Corona family of viruses

Corona family of viruses

Coronaviruses are a large family of viruses that cause flu-like symptoms in people. These groups of viruses affect both birds and mammals. In humans, these viruses will cause respiratory tract infections, which can be as mild as sinuses from a common cold, and some can be lethal like MERS, SARS, and Covid-19. The symptoms vary from one species to the next. For instance, in chickens, they cause upper respiratory tract diseases, while in pigs and cows, they cause diarrhea. Coronaviruses constitute of the subfamily Orthocoronavirinae within the coronaviridae family. These viruses are enveloped with a positive-sense single-stranded RNA genome and the nucleocapsid of helical symmetry. Their name corona is a name derived from the Latin corona meaning crown referring to the characteristic appearance reminiscent of a crown or solar around the virus particles when viewed under the two-dimensional transmission electron microscopy since the surface is covered in club-shaped protein spikes. The current covid19 has stopped economies and affected the entire world because it has intense respiratory symptoms, and there is no vaccine or cure for it.

The history of coronaviruses

The first cases of coronaviruses were discovered in the 1960s. The earliest discoveries caused infectious bronchitis viruses in chicken, and two human patients suffering from the common cold, later named human coronavirus 229E and human coronavirus OC43. Other strains that cause serious respiratory tract infections, including HCoV NL63 in 2004, SAR-CoV in 2003, MERS-CoV in 2012, and SARS CoV-2 in 2019.

Human coronavirus 229E (HCov-229E)

This is a common coronavirus species that infect bats and humans. This is an enveloped positive-sense, single-stranded RNA virus that enters the host cell through binding to the APN receptors. Together with the Human Coronavirus OC43, it is one of the viruses that are responsible for the common cold. It is associated with a wide range of respiratory symptoms from the common cold to high-morbidity outcomes like bronchiolitis and pneumonia. The high morbidity cases are seen in coinfection with other respiratory pathogens, with only one reported exception. While 229E infections are not exclusively associated with mild or asymptomatic diseases, there has been one reported case that led to acute respiratory distress syndrome in an otherwise healthy patient without other co-infectious pathogens. This virus, like the other coronaviruses, is detected in different parts of the world at different times.

Human coronavirus OC43

The HCoV-OC43 is a member of the species Betacoronavirus that infects both cattle and human beings. It enters the host cell by binding to the N-acetyl-9-0-acetylneuraminic acid receptor. Together with the human coronavirus 229E is one of the viruses responsible for the common cold. Like other coronaviruses within the genus Betacoronavirus, subgenus Embecovirus, it has a short spike-like surface protein known as the hemagglutinin esterase. This virus can cause severe lower respiratory tract infections like pneumonia in facts, people with compromised immunity, and the elderly. It is responsible for up to 15% of all common cold cases.

Severe acute respiratory syndrome coronavirus (SAR-(SAR-CoV)

This is a strain of the coronavirus that causes severe acute respiratory syndrome (SAR). It attacks the epithelial cells in the lungs. It enters the body by binding itself to the ACE2 receptor and affects palm civets, humans, and bats. On April 16th, 2003, there was a SARS outbreak in Asia and other secondary causes in the world. From December 2019, the pandemic due to Covid-19 has shown numerous similarities to the SARS outbreak, and the viral agent was identified as another strain of the SARS-related coronavirus. The initial symptoms include headaches, muscle pain, and fever, followed by the onset of other respiratory symptoms in 2-14days. The symptoms include pneumonia, cough, and dyspnea. Another common issue with patients attacked by this virus also has a decreased number of lymphocytes circulation in their blood. In the 2003 SARS outbreak, there were more than 8000 infections worldwide, and 10% of people died from the infections. The infection jumped from bats to humans through civet cats that had been bred for human consumption in China. It took nine months from the recognition of the outbreak, identification of the agents, containment, and resolution. As with Covid-19, the mortality rate was much higher with patients over 60 years old, with mortality for this patient subset being over 50%. In late May 2003, the wild animals sold at the local markets were tested and were found to have SARS strains that could be isolated from masked palm civets, although the animals did not show signs of illness. Later, the virus was found in raccoon dogs, domestic cats, and ferret badgers. This confirmed the theories that coronavirus was able to jump across species.

