Why do some pathogens have both lytic and lysogenic life cycles?

Some pathogens possess both lytic and lysogenic life cycles as a strategy to enhance their survival under host immune responses. The lytic cycle allows for the rapid production of new viral particles and immediate infection of adjacent cells, which can overwhelm the host’s immune defenses. In contrast, the lysogenic cycle involves integrating the pathogen's genetic material into the host's genome, allowing it to persist in a dormant state. This integration means that the pathogen can remain undetected by the host immune system and survive during periods when the host is undergoing stress or their immune response is active against the lytic form.

When the environmental conditions change or the host's immune response wanes, the lysogenic pathogen can switch back to the lytic cycle, reactivating viral replication and leading to new infections. This dual-cycle capability allows the pathogen to adapt to various circumstances, ensuring its longevity and continued transmission opportunities, particularly when faced with immune challenges.