Facts About Coronaviruses and Reducing the Risk of Infection
Coronaviruses and Their Effects
Coronaviruses are interesting and sometimes dangerous entities that infect humans and other animals. They often make us sick, but the severity of the illness varies. The infection may be minor, resulting in symptoms that are no more serious than the common cold. Sometimes it's potentially deadly, however. A coronavirus disease known as COVID-19 is currently of global concern.
Viruses can change over time as they gain, lose, or change genes. The genes are responsible for the characteristics of the virus. Every now and then, researchers announce that a novel variety of coronavirus has been discovered. Examples of varieties that have caused problems include the ones responsible for MERS (Middle East Respiratory Syndrome), SARS (Severe Acute Respiratory Syndrome), and COVID-19 (coronavirus disease 2019). Though the virus that causes the last disease was discovered in late 2019, it has become a major problem in 2020.
Health agencies around the world are tracking the spread of coronaviruses carefully. In this age of frequent international travel, infections can easily spread from country to country. Luckily, there are things that we can do to significantly reduce our chance of catching a virus. There are also ways in which we can boost the activity of our immune system, which protects us from infections.
What Is a Virus?
Viruses are very different from other living things. In fact, some scientists don't consider viruses to be alive. Unlike living organisms, they aren't made of cells. Instead, they consist of a core of nucleic acid (DNA or RNA) surrounded by a coat of protein. The protein coat is known as a capsid. Some viruses, including coronaviruses, have a lipid envelope surrounding their capsid.
Another difference between viruses and cellular organisms is that viruses can't reproduce on their own. They must enter a cell of a living organism in order to make new copies of themselves.
Although a virus has a simpler structure than a cell, it's still impressive. It has the amazing ability to trick the cells that it infects. It not only passes through the protective membrane surrounding a cell but also stimulates it to make virions (viral nucleic acid surrounded by a capsid, or individual virus particles) instead of its own products. The virions then destroy or damage the cell as they enter the outside world.
How Does a Virus Get into Cells?
The "goal" of a virus is to send its nucleic acid into a cell. The nucleic acid contains genes that encode the instructions for making new virions.
Viruses seem to have three ways of accomplishing their goal. Each method requires a virion to bind to receptor proteins on the cell membrane before an infection begins.
- Viruses that infect bacteria (bacteriophages) inject their nucleic acid into a bacterium while leaving their capsid outside.
- The lipid envelope of some viruses fuses with the cell membrane, which is also rich in lipids. The capsid and nucleic acid are then released into the cell.
- Some viruses enter cells by a process called endocytosis. The cell membrane forms an invagination or pocket that engulfs and surrounds a virion. The pocket then separates from the cell membrane, forming a sac with the virion inside. The virion later breaks out of the sac.
A coronavirus enters a cell by both membrane fusion and endocytosis. Researchers are studying the ways in which the virus attaches to the protein receptors of cell membranes and then enters the cells. If scientists can interfere with these processes, they should be able to stop an infection.
Viral Reproduction and Exit
Once inside the cell, the nucleic acid of the virus takes over its equipment, causing the cell to make new viral nucleic acid molecules and new protein coats. The virions are then assembled.
The virions may burst out of the cell, destroying it in a process called lysis. In some types of virus, however, the virions are released through the cell membrane in a gentler process. These additional methods still damage the cell, however, and usually kill it.
One "gentler" method by which virions leave cells is called budding. In the budding process, a virion produces a bud-like swelling on the cell membrane. As the bud splits off, a bit of broken cell membrane surrounds the released virus particle. This is the method by which many viruses get their lipid envelope.
Another method of viral release is called exocytosis, which is the opposite process to endocytosis. A vesicle (sac) carrying the virion fuses with the cell membrane and releases its contents to the outside environment. Coronaviruses are released by exocytosis.
Viral entry, reproduction, and exit are complex processes. Many details of the processes still need to be discovered. The benefits obtained from the discoveries could be wonderful, since viruses cause diseases in humans, animals, and plants. Understanding viral behavior could lead to new treatments for these problems.
