6. Pestilence and warfare
Who kills more?
Although we humans pride ourselves on our ability to destroy each other, most war casualties have been the result of infections, not enemy action. No, not infected wounds, either. Nowadays bullet holes and stab wounds are rarely fatal unless they hit a vital organ. Before antiseptics and antibiotics were available, however, wounds often became infected and frequently resulted in the loss of life or limb. Nonetheless, most casualties before modern times resulted from infections that killed soldiers who had not been wounded in combat—very often soldiers who had not even gotten into combat. Only since the twentieth century have improved hygiene and, to a lesser extent, enhanced firepower allowed humans to kill more people than microbes have.
The first major conflict in which more combatants were killed by other humans than by disease was the Russo-Japanese War of 1904–1906. Even here, this applied only to the cleaner and more hygienic Japanese. The Russians lost more men to disease than to enemy action, and they also lost the war. Whether World War I was a step forward is debatable. The armies on the western front were vaccinated and disinfected, and suffered most of their casualties from enemy action. The eastern front was quite a different story, and infectious disease retained the upper hand. By World War II, mankind had at last progressed to that point at which humans were more of a threat to human life than microorganisms.
Spread of disease by the military
Warfare is generally accompanied with an upsurge in infections, among both the military and surrounding civilian populations. Modern readers probably think the phrase “well-seasoned troops” refers to those with battle experience. Not so. In historical times, smart commanders gathered their recruits together and stayed somewhere safe and well supplied for a few months. During this period, the soldiers shared their infections and became “seasoned.” Being ill while properly fed and housed instead of in active service greatly reduced overall casualties from disease. We discussed the principles involved in the spread of disease in Chapter 3, “Transmission, Overcrowding, and Virulence.” Three factors are especially important in the spread of disease by warfare: crowding, mixing, and mobility.
• Crowding: Armies are crowds of men who eat, sleep, and work in close contact. Such conditions are ideal for the spread of disease. Moreover, hygiene is poor. Soldiers might be crowded together in camps, barracks, or trenches. Sailors are crowded on warships. Troop ships carrying soldiers packed like sardines are even more crowded. Only in recent times have hygienic measures been adopted. Very early in history, armies were doubtless dirty, but they were also relatively small and so were not especially prone to disease. As armies grew over the ages, they provided infectious disease with ever better conditions for spreading.
• Mixing: When armies are assembled, recruits gather from separate localities all over the nation or empire. As they mix together, they exchange their infections. Diseases previously confined to one locality or segment of the population are shared. During the American Civil War, about a third of the Northern troops fell ill before leaving their training camps, mostly due to intestinal ailments, including typhoid. In World War I, a similar proportion of draftees was rejected as unfit. Although the rural population was healthier, rural recruits fell prey to infections more often than those from towns and cities. The urban population had been exposed to diseases such as measles, mumps, chickenpox, diphtheria, scarlet fever, and tuberculosis early in life. Many rural folk, especially from remote areas, had never been exposed to these diseases. Thus, when these populations were mixed, the rural enlistees were vastly more susceptible.
• Mobility: Armies rarely stay put. Whether they advance, retreat, or merely march in circles, they carry infections with them. Armies carry disease across land, and navies carry disease across the seas. Even when armies are stationary, as in siege or trench warfare, new recruits are constantly drafted to the front and the sick are withdrawn. Prisoners transfer disease from one army to another, and deserters carry disease wherever they seek shelter. Infections are spread to civilians along the route of troop movements. In addition, wars often displace large numbers of civilian refugees, who flee to safety either individually or en masse. Ticks, mites, lice, and fleas travel with the humans they inhabit. Disruption caused by warfare also displaces rats and mice, which consequently move around with their accompanying fleas.
Another, though less universal, factor is the chaos generated by warfare, especially among the vanquished. This often leads to food shortages and malnutrition. Crops might be accidentally trampled, seized by the military, or deliberately destroyed. Poor nutrition weakens resistance to infection. Standards of hygiene lapse, especially among armies in retreat and civilian refugees. The chaos factor has probably had more impact in modern times. In medieval times and before, most people were unhygienic and malnourished anyway.
Is it better to besiege or to be besieged?
