The short answer
About 50,000 on Brazil’s side, most of them from diseases such as cholera, according to the historian Francisco Doratioto. For Paraguay, historians disagree: estimates run from 7% to 18.5% of the population (Vera Reber) to about half (Jan Kleinpenning) and 60% to 69% (Thomas Whigham and Barbara Potthast). On any count, a catastrophe.
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Brazil’s dead
The figure most often cited for Brazil comes from Francisco Doratioto, author of Maldita guerra (“Damned War”), a history of the conflict published in 2002: about 50,000 dead. Most of them did not fall in battle. They died of disease, cholera above all, in crowded camps in the marshes of southern Paraguay. Argentina and Uruguay, Brazil’s allies, lost thousands more.
To put that in proportion: Brazil’s whole army at the start of the war was about 18,000 men. The dead alone came to nearly three times that. The Empire filled the ranks with volunteers, forced recruits and at least 6,000 enslaved men freed to fight. The war that was supposed to last a few months lasted more than five years, and every year added to the count.
Paraguay’s dead: three estimates
For Paraguay the question is harder, and historians disagree sharply. Measured as a share of the population before the war:
- Vera Blinn Reber (1988): 7% to 18.5%.
- Jan Kleinpenning (2002): about half.
- Thomas Whigham and Barbara Potthast (1999): 60% to 69%.
Even the lowest estimate is a disaster for a small country. The highest approaches seven in ten. That is why the conflict is remembered as the bloodiest war in South American history.
Why the numbers differ so much
Part of the gap lies in the starting point: historians do not agree on how many people lived in Paraguay in 1864. Part lies in the dead themselves. Soldiers, civilians, refugees and the victims of hunger and epidemics were rarely counted apart. Whigham and Potthast built their estimate on a census taken just after the war; three years later Kleinpenning challenged their reading, and the debate went on.
Round single numbers that circulate without a source skip this argument. The honest answer is a range, with the name of the historian who calculated it.
Boys at Acosta Ñu
By the end, Paraguay was fighting with old men and boys. As early as Tuiuti, on May 24, 1866, thousands of Paraguayans died in a few hours. At Acosta Ñu, on August 16, 1869, children faced the Brazilian cavalry. Paraguay now keeps that date as its Children’s Day. On March 1, 1870, Francisco Solano López was killed at Cerro Corá, and the war was over.
How it began, and why it could only end with López’s death, is in What was the Paraguayan War?. What the victory did to Brazil’s army, and to the throne, is in Why did the monarchy fall in Brazil?
Sources
- Francisco Doratioto, Maldita guerra: nova história da Guerra do Paraguai (2002)
- Vera Blinn Reber, Hispanic American Historical Review (1988)
- Thomas L. Whigham and Barbara Potthast, Latin American Research Review (1999)
- Jan M. G. Kleinpenning, Latin American Research Review (2002)