Abnormality of immune system physiology Unusual infection 2018-11-04T22:23:03Z There are five general subtypes. (i) Opportunistic infection, meaning infection by a pathogen that is not normally able to cause infection in a healthy host (e.g., pneumonia by Pneumocystis jirovecii or CMV); (ii) Unusual location (focus) of an infection (e.g., an aspergillus brain abscess); (iii) a protracted course or lack of adequate response to treatment (e.g., chronic rhinosinusitis); (iv) Unusual severity or intensity of an infection; and (v) unusual recurrence of infections. Increased susceptibility to infection, as manifested by recurrent infection, severe or invasive infection, infection occurring in an unusual anatomical location, or infection with opportunistic organisms, that is unusual for a healthy individual of the same age.