In the realm of disease, it is undeniably better to give than to receive. Being sealed in a castle or walled city with a lot of other grubby humans, horses, dogs, rats, mice, lice, and fleas was usually worse than attacking. The defenders were obliged to take their livestock inside (together with their diseases) if they wanted milk or fresh meat. The defenders were unable to get rid of human or animal waste unless they were willing to haul it to the top of the walls and pitch it over at the enemy. Sewage and refuse piled up. Dead bodies could not be buried. Rats scavenged in the garbage. Fresh water was scarce and often contaminated.
Although the odds definitely favored the attackers, the downfall of the defenders was by no means inevitable. If a crowded metropolis is besieged by soldiers from rural areas, the urban/rural exposure factor noted earlier might come into play. The city population will have built up resistance to disease, and the rural population will lack previous exposure. A few captives, deserters, or envoys from the city could spread a devastating epidemic among the encircling army.
The siege of Mecca by the Ethiopians (569–570 A.D.) and the siege of Jerusalem by the Assyrians (701 B.C.) are both cases in which the attacker was routed by pestilence and the siege therefore failed. Mohammed was born in A.D. 570, and Islam had not yet been founded. Nonetheless, Mecca was already the holy city of the Arabs, and the Ethiopian Christians were hoping to destroy Allah’s sacred shrine, the Ka’aba. An epidemic, probably smallpox, brought them to their knees and killed their leader, Abraha, who rode on a white elephant. In the Koran, we read this:
“Have you not considered how Allah dealt with the Army of the Elephant? Did he not foil their stratagem and send against them flocks of birds which pelted them with clay-stones, so that they became like plants cropped by cattle?”—The Elephant, The Koran
The Islamic expansion of the seventh and eighth centuries spread smallpox throughout the Mediterranean area. Or perhaps we might argue that smallpox cleared the way for Islam to expand, much as it later cleared the way for the European colonization of America. The Islamic Empire crossed from North Africa to conquer Spain in 710 and penetrated into France in 731. By this time, Europe had recovered from the colossal population die-off from the bubonic plague of Justinian’s day and was adjusting to smallpox. The Arabs failed to take France but held much of Spain until the next Black Death pandemic, in the mid-1300s. (Even then, the Moors held Granada until 1492, the year Columbus sailed for America.)
Sometimes disease declines to take sides and strikes down besieger and besieged alike. The siege of Kaffa, which resulted in the entry of the Black Death into Europe, is a case in point. The plague spread from the encircling Tartar army to the besieged Italians, demonstrating that epidemic disease is only too likely to travel from one army to another.
Disease promotes imperial expansion
“God is usually on the side of the big squadrons and against the small ones.”—Roger de Bussy-Rabutin (1618–1693)
As explained before, civilizations tend to develop resistance to epidemic disease that then acts as a protective shield. Dense populations acquire a repertoire of infectious diseases. The denser the population, the greater its repertoire. Provided that it survives the initial onslaught, its people gradually become resistant to many of these infections. When disease-adapted populations contact other civilizations, the infections are transferred. The result depends on how much previous exposure to these infections the recipients have had. If the recipients are from a sparser culture with no previous exposure, they will be devastated. The most spectacular example is the depopulation of the New World by European diseases. However, similar die-offs on a more restricted scale have probably accompanied the spread of all major civilizations.
Small tribes of early man domesticated dogs to guard against predators and help in hunting. We might view diseases as being domesticated by larger societies. After a dense population center has adapted to a particular infection, this domesticated disease will guard against intruders and help during missions of aggression. When a densely populated city forms, it will have an advantage over smaller neighboring communities. Infectious disease will spread from the big city and decimate the neighboring cultures. Their territory can then be absorbed with less military effort. The invaders will occupy the new territory. If the original inhabitants who remain are too few to regain independence, they will be assimilated and, in time, become citizens of the growing empire. The cycle can now repeat itself. After an imperial nucleus has formed, it tends to grow like a snowball rolling downhill.
The growth of the Roman Empire proceeded in much this manner. Rome absorbed neighboring villages, then small towns, then the other Italic states, and so on. The Romans had the good sense to extend citizenship to the people they assimilated, giving biology a helping hand. Eventually, the expanding Roman sphere came into contact with the other major Mediterranean civilizations and their diseases. Although the halo of urban disease still provided valuable protection against barbarian incursions, it was of little use against other major urban blocks, such as the Greeks or Carthaginians. From this point on, disease no longer favored the Romans. Ultimately, Rome expanded far enough to make contact with a series of novel diseases that had evolved among the dense populations of Asia. The outcome proved disastrous for the Romans. Several major yet still unidentified epidemics, followed by the bubonic plague, depopulated the Roman Empire. Doubtless, the Romans gave the combined disease repertoire of Europe and North Africa to Asia in exchange. This reciprocal export of infection seems to have caused depopulation not only for the Romans, but also for the Chinese Han Empire.
