Question

What is the structure and origin of SARS-CoV-2 virus? What are its symptoms? Compare diseases caused by SARS-CoV-1, SARS-CoV-2, and MERS-CoV. Why do you think an effective vaccine can be available only in 1 -1.5-2 years? What treatment for COVID-19 do you know?

Answer 1

Severe Acute Respiratory Syndrome (SARS)-CoronaVirus (CoV) is a new pandemic that has affected almost all countries in the world.

• It belongs to the Coronaviridae family of Nidovirales order.
• As its name suggests, corona means a crown; it has crown-like spikes on the outer surface.
• Its size ranges between 65-125 nm in diameter.
• It is an RNA virus, a single-stranded RNA of size between 26-32 kb. A nucleocapsid protein coat covers the genome.
• The virus has a lipid bilayer membrane with enveloping glycoproteins and spike proteins.

Origin:

• All the coronaviruses have a zoonotic origin.
• The SARC Cov is believed to have come from palm civets, Rhinolophus bats, raccoon dogs, camel - mostly as carriers.
• The Cov 2 (COVID 2019) is believed to have come from the bat.

Symptoms:

• The incubation period can range from 1 - 14 days, with most people showing no or mild symptoms. Common symptoms include fever, tiredness, dry cough, nasal congestion, runny nose, sore throat, diarrhea.

SARC cov 1 disease -

• Responsible for the SARC breakout in China 2002.
• Infectivity of 9%.
• The incubation period of 4 days.
• Main symptoms fever, cough, shortness of breath.

MERS-CoV -

• Saudi Arabia, 2012.
• Transmitted through respiratory droplets and close contact.
• Incubation period five days,
• Main symptoms shortness of breath, chills, fever, generalized myalgia, nausea, vomiting, and diarrhea. Fatality rate 35%.

SARC cov 2 - 2019

• China - on going.
• Symptoms fever and cough(most common)—long incubation periods.
• The fatality rate can vary between 1.4% - 4.7%.
• Typically progress to viral pneumonia and required mechanical ventilation.

Effective vaccine development takes five stages of human trials and release. The target molecules are complicated to find out, given the high rate of mutation in the virus genome. A Large number of possible candidates are tested in the lab, then to animal and later to human subjects. Even after the vaccine is developed, it needs to be free from other viral bodies, should not cause unintended effects of large masses of different ethnicity, culture, and physiology. Government clearances and patents can also take time. The large scale production of vaccines and distribution to the public is also a time-consuming process.

Most cases of COVID does not need medication, as it can be mild or with no symptoms. Serious cases need ventilators for breathing and symptomatic treatments. There are reports of other bacterial drugs being effective against COVID 19, but CDC has not cleared them for general use.