Monthly Archives: September 2014

Thucydides and the Plague of Athens

The “Plague of Athens” was a severe epidemic, which struck the city between 430 and 427 B.C.E.; reemerging there in 425 B.C.E. It is believed to have originated in Ethiopia, and then to have spread throughout the Mediterranean. It hit Athens early during the Peloponnesian War (431-404 B.C.E), at a time when the city was under siege by Sparta. The Plague claimed the lives of about a third of Athens’ citizens. Yet the extent, to which it might have contributed to the ultimate Spartan victory in the war, or to the eventual decline of the Athenian empire, is not known.

The Athenian historian, Thucydides, in his History of the Peloponnesian War, provides the only known eye-witness account of the Plague. For that reason alone, Thucydides’ account is of great historical interest. Yet Thucydides also set down his own truly remarkable (considering the time) insights into the epidemiology of the Plague.

Thucydides (460-395 B.C.E.)
Thucydides (460-395 B.C.E.)

First, Thucydides noted that the most densely populated sections of Athens had the highest frequency of Plague victims. [The Athenian leader, Pericles, responded to the Spartan siege by moving people into Athens from the countryside. The resulting overcrowding unwittingly worsened the epidemic.] Second, Thucydides noted that physicians had highest likelihood of any group in the population of succumbing to the Plague. [Physicians were the ones most frequently exposed to affected individuals.] Moreover, Thucydides reported that the Plague could be transported from one place to another; an observation he made during the Athenian siege of Poteida (430/429 B.C.E.), when a reinforcing body of Athenian soldiers transmitted the Plague to Athenian soldiers already at Poteida. From this observation, Thucydides deduced that the Plague was not due to some “malign influence” confined to Athens and its immediate environs, as would have been consistent with Greek medical theory of the day (see below). [Incidentally, Plato tells us in his dialogues that Socrates was a veteran of the siege at Poteida.]

Taken together, these observations led Thucydides to put forward, perhaps for the first time, the notion that an affected individual might pass on a disease, directly, to another individual who is not yet affected. In contrast, medical theory of the day held that epidemics result from miasma: poisonous vapors, which inflicted anyone who might breathe them. Miasma could be caused by the weather, by the stars, or by the displeasure of the gods.

Miasma readily explained why large numbers of people could become ill at the same time. They simply breathed the same air. Yet Thucydides was in fact proposing something radically different; that is, contagions. And he did so twenty-three centuries before Pasteur, Lister, Koch and others in the 19th century established our modern germ theory of disease! Before then, western medicine continued to attribute epidemics to miasma.

Another of Thucydides’ key observations was that individuals who recovered from the Plague were resistant to future attacks. Moreover, he recognized that their resistance was specific. That is, survivors of the Plague were resistant to further attacks of the Plague, but not to other diseases. This insight too was remarkable since our modern concept of specific acquired immunity came even later than our concept of infectious disease. Thucydides’ deduction may have influenced his fellow Athenians, since those individuals who survived the plague comprised the few who were willing to care for those who fell ill.

Thucydides could not know the nature of the contagion he was proposing, although he thought it might be a fluid. And, while the epidemic in Athens is referred to today as a plague, it almost certainly was not bubonic or pneumonic plague.

Some modern references to the Plague of Athens presume that it was smallpox. Thucydides does mention the body “breaking out into small postules and ulcers,” and other aspects of his description of the disease are consistent with smallpox. Yet Thucydides also tells us that dogs too were susceptible to the Plague. However, humans are the only host for smallpox.

At any rate, the exact cause of the Plague of Athens is not known for certain. Modern experts have attributed it to a variety of pathogens, including Yesinia pestis, typhus, anthrax, measles, and even Ebola, in addition to smallpox. Yet none of the diseases associated with any contemporary pathogen exactly matches Thucydides’ description of the Plague of Athens. It is possible that the pathogen responsible for the Plague, and the Plague’s symptoms as well, might have changed over 24 centuries. Another possibility is that the pathogen responsible for the Plague has since become extinct.

Thucydides’ insights are not nearly as well known today as they ought to be. Perhaps that is because they had no lasting influence on his contemporaries or, for that matter, on those who came later. Consider how the history of medical science might have been different if Hippocrates, and others of Thucydides’ contemporaries, had been influenced by his observations.