Protozoa help keep Africa black
The most prominent example of disease fighting for the less densely populated side is the special case of Africa. As the original homeland of mankind, Africa retains many of our ancient tropical diseases. Malaria, sleeping sickness, and yellow fever combined to protect sub-Saharan Africa from Arab invaders and then Europeans. The natives of Africa have evolved at least partial resistance to many tropical diseases, and although they still suffer a major disease burden, outsiders are vastly more susceptible.
Tropical diseases have also kept other tropical regions fairly isolated from world culture until recently. What is so special about tropical diseases? Malaria, sleeping sickness, yellow fever, and several less-well-known tropical infections all must be spread by insects that cannot survive the cold. In contrast, diseases such as smallpox, measles, and influenza move directly from person to person. Consequently, they are not confined to particular climatic zones. Eventually, any population that is exposed will develop resistance to these airborne epidemic diseases.
Insect-borne tropical diseases cannot travel outside their own geographical hot zone. The only way people can become habituated to malaria or yellow fever is to migrate into the tropics and settle among the insects that carry these infections. For example, if yellow fever had been able to spread from Africa around Europe and the Middle East, the inhabitants of these colder regions would have built up resistance over several generations. Then when they entered Africa, they would have been resistant because of prior exposure.
Of course, African tropical diseases have spread, but only to the tropical zones of America and Asia. Such transported African diseases have continued to act as a biological force field to protect their carriers. In 1801, the black slaves in the French colony of Haiti revolted. Napoleon sent in experienced French troops who, other things being equal, should have easily suppressed the revolting slaves. Yellow fever, imported from Africa with the slaves, won the war by killing nearly 30,000 French troops. The slaves were mostly resistant to yellow fever because their African ancestors had adapted to it for many generations. Napoleon withdrew, and Haiti has been independent ever since.
Europe eventually conquered Africa because of superior military and medical technology. However, Europeans have never adapted biologically to the diseases of tropical Africa and must constantly take precautions such as antimalarial drugs and mosquito nets to preserve their health. Moreover, the European conquest of Africa has proven transient, with little permanent settlement, except in regions with temperate climates, such as South Africa. The inability of Europeans to live “naturally” in the tropics has hastened imperial withdrawal.
Is bigger really better?
The Persians tried several times to invade Greece. After Darius was defeated at the battle of Marathon in 490 B.C., his son Xerxes returned to Greece ten years later. Xerxes led the largest army the ancient world had ever seen, supposedly of 800,000 men, although it is hard to believe that these numbers were not wildly exaggerated. Of these, 300,000 rapidly succumbed to disease. The identity of the disease, or diseases, is not known. Plague and dysentery have both been suggested. Plague is usually a disease of settled communities, not of armies on the march. Dysentery seems more likely, although it mostly causes widespread debilitation with a sprinkling of fatalities, not death on a massive scale. In any case, the Athenians annihilated Xerxes’s navy—also oversized and badly organized—at the battle of Salamis in 480 B.C., and Xerxes quit his disastrous campaign and went home to Persia.
Despite Xerxes’s example, the idea that the way to win a war was by assembling the largest possible army of dirty, badly fed, poorly trained soldiers remained popular among ambitious leaders. The Crusades of medieval times (from 1096 to the early 1200s) are another example. Religious hatemonger Pope Urban II started the Crusades, supposedly to rescue the Holy Land from the Moslems. More likely, the real motive was to direct attention away from the corruption and incompetence of Vatican-dominated Europe. High points include the loss of 5,000 horses (out of 7,000) in an epidemic while the crusaders were besieging Antioch in 1098. Without their horses, the heavily armored crusader knights were helpless. Louis VII of France led some 500,000 men on the Second Crusade, and only a few thousand returned. Richard the Lionheart of England (1189–1199) left his country to wallow in economic insolvency while he went on the Third Crusade and failed to take Jerusalem. His massive army was reduced to a handful of survivors by malnutrition and infectious disease. The microorganisms were definitely on the side of the cleaner Moslems, with their smaller, better-trained armies.
