What Is a Virus

These unusual entities have different roles in our bodies

While some viruses help protect us, others hijack healthy cells to create an invading army that our immune system then adapts to and destroys. (Irina Bg/Shutterstock)

Viruses may be small, but their influence is huge. These simple organisms are just a nucleic acid-coated in protein, but they can result in a wide variety of illnesses. Some can be deadly; others can be beneficial and an important part of your immune response.

For centuries doctors could see the results of viruses—illnesses such as polio, rabies, herpes, mono, and smallpox—but the particles working behind the scenes weren’t detected until the dawn of the 20th century. That’s when scientists discovered a bacteria-like being with a unique feature: It couldn’t reproduce without another being’s cells.

According to Dr. Sophia Tolliver, a family medicine physician at the Ohio State University Wexner Medical Center, this is the main difference between viruses and bacteria. A bacterial infection comes from a microbe that can thrive in a wide variety of environments. A viral infection, on the other hand, comes from a microscopic parasite that requires very specific conditions for survival.

“They are unable to live or reproduce outside of a host body,” Tolliver said.

Scientists have identified more than 400 different viruses that can infect people. Others can infect animals, plants, even bacteria. It’s not clear how many viruses exist. By one estimate, there are more than 100 million different viruses that can infect all known species of vertebrates, invertebrates, plants, lichens, mushrooms, and algae.

And that’s just the viral estimate for our planet. Some scientists propose that an entity so abundant on Earth is likely found on other planets, too.

There is a debate as to whether viruses are truly alive, or simply a biological mechanism. Some scientists argue that viruses fail the qualifications for a living entity because they lack the self-replication feature found in all other organisms. Viral particles reproduce by binding to a host’s cells and inserting some of their genetic material. The host cell gets hijacked into making copies of the viral DNA necessary to grow the disease.

In a sense, when we catch a viral infection, we turn into a virus-making factory, churning out an exponential growth of these parasitic particles until our immune system puts a stop to it. All types of viral infections, from colds and flus, to hepatitis and HIV, propagate this way.

This makes viral infections tricky to treat. Antibiotics can kill off a bacterial infection by targeting its growth mechanism. Since viruses lack this mechanism, antibiotics have no effect.

Helpful Viruses

But some viruses can actually kill bacteria. The mucous membrane lining our digestive, respiratory, and reproductive tracts is host to bacteriophages (or “phages”). These viruses infect and destroy specific bacteria. Others can fight against more dangerous viruses.

Just as scientists have learned that there are essential and helpful bacteria that live inside us, it appears there are protective viruses also residing in our body.

And recent research out of San Diego State University suggests that these helpful viruses, or phages, are a natural part of our immune system.

This isn’t all new news. Phages have been used for nearly a century to treat sepsis caused by Staphylococcus aureus, salmonella infections, dysentery, and more. As drug-resistant infections become a greater concern, phages have taken on greater interest as a way to treat infection, including other viral infections.

Because when it comes to bad viruses, nobody wants to be a host for viral reproduction. That said, exposure to some viruses actually make us stronger, because they trigger our immune system to produce antibodies—special proteins that thwart microbial invaders. There’s a specific antibody to address each microbe we come in contact with, but they don’t come cheap. Tolliver says the main way we get these antibodies is through something called “active immunity.”

“The body fights off viruses and bacteria through its own immune system by mounting an immunological response and by making antibodies to help fight future infections,” she explains.

Another part of our defense system is called “passive immunity.” As the name suggests, our own body does not create this protection. Instead, passive immunity comes from protective antibodies that we inherit, like those we received from our mother’s milk or while in utero.

Until we’ve acquired these specific antibodies, we’re at the mercy of the harmful viruses that can infect us. Some just make us sick, but others can be deadly. Tolliver says the difference lies is the ability of a virus to use our own cells against us.

Fighting Viral Invasions

The common cold virus may only affect us for a week or two before our immune system puts an end to it. However, with HIV/AIDS, the virus can completely takeover—driving its own replication, and killing our cells in the process.

“With the advent of medications, this condition has gone from a virtual death sentence to more of a chronic disease where people can still live a full life,” Tolliver said.

The drugs used to treat HIV—known as antiretrovirals—work by suppressing viral activity. It prevents the virus from multiplying so it stops killing the patient’s cells. This strategy doesn’t kill the virus or cure the disease, but it does increase patient lifespan and reduce the disease’s transmission.

But antiretroviral drugs may not be the only option. We often assume that modern medicine offers the only answers to microbial infections, but ancient medicine can still provide some help. And emerging science is backing that up.

For example, one study that began in the early 2000s looked at otherwise healthy AIDS patients in their 50s and 60s. Instead of antiretrovirals, the nine participants in the study were given a traditional Chinese formula made of 13 different herbal extracts. By 2016, 8 of 9 had an undetectable viral load, and the remaining patient’s viral load was low. Other studies have shown that including traditional Chinese medicine in treatment can reduce some of the side effects associated with conventional antiretroviral therapy.

Modern science also recognizes that ancient forms of medicine may offer greater immune protection. Regular application of herbs such as andrographis and echinacea have been shown to reduce the impact and severity of certain viral infections.

There are even simpler methods we can all practice to keep from getting sick. Hygiene is huge. Washing your hands regularly, especially before touching your mouth, nose, and eyes, is an effective way to prevent infections.

The Centers for Disease Control states that hand-washing helps prevent diarrhea and respiratory infections, and may even help prevent skin and eye infections.

“Keeping hands clean is one of the most important steps we can take to avoid getting sick and spreading germs to others. Many diseases and conditions are spread by not washing hands with soap and clean, running water,” according to the CDC.

Keep in mind that regular soap will do just fine. Antibacterial soap not only contributes to antibiotic resistance, but it offers absolutely no advantage against viruses.

Finally, learn to take it easy, and make sure to get plenty of sleep, because nothing weakens our defenses like too much stress. Stress robs our body of resources that it could use to mount an immune attack, leaving us more vulnerable to viruses we may come in contact with.

“The level of stress in the body can influence how our bodies respond to illness and how strongly the body can fight an infection,” Tolliver said.