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Covid-19: Causes, Signs and Symptoms of Covid 19 | What is it?

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What is coronavirus & Signs and Symptoms of Covid 19?

The coronavirus refers to any virus belonging to a family of viruses called Coronaviridae or, in simple words, coronaviruses (CoV). There are about hundreds of these viruses which are mostly found circulating in the body of some specific animals such as bats, pigs, cats, and camels. In this article, you will get to know about all the signs and symptoms of Covid 19, Complications of Covid 19 and how does this affect the human body.

signs and symptoms of Covid 19

These viruses have obtained their name due to their characteristic appearance that resembles a crown, which in Latin is translated as “corona.” They have a typical shape with multiple spikes like projections on their surface, which resembles the points like projections on the crown.

Another typical feature is that these viruses have a single strand of RNA as their genetic material, unlike humans who have double-stranded DNA. Let’s talk about known types of Coronavirus then we will talk about the signs and symptoms of Covid 19.

What are the known types of coronaviruses?

The coronaviruses are broadly divided into 4 types, namely alpha, beta, gamma, and delta. Amongst hundreds of Coronaviruses, only 7 have been found to cause infection in humans. For decades, amongst these 7 viruses, four are known to cause only mild to moderate illness. These viruses are quite common and are known to cause “common cold”:

1. H-CoV 229E (alpha coronavirus)

2. H-CoV NL63 (alpha coronavirus)

3. H-CoV OC43 (beta coronavirus)

4. H-CoV HKU1 (beta coronavirus)

Rest of the 3 viruses that infect humans are only identified in the past 20 years. These are known to cause more severe infection with significantly higher complications and death rates & signs and symptoms of Covid 19 is also unpredictable. These viruses are as follows:

1. SARS coronavirus (SARS-CoV): that caused severe acute respiratory syndrome (SARS) outbreak, which began in November 2002 and ended in 2004 (the beta coronavirus).

2. MERS coronavirus (MERS-CoV): that caused Middle East respiratory syndrome (MERS), which began in September 2012 and is still known to cause sporadic and localized infection outbreaks.

3. SARS coronavirus 2 (SARS-CoV-2): is the virus responsible for the present outbreak, which is known to begin in December 2019 in the city of Wuhan in China.

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What is Covid-19 (Coronavirus)?

Covid-19 or the coronavirus disease 2019, is the infection caused by the SARS coronavirus 2, which was previously called as 2019 novel coronavirus (meaning new coronavirus 2019). The first case of Covid-19 is known to develop in the city of Wuhan in late 2019. Its origination has been linked to the wet seafood and poultry market of Wuhan. It has been believed to originate from the animal source likely bats, due to isolation of a similar coronavirus with genetic features that matches 88% to the virus causing the Covid-19. However, the theory has been challenged due to several gaps, and the exact source is still to be investigated by international bodies.

Since the report of the first case in China in late 2019, till 11th march 2020, when the WHO declared Covid-19 as a pandemic, it was found to cause infection in over 1 lakh people in the world. It was known to spread to 113 countries by then causing death in 4292 cases globally.

China had closed the Wuhan wet market from January 1st and extended the restrictions on their citizens to control the spread of the disease. However, due to uncontrolled travel out of china to different countries and from these countries to various parts of the world has eventually lead to the development of pandemic, which has now involved almost all countries in the world.

By the month of May, America, Britain, Spain, France have been the worst sufferers. However, they have shown either flattening of the curve or a significant decline in the number of reported cases. The disease is still quite active in many countries and has been showing a steady rise in the number of cases seen in India. The number of patients in the late may have risen to over 1 lack in India, with about 3500 deaths.

What are the signs and symptoms of Covid 19? complications of Covid-19?

The disease may cause no symptoms at all to severe symptoms and life-threatening complications.

Many people infected with the virus are thought to develop minimal to no signs and symptoms of Covid 19 at all and are thus considered to aid in the spread of infection amongst the community.

Incubation period: is the time between exposure from the virus to the development of symptoms. It is presently known to range from 1 to 14 days.

