What type of microorganisms can commonly survive despite an animal's immune response?

Parasites are a type of microorganism that can commonly survive despite an animal's immune response. This resilience is often due to their complex life cycles, which allow them to adapt and evade the host's immune mechanisms.

For instance, some parasites have developed strategies to alter the host's immune response, effectively dampening the host's ability to eliminate them. They may change their surface proteins to avoid detection or reside within cells where they are less accessible to the immune system. Additionally, parasites can reproduce quickly and in many cases, can exist in the host without causing immediate illness, leading to chronic infections that challenge the immune system over time.

In contrast, while bacteria, viruses, and fungi can also evade immune responses to some degree, parasites stand out due to their multifaceted survival tactics and often complex interactions with the host. Their ability to live and reproduce within various environments, including within the host, gives them a unique advantage in surviving immune attacks.