The current clinical case definition of<unk>  used by the United States' Centers for Disease Control and Prevention is based on both laboratory and clinical criteria. Laboratory criteria * Isolation of C.<unk> e from a Gram stain or throat culture from a clinical specimen, * Histopathologic diagnosis of<unk>  by Albert's stain Toxin demonstration * In vivo tests (guinea pig inoculation): Subcutaneous and intracutaneous tests * In vitro test: Elek's gel precipitation test, detection of tox gene by PCR, ELISA, ICA Clinical criteria * Upper respiratory tract illness with sore throat * Low-grade fever (above is rare) * An adherent, dense, grey pseudomembrane covering the posterior aspect of the pharynx: in severe cases, it can extend to cover the entire tracheobronchial tree. Case classification * Probable: a clinically compatible case that is not laboratory-confirmed and is not epidemiologically linked to a laboratory-confirmed case * Confirmed: a clinically compatible case that is either laboratory-confirmed or epidemiologically linked to a laboratory-confirmed case Empirical treatment should generally be started in a patient in whom suspicion of<unk>  is high.
Diphtheria
Spanish flu
Swine influenza
Plague 
Anthrax
Periodic fever syndrome
Murine typhus
Influenza