Common Signs and Symptoms of Covid 19 are as follows:

• Cough is mostly dry but can also be with sputum- one of the commonest signs and symptoms of Covid 19 (more than 80%).

• Fever (more than 80%) along with cough significantly increases the chances of Covid-19 infection. The fever is typically above 102 degrees Fahrenheit. People with extreme ages or low immunity may not develop a fever.

• Tiredness which can be typically extensive. Body ache.

Less common signs and symptoms of covid 19:

• Loss or change in sensation of the smell and/or taste. It has been increasingly seen to be associated with Covid-19 infection and is now considered as highly suggestive.

• Sore throat, sneezing, or runny nose.

• Difficulty in breathing. This is seen in people who develop moderate to severe cases complain of difficulty in breathing. This is thought to be an alarming sign and warrants immediate medical attention.

• Headache- less common

• Nausea, vomiting or diarrhea– uncommon

• Chest pain has also been seen in some cases.

• Blood in sputum- seen in rare cases.

• COVID toes and skin rashes- these are uncommon and can be seen with other viral infections. (However, it has been found to be more common with Covid-19 than others. COVID toes may present as reddish areas developing in the region of the toes and sole of a person. The exact cause is not known; however, it is thought that a skin reaction or the blockage of small blood vessels in the toes could be the reason behind it.)

Children tend to have the same signs and symptoms of Covid 19 as adults; however, they are believed to have a milder disease.

The disease may develop from mild to severe, over a period of a week or more, or may deteriorate suddenly, leading to life-threatening complications in a short time.

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How does the virus affect the human body?

After the signs and symptoms of Covid 19 you should also know how does the virus affect the human body. To understand how SARS- CoV-2 virus infects humans, we need to understand a few things about the virus. The virus is mainly made of two components:

Outer protein layer: the outer covering of the virus is made up of protein, which has spike-like projections that attach the virus to the surface of the human cells and allow it to enter.

Inner genetic material: inside the virus, there is a single-stranded RNA in the form of the genetic material which can produce new viruses. However, the genetic material of the virus is in itself incapable of replicating and thus needs a host such as a human cell to produce more virus cells.

signs and symptoms of covid 19

The behavior of the virus at the cellular level

The SARS- CoV-2 virus is believed to have an affinity for the ACE2 receptors present on the human cells. These are primarily present in the respiratory system, especially the lungs. They are also found in others of the body, such as the heart, liver, kidneys, etc. The virus is believed to get access to the human body by entering through nose, mouth, and eyes. It attaches itself to the mucous lining of the respiratory tract and enters the cells by interacting through ACE2 receptors. Once they are inside the human cells, they are known to hijack the protein-making machinery of the human cells. This allows them to use the human cells to produce millions and millions of copies of new viruses, which then spread to various parts of the body.

At the level of the lung

These viruses cause damage to an essential type of cells called ciliary cells. These cells have hair-like projections that beat rhythmically to move the mucus (protective fluid in the respiratory tract) out of the respiratory tract. By damaging these cells, the virus causes accumulation of the mucus within the lungs and thus restricts the absorption of oxygen from the air.

Along with this, the increase in the viral infection tends to stimulate the immune system, which causes infusion of the immune cells into the lungs to fight the infection. In moderate to severe cases of coronavirus, the infection tends to result in an exaggerated immune response, which often remains uncontrolled. It leads to damage to the normal cells of the lungs, which allows leaking of the fluid into the lung, further decreasing the capacity to absorb oxygen. As the damage increases, it eventually leads to respiratory failure, which needs to use for external support in the form of breathing machines or ventilators.

signs and symptoms of covid 19

At the level of other organs

In a significant number of severely ill patients, the disease leads to damage to the other organs of the body. These organs then eventually stop functioning properly, leading to life-threatening complications.

It is believed that the damage is the result of marked uncontrolled immune reaction and/or the viral infection itself.

• Heart and blood vessels: it has been found to cause low blood pressure, irregular rhythm of the heart, and some form of heart damage in some of the severely sick patients.

• Kidney damage: several studies have shown the disease to cause acute kidney damage. One study in Wuhan found acute kidney failure in 27% of the patients. Most of these patients were either elderly or had some underlying chronic diseases such as hypertension or heart failure.

