Why are new retroviruses in humans difficult to detect?

New retroviruses in humans are difficult to detect primarily because they can integrate into the host genome and remain dormant for long periods, evading the immune system. Their genetic material can also mutate rapidly, making it challenging for traditional detection methods to identify them consistently. Additionally, many retroviral infections may present with nonspecific symptoms, further complicating diagnosis and recognition. This combined ability to remain latent and evolve quickly contributes to the challenges in detecting new retroviruses.