a) Pathology of Influenza Infection

After the influenza virus has been inhaled into the human body, it will attack the epithelial cells in the lining of the bronchial tree and the nasopharynx.

The steps in which the influenza virus penetrates the respiratory system are as follow:

? The glycoprotein, hemagglutinin (HA), on the outer surface of the influenza virus binds to the layer of sialic acid coat of the target cell.

? After contact with the target cell has been established, the target cell will be triggered to engulf the influenza virus.

? The RNA of the influenza virus which is found in the inner surface of the influenza virus enters the nucleus of the target cell and the nucleus starts the replication of the RNA protein.

The glycoprotein, neuraminidase (NA), on the outer surface of the influenza virus breaks off the layer of sialic acid coat of the target cell to allow new viruses to be released from the cell and the new viruses will be spreaded across the mucous lining of the respiratory tract. After the replication of the RNA protein, cell lysis will occur after several hours.