With the news currently dominated by the coronavirus outbreak, Google searches about viruses (of the biological variety) have skyrocketed, as you would expect. So I started to wonder what were the most popular virus related questions that people are asking Google right now, and I thought I would answer nine of them!
Which virus causes chickenpox?
Chickenpox is caused by a virus called varicella zoster, which also causes herpes zoster (shingles) in adults. This virus is exclusive to humans and it mostly affects children, although it can be acquired at any age. Varicella zoster is transmitted from person to person by directly touching the blisters, saliva or mucus of an infected person. The virus can also be transmitted through the air by coughing and sneezing.
What virus is going around?
Well if you have been keeping up with the news recently, it won’t have escaped your attention that a new strain of coronavirus is going around. The outbreak of this virus originated in Wuhan, China, but it has rapidly spread across the world, with confirmed cases in Australia, France, the USA, Thailand, Singapore, Japan, Taiwan, Malaysia, Vietnam, South Korea and Nepal. As of the publication of this article, the coronavirus has killed at least 42 people and infected some 1,400 people since its discovery.
How do viruses differ from bacteria?
For a comprehensive explanation about the main differences between viruses and bacteria, I would recommend an article called Differences Between Bacteria and Viruses at ThoughtCo which does a better job of explaining the differences than I can. However, for those of you who would prefer a quick summary, I have included a chart below that shows the main differences between viruses and bacteria in six key areas.
|Cell Type||Acellular (not cells)||Prokaryotic cells|
|Size||20-400 nanometers||200-1000 nanometers|
|Structure||DNA or RNA within a capsid, some have an envelope membrane||Organelles and DNA within a cell wall|
|Cells Infected||Animal, plant, fungi, protozoa, bacteria, archaea||Animal, plant, fungi|
|Reproduction||Rely on host cell||Binary fission|
Which virus causes the common cold?
There are actually over 200 types of virus that can cause the common cold, but the most common one is the rhinovirus, which is thought to be responsible for at least half of all colds. Other viruses that can cause colds include coronavirus, respiratory syncytial virus, influenza and parainfluenza.
Which virus causes HIV?
The virus that causes HIV is the Human Immunodeficiency Virus…HIV. But if you want to be more specific, it belongs to a class of viruses called retroviruses and a subgroup called lentiviruses. HIV is called a retrovirus because unlike other viruses, retroviruses store their genetic information using RNA instead of DNA, meaning they need to make DNA when they enter a human cell in order to make new copies of themselves.
How are viruses transmitted?
There are a variety of ways in which viruses can be transmitted to humans. Some viruses can spread through touch, saliva, or the air. Other viruses can be transmitted through sexual contact, or by sharing contaminated needles. Insects, including ticks and mosquitoes, can transmit a virus from one host to another. Contaminated food and water are other potential sources of viral infection.
How does a virus reproduce?
Viruses cannot reproduce on their own, which is the reason why viruses are not considered as living. They can only reproduce by infecting host cells, and this process can be broadly divided into five steps:
- The virus binds to a host cell via a receptor molecule on the cell’s surface.
- The virus, or its genetic material, enters the cell.
- The viral genome is copied and its genes are expressed to make viral proteins.
- New viral particles are assembled from the viral genome copies and viral proteins.
- Completed viruses exit the cell and can then infect other cells.
These five steps are essential for viral replication, although the life cycle of viruses varies greatly between species and category of virus.
How many viruses are there?
If we are talking specifically about mammalian viruses that are harmful to humans, research published in Nature Ecology & Evolution in 2019 estimates that there are only 10,000 to 12,000 viruses in mammals that are potentially harmful to humans, compared to previous estimates of 500,000 to 700,000. The study also estimates that the total number of mammalian viruses is closer to 40,000, compared to previous estimates of about 1.5 million.
How many viruses do I have?
It was hard to find a credible number to answer this question, but I did find an interesting piece of research which suggests that people absorb approximately 31 billion viruses known as bacteriophages from their gut every day. Bacteriophages are viruses that only infect bacteria cells, and they therefore play an essential role in human health.
Pathogenic viruses causing infection in host organism image by nobeastsofierce and used under the standard license.