The Secret of the Yellow Death

by Suzanne Jurmain

  John Moran, as he looked at about the time of the mosquito experiments.

  December 23 came. Then December 24. Both Moran and the other “infected mosquito building” volunteers seemed healthy. Then on December 25 at ten a.m., Moran felt a little strange. He took his temperature, noted that it was 100 degrees, and carefully wrote the figure on his chart. Two hours later, Moran checked again. His fever had climbed to 103. When Christmas dinner was served, Moran went to the mess hall and picked at his turkey, cranberries, and mashed potato. Then he went back to his tent and lay on his cot. Around three in the afternoon, Reed walked in. “Merry Christmas, Moran,” he said. “Anything new?” Moran pointed to the temperature chart. Reed checked the figures, looked at Moran’s flushed face, put his hand on the young man’s forehead—and called an ambulance.

  John Moran had joined the list of yellow fever victims.

  The two men who had slept on the mosquito-free side of the building remained in perfect health. It was clear—once again—that infected mosquitoes and nothing else caused the disease.

  The work was almost done. The experiments had been a success. In the hospital, John Moran was soon on the road to recovery; and, to Reed’s immense relief, none of the infected volunteers had died in any of the tests. By the end of December the team had done what they set out to do. They had established that infected mosquitos carried yellow fever. They had proved a theory, and they had also discovered an important way to fight the dreadful sickness. Because scientists now knew that mosquitoes transmitted yellow fever, they also knew that killing mosquitoes would immediately stop the spread of the disease. With the help of Dr. Finlay and a group of volunteers, the American team had taken a huge step toward conquering a deadly illness.

  The culprit: a female Aedes aegypti mosquito sucking human blood.

  Late December 1900

  It was time to honor the Cuban scientist who had started it all.

  On December 22, Major General Leonard Wood, the governor-general of Cuba, and members of the local medical community gave a huge banquet to honor Dr. Finlay. Reed traveled into Havana for the festivities. Carroll, who was always short of money, didn’t go because he couldn’t afford a dress uniform. Still, the room at Old Delmonico’s Restaurant in Havana was jammed with Cubans and Americans. There were toasts and speeches, handshakes and applause. Dr. Finlay was given a bronze statuette and congratulated in Spanish and in English. For years he’d been laughed at. For years people had said his mosquito theory was a joke. And now—now that a bunch of Americans had proved his hypothesis—Carlos Juan Finlay was the toast of Havana, one of the greatest, most famous men in Cuba.

  It was a wonderful, happy time. Everybody seemed to be celebrating, and on Christmas Day two of the officers’ wives gave a party at Camp Columbia. Since there weren’t many pine trees in Cuba, the women decorated a guava bush. They wrapped up presents. And when Reed opened his, the whole group burst out laughing. The officers’ wives had given Major Reed a big wire model of a mosquito, which Reed accepted, he later wrote his wife, “with many blushes.”

  On December 27 there was another party. This time it was a ball that kept Reed up till one a.m. Then, a few days later, it was December 31, the last New Year’s Eve of the nineteenth century.

  It was a beautiful, balmy evening. Reed sat at the big table in his quarters, pen in hand. As the hands of the clock moved toward midnight, he wrote to his wife:

  11:50 P.M. Dec 31, 1900 Only ten minutes of the old century remain, Lovie dear. Here I have been reading that most wonderful book—La Roche on Yellow Fever—written in 1853. Forty-seven years later it has been permitted to me and my assistants to lift the dreadful pest of humanity. . . . The prayer that has been mine for twenty or more years, that I might be permitted in some way or sometime to do something to alleviate human suffering has been answered!

  With the help of Dr. Finlay and the team, Reed had done something most people only dream of. He had made a discovery that would save lives, prevent pain, and make the world a better, happier place.

  It was a sweet moment.

  But it didn’t mark a final victory in the war on yellow fever.

