Coronaviruses are a group of related RNA viruses that cause diseases in mammals and birds
In humans these viruses cause respiratory tract infections
Mild – common cold
Lethal – SARS – Severe Acute Respiratory Syndrome
MERS- Middle East Respiratory Syndrome
COVID-19 – Coronavirus Disease 2019
COVID-19 First identified in December 2019 in Wuhan.
Coronaviuses were first discovered in 1930s
Human coronaviruses discovered in 1960s
MRCA- Most Recent Common Ancestor of all coronaviruses existed 8000 BCE, some as 55 million years or more, showing long term co-evolution with bat and avian species.
α coronavirus -2400 BCE
β coronavirus – 3300 BCE
Ƴ coronavirus – 2800 BCE
Ə coronavirus – 3000 BCE
Natural reservoir for coronavirus gene pool are
β,α- coronaviruses in Bats
Ƴ,Ə – coronaviruses in Birds
Human coronaviruses like 229E ~ Ghana Grp1 Bt Cov 1686 and 800 CE
SARS related COV co-evoluted in Bats for a long time
Ancestors of SARS-COV first infected genus Hipposideridac (Leaf nose Bats) then spread to Rhinolophidae (Horse shoe Bats) then to Para docxurus ( Asian palm civet) and finally to humans.
In 2003, HCOV,SARS-COV has unique pathogenesis of both upper and lower respiratory tract infections.
Mild symptoms producing COV
- HCOV-OC43- Human coronavirus OC43 β-COV
- HCOV-HKU1- Human coronavirus HKU1 β-COV
- HCOV-229E- Human coronavirus 229E α-COV
- HCOV-NL63- Human coronavirus NL63 α-COV
Severe symptoms producing COV
- Middle east respiratory syndrome related coronavirus-MERS-COV, β-COV
- Severe acute respiratory syndrome coronavirus- SARS-COV, β-COV
- Severe acute respiratory syndrome coronavirus 2- SARS-COV-2, β-COV
So SARS-COV-2 β-COV has started infecting humans and has of now more than 11,924,855 cases and 545,332 deaths has occurred world wide.
