Coronavirus disease (COVID-19) is an infectious disease, caused by a newly discovered virus strain Severe acute respiratory syndrome coronavirus 2 ( SARS-CoV-2 ) .

People infected with this virus experience respiratory illness and in most cases recover without any special medical treatment. The disease could become serious for people of old age or people with existing medical problems like Cardiovascular disease, diabetes, asthma, Cancer.

Symptoms

Symptoms of corona virus

Lungs are the most affected by COVID – 19. The enzyme angiotensin-converting enzyme 2 ( ACE2 ) of the lungs is used by the virus SARS-CoV-2 to accesses the host cells. “ Spike “ a special surface glycoprotein is used by the virus to connect to ACE2 to enter the host cell. Severity of the disease in each tissue correlates with the density of ACE2 in each tissue.

Testing

The standard method of testing recommended by the World Health Organization ( WHO ) is a test done on respiratory samples obtained by collecting nasal secretions from the back of the nose and throat. Results of this test are available within a few hours. A strain of the Corona virus is isolated to publish the genetic sequence. Polymerase chain reaction ( PCR ) tests to detect infection by the virus are developed independently by the laboratories Methods for detecting infections involve identifying those who came in contact with infected people having fever, features of pneumonia, reduced white blood cell or lymphocyte count. Individuals with a high suspicion of infection chest CT scan is helpful to diagnose COVID – 19, for routine screening CT scan is not recommended.

Polymerase chain reaction ( PCR ) tests

PCR tests used in the diagnosis of infectious disease allows copying small amount of DNA many times over so as to have required quantity for detection & confirmation of infection

Covid Test-step 1

SARS-CoV-2 contains single-stranded RNA and not double stranded DNA. The RNA of the virus is extracted & then purified

Covid Test-step 2

Primers ( short DNA sections which are designed to bind with only virus DNA )

Nucleotides are building blocks that make up the DNA.
A DNA-building enzyme: this makes copies of the DNA.
A PCR machine heats the mixture which causes the double-stranded DNA to separate the primer as mentioned binds to the virus DNA as it cools. Several repeated heating & cooling continues until copies of DNA are created in millions.

Covid Test-step 3

Fluorescent dyes are added which bind to the copied DNA making them give light. There is a threshold set & if the fluorescence light crosses this the test is positive.

A big limitation of PCR test is it can only confirm the presence of the virus at the time of testing, it cannot tell if a person had the virus and recovered.

An individual who is highly contagious & capable of spreading the disease to a large number of uninfected people is a super spreader.

Antibody Tests

Antibody tests as the name suggests look for antibodies in a patient’s blood. Also known as Serological tests it detects people who have recovered from COVID-19 & those who had the virus but never showed symptoms.

The immune system develops antibodies that attach to the virus & eliminates it, in response to an infection. “IgM” produced initially by the body’s immune reaction are general antibodies that attack many infections. IgM antibodies take time to develop by the body’s immune system or may not even develop in some patients. Hence non detection of IgM antibody in a test does not rule out SARS-CoV-2 in a person. “IgG” is the antibody developed by the immune system that is specific to the virus. The time to develop IgG antibody varies in individuals but on an average takes 4 weeks. Most antibody tests detect IgG.

There is no vaccine to treat COVID – 19 yet, hence only supportive care is provided which includes fluid therapy, support of vital organs & oxygen support. Paracetamol is also recommended for first line use.

Virus attacks if not managed till a cure found, has had disastrous consequences in the past. Decreasing the infection rate, so as not to burden the health service, permitting proper treatment of existing cases and delaying additional cases is of utmost importance.
The treatment to fight this virus starts by educating the society on how to stop the spread
A person identified as the first to be infected is called Patient zero
Identifying people who come in contact with infectious people to control the spread is Contact tracing.

An individual who is highly contagious & capable of spreading the disease to a large number of uninfected people is a super spreader

Steps to be followed to prevent infection of COVID – 19

Avoid unnecessary travel and crowding, practice physical distancing
The virus is killed outside the human body by household soap. Wash hands regularly with soap & water. Hand can also be cleaned by alcohol based sanitizer. The protective bubble of the virus is burst in both this case.

Avoid touching the face, cover mouth & nose when sneezing or coughing.
Avoid smoking as it weakens the lungs

COVID – 19 was declared a pandemic by The World Health Organization ( WHO )
The outbreak of a disease that effects large proportion of population over a wide geographic area is termed a Pandemic. The virus spreads worldwide because there is no pre-existing immunity. Pandemics begin with an investigation phase.

Phases of a Pandemic

The Centers Disease for Disease Control and Prevention (CDC) currently has Pandemic Intervals Framework (PIF) in place for tracking the phases of an influenza pandemic. That framework is being applied to COVID-19.

Phase 1: Investigation Interval : A new type of virus that could have implications on human health found in animals or humans is identified & investigated

Phase 2: Recognition Interval : Increased number of cases are identified with high potential for person to person transmission.

Phase 3: Initiation Interval : Person to Person transmission of infection both efficient & sustained\

Phase 4: Acceleration Interval : Measures are taken to close down places where group formation is possible like schools, public meetings, prayer gatherings, Marriage functions, Birth & death ceremonies etc. Social distancing is encouraged ( Medication )

Phase 5: Deceleration Interval : There is a decrease in the case of infection related case.

Phase 6: Preparation Interval : Health officials monitor the virus and prepare for another wave of illness even after the pandemic subsides
Even after the pandemic has subsided, public health officials continue to monitor the virus and brace for another wave of illness.
The pandemic could be in different phases over different geographical region at any point of time. Example: It could be in Phase 2 in some parts of US & phase 4 in certain other parts

The World Health Organization (WHO) when on March 11, 2020 declared COVID – 19 a pandemic there were 118,000 cases and 4,291 people had lost their lives. As on April 19, 2020 the number of cases is 2,358,683 and 161,921 people have lost their lives

What is COVID-19?

COVID-19 is the official name given by WHO on February 11,2020, to the new disease caused by a novel or new Coronavirus. There were different types of human coronaviruses some which caused upper respiratory tract illness already known to the medical world. Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) causes COVID-19.
In COVID-19, CO stands for corona, VI for virus and D for disease; 2019 was it’s outbreak in Wuhan, China.

How does Corona virus / COVID-19 spread?

COVID-19 spreads mainly through respiratory droplets from person to person. When an infected person coughs or sneezes droplets could infect a normal person close by (within 6 feet). A surface or an object that has this virus could also infect a person with COVID-19.

How can I protect myself from COVID-19?

There is no vaccine yet to treat COVID-19 & hence prevention in getting exposed to the virus is the best option.
Keeping one’s hands clean by frequently washing with soap & water and also avoid touching eyes, nose & mouth
Avoiding close contact with people
Cover nose & mouth with a tissue when coughing or sneezing
Clean frequently touched surfaces like tables, doorknobs, handles, phones etc.

References

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