Structure of Coronaviruses
A coronavirus is named for its appearance under an electron microscope. The virions are covered by club-shaped projections or spikes made of protein. These reminded early observers of a crown or the rays of the sun's corona. "Corona" is the Latin word for crown.
A coronavirus virion has an irregular shape but is often roughly circular. It contains a single strand of RNA, or ribonucleic acid, which is helical and contains genes. The human body contains RNA too, but our genes are present in DNA, or deoxyribonucleic acid. The genes of other organisms and of many viruses are also present in DNA. The RNA molecule of a coronavirus virion is large and is surrounded by a protein capsid. This is in turn surrounded by an envelope made of lipid.
The information below is given for general interest. Anyone who has questions about a specific viral infection or who has symptoms of ill health that are severe, long-lasting, or recurrent should consult a doctor.
A Coronavirus Infection
Coronaviruses are transmitted in droplets released from the respiratory system. We release these droplets as we sneeze, cough, or speak. It's thought that the viruses are also transmitted though personal contact, such as by shaking hands. In addition, a person may become infected when they touch a contaminated surface.
Coronaviruses cause problems in the upper respiratory tract, but most of them don't produce a serious infection. The usual symptoms resemble those of the common cold and include a runny nose, sneezing, coughing, a sore throat, and a fever. Most people have been infected by a coronavirus at some time. There may be multiple incidences of infection in a person's life. The affected person usually recovers without help.
Coronaviruses may sometimes cause problems in the lower respiratory tract, such as pneumonia, but these problems generally occur in people who have a weakened immune system or in elderly people. In some cases—especially in children—the viruses cause problems in the digestive tract.
Antiviral drugs are available to treat some viral infections, but most can't be cured by drugs. Doctors have to treat the symptoms rather than the infection itself. They can prescribe medications to reduce fever, relieve pain, and make breathing easier, for example. Although the body generally has to destroy the virus on its own, medical support can be very helpful.
While most coronaviruses cause relatively benign infections, some can cause serious symptoms and may be deadly. The SARS virus and the MERS virus are examples. Their full names are SARS-CoV and MERS-CoV, where CoV stands for coronavirus.
The SARS Virus, or SARS-CoV
The first appearance of the SARS coronavirus was during a disease outbreak in 2002-2003. The last case of SARS was diagnosed in 2004. Like the MERS virus today, the SARS one was called a "novel" coronavirus because it was a new variety that had never been observed in humans before.
The first symptom of the infection was usually a high fever. This was often followed by a headache and body aches. Serious respiratory problems often developed, including pneumonia. Diarrhea was sometimes present, too. According to the World Health Organization, or WHO, 8,098 people were diagnosed with SARS and a total of 774 people died.
The MERS Virus, or MERS-CoV
The MERS coronavirus, or MERS-CoV, was first observed in 2012 in Saudi Arabia. Researchers know that it's potentially dangerous, but they still have much to learn about the virus.
According to WHO, as of the end of July 2019:
- 2,458 laboratory-confirmed MERS cases had been reported to WHO.
- 848 deaths from the infection had been reported to the organization.
- The MERS virus had been found in 27 countries. (The infection is most common in countries in and near the Arabian peninsula. So far, people in other countries with the disease have recently visited this area.)
The death rate from the infection (33%) might be a concern. WHO says that it may be lower than believed, however. Infected people without symptoms or with only minor ones may not be diagnosed with MERS and are therefore not included in the statistics. In addition, health agencies say that the current risk of infection is low for residents of North America. The CDC (Centers for Disease Control and Prevention) says that at the moment only two cases of MERS have been diagnosed in the United States. Both patients were healthcare workers and likely became infected in Saudi Arabia. They were both treated in hospital and recovered from the infection.
Health officials are aware of the potential for the virus to spread globally and are continuing to monitor the situation. They also say that we should follow the recommended procedures for reducing the chance of a viral infection. These procedures are described below.
The virus does not seem to pass easily from person to person unless there is close contact, such as occurs when providing unprotected care to a patient.— WHO (World Health Organization)
Transmission of the Disease
The transmission of the MERS virus is not well understood. It seems to pass from one person to another through close contact but probably not from casual contact. It may be transmitted via camels as well. The virus has been discovered in camels and some people have become sick after handling the animals. This doesn't prove that camels can transmit MERS to humans, though.
