American History Hotline

Episode: Was Disease the Biggest Killer in the Civil War?
Host: Bob Crawford
Guest: Dr. Catherine Olivarius, Associate Professor of History, Stanford University
Release Date: July 30, 2025

Episode Overview

This episode investigates one of the most persistent beliefs about the American Civil War: that disease claimed more lives than battle. Host Bob Crawford brings on Civil War and disease historian Dr. Catherine Olivarius (Stanford University) to answer a listener’s question and explore why disease was so deadly during the war, what conditions soldiers faced, how different armies coped, the rise of sexually transmitted infections, and the era’s limited medical understanding.

Key Discussion Points and Insights

Disease vs. Battle: The Reality of Civil War Deaths

• Main Fact: About two-thirds of Civil War deaths were due to disease, not combat.

  • “Yes. Actually, in the Civil War, approximately 2/3 of all the Civil War dead died from disease, not from bullets, not from battlefield injuries. So that's about 2/3 of approximately 750,000 people who died during the war.”
    — Dr. Olivarius [04:29]

• Numbers are approximate; wartime recordkeeping was poor, but both Union and Confederate soldiers were at risk.

Conditions and Contagion in the Armies

• Crowded, Unsanitary Camps:

  • Soldiers of all ages and from all regions came together, creating what historians call a "biotic soup" where diseases could easily mix and spread.
    “A lot of historians actually talk about the Civil War as a kind of biotic soup... you're just like, stirring this pot constantly with people moving around the country, bringing with them diseases, immunities, things like this, pathogens with them to the front.”
    — Dr. Olivarius [06:29]

• Food and Hygiene:

  • Young, inexperienced soldiers prepared their own food, often with poor hygiene.
  • “This is like a germ bonanza... If there was a water source close by, like a stream, you would wash in it. You would drink from it. You would probably defecate into it, too.”
    — Dr. Olivarius [07:28]

• Germ Theory’s Beginnings:

  • Germ theory was new and poorly understood by soldiers and many doctors.
  • As the war went on, recruitment standards for health slipped out of necessity, increasing exposure to contagion.

• Notable Quote:
  "Walt Whitman said something like 99.99% of war is diarrhea and 1% is glory... That's true of all wars before the modern era, but it's certainly true of the Civil War."
  — Dr. Olivarius [09:29]

Main Diseases Affecting Soldiers

• Typhus and Typhoid:

  • Leading killers, primarily via contaminated water, resulting in severe dehydration and diarrhea.

• Malaria:

  • Particularly bad for Northern soldiers unexposed to the disease before being sent south.

• Other Diseases:

  • Measles, dysentery, smallpox, diphtheria, and pneumonia also took many lives.
  • Wounds often turned fatal due to secondary infections (gangrene, sepsis) in unsanitary field hospitals.

Racial Disparities and Army Differences

• Union vs. Confederate Armies:

  • Union soldiers generally had slightly better chances due to superior logistics and medical services.
  • Confederates suffered significantly higher proportional death tolls due to chronic supply shortages and less effective ambulance/hospital systems.

• Black Soldiers:

  • Even in the better-supplied Union Army, Black soldiers faced higher disease and mortality rates, often because of worse medical care and more dangerous, unsanitary assignments.
    "Black soldiers in the union army had a much higher chance of dying from disease than did white soldiers generally, because they received worse medical care and because they were often given much deadlier assignments and sort of dirtier assignments, too."
    — Dr. Olivarius [05:42]

The Explosive Spread of Sexually Transmitted Diseases

• Syphilis, Gonorrhea, and the “Super-Spreader” War:

  • Pre-war: about 10% of adult men had gonorrhea or syphilis (urban estimate; likely inflated).
  • Post-war (1900): 18-20% of adult American men had active syphilis.
    "You can think about this war as a kind of super spreader event for syphilis where you have a lot of young boys... They sleep with prostitutes. And this becomes again, this kind of just recurring and snowballing problem..."
    — Dr. Olivarius [12:12]

• Long-Term Effects:

  • Tertiary syphilis led to disfigurement (e.g., loss of nose/cartilage), paralysis, blindness, dementia, and "infection of innocence" (wives and children).
  • With the postwar marriage boom, untreated STIs spread rapidly to civilian populations.