  Scientists still had to find a cure for the disease. They still needed to track down and isolate the actual germ. And of course there were dozens of other basic questions still to answer. Why, for instance, had a few volunteers not gotten sick when they were bitten? What happened to the germ inside the insect’s body? And could a female mosquito possibly transmit the yellow fever germ to her offspring through her eggs?

  Carlos Finlay became a hero in Cuba. The scientist, who died in 1915, would have been pleased to know that in 1933 the Cuban government issued these stamps in honor of the hundredth anniversary of his birth.

  Someday, Reed hoped, researchers might find the answers to those questions.

  Someday, he hoped, investigators would find the germ, invent a preventative vaccine, and maybe even figure out a cure.

  But right now the clocks at Camp Columbia were striking midnight. Outside a corps of army buglers sounded taps to mark the passing of the century. And as Dr. Walter Reed put down his pen, he knew with happy certainty that the first part of one great scientific problem had been solved.

  After December 31, 1900, the battle against yellow fever continued.

  As soon as the results of the Reed team’s work were known, public health officials launched an all-out campaign against the mosquitoes that carried the disease. In the United States and Cuba a virtual army of sanitation workers used poison fumes to kill mosquitoes that lurked in buildings and wiped out eggs by spraying oil on the pools, ponds, puddles, and containers of still water where the insects liked to breed. Killing the mosquitoes killed the yellow fever germs the insects carried, and by the end of 1901 there were no cases of the illness in Havana, Cuba. By 1905 the United States was free of the disease. And between 1902 and 1914—thanks to an effective battle against germ-bearing mosquitoes in Central America—U.S. workers were able to safely build the Panama Canal.

  As the threat of yellow fever gradually receded, people showered Dr. Finlay and the Reed team scientists with honors, thanks, and praise. Statues of Carlos Finlay were set up in Cuba. A medical society and an American elementary school were named after him; and—though he never won—Dr. Finlay was nominated for one of science’s greatest awards, the Nobel Prize in medicine, three times before his death in 1915.

  Sanitation worker spraying oil on water to stop mosquitoes from breeding in the early years of the twentieth century. Efforts like this wiped out yellow fever in Cuba, the United States, and parts of Central America by 1914.

  Although Walter Reed died of appendicitis in 1902, soon after his return from Cuba, he, too, became a hero. Researchers adopted Reed’s belief that all volunteers in scientific experiments should be fully informed of all the risks. In 1909 the American government named the Walter Reed Army Hospital in Washington, D.C., after the team’s chief investigator. And in 1929, Congress awarded all the American volunteer scientists (including Dr. Jesse Lazear) one of the nation’s highest honors, the Congressional Gold Medal, for their work on yellow fever.

  The Congressional Gold Medal for the conquest of yellow fever. This medal was awarded to each of the American scientists and volunteers who took part in the experiments. In addition to the medal, Congress awarded pensions to participants and decreed that the names of all the yellow fever scientists and volunteers be published each year on a special roll of honor in the Army Register.

  But while people and governments were honoring past work on the illness, twentieth-century scientists were looking for new ways to fight the terrible disease. Until his death in 1907, Dr. James Carroll continued to search for the yellow fever germ. Although his efforts were unsuccessful, Carroll ultimately came to believe that the disease is caused by a microbe that is much smaller than bacteria. Dr. Aristides Agramonte, who taught bacteriology in both the United States and Cuba before his death in 1931, tended to agree. And by 1927 scien
tists knew that the disease was produced by a virus—an extremely tiny, extremely simple microorganism that is so much smaller than bacteria, it cannot be seen with an ordinary microscope.

  Scientists infecting white mice with yellow fever. Studying the disease became easier after researchers learned that white mice could get yellow fever if the virus was injected directly into their brains.

