Most Uncivil

An entomologist started the U.S. Civil War.1 At 4:30 a.m. on April 12, 1861, at the harbor entrance to Charleston, South Carolina, a cannon shot rang out from Fort Sumter. The man who pulled the lanyard was Edmond Ruffin, the editor of the Farmers' Register and a naturalist who had devoted himself to the study and control of grain moths. The bombardment continued for 34 hours, and the next day the United States officially declared war on the Confederacy. It is oddly apropos that an entomologist fired the first shot in a war during which insects would kill far more soldiers than would canons, firearms, and bayonets.

The Civil War showcased forms of entomological warfare that military commanders had been refining for centuries. The bloodiest of American conflicts not only marked a culmination of insect prowess on the battlefield but also provided an ominous glimpse of what was to come in the next century. To understand the place of this conflict in the drama of entomological warfare, we must first appreciate the insect actors and their supporting cast of pathogens.

Of the 488,000 soldiers who perished in the Civil War, two-thirds died of disease—and insect-borne pathogens were among the primary killers.2 Although lice transmitted typhus, fleas carried plague, and mosquitoes spread yellow fever, these diseases claimed only a couple of thousand victims. Typhus was unknowingly suppressed by delousing, a popular pastime that the soldiers sardonically termed "skirmishing." Like primates grooming one another on the plains of Africa, the men patiently picked the eggs (nits) from each other's hair, a process that they called "(k)nitting work." The vermin were given nicknames alluding to human enemies: "bluebellies" by the South and "graybacks" or "Bragg's bodyguard" by the North. Infested clothes were boiled in salt water or singed over a fire, the sound of extermination being compared to that of popping corn. As for bubonic plague, biologists speculate that the disease never had a good chance to develop in the eastern United States, as the vector favored drier environments. And yellow fever may have been suppressed by a series of fortuitous frosts that limited the life span and range of the mosquito carrier during the war.3 Rather than these insect-microbial partners that we've already met, the Civil War featured a unique pair of deadly duos: flies carrying enteric pathogens and mosquitoes transmitting malaria.

As for intestinal maladies, the medical records of the Union allow more precise estimates than those of the Confederacy.4 There were 1,739,135 cases of diarrheal disease among the Federal troops leading to 44,558 deaths, and scholars estimate that the Confederates suffered more than a million cases with at least 30,000 deaths (see Figure 6.1). The various enteric pathogens were commonly transmitted by a retinue of flies that followed the armies and flourished in the detritus of war. Consider that the Army of the Potomac had 56,000 mules and horses, and one begins to get a picture of the tons of feces that littered the camps. Slit-trench latrines were rarely dug, so human excrement added to the mountains of animal dung. Battlefields were often littered with corpses, and even if human remains were buried before becoming flyblown, the shattered bodies of livestock were a maggoty windfall. But in an odd twist of entomological fate, the flies' affinity for decaying tissue sometimes turned these insects into medical saviors.

After major battles, the poorly equipped doctors were overwhelmed by casualties. Often, days would pass as the mangled men waited their turn, and blow fly maggots (family Calliphoridae) would infest the wounds. This would seem like adding horrific insult to injury, but perceptive doctors soon realized that the infested wounds healed faster and led to fewer amputations. Some, such as J. F. Zacharias of the Confederate army, even took the next logical step:

During my service in the hospital at Danville, Virginia, I first used maggots to remove the decayed tissue in hospital gangrene and with eminent satisfaction. In a single day, they would clean a wound much better than any agents we had at our command [scalpel and nitric acid].5

The fly larvae provided two benefits: they consumed the dead and decaying tissue, and they excreted a nitrogenous waste product, allantoin, which accelerated the breakdown of necrotic flesh and promoted growth of new tissue. However, the number of lives saved by the feeding and excrement of maggots was far exceeded by the lives lost to cholera, dysentery, and other such illnesses.

