This article is in collaboration with The Knowledge Society (TKS), a human accelerator program designed to create the next generation of Elon Musks and Steve Jobs. We are providing free, in-depth, reliable information to the public about Covid-19 and how best to equip yourself against it.
There’s no denying that 2020 is a time that will undoubtedly be inscribed into textbooks as one of the most important years in all of recent human history.
The supersonic progression of the coronavirus (Covid-19) is sending waves of terror across the entire globe, with tens of thousands of cases being announced every day.
This is all really scary stuff, and everybody wants to best protect themselves against the highly contagious disease. However, in order to do that, we must understand what exactly is a virus and how they work. We need to understand why Covid-19 propagates so unbelievably fast and how you can protect yourself against it. Fortunately, we’ve compiled all the information you need to do that.
What is a virus?
At a high level, a virus is essentially just a biological agent that reproduces inside the cells of a living host. When infected by a virus, a host cell quickly produced thousands of identical copies of the original virus.
Because of that broad definition, it is worth noting that similar to bacteria, there are both good and bad viruses. The viruses themselves are just microscopic infectious particles that consist of an RNA or DNA genome enclosed in a protein shell.
Before entering a cell, viruses exist in a form known as virions. During this phase, they are roughly one-hundredth of the size of a bacterium and are composed of 3 distinct parts: genetic material (either DNA or RNA), a protein coat which protects the genetic information, and a lipid envelope that surrounds the protein coat when the virus is outside of the cell.
Unlike human cells or bacteria, viruses don’t contain chemical machinery needed to carry out the chemical reactions to sustain life. Alternatively, viruses carry only a couple of enzymes that decode their genetic instructions. Thus, a virus must have a host cell in which to live to make more viruses.
How do they work?
Regardless of the type of host cell, all viruses follow the same basic steps in what is knows as the lytic cycle:
- A virus particle attaches to a host cell
- The particle releases its genetic instructions into the host cell
- The injected genetic material recruits the host cell’s enzymes
- Following that, the enzymes make parts for more new virus particles
- The new particles assemble the parts into new viruses
- The new particles break free from the host cell.
The Origins of Viruses
The origins of viruses are still unknown. There are 2 prominent theories in the scientific community: 1) The progressive hypothesis, that viruses came from genetic elements that gained the ability to move between cells; and 2) The Virus-First hypothesis, that viruses predate or coevolved with their current cellular hosts.
The Progressive Hypothesis states that mobile genetic elements — pieces of genetic material capable of moving within a genome — gained the ability to exit one cell and enter another. Retroviruses have a single-stranded RNA genome.
When the virus enters a host cell, an enzyme converts that single-stranded RNA into double-stranded DNA. This viral DNA then migrates to the nucleus of the host cell. Another viral enzyme inserts the newly formed viral DNA into the host cell’s genome.
The Virus-First Hypothesis states that viruses may have been the first replicating entities. Scientists predicted that viruses existed in a precellular world as self-replicating units. Over time these units became more organized and more complex.
Eventually, enzymes for the synthesis of the membranes and cell walls evolved, resulting in the formation of cells. Viruses, then, may have existed before bacteria, or eukaryotes.
Composition of Viruses
Viruses are noncellular, meaning they are biological entities that do not have a cellular structure. They, therefore, lack most of the components of cells, such as organelles, ribosomes, and the plasma membrane. There are four main morphological virus types:
Helical: “spring” shaped structure with the “payload” **(**typically single-stranded RNA, but ssDNA in some cases) The well-studied tobacco mosaic virus is an example of a helical virus.
Icosahedral Most animal viruses are icosahedral or near-spherical with chiral icosahedral symmetry. A regular icosahedron is an optimum way of forming a closed shell from identical subunits. The minimum number of identical capsomeres required for each triangular face is 3, which gives 60 for the icosahedron.
Many viruses, such as rotavirus, have more than 60 capsomers and appear spherical but they retain this symmetry. To achieve this, the capsomeres at the apices are surrounded by five other capsomeres and are called pentons.
Capsomeres on the triangular faces are surrounded by six others and are called hexons. Hexons are in essence flat and pentons, which form the 12 vertices, are curved. The same protein may act as the subunit of both the pentamers and hexamers or they may be composed of different proteins.
Prolate: This is an icosahedron elongated along the fivefold axis and is a common arrangement of the heads of bacteriophages. This structure is composed of a cylinder with a cap at either end.