  Once scientists had identified the virus, the next step was to make a vaccine that would prevent people from getting the disease. That, however, proved difficult. Although researchers worked on the problem, progress was slow until scientists discovered two facts that the Reed team had not known. In the late 1920s and early 1930s researchers learned that that some types of monkeys could actually get yellow fever and that, under special conditions, the virus could sometimes be grown inside the bodies of ordinary white laboratory mice. Using animals made experimental work much easier; and, finally, in 1936, Dr. Max Theiler developed a vaccine that safely kept humans from getting the disease.

  Research also continued on other fronts; and, during the twentieth century, scientists answered many of the questions about the cause and spread of yellow fever that had puzzled earlier investigators. Researchers learned that an infected female mosquito can pass the virus on to all her offspring through her eggs. They found that the yellow fever virus actually enters every cell of an infected mosquito’s body. And they discovered that a female mosquito transmits the disease by dripping infected saliva into the wound while she is sucking blood.

  The scientist Max Theiler, who won the Nobel Prize for developing a vaccine that prevented humans from getting yellow fever. To avoid risking the health of others, Theiler first tested the yellow fever vaccine on himself.

  Additional investigation uncovered more facts, and scientists soon realized that a mosquito must bite a yellow fever patient in the first three days of the illness in order to pick up the infection. They also learned that the virus may have to remain in the insect’s body for as much as seventeen days before the bug can infect a person with the disease. To scientists, this information was particularly interesting because it explained why some of the Reed team’s volunteers did not come down with yellow fever after being bitten. In some cases, it was clear that the team’s mosquitoes weren’t carrying the germ because they hadn’t bitten yellow fever victims during the crucial three-day infectious period at the beginning of the illness. In other instances, volunteers did not get sick because the germ was not allowed to stay inside the host mosquito long enough.

  Today, researchers believe that the yellow fever virus originated in West Africa and was brought to the Americas by slave ships carrying infected insects. They also know that the germ still lurks in the dense jungles of Africa and South America, where it infects monkeys and is carried by mosquitoes who transmit it to endless generations of offspring through their eggs.

  In Africa and South America dense jungles like this one still harbor mosquitoes that carry the yellow fever virus.

  Vaccination programs and mosquito extermination programs have slowed the spread of yellow fever, but it is impossible to completely eliminate the virus. Many poor countries cannot afford to pay for the lifesaving vaccine, and some people now believe that insecticides should not be used to kill mosquitoes because these poisons may damage the environment.

  Photograph of the yellow fever virus (the small circles) taken with an electron microscope. Viruses are so much smaller than bacteria that they can be seen only with an electron microscope capable of magnifying objects at least 190,000 times.

  At this moment there is still no cure for yellow fever, and deadly outbreaks of the disease can still occur. In the early 1960s, 30,000 people died during a yellow fever epidemic in Ethiopia. The illness continues to plague people in parts of Africa and South America. Only three companies—in France, Brazil, and Senegal—now rank as approved yellow fever vaccine producers and demand is sometimes high. When the government of Paraguay failed to provide enough vaccine during a 2008 outbreak of the fever, desperate people mobbed clinics, yelling, “Vaccinations! Vaccinations!”

  In the twenty-first century yellow fever is still one of the many diseases that threaten humans, and doctors are still trying to develop new ways to combat the illness. Some, but not all, modern research can be done with laboratory animals. For that reason, in countries around the world, many scientists and many ordinary people—like those who worked with Reed—are now knowingly risking possible illness, injury, or even death in order to voluntarily participate in experiments that test new vaccines, new treatments, new medical techniques, and new drugs that may one day benefit humanity.

  Appendix

  THE VOLUNTEERS

  Unfortunately, little is known about many of the young men who dared to participate in the mosquito experiments, the infected clothing and bedding experiments, or the experiments conducted after December 1900 that involved injecting blood from a yellow fever victim into a healthy volunteer. Lists of the volunteers who took part vary, and some names have probably gone unrecorded. The following partial list does, however, attempt to provide some information about those who were willing to risk their own lives to save others from the scourge of yellow fever.

