COVID-19 AKA WUHAN virus is caused by SARS COV 2, which was declared pandemic on FEBRUARARY 11, 2020 by WHO.
Family – Coronaviridae
Genus – Beta Coronavrus (SARS COV 2)
Suborder – Coronavirinae
Order – Nidovirales
Realm – Ribavirin- Group of viruses having RNA dependent RNA Polymerase (RDRP)
It is a type of Zoonotic virus, which means it is likely to originate from animals most probably from bats.
It is spherical shape and enveloped by club shaped spike. It’s diameter is 100-150nm. it’s outermost membrane is covered by club shaped spike projections (coded by S Gene).
It’s genome is composed of non- segmented, positive sense single strnded RNA. The size of genome is large about 30 kbs.
It’s genome contains genes for
Patient can be considered non infectious after 2 weeks of symptoms onset
Virus enters upper respiratory tract(URI) and binds to specific receptor present in lungs and that receptor is ACE 2 receptor(Angiotensin converting enzyme). Initially in asymptomatic phase (1-2 days) virus binds to ACE 2 receptors present in human airway with the help of receptor binding domain of spike protein. This leads to confirmational change and fusion of virus and host cell membrane. Following this Type 2 Transmembrane Serine protease(TMPR SS2) present on surface of host cell clears these ACE 2 receptors and further activate the spike glycoprotein of SARS COV2. This leads to confirmation changes in the host cell, due to which the virus enters into the host cell. Then, the uncoating of the viral particle occurs by releasing of Nucleic acid in cytoplasm and Further replication and Translation in nuclei. Upon completion of machinery, the virus gets assembled in cytoplasm and released by Exocytosis. These new viral particles further attack new cells
80% of infected person develop mild disease. 20% of infected person develop moderate to severe disease. These 20% may need oxygen therapy or ventilation support.