Table 2.

Leading Clinical Identifiers of Recognized Pandemic Diseases.

Disease	Salient Clinical Features
Smallpox	Typical widespread vesiculo-pustular rash, occasionally corneal opacification
Measles	Morbilliform rash, Koplik’s spots, conjunctivitis, rhinorrhea
Plague	Buboes (huge lymphadenopathy), pneumonia
Cholera	Sudden-onset profuse watery diarrhea, early hypovolemic shock
Yellow fever	Jaundice
Influenza H1N1	Flu-like illness*, severe disease and death in young adults
Influenza H3N2	Flu-like illness*
Influenza H2N2	Flu-like illness*
AIDS	Opportunistic infections, Kaposi’s sarcoma of skin and viscera, profound emaciation
SARS	Severe pneumonia
Ebola	Bleeding from multiple sites
MERS	Severe pneumonia
COVID-19	Severe pneumonia, silent anoxia, anosmia, ageusia, toe lesions mimicking chilblains, pediatric multisystem inflammatory syndrome

^*Fever, myalgia, respiratory symptoms, extreme weakness.

AIDS, acquired immune deficiency syndrome; COVID-19, coronavirus disease 2019; Flu, influenza; H1N1, hemagglutinin-1 neuraminidase-1; H2N2, hemagglutinin-2 neuraminidase-2; H3N2, hemagglutinin-3 neuraminidase-2; MERS, Middle East respiratory syndrome; SARS, severe acute respiratory syndrome.