How might we explain why Thucydides’ insights were largely ignored by his contemporaries and, indeed, lost to western medicine? One reason is that the ancient Greeks had precious little scientific knowledge that might have enabled them to understand the Plague. Moreover, Thucydides’ Athenian contemporaries made little distinction between medicine and religion. For instance, Sophocles (one of the great dramatists of classical Greece) believed that the plague had a supernatural cause, and that an oracle, rather than a physician, needed to be consulted for its resolution.

Hippocrates (about 460 to 370 B.C.E.) may have been the first physician to believe that diseases have natural causes, rather than being punishments inflicted by the gods. However, none of Hippocrates’ writings suggest the concept of a contagion. In any case, after Hippocrates’ death, the practice of Greek medicine actually regressed back to a more superstitious state.

What’s more, contrary to popular opinion; the Greeks did not actually invent the scientific method. Nor were their theories developed with the intent of experimental verification. Aristotle’s science held that nature did what pure logic suggested it should do. For example, he said that heavier objects fall faster than lighter objects, because it is their purpose to do so. Neither Aristotle nor his contemporaries actually looked to see if heavier objects indeed fall faster than lighter ones (they don’t). In fact, the first individual known to have actually tested this premise was Galileo (1564-1642). Only afterwards did observation become the basis for western science. And, this transition was not easy since, as we know well, the powerful churchmen of Galileo’s day rejected the concept that the universe might be governed by natural laws, since that notion might be at odds with the omnipotence of God.

References:

Hays, J. N., Epidemics and Pandemics: Their Impacts on Human History, ABC-CLIO, Inc., Santa Barbara, California, 2005.

Holladay, A.J., and J.C.F. Poole. 1979. The Plague of Athens, The Classical Quarterly 29:282-300.

Related Postings:

Edward Jenner and the Smallpox Vaccine, posted on the blog September 16, 2014.

Smallpox in the New World: Vignettes featuring Hernan Cortes, Francisco Pizarro, and Lord Jeffry Amherst, posted on the blog February 24, 2014.

 

 

 

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Edward Jenner and the Smallpox Vaccine

The Greek historian, Thucydides, discovered twenty four centuries ago that smallpox survivors were resistant to subsequent smallpox episodes. Thucydides’ remarkable perception, more than two thousand years before awareness of infectious agents, may have influenced his fellow Athenians, since those who survived the infection comprised the few who were willing to care for those who fell ill. Thucydides’ insight was lost to Western medicine. However, the independent perception in China, that that smallpox survivors are entirely safe from a second attack, led to the development there, about 1,000 years ago, of an empirically based smallpox control strategy, in which uninfected individuals were protected by inhaling powder prepared from dried smallpox scabs. The scabs were from individuals who survived a mild smallpox infection. They were dried to further diminish the likelihood of the recipient undergoing a severe infection.

By 1700, the process had spread to Africa, India, Arabia, and the Ottoman Empire. The Arabians streamlined this approach by transferring the dried postular material on the point of a needle. Lady Mary Wortley Montague, the wife of the British ambassador to Turkey, had her children undergo the process in the early 18th century, and then brought the practice to Europe, where British physicians dubbed it “variolation.” [See Cotton Mather, Onesimus, George Washington, and Variolation, posted on the blog November 20, 2013, for an account of the introduction of variolation to the New World.]

As might be expected, variolation carried risks that would not be acceptable today. However, those risks were tolerable in 18th century Europe, when as many as one person in ten died of smallpox. We now have the smallpox vaccine, which was the first, and arguably the most successful vaccine ever put into practice. Remarkably, the smallpox vaccine was developed in 1798 by an English country doctor, Edward Jenner, a half-century before the germ theory of disease, and 100 years before the actual discovery of viruses!

At thirteen years of age, Jenner was apprenticed to an English surgeon; a mister Ludlow. While Jenner was in Ludlow’s service, he heard the doctor suggest to an ill milkmaid that she might be coming down with smallpox. The milkmaid replied that she could not get smallpox since she already had cowpox. The notion, that having had cowpox protects one against smallpox, may actually have been common among English country folk of the day, but it was just as commonly dismissed by physicians.

At 21 years of age, Jenner continued his training under the prominent British surgeon, John Hunter. When Jenner ran the milkmaid’s comment by Hunter, the great surgeon encouraged his young protégé to investigate the matter further.

Now, perhaps the most remarkable part of the story. History usually credits young James Phipps as the first person “vaccinated” by Jenner. And, while Phipps, in 1796, was the first individual Jenner inoculated with cowpox, and subsequently challenged with smallpox, he was, in fact, not the subject of Jenner’s first experiment. Instead, that person was Jenner’s first son, Edward, Jr., born in 1789. Jenner inoculated Edward Jr. with swinepox when the infant was only 10 months old!

