Riveters pilots in dress uniforms The pilots doughboys with mules Mule Rearing African American Officers gas masks African American Soldiers 1

Diseases in World War I

Infectious Diseases

ID NousSommesIciInfectious diseases will always be with us. But in previous centuries, they were the major causes of death, both during wars, and during peace. It was not until the late 19th century that the germ theory of disease became firmly established. Virus disease was not recognized until into the 20th century. With recognition of micro-organisms came great advances in public health to control the spread of diseases. Early attempts at immunization against common diseases, particularly smallpox, were successful even without knowing the bacterial or viral basis for diseases. The late 19th century saw the development of more and better vaccines, notably against typhoid fever and tetanus. Other diseases such as malaria and yellow fever, could be controlled by identifying the insect vectors and either eliminating or controlling them. Prophylaxis against malaria was available, and routinely used. In many ways, the years before World War 1 marked the beginning of the conquest of infectious diseases. But only the beginning. In 1917, antibiotics were still 20 years in the future. Most of today’s vaccines had not yet been developed. Many among the general public knew nothing of prevention. Death from such diseases as tuberculosis and bacterial pneumonia were common by today’s standards. Overall, disease caused more deaths in the American Army than did enemy action.

As in previous wars, the training camps in the United States were breeding grounds for disease. The major childhood diseases, measles, mumps, and chicken pox, could sweep through a camp. More serious diseases such as meningitis and pneumonia were a constant threat. ID Camp Merritt NYCamp Merritt, NY
Recruits were screened for infectious diseases at entry, which helped somewhat. Colds, “flu”, and influenza were a constant problem, with secondary pneumonia carrying a real risk of death. Bacterial pneumonia, at this time, carried a 40-50% mortality. Without antibiotics, all that could be done was general supportive care. Until the advent of the H1N1 influenza epidemic of “Spanish flu,” simple seasonal influenza was rarely fatal. But the new influenza, appearing in 1918, proved to have a mortality rate in the 2-3% range. If 1000 soldiers contracted it, 50 to 100 would go on to “pneumonia”, and 25 to 50 would die. (See below)

This discussion of infectious diseases is focused on the American Expeditionary Force (AEF), that is, the troops in Europe. Many of these soldiers arrived in Europe already ill. Troop ships crossing the Atlantic in 7 to 15 days were packed full of troops in close quarters. Especially when the influenza epidemic began, it would prove nearly impossible to control disease outbreaks on ships. Once ashore, conditions were not greatly improved. Units were taken to makeshift training camps scattered throughout southern and central France, and lived under conditions which were not much less crowded than the troopships.ID CrowdedShipNewportNewsCrowded Troopship, Newport News, VA

The impact of the childhood diseases should not be overlooked.  Many soldiers came from remote areas and farms in the U.S.  They may have been particularly vulnerable to such illnesses.  Vaccinations to these diseases did not exist.  Even after reaching Europe, soldiers continued to fall ill to the diseases of children.  In terms of days lost, the most important disease was mumps.  There were 82,000 cases recorded in the AEF, with only 43 deaths, but with 1 million days lost to illness.  There were 8200 cases of measles, with 86 deaths.   Diphtheria struck 4700 soldiers, with 62 deaths.   

Meningococcal meningitis is particularly deadly. The disease can spread in populations of young people living in crowded conditions. The AEF recorded 1965 cases, with 911 deaths.

Other communicable diseases were present in the AEF.  Typhoid fever claimed 1200 cases, with 155 deaths.  Yet this was a major advance over previous wars.  The infection rate in the Spanish-American war was 142/1000 soldiers, but less than 1 per 1000 in the AEF.  Typhoid vaccine was available, and shots were mandatory for soldiers going overseas.  ID TyphoidVaccineTyphoid Inoculation was Routine for All Soldiers
Smallpox, despite near-universal vaccination, still counted for 30 cases, with 5 deaths.  Malaria, while not often fatal, was seen in 850 cases, with 4 deaths.  Dysentery, the scourge of armies in past centuries, was still present, but kept largely in check by sanitary measures.  There were 6200 cases, and 31 deaths. 

Tuberculosis, still a major disease at this time, was partly eliminated by screening.  The Army wouldn’t accept any recruit with TB, and would discharge any soldier who developed it.   Overall, it was estimated that 10,000 soldiers served with TB.  Screening was done by physical examination, and was much less effective than the mass use of chest x-rays.  The disease was endemic in the civilian populations of the day.  Death from TB had been declining during the entire 19th century, but there was an increase during the war among civilian populations.  Figures from the Army medical department showed that 4200 cases were recorded in the AEF, with 433 deaths.   