Figure 6.1. If this ward in Washington D.C.'s Carver General Hospital is typical, most of the soldiers are suffering from pathogens transmitted by lice, fleas, flies, or mosquitoes. Of the 488,000 soldiers who perished in the Civil War, two-thirds died of disease—and insect-borne pathogens were the primary killers. Fly-borne intestinal maladies and mosquito-borne malaria accounted for about 5 million cases and more than 150,000 deaths. (Library of Congress)

Figure 6.1. If this ward in Washington D.C.'s Carver General Hospital is typical, most of the soldiers are suffering from pathogens transmitted by lice, fleas, flies, or mosquitoes. Of the 488,000 soldiers who perished in the Civil War, two-thirds died of disease—and insect-borne pathogens were the primary killers. Fly-borne intestinal maladies and mosquito-borne malaria accounted for about 5 million cases and more than 150,000 deaths. (Library of Congress)

The various species of flies that feed on carrion, feces, and garbage are called "mechanical vectors." That is, they transmit the pathogens without the microbes reproducing within the insects. However, the offal heaps, dung piles, and cesspools provided plenty of opportunity for bacteria to flourish, so the flies had no difficulty picking up enough microbes to infect the soldiers. These insects operated as a public transportation system for pathogens with regular stops at the fetid latrines and field kitchens. In addition to the enteric diseases carried by flies, another malady has been attributed to these vectors: typhoid. However, Civil War physicians often lumped this disease with the other major, insect-borne disease: malaria.

The Union medical records reported 1,315,955 cases of malaria, with 10,063 deaths.6 Medical boards thought that malaria and typhoid could transform into one another, so they also reported typho-malarial fever, which accounted for another 57,400 cases and 5,350 deaths. In all, the Confederates probably added another million victims and 10,000 corpses to the tally. Although the physicians believed that typhoid and malaria were interchangeable diseases, the two maladies have little in common other than their symptoms.7 Victims suffer high fevers and incapacitating weakness, along with diarrhea, stomach pain, and nausea. While typhoid's fever may also cause a rosy rash and malaria's fever is sandwiched between bouts of soaking sweats and bone-rattling chills, these symptoms did not differentiate the maladies in the minds of 19th-century physicians. Both illnesses debilitate a person for weeks, but malaria is far more likely to remain within a victim's body for years.

Typhoid is caused by bacteria that enter via the digestive system and then spread to the bloodstream, bone marrow, and liver. The microbe uses the bile ducts to return to the intestinal tract, where it is passed in feces. The Civil War didn't produce the highest rate of typhoid among 19th-century conflicts. That dubious honor goes to the Spanish-American War in 1898, which saw 369 Americans fall in battle while 1,939 died of typhoid. Medical experts later concluded that the pathogen had been spread by flies that flourished in unsanitary military camps.

Malaria, on the other hand, has a rather more complicated story.8 The cause of the disease is a protozoan parasite—one of four species of Plasmodium— that proliferates in the gut lining of an Anopheles mosquito. Once the microbes burst from the insect's cells, the single-celled pathogens migrate to the mosquito's salivary glands. When the vector feeds on a host, the protozoa are injected into the bloodstream. On reaching the liver, the protozoa set up house and reproduce. Their offspring are released into the circulatory system, where they infiltrate red blood cells. Here, the microbe either continues to divide and attack blood cells or it produces gametes—the protozoa's version of eggs and sperm. These male and female gametes are ingested by another mosquito in the course of blood feeding. Once in the insect, the gametes fuse to form a zygote that enters the mosquito's gut lining, and the cycle is complete.

Despite confusion as to what caused malaria, it was the only insect-borne disease for which there was an effective intervention.9 Quinine could prevent malaria, but prophylaxis often failed due to underdosing; when higher amounts were used for treatment of infected soldiers, quinine provided significant relief. The Union Army consumed more than 19 tons of the drug during the war, and their blockade of the Confederacy drove the price of the quinine sulfate from $5 to $500 per ounce. Smugglers profited handsomely, with one sneaking $10,000 worth of contraband medicine inside a dead mule.

While the shortage of quinine was vexing, the greater problem was the excess of mosquitoes.

