Black troops as naturally resistant to tropical disease
01
What institutions accepted
U.S. military authorities treated Black soldiers as naturally more resistant to yellow fever and other tropical disease, influencing recruitment and assignments for service in Cuba during the Spanish-American War.
02
What the evidence supports now
Yellow fever is a viral disease transmitted by infected mosquitoes; the World Health Organization states that one vaccine dose provides lifelong protection. Malaria is caused by Plasmodium parasites transmitted by Anopheles mosquitoes. Long exposure can produce partial immunity to malaria, but WHO states that it never provides complete protection. Neither disease confers blanket protection through racial ancestry. An official Army history reports that half of 471 men of the 24th Infantry at Siboney contracted malaria or yellow fever; it does not separate the cases by disease.
03
Evidence for the overall belief
Open sources, locators and notes
- DocumentsHistorical beliefAfrican-American Dental Surgeons and the U.S. Army Dental Corps: A Struggle for Acceptance, 1901–1919U.S. Army Medical Department
Where in the source: Chapter I, “The Spanish American War: 1898,” paragraph beginning “In 1898”
The Army medical history says the War Department considered an advantage in employing African American troops in Cuba and the Philippines because they were thought to have greater yellow-fever immunity than white troops.
- SupportsPresent correctionYellow feverWorld Health Organization
Where in the source: Key facts; Overview; Prevention — Vaccination
WHO identifies yellow fever as a virus transmitted by infected mosquitoes and states that one vaccine dose provides lifelong protection. The page is not used to claim immunity following recovery from natural infection.
- SupportsImpactBlack Soldier/White Army: The 24th Infantry Regiment in KoreaU.S. Army Center of Military History / GovInfo
Where in the source: Printed p. 10
Official Army history recounting the 1898 belief that Black soldiers were naturally more immune to tropical disease, the 24th Infantry's assignment to Siboney hospital duty, and the finding that 50 percent of 471 men there contracted “one or the other” disease, malaria or yellow fever.
- SupportsPresent correctionMalaria — questions and answersWorld Health Organization
Where in the source: Opening summary; “What is malaria and how is it transmitted?”, paragraphs 1–2; “Who is at risk of malaria?”, paragraphs 2–4
WHO explains that malaria is caused by Plasmodium parasites transmitted by infected Anopheles mosquitoes and that long exposure can produce partial immunity, which never provides complete protection and may still permit infection.
04
Impact
An Army medical history records that the War Department considered African American troops advantageous for Cuba and the Philippines because they were thought to have greater yellow-fever immunity. In Cuba, commanders assigned the 24th Infantry to hospital work at Siboney under a broader theory of natural Black immunity to malaria and yellow fever. Racial ideas also contributed to designating four of ten federal “Immune” regiments for Black enlisted men and lieutenants, alongside efforts to recruit people believed to have acquired immunity or hot-climate experience and political efforts to expand Black military service. An official Army history reports that half of 471 men of the 24th at Siboney contracted one or the other disease.
Context
The federal authorization for “Immune” troops did not itself state that Black people were racially immune to yellow fever. The racial proposition is documented instead in War Department and Army thinking and in how Black troops were recruited and assigned; the statute itself did not contain that racial claim.
The reported 50-percent figure combines malaria and yellow fever; it is not a yellow-fever-only infection rate.
The “Immune” program combined distinct ideas: recruiters sought people believed to have survived yellow fever or become acclimated to hot climates, while racial doctrine generalized tropical fitness to Black people. Black lobbying, exclusion from many state units and political recognition also influenced the four regiment designations. The racial belief was a contributing factor, not the program's only cause.
The Army monograph says hospital work involved little additional contact risk because malaria and yellow fever are mosquito-borne. The documented consequence is the racialized assignment rationale, not a claim that nursing itself caused the infections.
of ten federal “Immune” regiments designated for Black enlisted men and lieutenants, for several documented reasons
men of the 24th Infantry at Siboney who contracted malaria or yellow fever according to official Army history
racial disease-resistance assumptions shaped U.S. tropical-service decisions during the war
Historical totals and effects are presented as contextual evidence, not as universal causal claims.
Institutional episode 01
United States
North America
In 1898 War Department thinking and Army decisions treated Black soldiers as especially suited to tropical service because they were believed to possess greater natural resistance. The claim directly informed the 24th Infantry's hospital assignment and contributed to the racial designation of four regiments in the broader “Immune” program. Official Army history records that 50 percent of 471 men reporting at Siboney nevertheless contracted malaria or yellow fever, a combined finding that contradicted the supposed racial immunity.
Institutions involved
- United States War Department
- United States Army
Institutional context
War Department planning and Army commanders used a medical theory that treated Black ancestry as conferring natural resistance to yellow fever, malaria or tropical climates. The War Department considered Black troops advantageous for overseas tropical service, and commanders ordered the 24th Infantry to hospital duty at Siboney under the theory that its soldiers were more immune than white troops. Separately, four of the ten federal “Immune” volunteer regiments were designated for Black enlisted men and lieutenants. Racialized ideas of tropical fitness contributed to that decision, but acquired-immunity recruitment, acclimation, lobbying, access to volunteer service and party politics also shaped the program. Disease among the 24th soon contradicted broad racial protection.