Jenner could not have known about microbes, and he left no records revealing his purpose in inoculating Edward Jr. with swinepox. It may be relevant that cowpox was relatively rare at the time, while a similar pox disease was more common in pigs. Regardless, Jenner’s baby son became sick on the eighth day with a pox disease, from which he fortunately recovered. Then, his father proceeded to challenge him with genuine smallpox!

Fortunately, Edward Jr. also resisted his father’s experimental attempt to transmit smallpox to him. His father tried again in 1791, when the boy was two, and again when he was three. Edward Jr. resisted each of Edward Senior’s smallpox challenges, most likely because the swinepox virus immunized him against smallpox. We can only guess how Mrs. Jenner regarded these happenings.

Jenner also used several other young children in his experiments, including his 11-month-old second son, Robert. One of these children died from a fever, possibly from a contaminant (streptococcus?) in the vaccine. In those days one could hardly know what might be in a vaccine.

In Jenner’s famous and classic experiment involving James Phipps, he used a lance to pierce a cowpox postule on the wrist of a young milkmaid, Sarah Nelmes. He then scratched James twice on the arm with the lance. Six weeks afterwards, Jenner challenged James with smallpox from a postule on the body of a smallpox patient. The smallpox challenge caused only a slight inflammation on James’ arm, indicating what now would be recognized as an immune reaction. During the next 25 years or so, Jenner challenged James twenty more times with smallpox, with never any sign of the disease.

JENNER Edward Jenner administering the first smallpox vaccination in 1796.  Painting by Ernst Board.

Not much else is known about James Phipps, who was only 8 years old when he was first inoculated by Jenner. Additionally, nothing is known about James’ parents and whether they may have consented to Jenner’s use of James. However, Jenner referred to his young subject as “poor James,” and looked after him in later years, suggesting he may have felt some remorse. Moreover, he eventually built a cottage for James and even planted flowers in front of it himself. Little is known of Sarah Nelmes.

Thankfully, the sorts of experiments Jenner carried out cannot be done today. Yet because of his efforts, the once dreaded smallpox virus now exists only in the laboratory.

More than a century would have to pass before it could be appreciated that the protection against smallpox that was generated by inoculation with cowpox and swinepox depended on the facts that these two viruses are immunologically cross-reactive with smallpox virus and that they produce a relatively benign infection in humans. [When contemporary vaccinologists develop vaccines to protect against viral diseases, they are essentially tapping into biological mechanisms that have been perfected through eons of natural selection. Indeed, the principal fact exploited by vaccinologists is that natural infection, by many different viruses, results in lifelong immunity against the same virus.]

Some final points:

It is possible that Jenner was not the first to use cowpox to vaccinate against smallpox. However, he was the first to eliminate the cow from the procedure. That is, he transmitted immunity from person-to-person, without the need for an infected cow. Nevertheless, he hung in his house the hide of the cow, which had initially given Sarah Nelmes cowpox.

Although Jenner demonstrated that his vaccine could be passed indefinitely from person-to-person, neither he, nor anyone else at the time, had the insight that this indefinite passage meant that the active agent in the vaccine must be able to replicate.

References:

Greer Williams: Virus Hunters, Alfred A. Knopf, 1960.

Cotton Mather, Onesimus, George Washington, and Variolation, posted on the blog November 20, 2013.

Related Postings:

Smallpox in the New World: Vignettes featuring Hernan Cortes, Francisco Pizarro, and Lord Jeffry Amherst, posted on the blog February 24, 2014.

Notable Individuals Who Survived Smallpox and One Who Didn’t: Featuring Abraham Lincoln, Elizabeth I, Josef Stalin, and Pocahontas, posted on the blog March 10, 2014.

Peter Piot: The Discovery of Ebola Virus

Peter Piot co-discovered Ebola virus in a laboratory in Belgium in 1976. Two weeks after the discovery, he risked his life in Zaire, now the Democratic Republic of the Congo, studying the Ebola outbreak at its source.

piot

Piot went on to have a distinguished career and is now best known for his advocacy of HIV/AIDS control and prevention, particularly in Africa. Toward that end, Piot participated in the first international project on AIDS in Africa, leading the way to understanding the African AIDS epidemic. He helped found and then served as Executive Director of the Joint United Nations Program on HIV/AIDS (UNAIDS) and then as Assistant-Secretary-General of the United Nations. It is safe to say that Piot helped to save hundreds of thousands, and perhaps even millions of lives. He currently serves as director of the London School of Hygiene & Tropical Medicine.