Disease versus enemy action
Before about 1800, plenty of rough estimates show that infections killed vastly more soldiers than the opposing army. During the 1800s, more detailed records began to appear. In the Crimean War (1854–1856), the British lost ten times as many soldiers from dysentery and typhus as from Russian action. The mere fact that accurate numbers were recorded is an indication that at last the military was beginning to worry about the loss of manpower from disease. The squalor of the Crimean war inspired Florence Nightingale to push for reforms in hygiene, both in the armed forces and back home in England’s filthy cities.
By the Boer War (1899–1902), in which the British fought Dutch settlers for control of South Africa, the ratio had sunk to five deaths from disease to one from enemy action. The turning point was the Russo-Japanese War (1904–1906), in which the Japanese lost only one quarter as many men from disease as from enemy action. Over the next decade, the world’s advanced countries copied the Japanese: After scrubbing their recruits clean, they inoculated them against typhoid, tetanus, smallpox, and other infections.
In World War I, most armies stayed relatively free of disease. The major exceptions were the Serbs and Russians, whose outdated and ill-disciplined armies suffered massive losses from typhus fever. The only significant epidemic among the Western Allies in World War I was syphilis, and this caused trivial damage in comparison with losses to disease in earlier wars. Venereal diseases are a special case because they are aided in their spread by embarrassment and secrecy. (The Spanish Flu of 1918–1919 killed more humans than the military actions of World War I, yet this was a worldwide pandemic shared by civilian and military alike, not a specifically military problem.) By World War II, antibiotics and insecticides had made their appearance, too. Soldiers and sailors#8212;and sometimes civilians in war zones or refugee camps—were dosed, disinfected, dusted, and deloused. In our modern era, infectious disease kills fewer soldiers than military action.
Since World War II, the major effect of infectious disease on the military of the industrial nations has been indirect. Providing ever more costly medical care to forestall every imaginable ailment has made armies more expensive. The result has been a decline in the advanced nations’ desires to intervene in the Third World, especially in the less hygienic parts. Thanks to rising health standards, the citizens of industrial nations have come to expect their full three-score years and ten. American conscripts in Vietnam had little wish to risk losing 50 to 60 years of life expectancy for little convincing purpose.
Typhus, warrior germ of the temperate zone
Which diseases were responsible for slaughtering the armies of Xerxes or the crusaders remains a mystery. As we approach more modern times, the identities of diseases that have overthrown armies start emerging from the mists of history. During the 1300s and 1400s, the Black Death killed soldier and civilian alike.
From 1494 to the early 1500s, syphilis caused major casualties among the military, but typhus soon emerged a far greater problem. In 1494, the French were forced to withdraw from Naples because of an outbreak of syphilis. In 1528, they were still fighting Spain for control of Italy and were forced to retreat from Naples again. This time the French lost 30,000 men to typhus. From the sixteenth century on, typhus became the major microbial player in the military arena.
Note that typhus and typhoid are quite distinct. Historically, they were confused because both cause fever and a rash. An unfortunate consequence of this is the use of two variants of the same original name for the two diseases. However, typhus results from the bacteria known as Rickettsias, which can grow only inside animal cells. Typhoid is the result of virulent Salmonella, which can be grown in culture. Typhus is transmitted by lice or ticks, whereas typhoid is spread by water or food contaminated with human waste.
Typhus is at home in cooler climates because the lice that spread it thrive in warm, dirty clothing, especially fur or wool. It is difficult today to imagine just how lousy and verminous our predecessors were—even the upper classes. Archbishop Thomas á Becket was assassinated in December 1170, and his body lay overnight in Canterbury cathedral awaiting burial the next day. He had on “a large brown mantle; under it, a white surplice; below that, a lamb’s-wool coat; then another woolen coat; and a third woolen coat below this; under this, there was the black, cowled robe of the Benedictine Order; under this, a shirt; and next to the body a curious hair-cloth, covered with linen.” As the body grew cold, the inhabitants of these multiple layers began to evacuate. “The vermin boiled over like water in a simmering cauldron, and the onlookers burst into alternate weeping and laughter.”