The most strategically important aspect of vector-borne disease was the way in which it set the stage for major campaigns. Mosquitoes often played the odd role of peacemakers, leaving opposing forces too sick to fight. The soldiers found that malaria "ate out their vitality, and even those who reported for duty dragged themselves about, the mere shadows of what they had been." Dozens of potential clashes were avoided, delayed, or minimized because of illness, but a couple of cases exemplify the importance of insect-borne disease.

Historians characterize Major General Frederick Steele as "quiet, unimaginative, fairly competent, lacking in drive or initiative and content to comfortably settle down like a police precinct captain"—in other words, a perfect man to stand by as his troops withered.10 Steele's 15,000-strong Army of Arkansas was supposed to drive the Confederates from the Mississippi River in a campaign that began in August 1863 and quickly bogged down. All the ingredients for a medical disaster were in place: an abundance of disease carriers (many of the Union soldiers had spent the previous summer in the South), a woefully inadequate supply of quinine, and a superabundance of what were, according to a military surgeon, "the largest, hungriest, and boldest" mosquitoes ever seen.11

The Army of the Arkansas never had a chance. Medical records showed a malaria rate of 1,287 cases per 1,000 men in the first year of the campaign—an impossibility unless one considers that this is a recurrent disease. That is, the average soldier suffered more than one bout of sweat, fever, and chills in the course of a year. Typically one-half to two-thirds of the men were too sick to answer reveille. And in some units, the losses were even worse; malaria reduced the Sixth Minnesota from 937 men to 79 in a matter of weeks. Although the Union fed 50,000 fresh troops into Steele's army, they could not offset the 178,000 medical casualties in the two years of the impotent campaign. Only once did the major general take the offensive, and the Confederates—who were also wracked by fever, but apparently less so than the Union—repulsed this feeble effort. In the end, Steele lost five times more men to disease, primarily malaria, than to combat. In other campaigns, however, what seemed initially to be a defeat by the insects turned into a victory of sorts.

From April to June 1862, two of the largest armies of the Civil War were poised for a massive conflict at Corinth, Mississippi.12 The scale of bloodshed promised to exceed that of Shiloh, earlier in April. However, this potentially decisive battle atrophied into a few minor firefights. By the time the Union was ready to attack, 173,315 soldiers were too sick to shoot. Swarms of flies first delivered a cornucopia of intestinal maladies. A colonel from Illinois took time from his bout of dysentery to note in his journal that he'd never seen house flies so thick. Then, by the end of May, the mosquitoes arrived in force and malaria swept through the camps of both sides.

Under the command of General Beauregard, the Confederates retreated down the Mississippi River valley. General Halleck's Union forces gave a halfhearted chase. Although some contend that Halleck feared his human enemy, what he genuinely dreaded was losing his army to disease. In retrospect, Halleck's strategy of not driving deep into the South paid off. By mid-summer the Confederate forces were suffering 179 cases of malaria per thousand men— three times the rate of Union soldiers. It seems that the general had made the critical link between ecology and disease, an association that others would fully grasp and exploit.

The devastating consequences of insect-borne diseases were not lost on the best of the war's commanders. They soon realized that the deadly phantoms could be turned into lethal weapons. This advance in military strategy required a novel version of the old rule of conflict. That is, when it came to entomological warfare, the best defense (against the insects) was a good offense (against the enemy).

No military mind of the 19th century surpassed General Winfield Scott's grasp of the strategic value of vector-borne disease, even without knowing the role that insects played on the battlefield.13 Scott's knowledge of yellow fever shaped his invasion plan during the Vera Cruz campaign of the Mexican-American War. Although he had no idea that mosquitoes carried "Black Vomit," he recognized that avoiding the hot, wet summer of 1847 was key to minimizing his losses on the march to Mexico City. Unfortunately, the War Department's logistical ineptitude put Scott's amphibious invasion—the first in U.S. history—months behind schedule. As a consequence, his troops were bedeviled by mosquitoes and paid a horrendous price before storming the Halls of Montezuma. In the course of the war, 1,192 American soldiers were killed in action while 11,155 died of disease. Although his efforts at strategic timing had been a bust, Scott knew that the key to beating the enemy was to first avoid losing to disease.