As a boy growing up in Belgium, Piot fantasized of having exotic adventures. One of his dreams was to travel to Africa, where he might lend a hand to underprivileged people. A more mature Piot, aware that infectious diseases caused most deaths in the developing world, thought that medicine might be an ideal means of fulfilling his fantasies. But, in medical school, one of his professors emphatically advised him: “There’s no future in infectious diseases…Just don’t do that, that’s a waste of time, we have antibiotics, we have vaccines, it’s all solved.”

However, Piot chose to ignore his professor’s advice. “But I wanted to go to Africa. I wanted to help save the world. And it seemed to me that infectious disease might be just the ticket and full of unresolved scientific questions. So I ignored him.”

[Aside 1: The view expressed by Piot’s professor was not altogether rare in the day. As noted in Virology: Molecular Biology and Pathogenesis (1), “Shortly before the emergence of HIV/AIDS in 1981, many health professionals held the opinion that the development of antibiotics against bacteria, and vaccines against poliovirus and other viruses, relegated the threat of infectious disease epidemics to history. Indeed, in 1962, Sir MacFarlane Burnet, who won the Nobel Prize in 1960 for his work on immunological tolerance, stated “…one can think of the middle of the 20th century as the end of one of the most important social events in history; the virtual elimination of the infectious disease as a significant factor in social life.”

AIDS and Ebola were not the only “new” infectious diseases to shatter the kind of optimism voiced by Burnet and others. There was also Lyme disease (caused by the bacterium Borrelia burgdorferi), Legionnaires’ disease (caused by the bacterium Legionella pneumophila), SARS, and West Nile virus. What’s more, rotaviruses are now a major cause of death, especially in children in the developing world, and hepatitis C virus may now affect more people worldwide than even HIV. Moreover, earlier pathogens, such as Mycobacterium tuberculosis, Corynebacterium diphtheriae, the dengue hemorrhagic fever virus, and yellow fever virus, have reemerged over the past 30 years. Making matters worse still, increasing resistance of bacterial pathogens to antibiotics, due in part to misuse of these once “miracle” drugs, is now a major threat to public health.]

The following, sometimes spine-tingling excerpts from Piot’s 2012 memoir, No Time to Lose (2), tell how 27-year-old Piot, two years out of medical school, helped to discover Ebola virus in a laboratory in Antwerp in 1976.

“On the last Tuesday in September 1976 my boss at the microbiology lab was alerted that a special package was on its way to us from Zaire. It was flying in from Kinshasa: samples of blood from an unusual epidemic that seemed to be stirring in the distant Équateur region, along the river Congo.”

[My notes: The blood sample was from a Flemish nun who had been carrying out missionary work in Zaire. She was stricken with a mysterious illness that was killing scores of people there. Piot was then working towards a PhD in Microbiology, awarded to him in 1980 by the University of Antwerp.]

“Nothing quite like this had happened in the two years I had so far been working in a junior position at a lab at the Prince Leopold Institute of Tropical Medicine in Antwerp, Belgium. But I knew it was part of the job. We sometimes took in strange samples of bodily fluids and tried to work out what they were. Our lab was certified to diagnose all kinds of diseases, including arbovirus infections like yellow fever, and the working hypothesis for this epidemic was reported to be “yellow fever with hemorrhagic manifestations.”

“I never actually worked with any suspected yellow fever. It wasn’t every day we received samples from as far away as equatorial Zaire. And it was clear this was an unusual sample, and that something pretty curious had occurred, because several Belgian nuns apparently died of the disease even though their vaccinations were completely up to date.”

“The next day—September 29—the package arrived: a cheap plastic thermos flask, shiny and blue. I settled down with Guido Van Der.” [The italics here, and in the following excerpts, are mine, for emphasis.]

“Groen—a shy, funny, fellow Belgian aged about thirty, a few years older than I—and René Delgadillo, a Bolivian postdoc student, opened it up on the lab bench. Nowadays it makes me wince just to think of it. Sure, we were wearing latex gloves—our boss insisted on gloves in the lab but we used no other precautions, no suits or masks of any kind.

We didn’t even imagine the risk we were taking. Indeed, shipping those blood samples in a simple thermos, without any kind of precautions, was an incredibly perilous act. Maybe the world was a simpler, more innocent place in those days, or maybe it was just a lot more reckless.

