Final answer:
A stealth virus is explicitly designed to hide itself from detection by anti-virus software.
Step-by-step explanation:
These viruses use various techniques to avoid detection, such as encryption, polymorphism, and rootkit capabilities.
One strategy is to modify its code to make it difficult for anti-virus programs to recognize its signature. Another method is to conceal its presence by interfering with the functioning of the anti-virus software or by using techniques to evade its detection mechanisms.
Overall, stealth viruses are a significant challenge for anti-virus software developers and require regular updates and improvements to keep pace with evolving stealth techniques.