The first question that crosses our mind is if we are at risk of contracting a viral infection in our lifetime. There are several viral diseases that can be easily transmitted among humans that we are exposed to almost every day of the year. Viral diseases are a concern to humans because of the symptoms after contracting a viral pathogen in the first place. Let’s talk about the dangers of contracting COVID-19 or more commonly known as coronavirus.
To read the most up-to-date information about COVID-19 click the link below:
What is a coronavirus?
According to the WHO (World Health Organization) coronaviruses belong to a wide family of viral strains that may cause illnesses of a broad spectrum including the common cold or even more severe respiratory diseases like the Middle East Respiratory Syndrome (MERS-CoV) and Severe Acute Respiratory Syndrome (SARS-CoV). Furthermore, new strains of the virus emerged continuously around the globe.
Coronaviruses are from a zoonotic origin, which means that they evolved and begun transmission from animals to humans. For example, investigations regarding SARS-CoV virus discovered this virus was transmitted from civet cats into humans and that MERS-CoV was transmitted from camels to humans. DNA makes us unique and generates a beautiful genetic makeup diversity; however, humans and mammals share more than 92% genetic information that can be easily affected when disease and pathogens enter the human genome (2).
Common Symptoms and Signs of Infection
One of the main characteristics of coronavirus infection is the flu-like and respiratory symptoms. These symptoms include: fever, cough, shortness of breath, respiratory or breathing difficulties. Coronavirus may lead to pulmonary infection and induce severe acute respiratory syndrome, or even kidney failure; which affects other organs either in acute of long term. All these symptoms and consequences of being infected with the novel coronavirus can be fatal and if untreated will eventually lead to death. To better understand the risks of contracting coronavirus we need to discuss the physiological effects in represents in the body.
Photo Credit: CDC: https://www.cdc.gov/coronavirus/2019-ncov/communication/index.html The Pathogenesis
Transmission of viruses is by airborne droplets through the nasal mucosa. Virus achieves replication locally within the cells of ciliated epithelium, which eventually leads to cellular damage and inflammation. The current coronavirus disease is known for causing pneumonia primarily, coronaviruses impair the respiratory tract immune system by generating damage in the tract mucosa, which at the same time tends to favor the development of bacterial pneumonia when left untreated. Viral pneumonia is highly associated with some other chronic diseases, such as chronic obstructive pulmonary disease and heart failure primarily.
Cross-species Transmission
The outbreak of viral pneumonia that developed in 2020 in the city of Wuhan, China is mainly designated a novel coronavirus 2019-nCoV by WHO (World Health Organization). This is attributed to the sequence in viral RNA and the genome associated with it. Many of the initial patients were exposed to the many wildlife animals at the seafood wholesale market, this market is known to sell farm animals, including bats and snakes among others. In order to comprehend where the virus may have developed a series of comprehensive sequence analysis were conducted. It appears that the coronavirus virus is a recombinant virus that evolved from the bat coronavirus previously known and another different unknown coronavirus through homologous recombination. It also appears the recombination enabled the new virus to develop a spike glycoprotein, which helps the virus adhere to cell surface receptors and facilitate transmission of the RNA into the cell more easily. It is highly important to understand cross-species transmission as this may have contribute to the development of 2019-nCoV.
Viral Pneumonia
Pneumonia that is caused by a viral pathogen rapidly progresses into gas exchange abnormalities at the alveolar level and is mostly accompanied by an inflammation cascade of the lung parenchyma. Diagnosis of respiratory abnormalities can be detected with imaging such as X-ray or CT Scan. Immune state of the host is critical in the progression of the disease. The elderly and individuals with a weakened immune system are more prone to develop pathophysiological symptoms and currently project the highest mortality rates.
COVID-19 Variants: Up to 2022.
Since the discovery of the novel SARS-CoV-2 several variants have been discovered and continue to be. There are four major variants of great concern up to 2022 and they were classified depending on their mutations, alpha, beta, gamma, and delta. A virus is prone to mutation and variants across the globe have been evolving ever since 2019. Mutations have an incidence relative to geographical area and therefore, become a circulating variant. Mutations are highly significant because they alter the way the protein structure produces immunologic responses in the body of a person with or without COVID-19. The B.1.1.7 variant was identified in 2020 and now has been reported more than 64 countries around the globe. This mutation produces an increased binding affinity to the cell surface receptors responsible for interacting with the ACE2 receptors; which only translates to a more rapid infection and transmission of the virus. In comparison, the B.1.351 variant has been associated with a higher incidence of severity of disease. Overall, mutations impact the efficacy of vaccine development. Another variant of significant concern is the B.1.1.28.1 variant discovered in Japan that was identified in patients from Brazil in 2021.