Fifteen years later, when General Scott formulated his "anaconda constrictor plan" for strangling the Confederacy, he again specified that victory was contingent on seasonality. He called for the campaign to take place in November, after "the return of frosts to kill the virus of malignant fevers below Memphis."14 The general's emphatic argument was not persuasive to the top brass, and the first attempt to take Vicksburg ensued in the summer of 1862. Camped in marshy areas with mosquitoes flourishing, malaria raging, and quinine in short supply, the troops were too sick to mount an attack on the Confederate positions that occupied higher, drier ground. Exemplifying the Union debacle was the Seventh Vermont, which arrived on June 25 with nearly 800 men and by the middle of July had fewer than 100 answer reveille. It didn't help the Connecticut regiment that their assistant surgeon prescribed daily drilling in the broiling sun, confidently maintaining that "if we don't exercise and perspire abundantly we shall get poisoned with malaria and die."15

General Scott's plans, had they been implemented, would have protected his troops from insect-borne disease. His insight was soon followed by the next step in the development of entomological warfare: using, rather than avoiding, blood-feeding insects. In this case, a Southern general rediscovered the strategy pioneered by Clearchus.

Beginning in spring 1861, the cry from the Union was "On to Richmond!" To the Northern mind, capturing the capital of the Confederacy would define victory. The first campaign was led by General George B. McClellan, who intended to lead the Army of the Potomac up the Yorktown peninsula and into Richmond.16 When the Union forces landed below Yorktown in April 1862, McClellan's medical director realized that a large swamp near the camp had the potential of spreading "malarial poison" once the weather turned warm. McClellan sought to avoid the impending epidemic by leading his army up the peninsula, while pushing back the Confederate forces with relative ease. However, as the Union troops closed in on Richmond in the early days of summer, increasingly fierce enemy resistance forced them to encamp near the sluggish Chickahominy River (see Figure 6.2).

Although malaria had been prevalent in this area for a century, the draining of swamps had dramatically reduced its incidence in the years before the Civil War. But war destroys culverts, drainage ditches, and canals while creating trenches, pits, and wheel ruts. As the summer wore on, corpses rotted in shallow, swampy graves and fetid latrines filled with human waste. Meanwhile, the mosquitoes and flies thrived. Malaria, typhoid, and dysentery descended on the Union camps with a vengeance, just as McClellan's nemesis had planned.

General Joseph E. Johnston, the Confederate commander in Richmond, knew exactly what he was doing when he refused to deploy his smaller army

Figure 6.2. The 5th New Hampshire Infantry slogging through the marshes along the Chickahominy River, outside of Richmond, Virginia. With his troops outnumbered, Confederate General Joseph E. Johnston kept the enemy pinned down in the swamps and allowed insect-borne disease, primarily malaria, to win a war of attrition. Thanks to mosquitoes and savvy military tactics, the Union's Peninsular Campaign of 1862 collapsed by late summer. (Library of Congress)

Figure 6.2. The 5th New Hampshire Infantry slogging through the marshes along the Chickahominy River, outside of Richmond, Virginia. With his troops outnumbered, Confederate General Joseph E. Johnston kept the enemy pinned down in the swamps and allowed insect-borne disease, primarily malaria, to win a war of attrition. Thanks to mosquitoes and savvy military tactics, the Union's Peninsular Campaign of 1862 collapsed by late summer. (Library of Congress)

in a direct engagement of the enemy. Through a series of constant withdrawals he'd slowed the Union forces until they were just five miles from the Confederate capital. There, he applied just enough resistance to keep them pinned down along the Chickahominy. By May, Johnston was drawing harsh criticism from his superiors for not throwing his men into a full counterattack. The political leadership saw the Union Army just a few miles from the heart of the Confederacy and thought Johnston's forces were dillydallying with defensive maneuvers. The frustrated general finally retorted, "I am fighting, sir, every day! Is it nothing that I compel the enemy to inhabit the swamps, like frogs, and lessen their strength every hour, without firing a shot?"17

The shrewd strategist knew that a bedridden enemy soldier was preferable to a corpse. The dead required a burial detail, if time and resources allowed, but the sick and wounded required care—doctors, nurses, beds, medicine, equipment, food, and transportation. Neither the dead nor the ill could fight, but the latter burdened the military machine. For each soldier who fell ill, two more were lost to the associated demands. And McClellan's army was foundering under the burden of 2,000 soldiers who languished in the Yorktown hospital—along with logistical costs of shipping home thousands more to recover or die.

