It was not a disease. It was a curse.

That's what the family of one Liberian Ebola patient told Dr. Kent Brantly after their relative died in the treatment center where he worked in July.

The logical next step, the family believed, was to seek revenge and kill the person who placed the curse.

Brantly, an American Ebola survivor, shared that story on Capitol Hill last week. "In societies like this," Brantly told the House Foreign Affairs Committee, "where fear and distrust of authority are the norm, many still deny that Ebola is real and actively seek other explanations for the deaths of their loved ones."

When stories circulate about a seemingly irrational response to disease, it's easy to dismiss the reaction as a bizarre denial of reality.

But is it so hard to understand? In fact, attributing Ebola deaths to a curse is not as unreasonable as it might first seem. Communicable diseases are "especially terrifying because they are so chaotic and unpredictable," says Dartmouth political scientist Brendan Nyhan, who specializes in the study of misperceptions and beliefs in health and politics. "It's existentially terrifying. It makes us psychologically want to find simple explanations and cures."

And we all are susceptible. It's not uncommon for belief to trump medical fact. There's a long tradition of denial, superstition, wishful thinking, risk-taking (calculated or not) and willful ignorance when it comes to illness and health — true over time, anywhere in the world and for people of varying backgrounds.

Here in the United States, some parents opt against vaccinating their children, convinced, against all scientific evidence, that the vaccines cause autism. Some cancer patients turn to herbal cures, hoping for a better outcome than standard medical treatment will provide, or they wrongly attribute certain cancers to deodorant or cellphone use. In Pakistan, extremists are doing their best to prevent polio vaccination on the grounds that it is "un-Islamic" or part of a CIA plot. In South Africa, home to some of the world's highest numbers of HIV/AIDS cases, former president Thabo Mbeke horrified public health experts when he claimed that HIV did not cause AIDS. His government promoted herbal remedies; its unwillingness to provide anti-retroviral drugs to AIDS patients resulted in premature deaths of some 330,000 people, a Harvard study found.

So perhaps it should not have surprised anyone to hear Brantly's story, or to learn that some West Africans believe Ebola is a hoax or have attempted to fend the disease off with home remedies such as bathing in and drinking salt water. "This is human psychology," says Nyhan, "It's not going to change and we shouldn't expect it to."

Some of the reaction in Ebola-affected areas is immediately understandable when put in context. Avoiding health facilities is reasonable if those facilities are associated with isolation and death, not cures. "When you have a disease that has a high case fatality, the people go into a treatment center isolation ward, most people don't come out alive," says Dr. Daniel Bausch, a Tulane University virologist who has long studied hemorrhagic fevers like Ebola and worked to contain the Ebola outbreak in West Africa. "So people attribute causality to that." And when medical professionals are themselves falling ill and dying of Ebola, it's easy to understand why patients might be averse to approaching them for care.

To put the reaction to Ebola into broader perspective, it's also important to consider the region's political history. In the past decade or so, both Liberia and Sierra Leone have emerged from debilitating civil wars. Just a few dozen doctors remained in Liberia by war's end, and there, as in Sierra Leone, much of the health infrastructure had been gutted by violence. With weak postwar governments and few or damaged health institutions, "there's an information void," says Nyhan. Rumors and misperceptions are easily disseminated.

In circumstances like this, conspiracy theories can easily take root. In Liberia, some are convinced that Ebola is a hoax concocted by the government to attract more foreign aid dollars. In Guinea, Daniel Bausch says, he and colleagues confronted beliefs that they were bringing in Ebola "to control populations" or harvest organs. In Pakistan, when extremists allege that vaccine campaigns are a CIA plot, the claim resonates because the U.S. government did use a vaccination campaign several years ago to help track down Osama bin Laden while he hid with his family.

Those who believe in conspiracy theories aren't necessarily on the fringe, but they are likely to be "discontented with the established institutions in their society and especially with elites," according to Rutgers University sociologist Ted Goertzel. Another study published earlier this year found that half of 1,351 Americans surveyed believe medical conspiracy theories — including that the government is withholding natural cures for cancer, and that doctors and the government deliberately vaccinate children "even though they know these vaccines cause autism and other disorders."

"Although it is common to disparage adherents of conspiracy theories as a delusional fringe of paranoid cranks," they are "otherwise 'normal,'" the authors concluded.

They are also hard to dissuade. When frightening, random or seemingly unpredictable events strike, people may take comfort in casting authorities as villains. And they may stubbornly resist embracing facts that challenge their strong or long-held beliefs, especially if those beliefs are linked with their sense of identity or their religious and cultural world views. "The fear of social stigma is incredibly powerful," says Nyhan. "Social pressure matters."

Beyond this, Nyhan emphasizes, "People are not scientists." Correct medical information has to be presented in a clear and understandable way — ideally by trusted community leaders, not outsiders.

In a study published earlier this year, Nyhan and colleagues found that disseminating pro-vaccination literature to more than 1,700 U.S. parents had no effect on motivating them to vaccinate their children. In some cases the literature actually made them more determined not to vaccinate. The study concluded that "attempts to increase concerns about communicable diseases or correct false claims about vaccines may be especially likely to be counterproductive" — a troubling implication for public health communication, and one with no simple, straightforward remedy.

Sometimes the most powerful — and tragic — lessons come from firsthand experience. When Ben Franklin weighed whether to immunize his son Francis against smallpox, there was a small risk the child could die of the dose included in the inoculation, known in those days as "variolation." Franklin opted against it, to his eternal regret: Smallpox killed the boy in 1736, when he was four.

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