Ebola’s end: History’s lessons
Ebola continues to ravage nations in West Africa, as a fragmented, private-sector relief effort reels under the challenge and governmental and multi-national aid starts to arrive.
A lethal virus that causes uncontrolled bleeding and leaves patients and corpses highly contagious could not have chosen a more hospitable locale than the West African nations of Liberia, Sierra Leone, Guinea and Nigeria for its worst-ever outbreak. Poor, under-educated, where the public-health systems are highly stressed in the best of times, the virus has evoked fear in the populace and dread in the medical community, where the number of infections have been called “unprecedented,” according to the World Health Organization.
On Aug. 28, the World Health Organization reported that 1,552 people had died of Ebola in West Africa. Though nobody knows the actual death toll, WHO said the disease could sicken or kill 20,000 before being brought under control. The 47 percent survival rate in the current outbreak is considerably higher than in previous ones.
The immediate trigger for the current unrest in Monrovia was the government’s decision to place an Ebola treatment center in a slum called West Point, says Gregg Mitman, a University of Wisconsin-Madison professor of medical history who was doing field work in Liberia this summer. “It’s the most dense slum in Monrovia, with little water and sanitation infrastructure. The idea of putting a treatment center there was deeply troubling, creating an unnecessarily risky situation. People were partly responding to that decision.”
Liberia, like most of West Africa, suffers shortages of trained people, medical equipment, and education. “There is virtually no public health infrastructure,” says Mitman. “I see wildly varying figures, with a high of 200 doctors for 3.6 million population. Some hospitals don’t have latex gloves, let alone other protective health care equipment. Between this and mistrust of the government, you have a situation ripe for Ebola’s spread.”
“The Ebola outbreak in West Africa is ‘a complete disaster,’ and health agencies do not yet grasp its scope, the president of the relief group Doctors Without Borders said Tuesday.
‘No one yet has the full measure of the magnitude of this crisis,’ the president, Dr. Joanne Liu, said in an interview. ‘We don’t have good data collection. We don’t have enough surveillance.'” Source: New York Times, 19 Aug. 2014.
Ebola is a hemorrhagic virus, and death is a frightening, gory affair. But Ebola is less contagious than influenza since it spreads by contact with body fluids, not through the air. Although two infected American aid workers were released from the hospital after treatment with an experimental drug, the doses now available can apparently be counted on one hand, and so will not halt the epidemic.
After decades of isolated Ebola outbreaks in Central Africa, the location and severity of the current epidemic were surprising, says Lawrence Madoff, a professor of medicine at the University of Massachusetts, and editor of Pro-MedMail, a global bulletin board on emerging disease.
“Ebola outbreaks characteristically ended much more quickly and spread less,” Madoff says, since they were in remote areas and affected hundreds, not thousands, of patients. Lacking familiarity with the disease, “it took longer to figure out what was going on and begin the process of isolating people.”
Lacking effective treatment or vaccine, “containment and control of outbreaks have depended on traditional public health measures,” Madoff says, “which boil down isolating patients in hospitals or other health care settings, and preventing transmission by education.”
As non-profit health organizations and governments confront the surging epidemic, The Why Files decided to look at how past epidemics have ended, as an attempt to foreshadow the eventual termination of the horror called Ebola. After all, epidemics all end – or at least, simmer down to a relatively manageable level. (Even the death toll of malaria has been cut significantly to an estimated 627,000 per year. That’s still unacceptably high, but the coordinated campaign to reduce contact with mosquitoes has been working.)
Smallpox: many steps to victory
Smallpox, a virus that causes hideous pustules on the skin, has been known since antiquity. Amid a resurgence in Europe during the 16th and 17th centuries, smallpox reached the Caribbean with Spanish conquistadores in 1518. Two years later, it entered Mexico, where it reportedly killed 67 to 98 percent of people infected.
Smallpox was used as a biological weapon in 1763, when a British commander distributed infested blankets to the Ottawa tribe in Pennsylvania. We’ve head accusations of similar behavior by other colonial powers, but according to one source,1 “In the territories administered by Spain, Portugal and France, it can confidently be asserted that the native die-off from disease was unintentional, since these countries relied on indigenous labor and contacts in order to exploit their colonies for their benefit.”
Still, the entry of smallpox, along with measles and typhus, sapped the vitality of Native Americans as they were confronting ruthless colonial powers.
Inoculation is a deliberate infection with a mild virus that confers immunity to the target virus. This early defense against smallpox originated in China or Persia, and traveled through Turkey to Western Europe at the beginning of the 18th century. During the American revolution, British soldiers had more exposure and immunity to smallpox, and General George Washington inoculated his troops for protection.
