COVID-19, A Zoonotic Disease: Its Transmission, Impact and Control
As the world is grappling with novel SARS-CoV2, it is time for us to understand more about the virus so that we may fear less and spread awareness to combat the virus. COVID-19, which started in the late December of 2019 in China was declared a pandemic by WHO on March 11, 2020. The term “Coronavirus” refers to a large group of viruses belonging to a family called Coronaviride (26-32 kb), comprising enveloped, (+) ssRNA viruses.
To begin with, the poster depicts how the virus originated and transmitted to become a global pandemic. It sheds light on the structure and life cycle of COVID-19 inside the host cell. The transmission rate of any infectious diseases highly depends on reservoir hosts. Molecular and phylogenetic analysis suggest bats to be the primary host and civets to be the intermediate host before spilling into humans. The coronavirus genome encodes four major structural proteins: the spike (S), nucleocapsid, membrane, and envelope protein. The S protein is responsible for facilitating the entry of the coronavirus into the target cell.
Secondly, the poster focuses on the significance of the One Health approach in combating the pandemic situation. For a layman, one health is an approach that states that people’s health is closely connected to the health of animals and our shared environment. Therefore, it is essential that the professionals from these sectors collaborate, coordinate, and communicate to prevent outbreaks of diseases, and protect people’s health. Furthermore, it also highlights the implementation of Herd Immunity, i.e., indirect protection of vulnerable people from infection when a sufficiently large population is immune to it. However, it isn’t yet clear if infection with the COVID-19 virus makes a person resistant to future infection. Research suggests that antibodies the immune system makes to fight the COVID-19 may only last a few months in people with mild illness.
Therefore, achieving herd immunity may be challenging due to its expeditious loss in protecting immunity. Moreover, there is no vaccine for SARS-CoV 2, which is the safest way to practice and achieve herd immunity in the population. Talking about vaccines, researchers around the world are working on developing vaccines. As of August 28 2020, New York Times update, 36 vaccines are in clinical trials on humans, and at least 89 preclinical vaccines are under active investigation in animals. At least eight types of vaccines are being tried against the coronavirus, and they rely on different viruses or viral parts; for instance, using the virus itself (inactivated or weakened), viral vector (replicating or non-replicating),
nucleic acid (DNA or RNA) and protein-based (protein subunit or virus-like particle). Indian vaccine-maker Zydus Cadila has created a DNA-based vaccine. On July 3, they announced approval to start human trials, becoming the second company in India to enter the Covid-19 vaccine race after Bharat Biotech. A vaccine in development by the AstraZeneca and the University of Oxford is based on a chimpanzee adenovirus called ChAdOx1 is in Phase 2/3 trials in England and India, as well as Phase 3 trials in Brazil, South Africa, and the USA. Pune’s Serum Institute of India is already one of the frontrunners to mass-produce the Oxford-AstraZeneca vaccine
Regarding the treatment for COVID-19, The FDA has not licensed any treatment. However, it has granted emergency use authorization to some treatments like the antiviral remdesivir and convalescent plasma from the patients who have recovered from COVID-19 etc. Their effectiveness against Covid-19 has yet to be demonstrated in large-scale, randomized clinical trials. Finally, the poster lists common symptoms of COVID-19 and ways to “flatten the curve” like social distancing, etc., in the hope of not overwhelming the NHS. The symptoms include cough, shortness of breath, temperature ≥ 38°C, chills, fatigue, body aches, loss of smell or taste, abdominal pain, diarrhoea, and vomiting etc. Symptoms may take up to 14 days to appear after exposure to COVID-19. There are still many questions unanswered, and research has never been more critical in these uncertain times.