Johnston finally attacked the Union forces on the last day of May in the Battle of Seven Pines. The two-day battle was indecisive in terms of the Peninsular Campaign, but it was a turning point for Johnston and his Confederate Army. The 55-year-old general was badly wounded and had to relinquish his command. He was replaced by a West Point classmate who had also been Winfield Scott's chief aid in the Mexican-American War. General Robert E. Lee proved to be nearly as aggressive as the mosquitoes, and McClellan began to lose his nerve.

The Union troops retreated to Harrison's Landing on the James River at the end of June, where the navy could protect them from Lee's counterof-fensive, but nothing could deter the insect onslaught. As summer came, the Union commanders began to fully appreciate the enemy's strategy. General John E. Wool realized that the Confederates were intentionally exploiting the unhealthy environment into which they had first drawn and now driven the Federal troops: "The rebels will do all in their power to keep McClellan where he is with his army, in the hope that death and desertion will so thin his ranks that by fall his army will be reduced by one-half."18

When surgeon Jonathan Letterman took over as medical director on July 4, he found the Union forces in a state of near collapse. He reported that "after about 6,000 had been sent away on transports, 12,795 remained," and at least one-fifth of these men were sick.19 Just two weeks later, another 7,000 soldiers were sent to the rear while replacements put the Union force at nearly 20,000. But these fresh troops were just so many mosquito meals and so much fly fodder. In August, Union leaders evaluated the fast-eroding situation. McClellan was losing a regiment a day between insect-borne disease and combat casualties among his sickly troops. With the epidemic certain to continue into autumn, the Army of the Potomac was ordered to withdraw. The Peninsular Campaign was over—the Confederacy had successfully allied with the insects to crush a larger army.

While large-scale applications of strategies that depended on insectan allies proved effective, only rarely did a commander have the acumen to pull off such a subtle scheme given that science had yet to reveal the intricacies of vector biology. Some of the more localized, tactical uses of insects as weapons were also quite cunning, while others were more like updates of ancient practices—as with the use of angry bees.

The 132nd Pennsylvania Volunteers at the Battle of Antietam demonstrated why commanders dread hysteria among the troops and how insect-induced panic can shape an engagement.20 Only a month into service, the Pennsylvania regiment was untested in combat until they closed in on the Roulette farm outside of Sharpsburg and the Confederate soldiers provided a baptism of fire. The green soldiers demonstrated that they had more courage than smarts by continuing their advance while seeking cover in the Roulette's bee yard. As they moved stealthily past the rows of hives, a cannon round ripped through the yard. The air was filled with angry bees and hot lead. Some of the men dropped their muskets and dashed into the nearby fields. The slapping, swearing regiment was disintegrating and the Union commanders worried that the panic would spread across the entire front. The Pennsylvania unit was ordered to doublequick march past the Roulette farm, which allowed the troops to escape the bees but left them without cover. The Confederates exploited the opportunity with a devastating volley of musketry. The survivors dropped to their bellies and bravely continued their advance on the enemy, proving that enraged bees have the potential to turn the tide of battle more decisively than lead balls.

