When viruses are outside of a host or on inanimate surfaces, they enter a dormant state. However, viruses still need to survive outside of the body, although it is not the same type of survival as we typically think of.
As we approach the year 2020, if we were to compare the likelihood of being struck by lightning, attacked by a shark, or winning the lottery to the likelihood of experiencing a global pandemic for the majority of the year, most of us would not have predicted the pandemic. Yet, here we are in 2023, still dealing with the aftermath of a small virus known as SARS-CoV-2. While infection rates have significantly decreased since 2021, people around the world have found new reasons to question viruses!
While we have answers to questions like “Why can’t we use antibiotics against viruses?”, there are still areas of research that are not fully developed. For instance, what do viruses do when they are outside of host bodies? If these organisms cause diseases, it is crucial to understand how they exist when they are not infecting us, right?
As we look towards our future after the pandemic, it is important to consider the implications of these unanswered questions.
So, before we discuss the activities of viruses outside and inside the body, and how they accomplish these activities, let’s first talk about what viruses actually are.
What Exactly is a Virus?
In simple terms, a virus is a microorganism. The main component of this microorganism is its genetic material, which can be either DNA or RNA.
However, viruses are unique exceptions. They defy the general rules of life. Normally, living organisms are defined as such based on whether they possess genetic material. Well, viruses do have genetic material, but they are not technically alive because they cannot reproduce or replicate on their own.
We consider viruses as tiny agents of infection. (Photo Credit: -CoreDESIGN/Shutterstock)
Viruses only begin their “life” when they land on or in living organisms, such as humans. Think of it this way: a virus drifts through the world in airplane mode until it finally finds a compatible host to infect. Once inside the host, it takes control of the host’s systems and machinery. In doing so, the virus manipulates the host into producing more copies of itself. This process is known as production or replication. When a virus starts replicating in a host, it infects the host and produces more and more copies of itself.
Can Viruses Infect Every Living Organism?
It is easier to answer this question by categorizing viruses into “specialist” and “generalist” categories. While most viruses can infect a wide range of species (generalists), many viruses are actually specific to certain hosts (specialists). This means that they have a limited range of species they can infect.
Let’s take the example of the dengue virus or DENV. This virus is transmitted by vector organisms, specifically various species of mosquitoes. A significant portion of the virus is transmitted by female Aedes aegypti mosquitoes. This virus is a specialist virus and can only infect a narrow range of mammalian species, such as humans, other primates, and other mammals like dogs and pigs.
Certain viruses have a limited range of targets, such as mammals, while others have the ability to infect all known vertebrates. (Photo Credit : -SaveJungle/Shutterstock)
In contrast, adenoviruses are considered generalist viruses as they have a wider range of targets and can infect all known vertebrates.
We now understand what viruses are and what they can infect, but there is still one aspect we need to explore. We already know that viruses are not technically “alive” unless they enter a host body. This naturally leads to the question of what viruses do when they are outside of a body.
What is the Role of Viruses Outside of the Body?
Similar to dust particles, viruses are incredibly small and can be found floating in the air all around us. When viruses land on non-living or inanimate surfaces, they do not have much activity.
Viruses enter a kind of dormant state while floating outside of a body or when they land on inanimate surfaces. However, viruses still need to survive outside of a body, although it is not survival in the way we typically think of it.
When outside of a host body, viruses do not focus on self-replication. Instead, they prioritize maintaining their ability to replicate.
Essentially, when a virus enters a host, it infects the host. Outside of a host, viruses focus on preserving their ability to infect a future host. Their main goal is to protect and maintain their capacity for infection outside of a host body.
What Factors Influence the “Infectibility” of a Virus?
Viruses are typically surrounded by a special coating or layer composed of multiple protein molecules. This protective layer is called a capsid.
The capsid coating serves to protect the RNA or DNA inside the virus, which is crucial for self-replication. Therefore, the capsid plays a significant role in safeguarding the virus and helping it maintain its infectibility.
If the capsid becomes compromised or degraded, the virus is less likely to survive, find a host, and successfully replicate.
How Do Viruses Ensure Their Survival Outside of Host Bodies?
In reality, they cannot. Since viruses are not living organisms, they have no control over where they land. Luck plays a major role in determining whether viruses can survive outside of host bodies or not.
For example, if they land on dry surfaces like copper, the viral capsid degrades at a faster rate. Similarly, if the virus lands on a soft surface instead of a hard one, the capsid is more likely to degrade quickly.
This is because viruses require moisture to survive and function. Soft surfaces, such as paper, cardboard, wood, and cloth, have better water absorption capabilities than hard surfaces, making them unfavorable landing spots for viruses.
It is not just the type of surface that viruses must contend with. Factors such as humidity levels in the surrounding air and the amount of light exposure can also influence whether a virus retains its infectibility or not.
In countries like China, banks utilize UV-C lights to sanitize bank notes. China also employs UV-C-emitting robots to clean hospital floors, and public transit buses are disinfected using UV-C light-emitting sheds. UV-A and UV-B light can also neutralize viruses, but the exact amount of exposure time required is unknown. In conclusion, viruses are vulnerable outside of a host body and their landing location is often a matter of chance. Various factors, including temperature, hardness, and surface cleanliness, greatly influence a virus’s ability to survive and remain infectious.