In 1542, 30,000 soldiers fighting for the Holy Roman Empire against the Turks were lost to typhus. In 1556, Maximillian II of Germany took 80,000 men to fight the Sultan of Hungary, but abandoned the campaign after losing most of his army to typhus. Assorted European wars supplied typhus with a steady stream of victims for the next few centuries.
Typhus was carried aboard ships and took a steady, massive toll among the sailors of the competing European imperial powers. It was especially lethal when allied to the poor nutrition and vitamin deficiency typical of long ocean voyages. The British navy stripped, scrubbed, and shaved its sailors before issuing clean clothes. They also issued lime juice to prevent scurvy (vitamin C deficiency). The British consequently lost far fewer sailors than their enemies, especially the French and Spanish.
The most famous outbreak of typhus was the destruction of Napoleon’s Grand Army in Russia. We have already noted Napoleon’s Haitian fiasco, but this was not his first brush with disease. In 1798, Napoleon invaded and occupied Egypt briefly. More than 40% of his men died, mostly from bubonic plague. Napoleon’s army was so weakened that the British easily ejected him from Egypt. However, Napoleon’s biggest bacteriological disaster came during his attempt to conquer Russia in 1812. The French Grand Army started with about 450,000 men. By October, only about 80,000 were fit to fight, and Napoleon began his retreat from Moscow. A mere 6,000 men made it back to France. Of course, the cold, poor nutrition, and the Russians didn’t help; nonetheless, typhus caused most deaths, with dysentery as runner-up.
After the Napoleonic era, the Western nations got cleaner. During World War I, typhus was confined to the eastern front. The Serbians lost 150,000 to typhus in the first six months of the war, including more than half of their 60,000 Austrian prisoners of war. Paradoxically, this aided the Serbs because the Austrians were so frightened by the typhus epidemic that they stayed out of Serbia for fear of infection. Overall, the Russians suffered most from typhus. During World War I and the Russian revolution that it triggered, the Russians encountered roughly 25 million cases of typhus and suffered 3 million deaths from typhus. (Among all other combatants in World War I, there were five million cases and about half a million deaths.) The typhus outbreak during the Russian revolution was so severe that Lenin stated, “Either socialism will defeat the louse, or the louse will defeat socialism.” In World War II, scattered outbreaks of typhus occurred, especially in concentration camps, but the use of insecticides such as DDT to eliminate the lice that carry typhus virtually eradicated the disease.
Jails, workhouses, and concentration camps
Jails and workhouses resemble refugee camps and concentration camps in many ways. In all of these, helpless humans are herded together, usually under unhygienic conditions. During the eighteenth and nineteenth centuries, typhus spread like wildfire in the overcrowded jails of industrial Europe. Cool, damp conditions, dirty clothes crawling with lice, and malnutrition combined to promote constant epidemics of typhus. Workhouses and orphanages for those without jobs or homes of their own were almost as bad. Ships carrying European emigrants to America or Australia often took aboard more passengers than they were intended for and suffered similar outbreaks of disease. Camps for refugees and prisoners of war were often overcrowded. Any overcrowded institution, whatever its original motivation, is vulnerable to typhus if hygiene lapses. Of course, other diseases also had a field day, but typhus was the biggest killer.
Although overcrowding is the most important factor, such institutions, whether barracks, prisons, nursing homes, or orphanages, have another serious drawback: Their inmates all share resources. They breathe the same air, drink the same water, and eat the same food prepared in the institution kitchens. Consequently, they also share any infectious agents that use air, water, or food as their mechanism for distribution. The steady increase in population, coupled with the tendency to share resources for economic reasons, has made modern society increasingly vulnerable to waterborne and foodborne disease, whether spread naturally or deliberately.
Germ warfare
Burning crops and poisoning the water supply were probably the earliest forms of biological warfare. Tossing dead or rotting animals into wells or waterholes was doubtless reasonably effective. Throughout history, there have been occasional sporadic attempts to deliberately spread infection for military purposes. These have mostly been ineffective or irrelevant. For example, the attempts of white settlers to spread smallpox to American Indians were largely irrelevant because smallpox had already spread by itself.
By medieval times in Europe, cattle infected with anthrax were being hurled over the walls into castles or walled cities to break sieges by spreading disease. Anthrax is a highly infectious cattle disease that is readily transmitted to humans. It causes a high death rate and was probably reasonably effective. Nonetheless, given the state of hygiene in most medieval towns or castles, there was little need to provide outside sources of infection. With plague, typhoid, smallpox, tuberculosis, dysentery, diphtheria, and measles always around, all that was usually necessary was to let nature take its course.
