To take viruses as an example, Chen Hao-yung explains that whether a virus is pathogenic (diseasecausing) for humans depends firstly on whether it can enter cells, and secondly on whether it can continue to reproduce and multiply inside them. The final crucial factor is whether it can coexist with cells. If a conflict arises between them, disease results.
以病毒為例，陳豪勇指出，病毒是否對人有「病原性」，首先要看它們是否能與細胞結合，其次是病毒進入細胞後是否能繼續複製增殖；最後的關鍵是能否與細胞共存，它們之間如果失去平衡，感染就產生了。