Are there any known viruses that affect iOS devices?

Yes, while iOS devices are generally considered secure, there have been instances of malware targeting them, though they are rare compared to other operating systems. Some known threats include adware and spyware that can infiltrate through malicious apps, often requiring users to jailbreak their devices. Apple's strict app review process in the App Store helps minimize these risks, but users should still be cautious about app permissions and sources.