In 1796, British physician Edward Jenner introduced the first vaccination by injecting an eight-year-old boy with lymph material from someone infected with cowpox, a related virus that is less dangerous. (Inoculation and vaccination are both deliberate tactics to boost the immune response to disease, with overlapping meanings.)
When the boy gained immunity to smallpox, vaccination spread. The British attempt to introduce smallpox vaccine to its colonies faced resistance in India, where the transfer of bodily fluids violated the caste system. “Vaccine was a hard sell in a lot of the Western world, let alone in a place like India, where there was a long counter-tradition of inoculation,” says J. N. Hays, emeritus professor of history at Loyola University of Chicago, and author of a history of disease2.
Smallpox is the only major disease that has disappeared in the wild. Although the vaccine deserves much of the credit, the latter stages of the anti-smallpox campaign (during the 1960s and ’70s) “hinged on successful isolation of cases,” Hays says. Thus while vaccines can indeed be a “magic bullet,” the victory over smallpox shows the value of mixing public-health tactics.
Cholera: A mixed message on public health
Public health is the attempt to treat a population as a whole rather than its members one-by-one. Many experts trace the foundation of public health to an outbreak of cholera in 19th century London. Cholera is a bacterial gastrointestinal disease, and a classic example of “fecal-oral” transmission.
You may know the story: In 1854, physician John Snow placed London’s cholera cases on a map. Noticing that they clustered around one water pump, he convinced the authorities to remove the pump handle, and the epidemic ended.
Snow deserves credit for sleuthing the source of the epidemic. But there’s more to the story. Even Snow recognized that the epidemic was already waning when the handle was removed, undercutting the connection between removal as cause and epidemic end as effect.
The relationship between water and cholera was also unclear. This was before the germ theory of disease was accepted (Louis Pasteur’s work on the subject began in 1860). Therefore, Hays says, “People had difficulty accepting that this could be caused by some microorganism, it had to be some combination of forces.”
Further investigation showed that the water pump was three feet away from a “cesspit,” a gathering pit for human waste. Yet even years later, Hays adds, “A lot of bright people in the Western world were still resisting” the idea that bacteria in the water caused cholera. The two were conclusively linked during an outbreak in Hamburg, Germany in the 1890s.
Cholera highlighted the limits of medical knowledge in other ways. “For much of the 19th century,” Hays points out, “what Western doctors were doing in responding to a disease that was enormously dehydrating was bleeding people, or giving them an enema. Their remedy for cholera was to bleed and flush the body of fluids, which is what the disease was doing anyway.”
Black death: a mysterious plague
The resolution of the greatest epidemic in European history carries an even more complex lesson about the decline of disease. Black death, or bubonic plague, peaked in Europe between 1347 and 1353, causing waves of deaths that took, in round numbers, 30 to 60 percent of the population.
Like cholera, the response to plague was plagued by misconceptions, says John Aberth, an independent historian of the black death from Vermont. “The largest social factor in black death was the flight of people, the abandonment of victims. Almost all doctors advised that it was contagious, could be spread person-person, and therefore, the best preventative response was to flee. ‘Flee early, flee far, return late’ [by the ancient Greek physician] Galen, was a typical response, but it was wrong, because plague is generally not spread by direct human contact but through the bite of fleas that live on rats.”
Although outbreaks of bubonic plague (caused by the bacterium Yersinia pestis), still occur, mass deaths do not. Why did plague fade away without significant medical help?
If the chain of infection is rat-flea-human, plague’s decline could result from something that affected any one of them, says Hays, “or it could be that Yersinia pestis, for reasons known only to itself, decided to become less virulent.” Since speculation is free, these theories could explain plague’s decline:
* A climate change during the “Little Ice Age” impaired flea survival and broke the chain of transmission.
* The hosts, black rats, were displaced by Norway rats. (This “old favorite does not seem to be good explanation now,” Hays says.
* People could have reduced disease transmission with quarantines.
* The brick houses that replaced thatched houses after the great London fire of 1666 reduced rat habitat and consequently plague itself.
Public health: the principles
Any account of the decline of epidemics must account for the wide variety of pathogenic organisms – virus, parasites, fungi and bacteria, and the vectors that transmit them to different hosts. “The disappearance of any one epidemics might be tied to something that happened at any step along the way,” says Hays. “It’s a chain of events that may be broken at any place.”
Although vast epidemics of black death are, thankfully, history, plague’s waxing and waning comprise a medical mystery. Hays points to a recent study the “argues that plague may survive for decades or centuries in burrowing rodents, and occasionally, for some reason, explode into the amplification phase, when the fleas seek the human being as host. The answer to where plague went may be that it’s still here.”