“Unscrewing the thermos, we found a soup of half-melted ice: it was clear that subzero temperatures had not been constantly maintained. And the thermos itself had taken a few knocks, too. One of the test tubes was intact, but there were pieces of a broken tube—its lethal content now mixed up with the ice water—as well as a handwritten note, whose ink had partially bled away into the icy wet.

“It was from Dr. Jacques Courteille, a Belgian physician who worked at the Clinique Ngaliema in Kinshasa. He described the thermos’s contents as two vials, each containing 5 milliliters of clotted blood from a Flemish nun who was too ill to be evacuated out of Zaire. … She was suffering from a mysterious epidemic that had so far evaded identification, possibly yellow fever.”

“I was still trying to find my way in the labyrinth of infectious diseases research, and this kind of thing made my heart beat faster. Guido and René picked out the one remaining test tube of blood from the thermos and set to work. We needed to look for antibodies against the yellow fever virus, and other causes of hemorrhagic or epidemic fever such as typhoid. To isolate any virus material, we injected small amounts of the blood samples into VERO cells, an easily replicable cell lineage that is used a lot in labs. We also injected some into the brains of adult mice and newborn baby mice. (I never liked this aspect of the work. Sometimes we needed to inject patient tissue into the testicles of rats, to isolate Mycobacterium ulcerans, the cause of Buruli ulcers, and it made me cringe.)”

All this work was done with no more precautions than if we had been handling a routine case of salmonella or tuberculosis. It never occurred to us that something far more rare and much more powerful might have just entered our lives.

[Aside 2: The italicized excerpts take me back to my postdoctoral days in the early 1970’s, when my colleagues and I routinely mouth-pipetted the much less (but still) dangerous SV40 (3), and the monkey kidney cell cultures that the virus was grown in. Indeed, we were more concerned with contaminating our cultures with mycoplasma, than with infecting ourselves with a simian virus.]

“In the next few days, the antibody tests for yellow fever, Lassa fever, and several other candidates all came up negative, and it seemed likely that the samples had been fatally damaged by their transportation at a semi-thawed temperature. We bustled nervously around the mice and checked our cell cultures four times a day instead of two. On the weekend, each of us popped in to check the samples. All of us, I think, were hoping something would grow.”

“Then it happened. On Monday morning, October 4, we found that several adult mice had died. Three days later all the baby mice had also died—a sign that a pathogenic virus was probably present in the blood samples that we had used to inoculate them.”

“By this time our boss, Professor Stefaan Pattyn, had also gleaned a little more information about the epidemic in Zaire. It seemed to be centered on a village called Yambuku, where there was a mission outpost run by Flemish nuns—the Sisters of the Sacred Heart of Our Lady of s’Gravenwezel. (S’Gravenwezel is a small town north of Antwerp.) The epidemic had been raging for three weeks, since September 5, and at least 200 people had died. Although two Zairean doctors who had been to the region had diagnosed the malady yellow fever, the patients suffered violent hemorrhagic symptoms, including extensive bleeding from the anal passage, nose, and mouth as well as high fever, headache, and vomiting.”

“Previously I had been excited about the work we were doing; now I was inflamed. If we were hunting for signs of a hemorrhagic virus, this was outbreak investigation of the most stirring variety. I truly loved the detective thrill of working in infectious disease. You came in and figured out what the problem was. And if you managed to figure it out quickly enough—before the patient died, basically—then you could almost always solve it, because, just like my medical school professor of social medicine had said, solutions had by this time been found for almost every kind of infectious illness.”

Piot relates that Pattyn “ knew we were not equipped to do the work in safety. In 1974 there were only three labs outside the Soviet Union that could handle hemorrhagic viruses: Fort Detrick, a military lab in Maryland that did high-security bioterrorism work on anthrax and other highly lethal diseases; the Army High Security Laboratory in Porton Down, in England; and the so-called hot lab at the Centers for Disease Control (CDC), in Atlanta.”

“Nonetheless, we continued to bustle around like amateurs in our cotton lab coats and latex gloves, checking our VERO cell lines. The cells began detaching from the glass sides of their containers: it was either a toxic effect or an infection, but either way, cytotoxicity had kicked in. That meant we might be close to isolating a virus, and we began extracting cells to cultivate them in a second line of VERO cells. And Pattyn had been told we should expect more samples from Zaire in the next few days.”

