Based upon the work of Petersdorf and Beeson, Durack and Street classified fever of unknown<unk> (FUO) into four distinct categories in 1991:
Fever of unknown origin classification
Fever of unknown origin epidemiology and demographics
Fever of unknown origin pathophysiology
Relapsing fever laboratory findings
Relapsing fever differential diagnosis
Paratyphoid fever laboratory findings
Scarlet fever differential diagnosis
Fever of unknown origin risk factors