SARS and MERS - Where all started
Coronaviruses have been here for a long time amongst the most prevalent causes of the common cold, second only to rhinoviruses. They are named for their specific virion look with the Spike (S) glycoprotein covering the virion's surface. They are part of the Orthocoronavirinae subfamily which encompasses four different genera: SARS-CoV2 belongs to one of them - betacoronaviruses. Little attention was paid to them until the severe acute respiratory syndrome (SARS) outbreak in November 2002 in Guangdong Province (China) and the Middle East Respiratory Syndrome (MERS) in 2012 in Saudi Arabi. SARS infected over 8,000 people and killed almost 800 by late July 2003, according to the WHO. MERS has infected ~2,500 people and killed ~900 since the outbreak in September 2012. Both SARS and MERS are characterized by atypical pneumonia with high fever, chills, dizziness, headache, myalgia, cough, and breathing difficulties; the mortality rate for SARS is 10% and for MERS the number climbs up to 50%. Both diseases are zoonoses, which means they are transferred from animals: Asian raccoon dogs for SARS-CoV and bats and camels for MERS-CoV. People were scared, the world was shaken at its very foundations, but the worst was hidden in the shadows...
SARS-CoV and MERS-CoV in numbers
Start November 2002 September 2012
End July 2003 N/A
Infected 8,098 2,442
Dead 774 842
Start site China Saudi Arabia
Mortality 15% 34.4%
Vaccine None None
Every coronavirus is an enveloped virion with the longest positive-sense ribonucleic acid (+RNA) functioning as its genome. The positive-sense RNA gives all coronaviruses the advantage of directly transcribing their genome part into proteins inside the host's cells and replicating the genome. The genome of SARS-CoV2 is 29,891 nucleotides long that encodes non-structural and structural proteins. The non-structural proteins serve multiple biochemical roles, including cutting the mRNA (messenger RNA, the nucleic acid chains that become translated into proteins inside the ribosomes) into smaller pieces and replication enzymes. There are four main structural proteins encoded by SARS-CoV2:
I. Prevailing symptoms:
There is no direct number on how many people can be the asymptomatic carriers
Social distancing and self-quarantine as well as the isolation of infected patients are necessary to flatten the curve of the spread of COVID-19, which is to slow the rate of new infections by taking protective measures. The basic measures you can take and yet save other people's lives are the Five Things.
Symptoms appear 2 to 14 days since the contact with a sick patient.
People are most contagious when they are most symptomatic.
Some people can spread the virus before showing any symptoms, although this has not been proven empirically yet.
CDC.gov: 'The virus that causes COVID-19 seems to be spreading easily and sustainably in the community ("community spread) in some affected geographic areas.'
In some groups of patients (data not known yet), re-infection has occurred.
IMPORTANT: The onset and duration of viral shedding and period of infectiousness are not yet known.
Remember that COVID-19 IS NOT A FLU!
The flu is a viral disease caused by Influenza viruses of the Orthomyxoviridae family, whereas coronaviruses make up their own family, Coronaviridae. The only thing that coronaviruses and flu viruses have in common is that they use RNA as their genomic material. The flu can manifest with similar prodromal symptoms, such as fever, coughing, malaise, sore throat. Pneumonia can be one of the complications of the flu, but never as deadly and as dangerous as the acute respiratory syndrome caused by SARS-CoV2.
Dr. Tedros Adhanom Ghebreyesus, Director-General of the World Health Organization (WHO) spoke on March 16 during the World Economic Forum and when calling for urgent action to ramp up efforts against COVID-19, he said 'We have a simple message for all countries: test, test, test.'