The Spectrum of Disease and The Iceberg Phenomenon

The spectrum of disease refers to the range of manifestations and severities of illness associated with a given diseases, illnesses, or injury. For example, HIV infection has broad clinical spectrum, from inapparent* to severe and fulminating**. 

The iceberg phenomenon describe a situation in which a large percentage of a problem is subclinical, unreported, or otherwise hidden from view. Thus, only the "tip of the iceberg" is apparent to the epidemiologist. (Examples of the iceberg phenomenon are given in the text.) Uncovering disease that might otherwise be below "sea-level" by screening and early detection often allows for better disease control. Consider:

* There is a cohort of HIIV+ prostitutes in Nairobi, Kenya that tend to remain symptom-free.
** That is, death.