Viruses may induce apoptosis if they infect a host cell. In the case of a harmful virus, would this effect be good or bad for a human host, and why?
This would be good for the human host.
When a virus infects a cell, the cell usually releases signals that stimulate natural killer cells and cytotoxic T-cells to release digestive enzymes and proteins such as perforin and granzymes. Perforin forms holes in the cell, allowing granzymes to enter. Granzymes cause a protein cascade that eventually leads to the death of the cell.
When an infected cell dies, the virus can no longer replicate and reproduce. Thus, the virus cannot infect other cells.