Human coronavirus NL63

The HCoV-NL63 is a species of coronavirus that was identified in a seven-month-old infant with bronchitis in 2004. The virus enters the host through the ACE2 receptors. It has symptoms common to the mild to moderate upper respiratory infections, severe lower respiratory tract infection croup, and bronchiolitis. This virus primarily affects young children and the elderly. It is also more common during certain temperate climates. It is estimated to cause approximately 4.7% of the common respiratory illnesses. Its divergence is about 1000 years, and it is not a new virus. It has, therefore, circulated human beings for centuries. It is mainly transmitted through direct contact with infected persons and is commonly passed in highly populated areas. It can survive up to one week outside the body in aqueous solutions and about three hours on dry surfaces. Consequently, most people will be affected by various strains of the coronavirus throughout their lives, although certain populations are susceptible to HCoV-NL63.

Human coronavirus HKU1

HCoV-HKU1 is a species of the coronavirus which originates from infected mice. This species of the virus enters the host cell through binding to the N-acetyl-9-0-acetylneuramic acid receptor. It is distinguished from the Betacoronavirus genus because it has the Hemagglutinin esterase. The first cases were discovered in 2005 in Hong Kong. The first case was of a 71 year of man hospitalized for acute respiratory distress and radiographically confirmed bilateral pneumonia.

The Middle East respiratory syndrome-related coronavirus

The EMC/2012 or MERS-CoV is a species of the coronavirus that affects camels, bats, and humans. In enters the host cell by binding to the DPP4 receptor. Initially, it was called the 2012 novel coronavirus that was first reported in 2012 from the sputum samples of people who fell ill in 2012. By July 2015, it has already been reported in 21 countries. It is among the viruses that have been categorized by WHO as a possible future pandemic. By 2017, there had been over 2000 reported cases, with about 600 deaths leading the mortality rate to 30%. The 182 genomes had been sequenced from 94 humans, and 88 donkeys by 2015.the human and camel strains are intermixed, and this suggests that there were numerous transmission events. Evidence suggests that the virus had been in bats for sometimes and infected camels in the 1990s.

Covid 19

Previously known as the severe acute respiratory syndrome coronavirus 2 (2019-nCoV). It is responsible for the on-going pandemic. It is close in genetics to the bat coronavirus, and it is likely to have originated from bats with the intermediate reservoir being pangolins and thus its introduction to humans. It is classified as a strain of the severe acute respiratory syndrome-related coronavirus because of its taxonomy. Human-to-human transmission of the SARS-CoV-2 has been confirmed in the 2019-2020 coronavirus pandemic. The transmission is primarily through respiratory droplets from sneezing and coughing in a range of about 2 meters. Persons may also be infected through contact with contaminated surfaces. Preliminary studies indicate that the virus remains viable in plastics and steel for up to 3 days, although it does not survive on cardboard and copper for more than a few hours. It is also inactivated by soap. Its incubation period is uncertain, but the World Health Organization suggests that the transmission from asymptomatic cases is not a major driver of transmission.

Conclusion

The current infections of Covid-19 have limited the quality of life and longevity throughout the world. For instance, today, keeping safe means staying at least one meter away from everyone, including family and friends, which has led to feelings of isolation. There is also the issue of the lack of fresh foods. Most local market places are on lockdown, and therefore, people no longer have places to buy vegetables and fruits. They, therefore, rely on canned foods, dried fruits, and cereals. People have been panic-shopping, leaving almost nothing on the shelves. This has meant that families could sleep hungry even if they have money. Businesses are locked down, meaning that some employers will not have money to offer paid leave to their employees, and therefore, many people will be jobless and without money to basic utilities.