  THE AMERICAN VOLUNTEERS

  Andrus, John (1879–1952). Private Andrus served in the army hospital corps and assisted the Reed team by caring for captive mosquitoes. On January 24, 1901, he overheard Reed and Carroll having an argument over whether Reed should offer himself as a volunteer in the yellow fever experiments. Reed was determined to participate. Carroll believed this was ill advised because of the major’s age and poor health. Andrus, who feared that if Reed got yellow fever the work would come to a standstill, finally offered to take Reed’s place in the experiment. On January 25, 1901, blood from a yellow fever patient was injected into Andrus’s body, and, several days later, the private developed the disease. Andrus, who subsequently received the Congressional Gold Medal, later wrote a description of his experiences with the team, which is included in the Philip S. Hench Collection at the University of Virginia. He is #25 in the photo on [>].

  Bullard, John (1872–1944). John Bullard was one of only two civilians who volunteered. He received the Congressional Gold Medal for his participation in the yellow fever experiments.

  Cooke, Robert (1874–1943). Dr. Cooke, a physician, was originally stationed at Pinar del Rio. He refused to accept payment for taking part in Reed’s tests, but was later given the Congressional Gold Medal for his participation in the “infected clothing and bedding” experiments. He is #4 in the photo on [>].

  Covington, Albert (1877–1934). Private Covington of the Twenty-third Battery, Coast Artillery Corps, was injected with blood from a yellow fever patient and became ill with the disease. He was later awarded the Congressional Gold Medal.

  Dean, William (1877–1928). Private Dean became sick after being bitten by an infected mosquito on September 6, 1900. His case was the first to truly convince Reed that yellow fever was carried by mosquitoes. He was later given the Congressional Gold Medal for his participation in the experiments (see [>], [>]).

  England, Thomas (1876–1943). Private England earned the Congressional Gold Medal because of his participation in the infected clothing and bedding experiments. He is # 24 in the photo on [>].

  Folk, Levi (1870–1936). Private Folk developed yellow fever after being bitten by an infected mosquito in the experiments. He later received the Congressional Gold Medal.

  Forbes, Wallace (1878–1948). Private Forbes, a member of the hospital corps, became ill with yellow fever after receiving blood from a victim of the disease. He was later given the Congressional Gold Medal.

  Hamann, Paul (1876–1933). Private Hamann became ill with yellow fever after participating in the team’s blood inoculation experiments. He received the Congressional Gold Medal.

  Hanberry, James (1875–1961). A member of the hospital corps, Private Hanberry participated in the mosquito experiments, became ill with yellow
fever, and was later awarded the Congressional Gold Medal.

  Hildebrand, James (1862–1935). Private Hildebrand was awarded the Congressional Gold Medal for his role in the yellow fever experiments.

  Jernegan, Warren (1872–1919). Private Jernegan was the only volunteer who participated in all three phases of the team’s experiments. He participated in the infected clothing and bedding experiment, the mosquito experiment (he did not get sick), and the blood injection experiments. He received the Congressional Gold Medal. He is #14 in the photo on [>].

  Kissinger, John (1877–1946). Private Kissinger, a member of the hospital corps, was in charge of the operating room at Camp Columbia when he became fascinated by the team’s experiments and agreed to be bitten by infected mosquitoes. Although he initially refused to accept payment for participating in the experiments, he later changed his mind and received money for his services. He also, subsequently, received the Congressional Gold Medal. Unfortunately, Kissinger never entirely recovered from his bout of yellow fever. After spinal problems destroyed his ability to walk, Kissinger’s wife supported her husband by doing laundry. Pensions from the government and from private donors eventually provided some financial relief, but, in his later years, Kissinger developed mental illness. Before dying, the former army private described his experiences in Cuba in an essay that is now part of the Hench yellow fever collection at the University of Virginia and can be read on their website. Kissinger is #10 in the photo on [>