Such uses of bees in the Civil War were more a matter of opportunism than planning—with one crafty exception. Faced with overextended supply lines, both Union and Confederate soldiers relied on plundering farms in order to feed themselves—and honey was a golden treasure. A feisty Georgia woman knew well the proclivities of hungry soldiers, and she prepared her entomological defenses accordingly.21 When the Union soldiers sauntered onto her property, they greedily eyed her beehives. But the men failed to see the cord running from one of the hives, across the yard, and through a hole in the door of her cabin. As they approached their sweet booty, she sprung the trap. Yanking the cord, she toppled the hive, sending the bees into a frenzy. The infantrymen were driven from the yard and some of the cavalry were thrown from their horses as the insects vented their wrath. Once the soldiers had left and the bees had exhausted their fury, she reset her booby trap and went about her business. She reportedly deployed her six-legged bodyguards on several occasions and the soldiers never succeeded in taking her food or supplies.

The tactical uses of bees in the Civil War almost seem quaint within the annals of biological warfare. But there were far more sinister gambits involving insects—tactics that darkly hinted at what would come as the science of entomology and the practice of warfare forged a diabolical alliance. With a bit of planning and luck, insects might be used to inflict yet another form of human suffering: hunger. The protracted course of modern warfare means that supplies are vital to victory. Whether the enemy dies from bullets or starvation doesn't much matter. During the Civil War, for the first time in history, a government was accused of having used insects to wage agricultural warfare. The Confederacy alleged that the Union had intentionally introduced a devastating crop pest from Mexico.

The harlequin bug (Murgantia histrionica), a strikingly patterned, orange-and-black, thumbnail-size insect, has a spectacularly catholic palate and a penchant for Southern crops. Piercing plants with its elongated mouthparts, the harlequin bug can destroy fields of asparagus, bean, beet, Brussels sprouts, cabbage, cauliflower, collards, eggplant, horseradish, kohlrabi, mustard, okra, potato, radish, and turnip. If none of these is on the local menu, then it will even attack fruit trees. And the best part—at least from the Union perspective—was that the harlequin bug rarely ventured north of the 40th parallel.

Although extensive crop damage added to the suffering of the South, there was never any direct evidence that Northern operatives had seeded enemy fields with this foreign mercenary.22 Entomologists now suspect that the insect probably moved up from Mexico on its own, but the importance of this episode lies not in its ultimate explanation but in what the accusation reveals about the role of insects as weapons. Whether or not the harlequin bug was conscripted by the Union, both sides were well aware of the potential for insects to be used as means of destroying the enemy's agriculture.23 And awareness of using living organisms to cause suffering behind enemy lines was not limited to starvation; inducing sickness was also considered.

Although science had not provided the essential knowledge that would have allowed insects to be weaponized during the Civil War, at least some military minds were contemplating how mysterious fevers could become part of a deadly arsenal. A shortage of know-how, rather than an abundance of morality, prevented insect-borne diseases from being made into weapons. The best-documented attempt at biological warfare failed, at least in large part, because the role of insects as vectors was yet to be understood.24

In 1863, Dr. Luke Pryor Blackburn attempted to smuggle clothing from yellow fever victims into the North as a means of spreading the disease. The Confederate surgeon also sent clothes gathered from yellow fever wards to President Lincoln in an assassination attempt. Although records indicate that

Dr. Blackburn (also known as "Dr. Black Vomit") was court-martialed for his efforts, his reputation apparently was unsullied, as he was later elected governor of Kentucky. Had the doctor known of the role played by the insect vector, he might well have been able to transport infected mosquitoes from afflicted regions into enemy cities.

It would not be long before scientific knowledge would catch up with military imagination. In the late 1870s, the work of Louis Pasteur and Robert Koch led to the germ theory of disease. In 1889, the little-known Theobald Smith, a medical doctor working for the U.S. Department of Agriculture's Bureau of Animal Industry, was the first scientist to definitively link an arthropod (the tick Boophilus annulatus) with the transmission of an infectious disease (Texas cattle fever). With this breakthrough setting the stage, Sir Ronald Ross and his team soon drew the link between malaria and anopheline mosquitoes. In 1900, Walter Reed and his associates discovered that Aedes aegypti was the vector of yellow fever. But the entomological breakthrough that would change the course of war in the dawning century involved one of the lowliest creatures, an insect incapable of flight and no larger that a typewritten "l"—as in louse.

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