• Notable Quote:
  “You might lose your nose.”
  — Dr. Olivarius [15:02]

• Treatment:

  • Mercury and calomel were prescribed, both toxic and ineffective.
  • “This many, many people in fact thought that, you know, they would rather take their chances with the disease rather than the alleged cure...”
    — Dr. Olivarius [17:58]

The State of Medicine During the Civil War

• No Antibiotics/No Real Sterilization:

  • Florence Nightingale’s ideas from the Crimean War began to influence nursing, but most soldiers and doctors still had little understanding of infection and sanitation was poor.

• Hospitals as Disease Factories:

  • Many soldiers avoided them, considering hospitals a place to die.

• Notable Scene:
  “Every single field hospital had what was called a pile outside of the back door. Basically, this is a pile of limbs that had been amputated by the surgeons...”
  — Dr. Olivarius [26:13]

• Surgical Procedures:

  • Reused equipment (e.g., saws for amputations); no gloves; surgeons worked down the line, increasing cross-infection.
  • “You have a surgeon... using the same exact saw on every single person... not using gloves, and they're just literally, you know, they're going down the line.”
    — Dr. Olivarius [27:16]

Civil War Death Toll in Historical Context

• The Deadliest U.S. War:

  • Civil War deaths (about 750,000) outstrip all other U.S. wars.
  • High proportion of Southern men killed or made casualties.
  • Disease deaths fell in later wars as sanitary practices and medical knowledge increased.

• Weaponry Worsened Outcomes:

  • Minié balls (bullets) shattered bones, increasing risk of fatal infection.

• Memorable Line:
  “Really before the 20th century, this is a kind of fact of life in war, which is that disease is going to really be what gets you for the most part.”
  — Dr. Olivarius [29:46]

Selected Notable Quotes and Timestamps

• "Approximately 2/3 of all the Civil War dead died from disease, not from bullets... about 2/3 of approximately 750,000 people who died during the war."
  — Dr. Olivarius [04:29]

• "Historians actually talk about the Civil War as a kind of biotic soup... just stirring this pot constantly with people moving around the country, bringing with them diseases, immunities..."
  — Dr. Olivarius [06:29]

• "Black soldiers in the Union army had a much higher chance of dying from disease than did white soldiers generally..."
  — Dr. Olivarius [05:42]

• "Walt Whitman said something like 99.99% of war is diarrhea and 1% is glory... That's certainly true of the Civil War."
  — Dr. Olivarius [09:29]

• "You might lose your nose."
  — Dr. Olivarius [15:02]

• "Every single field hospital had what was called a pile outside of the back door. Basically, this is a pile of limbs that had been amputated by the surgeons, by doctors."
  — Dr. Olivarius [26:13]

Additional Memorable Moments

• Dr. Olivarius’s dry humor:

  • When discussing which Civil War sites she’d visit:
    "I wouldn't necessarily want to be at Gettysburg myself. So. Yeah." — [04:04]

  • On the quality of treatments:
    “This many, many people in fact thought that... they'd rather take their chances with the disease rather than the alleged cure...” — [17:58]

• The powerful image of young soldiers returning home, unknowingly spreading syphilis to families in the postwar marriage boom.

Structure of the Episode (Timestamps)

• [04:13] Listener question: Were most Civil War deaths caused by disease?
• [04:29] Dr. Olivarius describes the death toll and main causes.
• [05:12] Comparing Union and Confederate armies, racial disparities.
• [06:19] The camp experience, crowd diseases, and hygiene realities.
• [09:41] The main killers: Typhus, typhoid, malaria, wound infections.
• [11:40] STDs: Spread, cultural impact, and failed treatments.
• [16:27] Mercury and calomel: Toxic 'cures' for syphilis.
• [18:47] Prevention: Abstinence, unreliable condoms, asymptomatic spread.
• [23:38] Hospitals, medicine, and the consequences of ignorance about infection.
• [27:55] How disease deaths in the Civil War compare to other American wars.

Conclusion

This episode powerfully illustrates that the deadliest element of the Civil War wasn’t enemy fire, but the omnipresent, invisible threat of disease. Poor sanitation, overtaxed medical services, rapidly moving armies, and misinformation about contagion created a perfect storm for illness—shaping not only the course of the war, but the generations that followed.

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