Envelope: Some species of virus envelop themselves in a modified form of one of the cell membranes, either the outer membrane surrounding an infected host cell or internal membranes such as a nuclear membrane or endoplasmic reticulum, thus gaining an outer lipid bilayer known as a viral envelope.
This membrane is studded with proteins coded for by the viral genome and host genome; the lipid membrane itself and any carbohydrates present originate entirely from the host. The influenza virus and HIV use this strategy. Most enveloped viruses are dependent on the envelope for their infectivity.
Complex: These viruses possess a capsid that is neither purely helical nor purely icosahedral, and that may possess extra structures such as protein tails or a complex outer wall.
Some bacteriophages, such as Enterobacteria phage T4, have a complex structure consisting of an icosahedral head bound to a helical tail, which may have a hexagonal base plate with protruding protein tail fibers.
This tail structure acts as a molecular syringe, attaching to the bacterial host and then injecting the viral genome into the cell.
Previous viral diseases
The Ebola Virus Disease is a rare but extremely severe and often fatal illness to humans, with a fatality rate of 50%! It infects dendritic cells, which normally display signals of infection on their surfaces to activate T lymphocytes — the white blood cells that could destroy other infected cells before the virus replicates further.
With defective dendritic cells failing to give the right signal, the T cells don’t respond to infection, and neither do the antibodies that depend on them for activation. The consequences are especially profound in the liver, where Ebola wipes out cells required to produce coagulation proteins and other important components of plasma.
Damaged cells in the gastrointestinal tract lead to diarrhea that often puts patients at risk of dehydration Ultimately, death is usually caused by damage to blood vessels leads to a drop in blood pressure, and patients die from shock and multiple organ failure.
It is believed that it stems from a family of fruit bats by the name of Pteropodidae. Ebola is introduced into the human population through close contact with the blood, waste, organs or other bodily fluids of infected animals.
Upon contracting it, the disease is easily transmissible to others via direct contact. The biggest outbreak recorded took place in 2014 in West Africa. The outbreak started in Guinea but moved across the borders to Sierra Leone and Liberia.
The H1N1 Flu Virus occurs in people that are in contact with infected pigs. When this occurs, it is called a “variant influenza virus”. Symptoms are similar to that of regular human influenza and can include fever, lethargy, lack of appetite, coughing, runny nose, sore throat, nausea, vomiting, and diarrhea.
People catch H1N1 the same way as the seasonal flu. When people who have it cough or sneeze, they spray tiny drops of the virus into the air. If you come in contact with these drops, touch a surface (like a doorknob or sink) where the drops landed, or touch something an infected person has recently touched, you can catch H1N1 swine flu.
People who have it can spread it one day before they have any symptoms and as many as 7 days after they get sick. Kids can be contagious for as long as 10 days.
The Zika Virus is a mosquito-borne flavivirus that was first identified in Uganda. Zika virus is primarily transmitted by the bite of an infected mosquito from the Aedes genus, mainly Aedes aegypti, in tropical and subtropical regions.
Aedes mosquitoes usually bite during the day, peaking during early morning and late afternoon/evening. This is the same mosquito that transmits dengue, chikungunya and yellow fever. Zika virus is also transmitted from mother to fetus during pregnancy, through sexual contact, transfusion of blood and blood products, and organ transplantation.
The incubation period (the time from exposure to symptoms) of Zika virus disease is estimated to be 3–14 days. The majority of people infected with the Zika virus do not develop symptoms.
Symptoms are generally mild including fever, rash, conjunctivitis, muscle and joint pain, malaise, and headache, and usually last for 2–7 days. The first recorded outbreak of Zika virus disease was reported from the Island of Yap (Federated States of Micronesia) in 2007.
This was followed by a large outbreak of Zika virus infection in French Polynesia in 2013 and other countries and territories in the Pacific. In March 2015, Brazil reported a large outbreak of rash illness, soon identified as Zika virus infection, and in July 2015, found to be associated with Guillain-Barré syndrome.
Thank you for reading our in-depth article about all things viruses. We sincerely hope that you learned a lot and stay safe amid this pandemic. Make sure to avoid social interaction and wash your hands frequently.
Covid-19 is contracted through the mouth, nose, and eyes so make sure to shield your face by any means necessary — whether it be by wearing a mask or by just staying home.
Washing your hands properly dissolves the outer layer of viruses known as lipids — preventing further function of the virus. Please share this article with everybody that you think will benefit from it and stay safe!