What is a characteristic of latent viruses?

Latent viruses are characterized by their ability to remain in a dormant or inactive state within the host organism for extended periods. During this time, they do not produce new viral particles and do not cause any symptoms. This dormant state can be disrupted, leading to reactivation of the virus, which may then replicate and potentially cause disease symptoms. The slow-growing nature of latent viruses is significant because it allows them to evade the host's immune response for a time, leading to a complex interplay between the virus and the immune system.

In contrast, the other options do not represent latent viruses accurately. Immediate replication and high virulence describe acute infections, where the virus rapidly takes over host cells and generates ample viral particles, often resulting in noticeable symptoms soon after exposure. Similarly, the inability to evade the host immune system pertains to viruses that are consistently active within the host and are unable to hide from immune detection. Lastly, causing active infection within hours of exposure pertains to viruses that establish an infection rapidly, which is opposite the behavior of latent viruses. All these factors highlight the unique nature of latent viruses, making the correct answer an accurate representation of their characteristics.