WHO recommends that people wash their hands before and after approaching camels and that they avoid animals who are obviously sick. They also recommend that people avoid eating or drinking raw or undercooked camel meat, milk, or urine. (Yes, some people do drink camel urine.)
People who visit countries with MERS cases need to make sure that they take steps to avoid infections. The majority of these countries are located around the Arabian Peninsula. In 2015 an outbreak occurred in Korea, however. According to the CDC (Centers for Disease Control and Prevention), so far this has been the largest outbreak of the disease outside the peninsula. It originated from a traveller returning to Korea from an infected area. The WHO web page mentioned in the "References" section below is useful for travellers because it contains the latest news about MERS outbreaks.
Possible Symptoms and Treatment
Like the SARS virus, the MERS one produces symptoms beyond the respiratory system. In people who get sick from the infection, the patient generally has a fever, shortness of breath, and a cough. The respiratory system symptoms may be severe. The patient may also experience diarrhea, nausea, and vomiting. Possible complications include pneumonia and kidney problems.
Strangely, some people don't get sick when they're infected by the MERS virus or experience only mild symptoms that resemble those of a cold. According to the CDC, older people and people with pre-existing medical conditions may be more likely to experience severe symptoms. These conditions include:
- a weakened immune system
- a chronic lung disease
- kidney disease
At the moment, there is no specific treatment for MERS. Medical care is very important, though. Doctors can support the patient's recovery by relieving symptoms and protecting vital organs.
The COVID-19 Outbreak in 2020
In January, 2020, the discovery of a novel strain of coronavirus in China was reported. The strain was at first called 2019-nCoV because it was discovered at the end of 2019. The "n" means novel. The current name of the virus is SARS-CoV-2. The name of the disease that it causes is COVID-19. The virus has spread to multiple countries. Its name shows that it is related to the first SARS virus.
At the time when I last updated this article, 3,090,445 people in the world had been infected by the virus and 217,769 people had died from the infection. The virus seems to produce relatively mild symptoms for many people, but in some cases it produces a disease that resembles pneumonia and is more serious. The rate at which the virus is spreading around the world is a concern.
There are still many unknown factors about the virus and the disease. The death rate may be lower than suggested because many people may have a mild version of the disease. Some infected people apparently have no symptoms. Both of these groups may never realize that they have a coronavirus infection because they don't seek or receive a diagnosis. Statistics such as these wouldn't be reported by WHO. On the other hand, some worrying reports about the potential effects of the virus have appeared. More research is needed to understand the situation.
Many of the people who have died from the viral infection have been older than sixty. Some were already sick from another problem. This doesn't make the situation better, of course. The fact that anyone has to die is tragic. Younger people have died from the illness, however. It's not exclusively a disease of older people or (apparently) of someone weakened by another condition. The virus is puzzling in many ways.
Researchers around the world are working hard to find antiviral substances to fight the SARS-CoV-2 virus and an effective vaccine to prevent the disease that it causes, which is a hopeful sign.
The Latest Information About COVID-19
The World Health Organization is currently releasing daily situation reports containing the latest disease statistics related to COVID-19. These reports can be accessed via the last link in the "References" section at the end of this article. The outbreak is still in progress and statistics are changing on a daily basis.
Chinese officials have worked hard to prevent the spread of the disease. Many of their cities were on lockdown when the disease was at its worse. The efforts seem to have been successful and have shown that the virus can be beaten. The epidemic in the country appears to be over, although a few cases are still being reported. Unfortunately, the number of new cases outside of China is increasing in some places.
The World Health Organization (WHO) is monitoring the situation carefully. On March 11th, 2020, they classified the coronavirus outbreak as a pandemic. An epidemic is widespread but affects a limited region, such as one country. A pandemic affects many countries. Who currently classifies the risk of catching the disease as high on a global level.
