What type of infections do viruses primarily cause?

Viruses are capable of causing systemic infections, which affect the entire body rather than a specific localized area. Systemic infections involve the spread of the virus through the bloodstream or lymphatic system, leading to widespread symptoms and complications that can impact multiple organ systems. For instance, diseases like influenza and HIV represent systemic viral infections, where the virus affects not only the respiratory or immune systems but can also lead to broader health issues throughout the body.

Localized infections, on the other hand, are typically caused by bacteria or other pathogens that remain confined to a specific area, like a wound or an abscess. While viruses can cause respiratory infections, they often do so in the context of a systemic response. Skin infections, typically associated with viruses like herpes or warts, are also localized rather than systemic in nature. Thus, while other answer choices may indicate specific types of infections, they do not encapsulate the broader impact that viruses can have on the body's overall health and function.