Friday, January 2, 2009 3:33 PM
SARS-CoV (Severe Acute Respiratory Syndrome-coronavirus)Do you know that?
-it is a group IV virus (+)ssRNA
-falls under the family of Coronaviridae
-it is air borne transmit
-it is an emerging virus
Introduction:
In Singapore, the virus was introduced through 3 ladies that went to Hong Kong for tourism purpose. Under the same hotel, there is a professor from China is infected with SARS-CoV. The virus was spread through when the 3 ladies shared the same lift with him. Initially, there was no symptom. Till when came back to Singapore, there was not much symptom but fever and cough. After went to clinic. The symptoms still persist. They were admitted to the hospital and diagnosis that they were suffered from SARS-CoV.
History of virus:
The origin of SARS is still uncertain as not much research is done.
Unique feature:
-it is (+) RNA virus in Group IV. It is very infectious like rhino virus
-it is a envelop virus
-it is very sensitive to heat
-it is unstable at ≥30̊C
Where does the virus infect?
-respiratory tract
Do you know the symptom?
All symptoms will appear after 2-10 days of infection.
Initial symptom
-fever (≥38̊C)
-myalgia
-lethargy
-cough
-sore throat
Late symptom
-shortness of breath
Lab diagnosis:
-PCR
-immunofluorescence
-ELISA
Treatment:
- Vaccination (Prednisone)
But negative effect is the immune response will decrease
-since the virus is unstable with heat ≥30̊C, therefore, for now the virus will hardly infect any human.
How it replicate?
1. Attachment: the virus antigen is attaching the receptor of the host cell. In order to gain entry to the host cell (endocytosis)
2. Entry: the virus enter the cell (but till now still not clear that whether the virus fuse with the host cell membrane)
3. Uncoating: the virus uncoat it’s envelop allow gene expression to take place
4. Replication: The immediate genes produce RNA polymerase and start to duplicate its genome (early gene) the RNA of the virus produce (-) RNA and use it as a template to produce more (+) RNA. The late gene of the RNA will produce the protein that is needed to infect other cell but at a later time.
5. Assembly: the duplicated RNA will assemble with the protein that is produced to form virus
6. Release: once the virus is ready and it is release through exocytosis