19th Century US Epidemics: Yellow Fever, Cholera, Smallpox & Tuberculosis

The late 1800s saw devastating infectious disease epidemics that shaped American public health, urban development, and scientific understanding.

Yellow Fever

• Cause: Flavivirus; transmitted by Aedes aegypti mosquito (proven 1900 Reed Commission).
• Epidemics: 1793 Philadelphia (5,000 deaths, 10% population), 1878 Mississippi Valley (20,000 deaths), recurrent in Gulf/Atlantic ports.
• Symptoms: Fever, jaundice (liver necrosis), black vomit (GI hemorrhage), renal failure. Case fatality 20-50%.
• Impact: Quarantine laws, port sanitation, catalyzed mosquito control.

Cholera

• Cause: Vibrio cholerae O1/O139; water/food contaminated with feces.
• Pandemics in US: 1832, 1849, 1866, 1873 — entered via immigrant ships to NYC, New Orleans; spread via canals, rivers, rail.
• Symptoms: "Rice-water" diarrhea, vomiting → profound dehydration, electrolyte collapse, death in hours.
• Impact: Sanitary reform (sewers, clean water), John Snow's epidemiology, germ theory acceptance.

Smallpox

• Cause: Variola virus (orthopoxvirus); respiratory droplet, fomite spread.
• Epidemiology: Endemic with epidemics; 1860s-70s Civil War outbreaks; 1898-1904 last major waves.
• Symptoms: Prodrome (fever, malaise) → centrifugal rash (macules→papules→vesicles→pustules→scars). CFR 30% (variola major).
• Impact: Vaccination mandates (Jacobson v. Massachusetts 1905), eradication 1980 (global).

Tuberculosis (Consumption)

• Cause: Mycobacterium tuberculosis; airborne droplet nuclei.
• Burden: Leading cause of death 1800-1900; 1900: 194/100,000. Urban tenements, immigration, crowding.
• Symptoms: Chronic cough, hemoptysis, night sweats, weight loss, fever.
• Impact: Sanatorium movement, public health nursing, BCG vaccine (1921), streptomycin (1944), modern DOTS.

Other Notable Late-1800s Epidemics

• Typhoid fever: Salmonella Typhi; water/food; "Typhoid Mary" (1907).
• Diphtheria: Corynebacterium diphtheriae toxin; childhood scourge; antitoxin 1890s.
• Scarlet fever: Strep pyogenes erythrogenic toxin; rash, strawberry tongue.
• Influenza: 1889-90 "Russian flu" (likely H3N8 or coronavirus); 1M+ deaths globally.

Legacy for Modern Public Health

• Vital statistics registration, disease reporting.
• Municipal water/sewer systems.
• Quarantine authority, police powers.
• Pasteur Institute model → labs, vaccines.
• Germ theory replacing miasma theory.
• Social determinants recognized: housing, poverty, immigration.

These epidemics killed hundreds of thousands but catalyzed the infrastructure and science that underpin modern disease control.