However, latency is also an outcome of infection with environmental organisms such as Cryptococcus neoformans, which require no host in their replicative cycles. Latency is an integral part of the pathogenic strategies of microbes that require human (and/or mammalian) hosts, including herpesviruses, retroviruses, Mycobacterium tuberculosis, and Toxoplasma gondii. Hence, latency is a temporally unstable state with an eventual outcome that mainly depends on host immunity.
In addition, it can predispose the host to other diseases, such as malignancies. Latency is clinically important because some latent microbes can be transmitted to other hosts, and it is associated with a risk for recrudescent microbial growth and development of disease.
The host avoids progressive damage caused by interaction with the microbe that may translate into disease, and the microbe secures a stable niche in which to survive. Latency has advantages for both host and microbe. The mechanisms contributing to latency are diverse and depend on the nature of both the microbe and the host. The state of latency occurs when a microbe’s persistence in a host produces host damage without perturbing homeostasis sufficiently to cause clinical symptoms or disease.