The reason germ warfare has been of little account until recently is that plenty of dangerous infections were already in circulation. If the enemy is crowded and unhygienic, some natural disease will undoubtedly attempt a biological assault without waiting for artificial prompting. Only in our modern disinfected age has deliberately spreading disease become a meaningful threat.
Psychology, cost, and convenience
During the Vietnam War, the Viet Cong guerillas dug camouflaged pits as booby traps. Within these, they often positioned sharpened bamboo stakes or splinters smeared with human waste. Although it was possible to contract a nasty infection from these, the main purpose was psychological. Worrying about possible booby traps slowed the movements of American troops out of all proportion to actual casualties. Thus, the threat of chemical or biological warfare might have great psychological effect.
Taking protective measures is costly and inconvenient. Vaccinating soldiers against all possible diseases that might be used is expensive and time-consuming. Moreover, vaccines often have side effects. Consider the anthrax vaccine used by the U.S. army. It was approved in 1971, has been thoroughly tested, and is considered relatively safe. It produces swelling and irritation at the injection site in 5% to 8%, and causes severe local reactions in about 1% of those inoculated. Major systemic reactions are “rare,” but the vaccine has not been widely used. Vaccination requires six inoculations, plus annual boosters. Although it works against “natural” exposure, it is uncertain whether it would protect against a concentrated aerosol of anthrax spores.
Even without germ warfare, drugs given to troops from temperate countries to ward off malaria and other tropical infections can damage health if taken over a long period. Constant exposure to insecticides can damage the nervous system. Dressing infantry in protective clothing and respirators hampers mobility. In hot climates, extra clothing can also cause heat stress.
Anthrax as a biological weapon
Anthrax is a virulent disease of cattle that infects humans quite easily, causing a high death rate. It is caused by a bacterium, Bacillus anthracis, which is easy to culture and forms spores that can survive harsh conditions that would kill most bacteria. The spores can lie dormant in the soil for years before germinating upon contact with a suitable host. In some ways, anthrax is the ideal biological weapon: lethal, highly infectious, and cheap to produce, with spores that store well. As noted, during the Middle Ages, cattle infected with anthrax were sometimes hurled into castles or walled cities to break sieges.
The problem with anthrax is that the spores are so tough and long-lived that getting rid of them after hostilities are over is almost impossible. After your enemy has been eliminated, the idea is to move in and occupy his territory. Unfortunately, anthrax spores persist so long in the soil that they are likely to infect the invaders. Off Scotland is the tiny island of Gruinard, which the British used to test anthrax during World War II. Thousands of sheep were used as victims, and large amounts of anthrax spores were scattered around. Although the island has been fire-bombed and disinfected, it remains uninhabitable even today because anthrax spores still survive in the soil.
Amateurs with biological weapons are rarely effective
In 1995, the American Type Culture Collection (ATCC) shipped a culture of Yersinia pestis (bubonic plague) to a member of a group of white supremacists. The activist was convicted of falsifying a federal certification number that he used to fool the ATCC into thinking he was associated with a bona fide institution. In 1998, the FBI arrested the same individual for possessing Bacillus anthracis (anthrax). However, it turned out to be a harmless vaccine strain! Ironically, U.S. Army researchers isolated these harmless, nonsporing derivatives of anthrax for use in immunization.
Even more farcical was the report in July 1998 of a plot by Republic of Texas separatists to assassinate President Clinton. Their plan was to use a cactus thorn coated with the AIDS virus, anthrax, and botulism. A modified cigarette lighter would have fired the projectile. This incident illustrates another weakness of germ warfare: the introduction of needless complications. If you are going to shoot someone, why not use an unmodified gun with an ordinary bullet?
The ATCC received a lot of publicity for supplying white supremacists with plague and Iraq with anthrax in the 1990s. Not surprisingly, a variety of proposals for more regulations were put forward. However, any country that possesses hospitals with microbiological laboratories can wage germ warfare. Major hospitals and research centers in all nations possess stocks of lethal microorganisms that are needed for diagnostic comparisons and to prepare vaccines and antisera. This is especially true of poor nations where virulent infections are frequent. Thus, any reasonably informed hospital microbiologist or clinical technician could obtain cultures of dangerous biological agents if desired. This situation makes both export controls and intensified security procedures for research laboratories futile. Indeed, in many third-world countries, the germs of lethal diseases could be directly isolated from infected people or animals during outbreaks.