Why this persisted
Administrative adoptionWar Department deployment planning and the Army's Siboney hospital assignment operationalized the belief that Black troops were naturally better suited to tropical service. The four Black “Immune” regiments also reflected that belief, but within a program shaped by acquired-immunity recruitment, acclimation, lobbying and politics.
How correction happened
UndocumentedThe 24th Infantry's disease experience contradicted the racial assumption during the war, and neither Black nor white “Immune” regiments demonstrated the promised immunity. A historical account records that belief in Black tropical fitness still influenced Army organization in 1899; the existing record does not identify a dated War Department or Army act formally repudiating the broader racial theory.
Consequences
- War Department deployment planning treated supposed Black yellow-fever immunity as an advantage for tropical service
- The 24th Infantry was assigned to hospital duty at Siboney under a theory of greater natural resistance
- Racial ideas contributed to designating four federal “Immune” regiments for Black enlisted men and lieutenants within a multi-cause program
- A combined malaria-or-yellow-fever rate of 50 percent among 471 men of the 24th contradicted broad racial immunity
Evidence for this episode
10 evidence linksOpen sources, locators and notes
- DocumentsInstitutional carrierBlack Soldier/White Army: The 24th Infantry Regiment in KoreaU.S. Army Center of Military History / GovInfo
Where in the source: Printed p. 10
The official Army monograph identifies commanders as assigning the 24th Infantry to Siboney hospital service under the period theory that Black soldiers were more immune to malaria and yellow fever than white soldiers.
- ContextualizesMechanismFrom Buffalo Soldier to Bath Attendant — Hugh HayesNational Park Service
Where in the source: “The Spanish-American War,” first paragraph
Official NPS account noting that people inside and outside the War Department believed African American soldiers could handle Cuba's tropical climate better than white soldiers.
- DocumentsConsequencesBuffalo Soldiers and the Spanish-American WarNational Park Service
Where in the source: Paragraph beginning “The terrain and climate were challenging”
Official NPS history stating that Black soldiers of the 24th Infantry served as nurses and hospital orderlies during the yellow-fever outbreak because of the stereotype that Black troops were physically better able to endure tropical conditions.
- ContextualizesContextThe Black “Immune” Regiments in the Spanish-American WarArmy Historical Foundation
Where in the source: Paragraphs beginning “Concerned about the health risks” through “Many erroneously believed”
The synthesis separates the statute's immunity requirement and recruitment of people believed to have prior exposure or acclimation from the racial belief in natural Black tropical fitness. It also documents Black lobbying, political recognition, five initially planned Black regiments and the reduction to four.
- DocumentsInstitutional carrierAfrican-American Dental Surgeons and the U.S. Army Dental Corps: A Struggle for Acceptance, 1901–1919U.S. Army Medical Department
Where in the source: Chapter I, “The Spanish American War: 1898,” paragraph beginning “In 1898”
The Army medical history names the War Department as contemplating overseas use of African American troops under the supposed yellow-fever advantage and lists the Black Regular and National Guard regiments deployed to Cuba.
- DocumentsConsequencesAfrican-American Dental Surgeons and the U.S. Army Dental Corps: A Struggle for Acceptance, 1901–1919U.S. Army Medical Department
Where in the source: Chapter I, “The Spanish American War: 1898,” paragraph beginning “In 1898”
This passage supports the consequence concerning War Department deployment planning. It does not by itself establish the “Immune” regiments or the 24th Infantry's hospital assignment.
- DocumentsConsequencesBlack Soldier/White Army: The 24th Infantry Regiment in KoreaU.S. Army Center of Military History / GovInfo
Where in the source: Printed p. 10
The Army monograph directly links the racial theory to the 24th Infantry's Siboney hospital assignment and reports that 50 percent of 471 men contracted malaria or yellow fever, without disaggregating the two diseases.
- DocumentsConsequencesThe Black “Immune” Regiments in the Spanish-American WarArmy Historical Foundation
Where in the source: Paragraph beginning “Many erroneously believed”
The synthesis documents racial tropical-fitness arguments surrounding the Black “Immune” regiments, General Orders No. 55's initial five-regiment designation and the later reduction to four, while also recording other motives.
- DocumentsMechanismThe Black “Immune” Regiments in the Spanish-American WarArmy Historical Foundation
Where in the source: Paragraphs beginning “Congress settled” and “Many erroneously believed”
The article shows how statutory immunity language, prior-exposure and acclimation recruitment, racial belief, lobbying, access to service and party politics converged in the “Immune” program; it does not support a single-cause account.
- ContextualizesInstitutional correctionThe Black “Immune” Regiments in the Spanish-American WarArmy Historical Foundation
Where in the source: Final two paragraphs, beginning “The War Department was much fairer”
The account states that neither Black nor white “Immune” regiments showed immunity and records seven officer and 241 enlisted disease deaths, yet says belief in Black tropical fitness still influenced two 1899 volunteer regiments. This is evidence against an immediate formal repudiation, not itself a documented correction act.
Source registryEach source is registered once and can carry several precise evidence relationships.7 sources
- 01Black Soldier/White Army: The 24th Infantry Regiment in KoreaU.S. Army Center of Military History / GovInfo3 evidence links
- 021 evidence link
- 031 evidence link
- 043 evidence links
- 05The Black “Immune” Regiments in the Spanish-American WarArmy Historical Foundation4 evidence links
- 061 evidence link
- 071 evidence link