Peter Beilenson is weary; you can hear it in his voice. As Baltimore’s city health commissioner, he’s spent countless hours trying to allay public fears about West Nile virus, and so far, it doesn’t seem to be working. After fielding 39 television interviews in three weeks, with reporters grilling him over the supposed West Nile epidemic, if anyone from the media asks him about crows, mosquitoes or the virus itself, he sighs.
“West Nile is just a completely overblown threat,” he tells them, “you’re rousing fear without any real cause. Why don’t you focus on a real new threat?” he asks. “Like hepatitis C, the number one cause of liver cancer, failure, and transplants, why don’t you cover that? Or the divergent epidemic of multidrug-resistant AIDS?” Then he sighs again. “I mean, you may as well be covering every new gonorrhea case ... why are you doing this?”
Their answer, says Beilenson, is straightforward: “They say, ‘we don’t want to cover this, it’s ridiculous, we know it’s not a big deal,’ but the news directors and producers push them into it because it’s a sexy story.”
So what’s sexy about it? It’s dramatic: Victims are innocent, perhaps just working in the garden or watching their kid’s soccer game, when suddenly a mosquito strikes and their life is in danger.
Headlines and news stories are filled with sexy diseases: depending on what you read, mad cow disease may kill us at any moment, West Nile virus could be the next black plague and the person coughing next to you on the bus probably has antibiotic-resistant tuberculosis. Or it may all just be a bunch of nonsense. No one seems quite sure. There’s so much sensationalized and conflicting information out there, it’s hard to know where true concern lies. With West Nile virus recently showing up in metro Detroit in dead crows and blue jays, Baltimore’s experience this spring with the same threat should be instructive.
The problem is multifaceted, says Diane Griffin, professor and chair of molecular microbiology and immunology at Johns Hopkins in Baltimore. First of all, we like to feel in control. Though daily activities like, say, smoking and driving are more likely to be fatal than getting bitten by a mosquito, we tend to worry more about those mosquitoes.
“There’s no way to control getting bitten by a mosquito,” says Griffin, and though it’s extremely unlikely, “you could get bitten by a mosquito today and be dead in two weeks. It occurs suddenly, and you have no control. While driving your car, even though that’s a much riskier undertaking that we do every day, people think they’re more in control of what’s going on.” So they feel safe.
And then there are the media. As Beilenson points out, “there is a trend mediawise to cover things on a case-by-case basis,” which means diseases like West Nile end up in the headlines often and feel like a bigger threat than they actually are. “The media plays a big role in hyping up the scare factor in a lot of infectious diseases,” says Griffin. “It’s not in their best interest to put these diseases in context of how few people are actually affected in the great sphere of things.” If they did, there wouldn’t be a story.
In light of this, we’ve gathered medical experts to help put some of these “sexy diseases” in context, to see what’s news and what’s not.
In May of 1993, a young, robust Navajo man was rushed to a New Mexico hospital. He’d been generally healthy, except for a touch of the flu during the last week, but suddenly he couldn’t breathe. He died almost immediately. Doctors soon realized the man’s fiancee fell victim to the same fate only a few days earlier.
Investigators wasted no time: They started probing several nearby states, and within hours, they turned up five more young, healthy people who died suddenly from respiratory failure. Soon the death toll approached 20.
As researchers searched for the cause of the outbreak, a flurry of media reports about a mysterious disease began spreading fears. The outbreak was eventually traced to hantavirus, a rodent-borne disease that’s spread when someone inadvertently stirs up particles of infected rodent saliva, urine or feces while dusting, vacuuming or cleaning out barns.
Hantavirus claimed its first life in 1959, and today, according to the Centers for Disease Control, there is still no cure. Combine that with the dramatic details of the disease — victims who start off feeling a little achy and feverish can die within 48 hours — and you’ve got shocking newspaper articles and a potential for panic.
But adding some context can assuage much of the fear. “About half the rats in Baltimore carry hantavirus,” says Greg Glass, associate professor of molecular microbiology and immunology at Johns Hopkins, “and there are lots of rats in Baltimore. But the truth is, even in places where the virus is very common in the rodents, the proportion of people who get infected is very, very low.”
Hantavirus comes in many different strains: The one in the Southwest produces the dreaded pulmonary syndrome, the one in Baltimore rats causes a rarely fatal kidney disorder, while other strains cause variations of both problems. Each hantavirus strain works in much the same way: They attack the cells lining capillaries and cause plasma to leak into the organ’s open spaces. When this happens in the lungs, patients drown in their own fluids; in the kidneys, fluid buildup causes the organ to fail.
