yes

A disease producing organism is a pathogen. An invasion of the body by a pathogen is an infection. Although an infection is a generalized name for the body's response to any invasion by any pathogen.

Lymphadenitis may be either generalized, involving a number of lymph nodes; or limited to a few nodes in the area of a localized infection.

one that enters the bloodstream and causes general systemic symptoms such as fever, chills, low blood pressure, or mental confusion.

a fever is triggered by your immune system when an infection is detected. You can have many many types of infections without an immune response, because it may not be detected by the body yet, just effected