Which agents are used in germ warfare?
Among the bacterial diseases, anthrax, brucellosis, tularemia, glanders, melioidosis, and bubonic plague have all been considered for use by the military. Assorted viruses have been suggested, including emerging diseases such as Lassa fever and Ebola virus, but the only consistent choice among viruses is smallpox. If we stick to the idea that germ warfare should be cheap and simple, we can eliminate the viruses. Although they seem more intimidating because they cannot be cured by antibiotics, viruses are difficult to culture because they replicate only in cells of other creatures. Although viruses can be cultured in egg yolks or cultured mammal cells, this requires high technology and trained staff. Granted, substantial batches of virus are grown for vaccines in advanced nations, and a relatively small volume of virus preparation could infect millions. Nonetheless, for quick-and-dirty backyard operations, we should stick to bacteria that can grow by themselves in culture.
Brucellosis, caused by Brucella, is a disease of cattle, camels, goats, and related animals. The United States developed it as a biological weapon from 1954 to 1969, although its choice seems curious. In humans, brucellosis behaves erratically, and although victims often fall severely ill for several weeks, it is rarely fatal, even if untreated. Tularemia, caused by Francisella tularensis, is a disease of rodents, with a death rate of 5% to 10% in humans, if untreated. Melioidosis, caused by Burkholderia pseudomallei, is related to glanders (Burkholderia mallei), a disease of horses. Melioidosis is a rare disease of rodents from the Far East that is spread by rat fleas. Despite being only “pseudo”-mallei, melioidosis is worse than glanders and is fatal around 95% of the time in humans.
During and just after World War II, bubonic plague was popular. Although normally transmitted by fleas, Yersinia pestis can be grown easily in culture and can be distributed by spraying. In July 1948, the Red Star, the official Soviet Army newspaper, described a captured Japanese germ warfare facility located in Manchuria. It produced nearly a ton of bubonic plague bacteria per month. The Russians claimed that the Japanese had used prisoners for testing, generally with fatal results. The British biological warfare center at Porton Down also kept large-scale bubonic plague cultures on hand for several years after World War II. In the 1960s, the United States might have experimented with spreading plague among rodents in Vietnam, Laos, and Cambodia. As with much information about biowarfare, this is disputed and uncertain. In 1969, President Nixon announced a ban on chemical and biological warfare research. Since then, interest in bubonic plague has faded.
The Soviet germ warfare program is supposed to have concentrated on anthrax and smallpox (including artificial mutants and hybrids). For an industrial nation, preparation of a virus whose particles are fairly stable and long-lived, such as smallpox, is feasible. In addition, the eradication of smallpox led to the abandonment of smallpox vaccination and, hence, the emergence of vulnerable populations. For a third-world nation, a virus would be a dubious choice. Anthrax is a good deterrent, but occupation of territory after anthrax release is hazardous. For the Soviet Union, with its vast expanses of thinly populated land, this consideration was perhaps minimal.
World War I and II
The Germans made some amateurish attempts to infect animals in World War I. German agents inoculated cattle and horses shipped to the Allies from the United States in 1915 with anthrax and glanders, respectively. Similar schemes were tried in France in 1917. German agents based in Zurich were accused of spreading cholera in Italy. No significant effects can be traced to these attempts; whether they were technical failures or the accusations were mere propaganda is debatable.
The Japanese have been accused of spreading bubonic plague in China during World War II. The Japanese probably had the capacity to grow large cultures of plague. There are accounts of attacks by small numbers of Japanese aircraft that dropped cotton rags, rice grains, and other materials supposedly carrying plague bacteria or perhaps plague-infested fleas. Undoubtedly, minor outbreaks of bubonic plague occurred in central China during the war years. Some 100 to 200 cases of plague were reported, mostly fatal. The Chinese government claimed that these were due to biological warfare, and the U.S. Surgeon General at the time apparently accepted this.