While there is no cure, some patients caught in the early stages can receive medical treatments (such as kidney dialysis) that allow them to successfully ride out the infection; some kidney patients undergo an unexplainable “spontaneous” recovery. As of December 2000, 277 cases of hantavirus pulmonary syndrome have been reported since the death of the young Navajo man in New Mexico. According to Glass, approximately .1 percent to .2 percent of people get infected with hantavirus. “This is in the ballpark of being significant from a public health perspective,” he says, which means it’s a disease for which prevention and careful monitoring is essential, but it doesn’t warrant fear and lifestyle change.
According to Glass, there are plenty of other rodent-borne diseases that are more worrisome than hantavirus. “Take leptospirosis,” he says. “It can also be a very severe disease, and if you survey people here in Baltimore, 16 percent of them have been infected with leptospirosis, so it’s orders of magnitude more common than hantavirus, yet people aren’t cognizant of it.”
Regardless of the numbers, people seem to worry more about hantavirus. “We liken the risk of hantavirus to an airplane crash,” says Glass. “Rationally, the risk is minimal, but it still scares people. Planes do crash, and people do get hantavirus — when they do, it’s dramatic. That’s what scares folks.”
Mad cow disease
Perhaps even more than hantavirus, mad cow disease comes with a portfolio that could induce terror in almost anyone. Proteins called prions contort into abnormal shapes the body can’t process, resulting in a progressive neurological disorder that slowly eats away at its victims’ brains, leaving them disoriented, trembling, and unable to eat.
The disease was first recognized in 1986, and by 1993 about 1,000 new cases were diagnosed in cattle each week. At the end of 2000, more than 177,500 cattle in the United Kingdom alone fell victim to mad cow disease, otherwise known as bovine spongiform encephalopathy (BSE). The disease has spread to cattle throughout France, Germany, Portugal, Spain, Italy and other European countries. Now it has spread to humans as a variant form of Cruetzfeldt-Jacob Disease (CJD), the human equivalent of BSE that occurs spontaneously or genetically in humans.
According to Donald Burke, professor of international health, “At its peak in Britain, there was enormous exposure of the human population to the disease. It was thought to be a curiosity, a hypothetical concern until human cases started to appear.” To date, there have been at least 84 cases of variant CJD, but since the disease has a long incubation period — about six to 10 years — the impact of BSE on the population in Europe is still unknown. So is the method of transmission: researchers believe variant CJD is caused by contaminated meat products (most likely those containing nervous tissue), but one victim was a vegetarian, which has raised questions about methods of transmission aside from eating meat.
So what about the United States? “We have not had a known-infected cow in the U.S.,” says Burke, “and we’ve had no known-infected human. But roughly 10 to 15 percent of Americans go through the U.K. sometime in their life, and lots of products made in the U.K. end up in the States. Given that we don’t know how the disease is transmitted, there are still a fair number of questions about it. If the question is, is mad cow disease still a theoretical risk in the U.S., the answer is yes.”
And “theoretical” is risk enough for public health officials to mount an enormous effort to contain BSE before it spreads. “The thing is, these are high stakes we’re talking about here,” says Burke. And because the stakes are high, the United States Department of Agriculture (USDA) has placed strict prohibitions on cattle imports to prevent the BSE from entering the United States. And because the spread of BSE in the U.K. is largely blamed on the practice of feeding cattle byproducts to other animals, the Food and Drug Administration (FDA) forbids the use of most animal products in feed. It has also established a strict system for monitoring pharmaceutical products derived from cattle to ensure that BSE contaminated sources aren’t used.
“We’re all coming off the awareness of the AIDS epidemic,” says Burke. “Everybody was slow to respond to AIDS, and we don’t want that to happen again.”
Health officials are justifiably nervous, and the public can tell. Media reports on mad cow disease appear weekly, if not daily, in many major newspapers in this country, and their message carries a daunting mad cow-disease-is-coming-to-get-us message. “People shouldn’t worry about eating beef products in the United States,” says Diane Griffin, “and I think that’s true in Europe as well.” Even in the U.K., the human exposures are most likely from products that contain bones or nervous tissue.
According to Griffin, the muscle tissue that makes up steaks isn’t likely to be the source of infection. “I avoid eating sausages in Europe,” she admits, “but I don’t avoid eating steak anywhere, or sausages in the U.S.” At the same time, she recognizes the public health concern: “I think there is reason to be vigilant, and one would hope that the USDA is looking carefully at the possible introduction of the disease into the United States. But from the public point of view, I don’t think there’s anything to be concerned about, other than just being glad that the USDA is taking precautions.”
