An explosion of pathogens, or perhaps just of fear

Over the last decade or so, popular works on infectious diseases have lined bookstore shelves and pumped adrenaline through readers’ veins. Laurie Garrett’s groundbreaking “The Coming Plague” launched the trend, followed by such apocalyptic titles as “Epidemic,” “Timebomb,” “Maneater” and “Scourge.” “The New Killer Diseases” now joins this company, released just in time to snag Californians fearful of the recent arrival of the mosquito-borne West Nile virus.

From the perspective of an infectious diseases specialist, all such books serve a worthy mission. They deliver current facts and research, even vivid battle scenes (picture brave cells and molecules versus evildoers played by viruses and bacteria) with the thoroughness of a class in Immunology 101.

But one problem of “The New Killer Diseases” is that several villains profiled -- like E. coli 0157 or Group A strep -- aren’t mutants in the technical sense at all. Literary license? For organisms like HIV and antibiotic-resistant bacteria, the term comes close enough. More troubling, however, is the alarmism of the book’s title, which weaves through its chapters. This book, even more than some of its brethren, tries to scare readers’ pants off by suggesting that humanity is facing an onslaught of murderous plagues unlike any other time in history -- a debatable view at best.

Take “The Case of Jeannie Brown,” a chapter based on the true story of a single mom from North Carolina. Jeannie’s painful shoulder plus fever, vomiting and sunburn-like rash go undiagnosed for days. After a blow-by-blow account of her illness, the authors deliver their coup de grace with ghoulish fervor:

“The autopsy had been a revolting experience.... It showed that Jeannie was killed by a wild infection doctors call ‘invasive Group A streptococcus.’ The media call it ‘flesh-eating bacteria.’ This ravenous bacteria had turned Jeannie’s kidneys into a mass of jellylike pus, her heart into a squishy sponge. A microbial war had been raging inside her body for at least a week, the rapidly multiplying bacteria knifing through muscle, organ and blood vessel cells while a few meager white cells tried to tackle them.”

Ever since Jim Henson, the beloved Muppeteer, died in 1990 of invasive Group A strep infection, tabloid-style journalists have exploited its drama. Aside from its usual mischief (tonsillitis, skin infections and the like), the classic sore throat germ dives deep into the blood and tissues of 10,000 to 15,000 Americans per year, killing roughly 20%. But there’s a back story that isn’t found in “The New Killer Diseases.” Since microbiologists started tracking Group A strep in the mid-19th century, it has periodically made deadly sorties. Though it is always the same bug, its virulence varies according to its changing portfolio of toxins and “M proteins.” Consequently, today’s uptick in cases doesn’t really represent a new breed at all, despite the horror of Brown’s death. Most experts believe it’s just another phase of a historic cycle.

A few decades ago, in fact, Group A strep wreaked a different kind of havoc. Back then its signature ranged from scarlet fever and postpartum sepsis to chronic nephritis (patients with this insidious kidney condition can be well one day and on dialysis the next) and rheumatic fever, still a leading cause of heart disease. In many countries with limited health care, these syndromes continue to abound. Doctors must remain on the lookout for Group A strep, but the problem with the story told in “The New Killer Diseases” is that it sheds little light by focusing on one badly handled case.

Elinor Levy, a biophysicist-turned-immunology professor, and Mark Fischetti, a veteran science writer, fare better in treating the recent crop of animal-to-man diseases that are genuinely new or newly imported -- for example, severe acute respiratory syndrome, bovine spongiform encephalopathy (also known as mad cow disease) and West Nile virus. They excel at describing the sleuthing and science that helped to break the code on these and other emerging infections.

Along the way, the authors introduce more victims: the heroic Italian public health specialist working in Vietnam who recognized, then succumbed to SARS; a young woman in England with neurologic meltdown from BSE; a retired resident of Queens, N.Y., who acquired a strain of West Nile virus that hitched a ride from Israel and quickly spawned paralysis and brain inflammation (such complications usually occur in only 1 in 150 West Nile-infected patients). Three heart-rending sagas, yes, but aren’t such richly detailed disasters bound to alarm?

And what about the bigger picture? Since the late 1990s, for example, BSE and West Nile encephalitis have claimed no more than 600 European and American lives in total. In contrast, cerebral malaria (a condition that can be reversed with drugs that cost a dollar or two per patient) has silently killed several million African children, many of whom never got close to medical help. Now there’s a killer disease.

A Washington postal worker who survived anthrax and now suffers from post-traumatic stress disorder (he suspects the anthrax mailings were a secret government experiment) is the book’s segue into bioterrorism. A 3-year-old whose juicy bite of cantaloupe at a Milwaukee salad bar led to bloody diarrhea, kidney failure and death introduces E. coli 0157. In these and other poignant stories the authors describe the genetic, immunologic and vaccine development research that reveals the wondrous toolbox of modern microbiology. On the political side, arguments for better public health communication and interagency linkages (during the anthrax letter crisis, the FBI, CIA, EPA, FEMA and CDC shared turf rather clumsily) come through loud and clear, as does the case for stronger oversight of our domestic food supply.

In the United States alone, as Levy and Fischetti point out, food-borne germs cause 76 million illnesses and 325,000 hospitalizations a year. Fortunately, with 5,000-plus annual fatalities, the odds of death are low. That’s not to downplay the casualties, economic costs or future threats of food-borne infection, however. In recent years, the global flow of fruits, vegetables and other exotic treats has brought some unhappy surprises: parasite-laden raspberries, cholera-carrying crabs, goat cheese laced with dangerous bacteria.

Do you remember your grandmother’s old-fashioned meat grinder? It might be worth resurrecting. Today’s ground meat often comes from supersized processing plants. As a result, a single patty at a supermarket may contain the commingled flora (salmonella, E. coli 0157, Campylobacter) of up to 1,000 head of cattle. No wonder so many restaurants refuse to serve a hamburger medium rare. (By the way, in addition to germs, most of us regularly consume industrial-strength antibiotics fed to American cows, pigs and poultry. These growth-promoting agents foster drug-resistant bacteria whose resistance genes eventually migrate from animal intestines to human guts to hospitals. In European Union countries, such antibiotic fortification is now banned, and Levy and Fischetti share that position.)

But is it realistic to expect Betty Crocker perfection with respect to food, even in privileged, industrialized societies? Reacting to several recent spates of diarrhea on cruise ships (the guilty party was an intestinal virus called the Norwalk agent), “The New Killer Diseases” complains: “Defiant germs are persisting in even the cleanest environments.” It seems that “The New Killer Diseases” wants to cause a furor over a very basic fact: We’re surrounded by microorganisms. From a purely evolutionary point of view, that’s not a problem. There’s plenty of evidence suggesting that an occasional cold or bout of diarrhea enhances lifelong immune defenses (assuming you’re basically healthy to begin with).

Since I graduated from medical school in 1976, more than 30 new or resurgent infections have made newspaper headlines. In population terms, their effects have varied from minor to apocalyptic. In individual terms, as with all diseases, each one has brought human suffering and grief. But even the bona fide tragedies do not justify scaremongering. That’s where “The New Killer Diseases” and I part ways. Looking back on recent medical history, perhaps the more sensible response to our environment is not Levy and Fischetti’s but that of CDC chief Dr. Julie Gerberding. Emerging infections are “the new normal” in the world, she said in a speech earlier this year. So let’s not waste energy decrying biologic adaptation and change, she suggested. Instead, use common sense, wash your hands, apply mosquito repellent and sign up for a flu shot.