At this point in the story, Pattyn received a message from the Viral Diseases Unit of the World Health Organization (WHO), instructing him to ship all of the Belgium lab’s samples of the mysterious new virus to Porton Down in Britain.

“Pattyn was furious, and I too was upset. It looked as though our outbreak investigation was over before it had even begun. Glumly, we prepared to pack everything in tightly sealed containers: the patient serum, the inoculated cell lines, and the autopsied mouse brains and samples. But then Pattyn told us to keep some of the material back. He claimed that we needed a few more days to ready it for transport. So we kept a few tubes of VERO cells, as well as some of the newborn mice, which were dying. Perhaps it was a stubborn rebellion against the whole Belgian history of constantly being forced to grovel to greater powers. That material was just too valuable, too glorious to let it go. It was new, it was exciting—just too exciting to hand it over to the Brits or, in particular, to the Americans.” [A few days after Porton Down received the samples from Antwerp, the British lab passed a portion on to the CDC in Atlanta, which was the world’s reference lab for hemorrhagic viruses.]

So, with some of their sample material held back, the misadventures in the Antwerp lab kept on. “There was a rack of secondary tubes in the lab, which we had inoculated after the first VERO cell line was killed. We knew there was something in there—something that was trouble—but still, we had taken out the rack so we could examine the tubes under the microscope. Doing that kind of work wasn’t Pattyn’s job. He was a micro-manager but he wasn’t a technician, and in fact he could be rather clumsy. But impulsively he reached for one of the precious tubes, to check it out himself under the scope, and as he did so it slipped from his hand and crashed on the floor.

Little René Delgadillo was the one who got his shoes splashed. They were good, solid leather shoes but René bleated, “Madre de Dios” (Mother of God!) while Pattyn swore, “Godverdomme” (Goddamn!)—and there was a moment, just a beat, of blank fear. Immediately we whisked into action: the floor was disinfected and the shoes removed. It was just a small incident. But it struck me only then how lethal this thing really might be and the huge risks we had been taking in handling it so cavalierly.

Piot then relates that electron micrographs of the new virus, prepared at the university hospital, showed it to be strikingly similar morphologically to the Marburg virus.

“Marburg was clearly a very scary illness, and as we did not have Marburg virus–specific antibodies, we could not definitely conclude whether our isolate was Marburg. Perhaps it was a different virus with similar morphology.”

“Pattyn was not suicidal. Once he had established that ‘our’ virus was—at the very least—closely related to the terrifying Marburg, he had the sense to shelve all further work on it and sent the remaining samples directly to the high-security lab at the CDC.”

Shortly afterwards, the CDC informed the Belgium lab that the mystery virus did not react with Marburg antibodies, and was indeed a new, previously unknown agent. Recalling the earlier advice from his medical school professor, Piot remarked, perhaps with some satisfaction, “… my professors were wrong.”

Piot then tells us, “I was still very excited. It felt as though my childhood fantasy of exploration was almost within my reach. I kept arguing that we had to follow up our work, go to Zaire and check out the epidemic. I felt strongly that we shouldn’t hand this world-class discovery over to some other team. We had identified this virus, after all, so we should be the ones to establish its lethality and its real effects on the ground.”

Piot then relates the political machinations that enabled him to fulfill his dream of going to Africa, where he would help to analyze and contain the deadly epidemic. In Zaire, in the quarantine zone, Piot lived among dying Zairians, repeatedly risking his life collecting blood samples from victims and gradually helping put together a picture of how the virus (eventually known as Ebola, after the river where its first outbreak occurred ), was transmitted.

Piot’s experience in Zaire led him to believe that he might benefit from additional training in infectious diseases. So, he came to the United States to receive further training on sexually transmitted diseases. Upon returning to Belgium, he became the go-to doctor for people arriving from Africa with exotic tropical infections. The emergence of the African AIDS epidemic led Piot back to Africa. He was now well prepared to lead the world’s response against the newer and eventually much graver HIV/AIDS epidemic there (4, 5).

(1) Virology: Molecular Biology and Pathogenesis, by Leonard C. Norkin, ASM Press, 2010.

(2) No Time to Lose: A Life in Pursuit of Deadly Viruses, by Peter Piot, W. W. Norton & Company, 2012.

(3) SV40-Contaminated Polio Vaccines and Human Cancer, posted on the blog, July 24, 2014

(4) The American Public’s Response to the 2014 West African Ebola Outbreak, posted on the blog, August 10, 2014.

(5) Thabo Mbeki and the South African AIDS Epidemic, posted on the blog, July 3, 2014.