Almost everyone has encountered a food-borne illness in one way or another. Diane Griffen remembers sitting in a restaurant in Lima, Peru, with a friend who had a craving for some egg custard pie. The pie, slumped in an unrefrigerated case in the middle of the room, had obviously seen better days. I wouldn’t do it if I were you, she told him. But he did. “Oh, he got sick as dog,” she says now with a chuckle. “It was so predictable. If you were ever going to get food poisoning, this was the perfect chance.” He was miserable for about 24 hours, but then it passed, which is precisely what most people expect from food-borne illnesses.
At the same time, “There’s actually much more of a problem with food-borne illness from things like E. coli than mad cow disease, even in the U.K.,” says Griffin. However, since many food-borne illnesses are familiar, and most aren’t fatal, they don’t get much press or concern. But the CDC estimates that food-borne pathogens cause 76 million illnesses each year in the United States alone. About 325,000 of those infected end up in the hospital, and about 5,000 die. Beyond those, there are an estimated 62 million illnesses blamed on unknown agents.
“In most cases,” says Lynn Goldman, professor of Environmental Health Sciences, “we don’t know what made people sick. So odds are, if you’re sick, hospitalized or dying of food-borne disease, no doctor has actually made the diagnosis about which bug did it to you.”
There are several pathogens that Goldman refers to as “the known killers,” those responsible for 1,500 deaths each year: salmonella, Listeria, and toxoplasma. Their symptoms range from diarrhea, fever and abdominal cramps to meningitis. In pregnant woman, infection can cause premature delivery and stillbirth.
Food poisoning used to be associated with church-picnic type outbreaks, where a group of people gathered at a picnic eat the same bad chicken salad and all got sick at once. “Now,” Goldman says with a nervous laugh, “the outbreaks we see are among completely unrelated people in completely different geographic locales.” In part, this is because of today’s highly sophisticated global food distribution system, which has caused a drastic change in the nature of food-borne illness.
Now, illnesses from things like produce, which were once thought to be harmless, aren’t uncommon. In a recent outbreak of cyclospora, cases that popped up around the country were later traced to Guatemalan raspberries irrigated with sewage-contaminated water. “If you think about it,” Goldman points out, “if you were traveling in Guatemala, you would be really careful about eating those kinds of foods.”
This is true, and it represents a new territory for specialists here at home: “This is leading to completely new approaches to control and protection in the U.S., because obviously, we can’t impose our water pollution laws on the governments of other countries, but we do need to make sure our food-safety standards are protecting people here.”
But imported foods aren’t the only risk factor: “When I trained in pediatrics nearly 20 years ago,” says Goldman, “we were taught as long as things are refrigerated, you don’t have to worry, but that isn’t the case anymore.” Listeria, which has been found in products like prepackaged cheeseburgers, is known to grow in cold conditions.
So what’s a consumer to do?
Carefully wash fruits and vegetables, advises Goldman, and take extreme caution with raw poultry and eggs, making sure to clean all contacted surfaces with soap and hot water. Eggs should be completely cooked; for meats, it’s the internal temperature that matters. Cook ground meat and pork to 160 degrees Fahrenheit; beef, veal and lamb steaks, roasts and chops to at least 145 degrees; and poultry to 180 degrees. No one — especially children and the elderly — should drink unpasteurized dairy products or juices.
West Nile virus
As many news stories have pointed out, West Nile virus is creeping steadily from state to state. Indeed, this virus, first isolated in 1937 from a woman in the West Nile district of Uganda, is one to keep an eye on. It has cropped up in Europe, the Middle East, west and central Asia, Oceania, and now, North America. And according to Butch Kinerney, spokesperson for the United States Geological Survey, it shows no signs of slowing down, having spread to 15 states and the District of Columbia.
“It’s spread much more quickly and much further geographically than we had expected it to do this year. There’s nothing geographically to stop it from moving to another part of the country.” Kinerney adds that the virus has been found as far west as Marion, Ind., and as far south as the Florida Panhandle, though it hasn’t been detected in some of the states in between.
The virus is spread by mosquitoes, which extract the virus when feeding on infected birds, then transmit it to people. Infected birds spread the virus to new mosquito populations (and thus to humans) as they migrate into yet-to-be-exposed areas.
“It’s much more likely that I’ll be run over by a bus than it is I’ll catch West Nile virus,” says Mark Wilson, associate professor of epidemiology and of ecology and evolutionary biology at University of Michigan, adding, “the current risk as we know it today is very minimal ... we know of no human fatalities in Michigan so far.”
Not everyone bitten by an infected mosquito will become sick. Most will just develop antibodies to the virus, which essentially vaccinate them against future infection. The virus can cause meningocephalitis, but only in a very small percentage of people. The majority of those infected have either no apparent illness, or what Gubler calls “a very mild nonspecific viral syndrome.” Less than 1 percent of infections, primarily in the elderly, result in neurologic problems that range from muscle weakness and confusion to meningitis, encephalitis and death.
