A high level of C-reactive protein (CRP) in the blood indicates inflammation in the body, which can be caused by various factors, including infections. Here are some infections that can cause high CRP levels:

• Severe bacterial infections, such as sepsis
• Fungal infections
• Upper respiratory tract infections caused by influenza virus and adenovirus
• Inflammatory bowel disease (IBD)
• Osteomyelitis (infection of the bone)

It is important to note that a high CRP level does not necessarily mean that there is a medical condition that needs treatment, especially if the levels are only slightly elevated. Several factors, such as smoking, recent injury, and certain health conditions, can raise CRP levels.