Reducing the Risk of Infection
There are a variety of ways in which people can greatly reduce the chance of getting sick from a viral or a bacterial infection. The steps can also reduce the chance of infecting someone else. Here are ten suggestions that are recommended by health agencies.
- Wash hands frequently, especially before eating and after a high-risk event such as using a bathroom.
- Wash hands for at least twenty seconds per session. One common suggestion that may be helpful for children (and perhaps for adults too) is to wash the hands for as long as it takes to sing "Happy birthday to you" twice.
- Use soap and water to wash the hands, but if these aren't available, use an alcohol-based hand sanitizer instead.
- Wash or disinfect objects that are touched frequently, such as door knobs, faucet handles, and toilet flushers.
- Flush toilets when the lids are down to avoid contact with the spray that's released and to prevent the germ-laden spray from spreading through the air.
- Consider using a towel with a different colour or pattern for each family member. This will reduce the chance of an infection passing from one person to another.
- Don't touch your mouth, nose, or eyes. This requires some practice, as I've discovered myself. You should begin "training" yourself while you and your acquaintances are healthy so that you are prepared if a virus reaches your community.
- If you have to touch your face to wipe your nose with a tissue (for example), immediately throw the tissue away and then wash your hands.
- Avoid close contact with people if they are obviously sick. As COVID-19 is spreading, health professionals are recommending that we use social distancing around other people even if they appear to be healthy.
- Cover your mouth or nose when you sneeze—but not with your hands, which can transfer the germs to other surfaces when you touch them. Use a tissue. If you don't have one, sneeze (and cough) into your sleeve, and wash the area or clothing as soon as possible.
Another important action is to try to work at home when you're sick instead of going to your workplace. This is especially important with respect to COVID-19, since the virus that causes the disease is so infectious. If it's impossible to work at home, social distancing should be maintained at work whenever possible.
How many of the ten suggestions do you follow to prevent viral infections?
The Use of Masks for the COVID-19 Infection
Specialized medical masks are in short supply and must be kept for health professionals treating coronavirus patients. The CDC says that there is some value in other people wearing less-specialized masks during the current disease outbreak, though. At the time when this article was last updated, their website gave the following information.
"CDC recommends that people wear a cloth face covering to cover their nose and mouth in the community setting. This is to protect people around you if you are infected but do not have symptoms."
The organization also says that someone who has trouble breathing or who is incapacitated shouldn't wear a mask, however.
The value of masks for people without symptoms seems to be an evolving topic. If you investigate the latest news about masks for the public, make sure that you look at reliable sources giving information about their construction and their potential benefits.
Medical sources say that we shouldn't become overconfident if we wear a mask. Social distancing is still important to help prevent the spread of disease. It's also important to handle a potentially contaminated mask carefully once we want to remove it. This topic is something else to investigate.
The CDC page mentioned in the "References" section below should be read carefully to get the latest recommendations from the organization with respect to COVID-19.
Maintaining a Healthy Immune System
While it's important to follow steps to reduce the chance of catching a virus, the steps aren't foolproof. Therefore, it's a good idea to keep the immune system functioning well. If the immune system is strong, it will be able to destroy many viruses.
A healthy lifestyle boosts immunity. A good diet that emphasizes a wide variety of whole, unprocessed foods and is low in sugar should be very helpful for improving and maintaining immunity. Moderate and regular exercise has been shown to boost the immune system, while smoking weakens it. Getting adequate sleep and taking steps to relieve stress can also help the immune system to function efficiently.
Although following a healthy lifestyle isn't a guarantee that we won't get sick, it can certainly improve the odds. It also increases the chance that any infection that we experience will be mild instead of serious. Since another of its benefits is to reduce the chance of other diseases besides infections, it's a good idea to follow a healthy lifestyle whenever possible.
This content is accurate and true to the best of the author’s knowledge and does not substitute for diagnosis, prognosis, treatment, prescription, and/or dietary advice from a licensed health professional. Drugs, supplements, and natural remedies may have dangerous side effects. If pregnant or nursing, consult with a qualified provider on an individual basis. Seek immediate help if you are experiencing a medical emergency.
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© 2013 Linda Crampton