Though the risk of West Nile virus is very small, the CDC doesn’t take it lightly. In 1999 there were 62 cases and seven deaths, in 2000 there were 21 cases and only one death. This impressive decrease in numbers was the result of an intensive surveillance, prevention and control program, which included giving away more than half a million bottles of insect repellent.
Clearly, the threat of West Nile virus doesn’t warrant staying indoors. What it does warrant, says Gubler, is “good surveillance, prevention and control programs. Because the best way to prevent human disease is to be able to proactively monitor virus activity in a particular area and implement mosquito control.”
Between 1985 and 1992, as the number of tuberculosis cases in the United States surged, many Americans paid no mind. They thought it was a problem of drug users, AIDS patients and the homeless population. But when a New York state prison guard came home from work one day with a fatal case of multidrug-resistant TB, his story hit the newspapers, and people noticed.
“Here was a white, middle-class guy with no bad habits who contracted multidrug-resistant TB and died from it through no fault of his own,” remembers William Bishai, associate professor of international health. “It really got people’s attention.”
His death led to massive alarm, and an infusion of money into TB research and control — in the ’90s, one billion dollars was spent controlling TB in New York City alone. TB rates have been creeping down ever since, but according to Bishai, that doesn’t mean the problem has been solved.
“It’s amazing how short our memory is,” he says with a sigh. “Because the rates have been going down for seven years, already federal and state authorities are trying to cut TB spending.” And according to Bishai, these cuts are drastically premature. It’s true that the number of TB cases in the United States has been slowly decreasing, but that’s not true for the rest of the world.
“TB remains a threat,” says Bishai. “In the year 2001, there will be more TB cases and deaths than ever before in the history of the world. The rates of infection are going up, and they never stopped going up — the epidemic is completely out of control.”
That said, it’s still true that the rates in the United States are decreasing, but Bishai fears that may not be the case for long. “Our long-term health is threatened by TB, mostly because of inadequacies of treatment overseas, a lack of resolve in the U.S. to continue what we’ve done to control TB, and the fact that global travel makes this a shrinking world.”
TB is a bacterial infection that’s spread through aerosols from an infected person. Though they may show no symptoms of disease, if a person with TB coughs, the infectious bacteria linger in the air for several hours, sometimes days, depending on ambient sunlight. All it takes is a deep breath to catch TB, because, as Bishai points out, “we share the air.”
More often than not, TB is treatable, says Diane Griffin. “The real risk with tuberculosis isn’t getting infected, it’s getting proper medical care if you do get infected.”
A lack of proper care can cause immediate problems for patients, and long-term problems for others in the form of antibiotic-resistant TB. For now, Griffin points out, drug resistance is seen in “a very, very small portion of TB strains.” But, Bishai warns, there is a growing epidemic of drug-resistant TB in the former Soviet Union, and similar problems are on the rise in the Americas, Southeast Asia, and many parts of sub-Saharan Africa. “It’s really just a plane ride away,” he says. “Those problems are serious, and anyone can jump on a plane, come over here, and bring it to us. So we have to remain vigilant.”
A global perspective
Ultimately, it’s not just a question of vigilance but also perspective. West Nile virus may not seem quite as great a threat when it’s compared to a disease like malaria, “a huge, huge problem in much of the world,” according to Griffin. Malaria infects 300 million to 500 million people annually and kills 1.5 million to 3 million per year, she says, noting a person in Asia or Africa is far more likely to get malaria than West Nile virus.
In the deadly array of diseases that afflict many countries, West Nile hardly registers as a concern. The glare of media attention on diseases that strike in wealthier, developed nations can skew world health priorities, according to Griffin. Sensing a market, drug companies are already beginning to develop a vaccine for West Nile virus. But they’re less eager to commit extensive resources to developing a malaria vaccine.
Though they aren’t the flashy, disease-of-the-week types, cholera, typhoid, measles, yellow fever and other diseases still cause outbreaks and epidemics that ravage much of the world. People in many developing countries face a day-in, day-out threat from one or more infectious diseases. For every “trendy” disease that captures American media attention, a major infectious disease is exacting its quotidian toll. “The dichotomy,” says Griffin, “is we focus so much attention on diseases that cause very few cases here, while we are willing to totally ignore diseases causing hundreds of millions of deaths per year in other parts of the world.”Rebecca Skloot is a science writer based in Pittsburgh, Pa. This article first appeared in Johns Hopkins School of Public Health Magazine. E-mail feedback to [email protected]