drying process is very important in decontamination since it will allow cells to evaporate. 

As long as you're taking all the proper preventative measures to protect yourself from viruses, you don't have to panic.

Related stories about staying healthy:

• Does hand sanitizer work? The difference between sanitizer and soap
• The best hand soap
• The best hand sanitizer
• The best disinfecting cleaners

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