• Liver damage: A few of the studies have reported some damage to the liver cells.

• Immune system: the function of the immune system is to protect the body against invading microbes, including viruses. However, sometimes the severe infection can trigger an intense immune response. This, in turn, leads to damage to the body cells, causing multi-organ failure. A specific kind of exaggerated immune response called cytokine storm is also seen where an excessive amount of cytokine is released. This can lead to widespread damage to the parts of the body, including the brain.

• It has also been found that the children are relatively better protected and suffer from less severe infection. This is believed to be due to less complicated immune response seen in children against the infection.

• Brain and nervous system: multiple studies have shown severe Covid-19 cases developing neurological problems. The disease is now known to cause acute cerebrovascular disease, encephalopathy, agitation, and mental confusion.

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How does it spread?

The human to human spread occurs mainly via respiratory droplets. There are lots of signs and symptoms of covid 19. It is believed that the tiny virus travels through the air, laden in the small respiratory droplets which are produced when a person coughs, sneezes, or talks. These respiratory droplets are very light and have the ability to float in the air and spread to nearby areas. Thus CDC has advised staying at least 6 feet or 2 meters away from another person.

Is coronavirus an airborne disease- know more?

There are many studies from different countries, which has shown that virus can spread from a healthy-looking infected person called as an asymptomatic carrier. The person might not develop any symptoms at all or eventually develop symptoms in several days. One study has shown the infected person tends to shed the virus at its peak about 1 or 2 days before developing symptoms.

Spread from a surface: the virus can also spread when a person touches any surface with the virus on it. The virus gets access to the respiratory tract when the person touches his face, mouth, nose, or eyes. This mode of spread exists but is not considered as a primary method of transmission of the virus.

Spread from infected feces: transmission of the virus by consuming any item which is contaminated by infected person stool has been contemplated but not completely established. Some of the studies have found the virus in the stool of an infected person, which supports this notion.


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What are the risk factors for developing Covid-19 infection?

After the signs and symptoms of covid 19, According to the WHO, anyone can develop the infection if exposed to the virus. Several external and internal risk factors determine the chances of contracting the infection and developing significant disease. These are given below:

External risk factors:

1. Recent travel history to area or locality with the ongoing community spread as determined by the government authorities.

2. Close contact with an infected person. Close contact is defined as staying within 2 meters or 6 feet distance from an infected person.

3. Occupational risk factors. Occupations such as doctors, nurses, and other medical staff have been particularly found to have a higher rate of infection due to the regular handling of infected patients or materials. Another group that has been affected is the police officials who may contract the infection due to coming in contact with the infected individuals.


Internal risk factors:

1.Age: WHO has said that all age groups can catch Covid-19. However, middle-aged or older, especially people aged 60 years and above, are more prone to develop the significant disease and its complications.
2.Sex: men have been found to be affected more than females
3.People with underlying diseases or medical conditions
• Long-standing lung disease (COPD, moderate to severe asthma and others)
• Serious heart issues (heart valve disease, NYHA 3-4, coronary artery disease or history of cardiac surgery)
• Severe renal insufficiency (needing hemodialysis)
• Severe hepatic disease (cirrhosis ≥Stage 4)
Diabetes mellitus (poorly controlled insulin-dependent diabetes or with complications)
• Morbid obesity (body mass index [BMI] >40)
• Cancer with metastasis
4. People who are immunocompromised
• Drug-induced (chronic use of steroid or other drugs that suppress immunity)
• Patients with organ transplantation who are under immunosuppression
• Blood cancer
• Cancer therapies such as chemotherapy etc.
• Poorly controlled HIV with CD4 < 200/mm
5. Pregnant females

Source: WHO and ISIDOG COVID-19 2020 guidelines

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What is the likely course of Covid-19, if you get infected with the virus?

Generally, about 23% of the infected patients need hospitalization. This can be an overestimate as the true number of infected patients can be much higher.

People requiring hospital admission usually need to stay for a longer duration (often more than 20 days). This is often due to the requirement of keeping them in isolation and the need for serial negative results on the PCR test before sending them home.

