Pathogenic Properties of Virus

• Viruses have mechanisms to evade host defenses viruses grow inside host cells to hide from immune defense.

• Kill immune cells e.g. HIV – TH Cells.

• Cytopathic effects: - The visible effects of viral infection on host cell. Some effects will kill the cell and some will just change the cells.

• Viruses stop DNA, RNA and/or protein synthesis e.g. Herpes virus block mitosis.

• LySOSomal autolysis of host cells e.g. Influenza: bronchiolar epithelium.

• Production of inclusion bodies (visible viral parts inside the cell) can identify a particular virus e.g. Rabies virus: Negri bodies.

•  Syncytium formation (neighboring cells fuse together) e.g. Varicella Zoster virus.

• Change in cell function e.g. Measles, production of interferons by host cell (triggers host immune response), induce antigenic changes on host cell surface (triggers destruction of infected cell by host immune response).

• Induce chromosomal changes, cell transformation: may activate or deliver oncogenes resulting in loss of contact inhibition (cancer) e.g. Papilloma virus.