COVID-19 INTRODUCTION:
Corona virus disease 2019 abbreviated as (COVID-19) is basically a disease that is infectious in nature and has a causative agent called severe acute respiratory syndrome corona virus 2 or (SARS-Cov-2). Corona virus disease is the reason of the present corona virus pandemic (2019-20), this type of corona virus first came into view in December in the year 2019; it was first identified in Wuhan that is actually the capital of China’s province Hubei. If we want to be more specific the first confirmed corona virus case in Hubei province in November 2019. Till April 26, 2020 there are 2.56 million corona virus cases reported which affected 185 countries as well as territories and has a death rate that exceeds 177,000. Corona virus has a large recovery rate if identified on time; around 686,000 persons overcame the disease and are recovered from this disease. Corona virus has a survival time of about 72 hours.
First three days right after the appearing of corona virus symptoms are considered the most risky of being contagious but the spread of COVID-19 can be possible in any of disease stages even before the onset of symptoms.(“COVID-19 History,”.
MICROBIOLOGY:
Corona virus is morphologically pleomorphic or sphere likes (spherical) in nature and its RNA has a covering of glycoprotein which is club shaped. There are four subtypes of corona virus known as alpha, beta, and delta along with gamma. Every subtype has several serotypes. Some of these re affecting Human race while others affect our animals like cats, dogs, mice, birds and pigs as well
Figure: Morphology and constituents of corona virus.
Mode of Spreading:
It is a contagious as well as communicable disease .Airborne droplets from the affected person can also be the cause of Corona virus spread .Ciliated epithelium is the site of viral replication which causes cell damage along with infection in effected area. The Angiotensin converting enzyme 2 also called (ACE.2), it’s basically a membrane exopeptidase of corona virus receptor that it uses for human cell entry.(Kumar, Malviya, & Sharma, 2020
THE KEY FEATURES AND MECHANISM OF ENTRY OF HUMAN CORONAVIRUSES:
The virulence mechanism of SARS-CoV-2 is described stepwise in the figure from attachment to replication process every detail is present.(Shereen, Khan, Kazmi, Bashir, & Siddique, 2020
FIGURE: Mechanism of Action of SARS-COV-2 (Human corona virus)
THE GENOMIC VARIATIONS PRESETIN SARS-COV-2:
Corona virus origins: genome analysis suggests that two viruses may have combined: Scientists are trying their level best in understanding origin of COVID-19 and the virusSARS-CoV-2 that causes it. According to genomic comparisons SARS-Cov-2 virus is resultant of genetic recombination of two different viruses; it means that the exact origin of virus is not clear.
Genomic data:
The corona virusSARS-CoV-2 has RNA molecule containing 30,000 bases that have 15 genes, along with S gene encoding a protein located on the viral envelope surface. According to comparative genome analysis SARS-COV-2 is a member of Beta corona virus family and resembles very closely to SARS-COV-1 which was the cause of acute pneumonia endemic that occurred in 2002 (November) in Guangdong (China) and there occurred an outbreak in 29 countries around 2003The bats of genus Rhinolophus are considered the reservoirs of corona virus whereas the carnivorous plant the palm civet (Paguma larvata) acted as intermediate host between bats and the very first of human cases. From that time many Beta corona viruses are discovered, mostly in bats but some in humans as well. Example: RaTG13, that was isolated from bats (species Rhinolophus affinis) according to recent studies are quiet symbolic to SARS-CoV-2, having genome sequences that are 96% identical. Hence, the results show that bats of genus Rhinolophus specifically are reservoir for SARS-COV as well as SARS-CoV-2 viruses. Reservoirs are one or in some case several animals that are not particularly sensitive to virus because of strong immune system but are considered carriers for the virus.
The Recombination mechanism of SARS-COV-2:
On close inspection we learned that, a virus very similar to SARS-CoV-2 was discovered in pangolin on February 7, 2020. The 99% of the genomic similarity suggests that bats are more likely reservoir. The Malaysian pangolin (Manis javanica) has 90% of genomic similarity. Results show that COVID-19 present epidemic is not spread by Malaysian pangolin but bats. According to genomic comparison SARS-COV-2 virus is resultant of recombination of two viruses, one virus similar to RaTG13 and other similar to pangolin virus. The two pre-existing viruses basically make a chimera. The most important thing is to understand that the new virus is a recombined form of the two viruses and has the tendency to infect a novel host species (in this case Humans).For the successful recombination occurrence the simultaneous infecting of the same organism by two divergent viruses is a must.