Treatment and Current Clinical Trials
As of February 25th, 2020, clinical trials in Nebraska started recruiting hospitalized patients adult recently diagnosed with CoVID-19. The initial trial participant is a traveler who was repatriated after being placed on a quarantine period on the Diamond Princess cruise ships that is known to have docked in Yokohama in Japan. Since there are still no therapeutic agents specific to treat coronavirus (CoVID-19) approved to this date by the Food and Drug Administration (FDA) clinical trials have begun to better understand how to deter this disease. All participants of the clinical trial will have a physical exam before receiving the potential therapy. The study is double-blind meaning there will be two groups of people in the study, one will get the therapeutic agent and the other one will receive placebo.
End of the Pandemic Vaccine Development
Ever since the coronavirus emerged, scientists across the globe have worked tirelessly to provide the world with a vaccine that will bring the ongoing pandemic to an end. Successfully, two experimental vaccines have been developed. Among the successful vaccines, Pfizer in collaboration with BioNTech and Moderna, developed vaccines that will begin to be administered in December 2020 in an effort to deter the pandemic that has affected the world. The development of these vaccines involves several booster shots to increase its efficacy.
Some other vaccines have also been developed for lower-income countries where resources are scarce and new measurements in public health need to be implemented. In addition, emerging new single-dose vaccines are designed to assist a greater number of individuals have access to a SARS-CoV-2 vaccine. Heard immunity is the main goal to achieve in order to overcome the pandemic. This means, the greater the people vaccinated against the virus the more protection for the overall population.
For more up-to-date information regarding COVID-19 please visit: https://www.cdc.gov/coronavirus/2019-ncov/index.html
References:
1. “Coronavirus.” World Health Organization, World Health Organization, http://www.who.int/health-topics/coronavirus.
2. “Genetic Similarities of Mice and Men.” 23andMe Blog, 19 Nov. 2019, blog.23andme.com/23andme-and-you/genetics-101/genetic-similarities-of-mice-and-men/.
3. Mlcochova P, Kemp SA, Dhar MS, Papa G, Meng B, Ferreira IATM, Datir R, Collier DA, Albecka A, Singh S, Pandey R, Brown J, Zhou J, Goonawardane N, Mishra S, Whittaker C, Mellan T, Marwal R, Datta M, Sengupta S, Ponnusamy K, Radhakrishnan VS, Abdullahi A, Charles O, Chattopadhyay P, Devi P, Caputo D, Peacock T, Wattal C, Goel N, Satwik A, Vaishya R, Agarwal M; Indian SARS-CoV-2 Genomics Consortium (INSACOG); Genotype to Phenotype Japan (G2P-Japan) Consortium; CITIID-NIHR BioResource COVID-19 Collaboration, Mavousian A, Lee JH, Bassi J, Silacci-Fegni C, Saliba C, Pinto D, Irie T, Yoshida I, Hamilton WL, Sato K, Bhatt S, Flaxman S, James LC, Corti D, Piccoli L, Barclay WS, Rakshit P, Agrawal A, Gupta RK. SARS-CoV-2 B.1.617.2 Delta variant replication and immune evasion. Nature. 2021 Nov;599(7883):114-119. doi: 10.1038/s41586-021-03944-y. Epub 2021 Sep 6. PMID: 34488225; PMCID: PMC8566220.
4. Gómez CE, Perdiguero B, Esteban M. Emerging SARS-CoV-2 Variants and Impact in Global Vaccination Programs against SARS-CoV-2/COVID-19. Vaccines (Basel). 2021;9(3):243. Published 2021 Mar 11. doi:10.3390/vaccines9030243
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6. Ji, Wei, et al. “Cross-Species Transmission of the Newly Identified Coronavirus 2019-NCoV.” Journal of Medical Virology, U.S. National Library of Medicine, Apr. 2020, http://www.ncbi.nlm.nih.gov/pubmed/31967321.7. Tyrrell, David A.J. “Coronaviruses.” Medical Microbiology. 4th Edition., U.S. National Library of Medicine, 1 Jan. 1996, http://www.ncbi.nlm.nih.gov/books/NBK7782/.
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Esther Juárez 