Re-emerging dias: gone today, here tomorrow?
成长规划We have two choices. Follow Choice 1, and the headlines in 10 years will probably report the latest internecine squabbles in Congress, or which athlete signed for how many millions. Choice 2, on the other hand, could lead to headlines such as "New Flu Strain Spreads: Death Toll Reaches Half Million."
In 1969, Surgeon General William Stewart, testifying before Congress, said that we could "clo the book on infectious dia." Antibiotics and vaccines had left the medical community flush with a string of impressive victories, from penicillin to polio. The war, they thought, was almost over.
Today, confronted with what have become known as emerging and re-emerging dias, we know better. "'Emergence' is in fact regression, a return to the standard that prevailed universally in the previous century,"1 Nobel Laureate and Columbia biologist Joshua Lederberg wrote in a special infectious dia issue of the Journal of the American Medical Association. A report in the same issue quantified the growing threat: In the United
States between 1980 and 1992, the death rate due to infectious dias incread 58 percent.2 AIDS accounts for slightly more than half of that jump, but other conditions, especially respiratory infections, also contributed significantly.
早读Since the heady days of victory declarations, new dias such as AIDS and Ebola have suddenly appeared, and old afflictions, thought conquered, have flared. Diphtheria is making a comeback in the former Soviet Union. Tuberculosis -- which never really went away, though upscale opera buffs might have thought it was confined to productions of "La Boheme" -- is once again a threat in urban centers, including New York City. Group A streptococcal conditions are on the ri, which means that scarlet fever could become familiar again. And everyone in the infectious-dia field fears the day when a powerful new strain of flu sweeps the world. "The war has been won," one scientist recently quipped. "By the other side."
Keeping our eyes on moving targets
In fact, that ntiment may reflect as much hyperbole as the former surgeon general's. Pe
rhaps a better snapshot of the current situation is that the battle has been joined. The World Health Organization and the Centers for Dia Control and Prevention have revved up their efforts to check infectious dias, including re-emergent ones. In October 1995, WHO established a new division devoted to worldwide surveillance and control of emerging dias. The CDC came up with a prevention strategy in 1994. Although Congress funded CDC's efforts to the tune of only $6.7 million in 1995-less than Dustin Hoffman's salary for starring as an infection fighter in "Outbreak" -- they have raid the figure to $26 million for 1997. Public awareness of infectious dia, perhaps due in part to such movies, may have influenced Congress' outlook.
WHO has identified six dias who worldwide re-emergence should be monitored: diphtheria, cholera, dengue fever, yellow fever, and -- believe it or not -- bubonic plague. A list of dias for the United States might differ, but, as Lederberg also put it, "We arrive at the realization that world health is indivisible, that we cannot satisfy our most parochial needs without attending to the health conditions of the globe." With a crowded marketplace in Kikwit, Zaire, site of the last Ebola flare-up, less than 24 hours away from
银行信贷业务a New York City subway, borders are meaningless to pathogenic microbes.
忍耐的名言 Lists may help public health authorities focus their attention, but their value is limited. "Ask anyone 15 years ago about what dias should be on such a list and no one would have said AIDS," notes Stephen Mor of the epidemiology division in Columbia's School of Public Health. "We didn't even know it existed. Now it's at the top of every list. The reality is that any list I give you will be deeply flawed. That said, there are re-emerging conditions that are hardy perennials, and they have not been eliminated."
微信昵称女 Every returning condition marches to the beat of a different drum. "The re-emerging infections each have a little wrinkle to them that is important," says Dr. Glenda Garvey, Columbia clinical professor of medicine and interim chief of infectious dia at Columbia-Presbyterian Medical Center. "TB is the result of socioeconomic conditions and human behavior." Prisons and homeless shelters are ideal venues for TB spread, with confined populations in clo quarters. With our help, strains of TB have also developed drug resistance; incomplete cours of antibiotic therapy allow the hardiest bugs to surviv向远处看>小学生垒球
e and develop new, more powerful lineages. "It is possible," Mor says, "that the multi-drug-resistant strain of TB that has spread throughout the East Coast originated in a homeless shelter across the street from Columbia-Presbyterian." TB also hitched a ride on the HIV wagon by attacking the immunocompromid-an emerging dia thus helping re-ignite an old one.
"The return of Group A strep may be due to a change in virulence," Garvey says, reflecting mutation in the exterior of the bacterium. The misnamed "flesh-eating bacteria" of 1994 were a type of Group A strep infection, as are rheumatic and scarlet fevers. "Scarlet fever was a problem for my mother's generation," says Mor. "It esntially disappeared, and for no good reason. We don't understand why [dias] flare from time to time, and until we do I'm uncomfortable ignoring them."
电影无问西东Flu likewi changes its coat and in turn its level of virulence. "If there is anything in this business you can safely put on a list of dias that are coming, it's flu," Mor says. Rather than the flus that lay everybody up for a weekend every winter, the strain Mor dr
eads is the kind that killed 22 million in the pandemic of 1918-19. "Tho process in nature that have given us the pandemic influenzas are not finished.