A significant number of people who are hospitalized develop complications. So, if you already know the signs and symptoms of covid 19 know about its complications also. Following are the complications:

1. Acute respiratory distress syndrome (ARDS)- commonest complication.

2. Septic shock- common complication.

3. Acute kidney injury

4. Injury to the heart (myocardial injury)

5. Multi-organ failure

6. Development of secondary infections (bacterial or fungal)

7. Blood clots

8. Guillain-Barré syndrome

9. Necrotizing encephalopathy (in the brain)

10. Kawasaki disease

About 2% to 3% of the diagnosed Covid-19 cases die due to the complications. The death rate varies amongst the countries and can be much less when asymptomatic cases are also considered.

Most of the deaths in Covid-19 occur due to ARDS and multi-organ failure. Most of the deaths are seen in the elderly and in people with multiple underlying health conditions.

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How can you prevent yourself from getting infected?

As of now, no vaccine is available that can protect you against this infection. To prevent yourself, you need to follow the standard infection control measures, which aim to minimize the chances of contracting an infection. If you already know about the signs and symptoms of covid 19 follow below points to prevent yourself from getting infected.

These are as follows:

Avoid close contact:

Follow social distancing by maintaining a distance of 2 meters or 6 feet. This is especially important for people who have a higher risk of developing a serious diseases. Avoid crowds and social gatherings, as many people carry the virus without developing any signs and symptoms of covid 19.


Cover the mouth and nose:

CDC has advised everyone who is going out in public, to cover their mouth and nose with a cloth face cover. The CDC has asked the general public not to use a face mask, which is meant for the doctors, nursing staff and other healthcare workers.

Cloth face cover is to be avoided in the following cases:

• Child below 2 years of age

• Person with trouble in breathing

• Unconscious person

• Person who can’t remove the mask


Hand hygiene and cleaning:

CDC has advised everyone to wash their hands frequently with soap and water. This has to be done, especially after coming from a public place, or after sneezing, coughing or blowing your nose. To effectively kill the virus, the handwashing should be done for at least 20 seconds.

In case if soap and water are not available, one should use a hand sanitizer containing at least 60% of alcohol. You can look for a hand sanitizer containing 70% to 80% isopropyl alcohol and ethyl alcohol.

Each time you wash hands or use sanitizer, you should cover all areas of writing and rub them against each other.

Know more about CDC recommendations for how to maintain hand hygiene.

Know the steps to follow in cleaning the hands.

Avoid touching your face, eyes, nose, and mouth: especially when you are in a public place or have been to such a place.


Cover sneezes and coughs:

CDC has advised covering your mouth and nose while coughing or sneezing. This helps to prevent the spread of the respiratory droplets, which may contain the virus if you are carrying it. CDC has advised you to use a tissue or inside of your elbow to cover your cough or sneeze. The tissue has to safely dispose of into a bin, and you need to clean your hands to soap and water or hand sanitizer.


Clean and disinfect surfaces:

CDC has advised to clean and disinfect the surfaces which are frequently touched. These surfaces are door handles, mobile phones, keyboards, light switches, tables, toilets, sinks, and tap handles.

This can be done by using household bleach, which contains 5.25% sodium hypochlorite. The bleach has to be mixed with water in dilution of 1:99 (1 part bleach to 99 parts of water) to clean the general household area.

In places where bleach can’t be used,e.g., metals, it is advised to use alcohol such as isopropyl 70% or ethyl alcohol 60% to clean the item.

Know more about how to clean different surfaces.


Practice food safety:

Properly heat and cook food. Avoid having semi-cooked or raw food and keep it away from the cooked food. Use separate chopping boards and knives for raw meat and cooked food. Wash hands in between handling of raw and cooked food. Sick animals or animals that have died due to a disease shouldn’t be consumed.


Monitor your health:

Be tentative about your health and any symptoms which may indicate a viral infection especially, fever, cough, shortness of breath, or loss of taste or smell sensation. Take temperature if you develop any symptoms. In case of any significant symptom or increased temperature, consult a doctor immediately, and follow his advice.

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