While fighting plague comes down to fighting rats, the Ebola crisis must be solved without vector control, and without a magic bullet — a vaccine or good drug.
In other words, the response to Ebola must rely on tried-and-true generic infection-control procedures. “We have developed a way to control epidemics in the 20 century,” says Carol Byerly, an adjunct professor of history at the University of Colorado, who has written about yellow fever control during the building of the Panama Canal in the early 1900s.
In 1937, Byerly notes, Wade Hampton Frost of the U.S. Public Health Service see pp. 223 here “wrote a whole protocol, involving finding patient 0 [the first patient], and isolating, treating and educating. That is what is going to work in this case: to find all the cases, isolate, treat and test all their contacts.”
Infectious diseases “love chaos, and thrive on war, famine, revolution and poverty of course,” says Byerly. “What comes to mind is the importance of effective government and a robust public health system.”
Many tools can be chosen to battle infectious disease. During a malaria outbreak in Italy in the early 20th century, Byerly says, “The government wanted to build an industrial economy, and needed a stronger population, so it offered quinine [a malaria medicine], but the peasants did not trust it, understand it.” Eventually, she says, the government established schools to teach modern medicine, and used them to distribute quinine and organize efforts to control the mosquitoes that spread malaria.
The successful campaign included education, vector control and medical treatment of individuals. These days, efforts to control malaria also rely on bed nets and long-lasting insecticides that kill mosquitoes that roost inside houses at night — two options that were not present in Italy.
As Byerly observes, the example shows that “Every epidemic is unique: the pathogen, the culture, human behavior and institutions all interacting, the time and place.”
Ebola – the upshot
Mitman, a medical historian, says Ebola in West Africa must be understood and controlled through an appreciation of its cultural and political context. Although a decade of peace has followed the Liberian civil wars fought between 1989 and 2003, “the generation that grew up during the war is very suspicious, fearful and mistrustful of the government.”
The quarantine being used to restrict Ebola in West Africa are threatening the food supply, says Mitman. “West Point [a Monrovia slum] was cordoned off, and no supply was getting in, and people can’t get out. Food prices are rising, and this has the potential for a larger humanitarian crisis.”
There is also a hesitancy toward outside do-gooder, he adds. “Liberians have been the subject of medical research for a long time. It was always people flying in, doing their work, and flying out. There was not a huge investment in building medical knowledge and public health capacity within communities that have been the subject of study by Western doctors and scientists.”
That skepticism and suspicion appears in social media, Mitman says. “Even among friends, rumors circulate that Ebola might have been introduced by western biomedicine so they could test the vaccine on us.” However, Mitman also sent this optimistic Aug. 3 blog post from Liberia.
On Aug. 4, the World Bank pledged up to $200 million to support the battle against Ebola in Africa. By August 19, 60 Centers for Disease Control (CDC) staff in Guinea, Liberia, Nigeria, and Sierra Leone were doing surveillance, contact tracing, database management and health education to aid the response.
But Mitman urges prudence as outside experts ramp up their involvement. The epidemic can only be contained by isolating and treating patients, but “the critical point is, when the CDC says we know how to contain Ebola, perhaps they do in the U.S., but even there, there are going to be segments of the population where suspicions arise.”
If outside experts “go into an African village and start asking questions without starting by talking with village elders, doors will be closed,” Mitman says. “You can’t go in there as a medical expert and simply say, ‘Tell me all your contacts.’ It’s not going to happen and it’s going to create further problems. Cultural sensitivity is key to engaging local people who are critical to the success of containing this outbreak.”
You’ve seen the photos. Isolating carriers of a dangerous virus takes equipment, training and time. Although scientists and doctors around the world have shifted their attention to drugs and vaccines, don’t count on a magic bullet any time soon.
And that returns the issue to resources, says Hays, the historian of epidemics. “If there is anything that worries me — in theory we are pretty good at knowing how to control disease — it’s whether we are willing to spend the resources that may be necessary to do it.”
– David J. Tenenbaum
Kevin Barrett, project assistant; Terry Devitt, editor; S.V. Medaris, designer/illustrator; David J. Tenenbaum, feature writer
- Plagues in World History, John Aberth, Rowman and Littlefield, London, 2011. ↩
- The Burden of Disease, J.N. Hays, revised edition, Rutgers University Press, 2009 ↩
- On Aug. 24, the head of the Centers for Disease Control discussed the assistance program. ↩
- Taking a page from the history book? Nigeria draws on polio mistakes to contain ebola outbreak. ↩
- The World Health Organization Disease Outbreak News provides up-to-date coverage of potential epidemics. ↩
- Article in Science suggests double vaccines ‘could hasten the end of polio.’ ↩