Two questions arise:
Q1: Which organism was the one in which this recombination occurred? (a pangolin, a bat, a snake or some another species?)
Q2:Most importantly what were the conditions under which this recombination took place?.(“World Economic Forum,”
FIGURE: SARS-COV-2 Hosts and Reservoirs
IMMUNITY FOR CORONAVIRUS:
The word ‘immunity’ means the complete protection from an disease, It can be achieved by the presence of antibodies, or proteins produced by the body that can neutralize or can destroy toxins or other disease causing carriers. Immunity can be divided into two different categories: active immunity and passive immunity. Both types can play a role in future protection from COVID-19.
Figure: immunity of coronavirus
ACTIVE IMMUNITY:
The CDC (center for disease control) explains that active immunity “results when exposure to a disease organism activates the immune system to produce antibodies to that disease, and it can Be done by two ways: Through infection with the actual disease, which is we termed as natural immunity, or through a vaccination which is known as vaccine-induced immunity. Active immunity is often longer-lasting and may sometimes even provide life-long protection but it is entirely based on the disease itself one important thing that active immunity is not immediate. It can sometimes take several weeks to develop both natural immunity and vaccine-induced immunity. it provide protection against corona virus through infection by the virus or From a vaccine. And while vaccine-induced immunity is still a huge question mark and will continue to be for at least another year until more trials are completed researchers are currently looking at the immunity gained by those who have recovered from COVID-19.
PASSIVE IMMUNITY:
Passive immunity is that when a person is given antibodies. This can happen in utero or through antibody-containing blood products such as immune globulin, or a substance which is made from human blood plasma administered but passive immunity doesn’t last as Far as active immunity, and loses effectiveness within a few weeks or months. Of course, this passive immunity may also be helpful when it comes to COVID-19 primarily by the potential use of convalescent serum or blood plasma.
PLASMA ACTION:
It is collected from those who have previously recovered from COVID-19. But the use of convalescent plasma is not exactly new and it’s also been used as a treatment option in many other infectious diseases, including Ebola same research found that, for five critically-ill patients with COVID-19, convalescent plasma treatment resulted in “an improvement in clinical status” in all patients, concluding that convalescent plasma may be a helpful treatment for those with critical cases of COVID-19. Scientists say plasma won’t be a magic bullet. But our options for treating corona virus are so limited; the hope is it could help until a vaccine is found. It includes injecting The COVID-19 patients with blood plasma from people who have recovered from the illness. The U.S. Food and Drug Administration on March 24 allowed doctors to use plasma from recovered patients to treat those with “serious or immediately life-threatening COVID-19 infections” under an emergency approval system. each patient will receive one unit of plasma, which is about 200-250 cubic centimeters. But because the amount of antibody in donors may vary, researchers are currently seeking ways to produce a more concentrated and egg dose. The Department Of health has constituted a five-member committee to prepare the plasma extracted from the blood of the patients who recovered from corona virus recently which will be used to treat other patients suffering from the same disease.
Figure: plasma action
COVID-19 influences the various people in various ways. Most people who are infected can experience mild to moderate disease and recover without hospitalization.
Figure: common symptoms
The most common symptoms include:
- Fiver
- Dry cough
- Fatigue
Less common symptoms include: - Malaise and pain
- Bruise the throat
- Diarrhea
- Conjunctive disorder
- Checkers
- Loss of taste or odor
- A skin rash or finger or toe discoloration
Grave symptoms: - Breathing pain, or shortness of breath
- Pain in the throat, or pressure
- Loss of speech and/ or motion
Figure: COVID-19 symptoms
If you have severe symptoms seek urgent medical attention. Contact your doctor or health care provider always before you visit.
- Individuals who are otherwise healthy with mild symptoms should treat their symptoms at home.
- It takes an average of 5–6 days for someone to show symptoms to be infected with the virus, but it can take up to 14 days
- Symptoms of COVID -19:
Here are some common symptoms of corona virus which is show after the attaching of corona virus.
Day 1:
At the first day most common symptoms are shown like temperature above the 100 Fahrenheit. Dry cough are most common and muscle aches and pain we always feel tired and uncomfortable .Throat will be sore with blocked nose, rainy nose and about 138 patients suffering with diarrhea and nausea day by day prior to development of fever.
Development of these symptoms is not compulsory for example if you have illness then it is similar to common illness such as common cold and flu. In some people all symptoms are not shown expert says this.
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