Trench conditions were awful.  Poorly nourished, living in trench conditions, soldiers of all armies were susceptible to all of the epidemic diseases, and others besides.  Most American troops spent relatively little time in the trenches, and were spared the worst of trench diseases.  (see below)

Venereal diseases, primarily syphilis and gonorrhea, were a chronic problem for all armies, and the AEF was no exception.  Control of venereal diseases was primarily prevention.  There were treatments for syphilis, but these involved mercury compounds, toxic in themselves. Gonorrhea could be treated, somewhat ineffectively, with local antiseptics, a process best left undescribed.  The antibiotic treatments which have relegated these scourges to mere annoyances didn’t exist, and treatment was primarily a matter of waiting for them to heal.  Venereal disease was a serious discipline problem, which meant that the medical system became involved with the Army judicial system.  Neither the doctors nor the lawyers were happy with this involvement.ID SavenayHospCenterSavenay Hospital Center, France

 Death from any of these infectious diseases is a relatively rare event today. Or at least, in America, and in most Western countries. A century ago, it was not so. Tuberculosis, while declining, was still known as the “captain of all these men of death”. Pneumonia was a common cause of death. For example, John McCrae, the Canadian surgeon-soldier who wrote “In Flanders Fields”, died of pneumonia in January, 1918. Small children regularly died of infections. While all of these were beginning to come under control by the early 20th century, people still lived with infectious death as a regular occurrence. So, while many soldiers died of diseases, this was not viewed at the time as a failure of the medical system. Instead, the rate of disease deaths was seen as low relative to the previous century. The medical system, and particularly the preventive measures taken by the American army, we considered to have done an acceptable, even admirable, job in controlling infectious disease.

Diseases in World War I

Tetanus

Tetanus bacteriaTetanus bacteriaOne of the great successes of Army medicine in the war was the virtual elimination of tetanus. In the AEF, of 500,000 wounds and injuries only 23 cases were recorded, with no deaths. Yet the war was fought in the mud and dirt of the trenches, and these were the ideal environment for the development of tetanus in wounds.

Tetanus is caused by a bacterium, specifically Clostridium tetani. The characteristic symptoms include rigidity and muscle spasms, therefore the popular name, “lockjaw”. The spores of Clostridium are found widely in soil, and can survive for a long time. Entering the body through a wound, the spores become live bacteria, and release the toxins which produce the clinical symptoms. Beginning in 1914, in the British and French armies, tetanus antiserum was routinely given to patients with dirt-contaminated wounds. Made at that time by harvesting serum from horses injected with modified tetanus toxin, antiserum was effective immediately. Tetanus toxoid, which produces active immunization, was not developed until 1924. In any case, it takes several weeks for the body to build up significant immunity.

ID Tetanus ImageImage of Clostridium tetaniThere is still some controversy about whether the antiserum was responsible for the rapid reduction in the incidence of tetanus. As outlined elsewhere, all of the medical services brought improved evacuation and better treatment of wounds. Specifically, the use of wound debridement, removing all dead and damaged tissue, and thorough surgical cleaning of wounds, would have been enough to greatly reduce the incidence of tetanus. At the time, physicians felt that the deciding factor was the use of tetanus antiserum. It seems clear that both were effective, and the net result was virtual elimination of tetanus from battle casualties.

Diseases in World War I

Trench Diseases

ID TrenchFootPosterWW1

A number of diseases were characteristic of trench life.  Virtually all front-line soldiers contracted lice.  Indeed, the first thing that was done for troops rotating out of the front line was to delouse and bathe them, and give them clean uniforms. Rats were common in the trenches, raising the potential for typhus and other rat-borne diseases.  

Nutrition in the trenches was very poor. Army rations in general had improved greatly by 1917. But food for soldiers in the front lines had to be cooked back of the lines, then brought forward in containers through communicating trenches. Because of the risk to the carriers, this was done in darkness whenever possible, making meals irregular and subject to interruptions. Water supply was also a chronic problem. Water had to be purified, transported forward, and then brought to the front trenches, a process which was also subject to interruption. Contamination of both food and water was a constant problem.

ID Trench FootThen, there was trench foot.  This was a condition brought about by constant immersion in cold water, without chances to dry off.  Technically, this was a cold injury rather than an infection, but secondary infection usually appeared if the injury was not treated.  Trench foot was a constant source of troops having to be evacuated, and affected all armies more or less equally.    The American army recorded 1800 cases during 1917-18, although only 5 deaths.