The evidence is not convincing. Bubonic plague has been endemic among the rodents of southern China for centuries. The dislocation caused by war easily accounts for sporadic appearances of plague among humans, even in areas distant from the major plague reservoirs. Furthermore, plague bacteria were not isolated from the material dropped by the Japanese, although several attempts were made to do so. In any case, plague is caught either from flea bites or by breathing in airborne bacteria. Most bacteria are killed by stomach acid, so contaminated rice is useless in spreading plague. Contaminating cotton rags was also pointless. Spraying a culture of plague would be the only efficient way to infect large numbers of people, as the Japanese must surely have known. What the Japanese were doing is puzzling, but it seems unlikely to have been an effective form of germ warfare.
Germ warfare against rabbits
The Australian attempt to destroy rabbits with myxomatosis in the 1950s received much publicity. But rabbits have the distinction of being the first animal targeted for scientific germ warfare by no less a celebrity than Louis Pasteur. This happened in France in 1887. The rabbits had been burrowing above a wine cellar belonging to Madame Pommery of the city of Rheims. Dislodged stones had fallen, smashing bottles of champagne. Pasteur dispatched his assistant with a culture of fowl-cholera. Three days later, 32 dead rabbits were found and the rest had disappeared. Pasteur then sent his assistant to Australia. Here he met with dismal failure. The infection failed to spread among the rabbits. In addition, the cattle breeders were frightened that their herds might be infected and opposed the program. The project was abandoned.
Half a century later, the Australians deployed a virus. The first year, myxomatosis killed more than 99% of the rabbits it infected. Ten years later, it killed only 20%. The tiny proportion of resistant rabbits who survived the first onslaught did what rabbits do best—they produced lots more rabbits. In short, the Australians selected for the evolution of a myxomatosis-resistant rabbit. Today the rabbit population is booming again and the Australians are ready for another round of germ warfare. Rabbit calicivirus emerged in China in 1984 and spread from there to Europe, Africa, and America. It showed its virulence by killing 64 million rabbits on rabbit farms in Italy. The virus spreads among domestic rabbits and then escapes into local populations of wild rabbits. The virus is highly specific and affects only European rabbits (these are often found on other continents, like the rabbits that plague Australia). The fatality rate is about 95%.
Coordinated release of the virus at 200 to 300 sites in Australia was arranged. The Australians hoped this would minimize the emergence of genetically resistant rabbits or of milder virus. Calicivirus release in the drier parts of Australia (Western Australia, Northern Territory, and South Australia) resulted in a 95% death toll within a few weeks, much as expected. In other areas, eradication has been more erratic. The Australians might gain a few years’ respite, but the 5% survivors will not take long to rebuild a rabbit population that will be resistant to calicivirus.
Germ warfare is unreliable
Perhaps one reason the major nations so readily agreed to outlaw germ warfare is that it is ineffective. In practice, bullets and bombs are easier to produce and handle than biological weapons. Another issue is that even the fastest diseases, such as pneumonic plague, take at least 24 hours to kill. And 24 hours is plenty of time for a retaliatory nuclear exchange. Another drawback is the problem of delivery. Spraying is the standard method of distributing germs. Unfortunately, this relies on the weather. First, a breeze is needed—and second, the wind must blow in the right direction!
During the 1950s, the British government field-tested harmless bacteria. When the wind blew the germs over “healthy” farmland, most airborne bacteria survived and landed alive and well. In contrast, when the bacteria were blown over industrial areas, especially oil refineries, the airborne bacteria were wiped out. Many airborne industrial pollutants are lethal to bacteria and viruses. Even if the wind is favorable, most of the population of an industrial nation is found in cities, protected from airborne germs by air pollution!
Genetic engineering of diseases
Let’s take a harmless laboratory bacterium, such as Escherichia coli, and make it dangerous. We insert genes for invading human cells. We provide genes for tearing vital supplies of iron away from blood cells. We add genes for potent toxins that kill people in tiny doses. What have we made? An unstoppable disease that will wipe us from the face of the Earth? No, we just converted Escherichia coli into its near-relative, Yersinia pestis, the agent of bubonic plague. The reason we are not all dying of the Black Death today is not due to any lack of virulence by Yersinia pestis, but to modern hygiene. Improving diseases by genetic engineering is of minor significance. What we should really worry about is being in Mother Nature’s gun-sights. Any army that neglects hygiene is crying out for disease to thin its ranks. We don’t need “new and improved” diseases: Any of the old favorites could handle the mission, given favorable conditions.