Diseases in World War I

The Great Influenza Epidemic

Spanish Flu WavesThree Waves of the Great Influenza Epidemic

At the end of the war, a new horror swept across the battlefields, and the entire world. The “Spanish flu” was named such because Spain wasn’t in the war, and therefore had no press censorship. The first big outbreaks were reported in the Spanish press, hence the name. This was a classic case of shooting the messenger. The true origin may not ever be clearly known, but was not in Spain. In the US it first appeared at Camp Funston, on Fort Riley, near Manhattan, Kansas, in the spring of 1918. Other theories of origin blame the British Army camps in northeastern France, or the importation of large numbers of Chinese laborers. Whatever its ultimate origin, it spread rapidly to other training camps. More importantly, it swept the world in 1918 to 1920.

Spanish Flu in the ArmyInfluenza Deaths in the ArmyInfluenza usually carries a mortality of rate of less than 1 in a thousand, largely from secondary pneumonia. During the fall of 1917, there were cases recorded among troops in Europe, with some deaths from secondary pneumonia. But in 1918, a new strain appeared. It was apparently capable of causing death not just by secondary pneumonia, but also by primary lung consolidation and failure. This new strain killed more than 2.5% of cases, and in some populations as high as 10%. Moreover, while influenza usually causes deaths only in the very young or the old, this strain caused mortality in young people of 20 to 35 years, the age of most soldiers. It attacked in three waves: spring of 1918, fall of 1918, and winter of 1918-19. The second wave was the most lethal of the three, and caused civilian deaths throughout the US, as well as around the world. In the AEF, cases peaked in the week of September 15-22, with 5-10% going on to develop pneumonia. Totals for the AEF were recorded at 192,000 cases of influenza, 29,000 of pneumonia, and a total of 13,000 deaths. By War Department estimate, 25% of the Army, over 1 million men, fell ill. Army-wide, influenza and pneumonia accounted for nearly 30,000 deaths, more than half the 52,000 non-combat deaths during the war.

Influenza is caused by a virus, a micro-organism twenty times smaller than a bacterium.  In 1918, medical scientists had barely discovered viruses, and had little or no idea how to combat them.  The best microscopes of the day couldn't see them.  Today, we know that the "Spanish Flu" was the H1N1 strain of influenza.  We can even see the virus with an electron microscope.  We can immunize Spanish Flu Pictureagainst it, and all of the other strains of influenza.  We can give antibiotics for the secondary pneumonia.  And we can support patients with ventilators if their lungs fail.  But in 1918, all physicians could do was to support the patient, quarantine as best they could, and ride out the epidemic.  

Navy personnel, serving on crowded ships, were particularly vulnerable. The Navy recorded 100,000 hospital admissions, with 5,000 deaths. This was out of a total of 600,000 men, a 17% infection rate. Other evidence suggested that the incidence was more like 40%, as light cases went unhospitalized and unrecorded.ID TroopsOnLeviathanTroops Crowded onto the Leviathan, a German Liner Converted to American TroopshipSpanish Flu Walter ReedFlu Ward, Walter Reed Army Hospital, Washington, DC

Other allied armies were equally affected, as were the Germans and Austrians. One of the causes that has been cited for the failure of the German spring offensive is that widespread illness blunted the offensive power of the German army.  We still don’t know whether the Germans were more affected than the allies. But given that Germans were starving on the home front, and that German front line troops were poorly fed and often malnourished, it is definitely possible.

The effects on the civilian population were far more serious. About a quarter of the US population fell ill. Even President Wilson caught the flu, while he was in Paris in early 1919. Perhaps one-third of the world population were stricken. India, as an example, had 50 deaths per 1000 people who fell ill. The total number of deaths is not accurately known. The death toll was thought at the time to be 20-30 million. Recent studies have revised this upwards, to 50 million deaths throughout the world, with a possible upper limit of 100 million. The epidemic killed many more than the war itself. Was the war responsible? Perhaps, it was. Current studies on recovered samples of the virus indicate that it was a mutated version of an older, less lethal virus. Clearly, the war was not the cause of the mutation. But the conditions of the war, with soldiers and civilians moving about the world, as combatants and as refugees, almost certainly contributed to its rapid spread, and probably to the death toll.

Current References on the Great Influenza Epidemic

 Laura Spinney.  Pale Rider:  The Spanish Flu of 1918 and How it Changed the World.  Public Affairs, New York.  2017

 John M. Barrey.  The Great Influenza.  The Epic Story of the Deadliest Plague in History.  Penguin Books, New York, 2005.

Gina Bari Kolata.  Flu: The Story of the Great Influenza Pandemic of 1918 and the Search for the Virus That Caused It.  Farrar Straus Giroux, 1999.

WW1 Medicine

Contact: WW1.Medicine@worldwar1centennial.org

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American Military Medicine in World War I
This web resource has been generously contributed by and is being curated by:

  • Charles W. Van Way, III
  • W. Sanders Marble
  • George Thompson

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