Successes and Failures in Fighting Disease
ON August 5, 1942, Dr. Alexander Fleming realized that one of his patients, a friend, was dying. The 52-year-old man had contracted spinal meningitis, and despite all of Fleming’s efforts, his friend had now sunk into a coma.
Fifteen years earlier, Fleming had stumbled on a remarkable substance produced by a bluish-green mold. He called it penicillin. He noticed that it had the power to kill bacteria; but he could not isolate pure penicillin, and he tested it only as an antiseptic. In 1938, however, Howard Florey and his research team at Oxford University took up the challenge of producing a sufficient quantity of the drug for trials on humans. Fleming called up Florey, who offered to send all the penicillin he had available. It was Fleming’s last chance to save his friend.
An intramuscular injection of penicillin proved insufficient, so Fleming injected the drug directly into his friend’s spine. The penicillin destroyed the microbes; and in just over a week, Fleming’s patient left the hospital completely cured. The era of antibiotics had dawned, and a new milestone had been reached in mankind’s fight against disease.
The Age of Antibiotics
When they first appeared, antibiotics seemed like wonder drugs. Hitherto incurable infections caused by bacteria, fungi, or other microorganisms could now be treated successfully. Thanks to the new drugs, deaths from meningitis, pneumonia, and scarlet fever declined dramatically. Hospital infections that had formerly meant a death sentence were cleared up in a few days.
Since the time of Fleming, researchers have developed dozens of additional antibiotics, and the search for new ones continues. During the last 60 years, antibiotics have become an indispensable weapon in the fight against disease. If George Washington were alive today, doctors would doubtless treat his sore throat with an antibiotic, and he probably would recover in a week or so. Antibiotics have helped practically all of us shrug off one infection or another. However, it has become apparent that antibiotics do have some drawbacks.
Antibiotic treatment does not work for diseases caused by viruses, such as AIDS or influenza. Furthermore, some people have an allergic reaction to certain antibiotics. And broad-spectrum antibiotics may kill off the helpful microorganisms in our bodies. But perhaps the greatest problem with antibiotics is their overuse or underuse.
Underuse occurs when patients do not complete the prescribed antibiotic treatment, either because they feel better or because the treatment is lengthy. As a result, the antibiotic may not kill off all the invading bacteria, allowing resistant strains to survive and multiply. This has frequently happened in the case of treatment for tuberculosis.
Both doctors and farmers have been guilty of overuse of these new drugs. “Antibiotics have often been overprescribed in the United States, and they are used even more indiscriminately in many other countries,” explains the book Man and Microbes. “They have been fed in huge quantities to livestock, not to cure disease but to aid growth; this is a major reason for heightened microbial resistance.” The result, the book warns, is that “we may be running out of new antibiotics.”
But apart from these concerns about antibiotic resistance, the second half of the 20th century was a time of medical triumphs. Medical researchers seemed capable of finding drugs to fight practically any malady. And vaccines even offered the prospect of preventing disease.
Victories for Medical Science
“Immunization is the greatest public health success story in history,” stated The World Health Report 1999. Millions of lives have already been saved, thanks to massive worldwide vaccination campaigns. A global immunization program has eliminated smallpox—the lethal disease that claimed more lives than all the wars of the 20th century combined—and a similar campaign has almost eradicated polio. (See the box “Triumphs Over Smallpox and Polio.”) Many children are now vaccinated to protect them against common life-threatening diseases.
Other diseases have been tamed by less-dramatic methods. Such waterborne infections as cholera rarely cause problems where there is adequate sanitation and a safe water supply. In many lands increased access to doctors and hospital care means that most diseases can be identified and treated before they become lethal. Better diet and living conditions, along with enforcement of laws regarding proper handling and storage of food, have also contributed to improving public health.
Once scientists tracked down the causes of infectious diseases, health authorities could take practical steps to halt an epidemic in its tracks. Consider just one example. An outbreak of bubonic plague in San Francisco in 1907 killed few people because the city immediately launched a campaign to exterminate the rats whose fleas transmitted the disease. On the other hand, starting in 1896, the same disease had caused ten million deaths in India within 12 years because its underlying cause had not yet been identified.
Failures in Fighting Disease
Clearly, significant battles have been won. But some public health victories have been confined to the richer countries of the world. Treatable diseases still kill millions of people, simply for lack of sufficient funds. In developing countries many people still lack adequate sanitation, health care, and access to safe water. Fulfilling these basic needs has become more difficult on account of massive migrations of people from the countryside to the megacities of the developing world. As a result of such factors, the world’s poor suffer what the World Health Organization calls a “disproportionate share of the burden of disease.”
Shortsighted selfishness is the principal cause of this health imbalance. “Some of the world’s worst infectious killers seem distant,” states the book Man and Microbes. “Some of these are limited entirely or mainly to poor tropical and subtropical regions.” Since wealthy developed countries and pharmaceutical companies may not benefit directly, they begrudge allocating funds for the treatment of these diseases.
Irresponsible human behavior is also a factor in spreading disease. In no way is this harsh reality better illustrated than in the case of the AIDS virus, which spreads from one person to another through body fluids. Within a few years, this pandemic has swept across the globe. (See the box “AIDS—The Scourge of Our Time.”) “Human beings have done it to themselves,” asserts epidemiologist Joe McCormick. “And that’s not moralistic, it’s just a fact.”
How did humans unwittingly cooperate with the AIDS virus? The book The Coming Plague lists the following factors: Social changes—especially the practice of having multiple sex partners—led to a wave of sexually transmitted diseases, making it much easier for the virus to take hold and for one carrier to infect many other people. The widespread use of contaminated, secondhand syringes for medical injections in developing countries or for illicit drug use had a similar effect. The billion-dollar global blood industry also enabled the AIDS virus to pass from one donor to dozens of recipients.
As mentioned earlier, the overuse or underuse of antibiotics has contributed to the appearance of resistant microbes. This problem is serious and is getting worse. Staphylococcus bacteria, which often causes wound infections, used to be eliminated easily by penicillin derivatives. But now these traditional antibiotics are often ineffective. So doctors must turn to newer, expensive antibiotics that hospitals in developing countries can rarely afford. Even the newest antibiotics may prove unable to combat some microbes, making hospital infections more common and more deadly. Dr. Richard Krause, former director of the U.S. National Institute of Allergy and Infectious Diseases, bluntly describes the current situation as “an epidemic of microbial resistance.”
“Are We Better Off Today?”
Now, at the start of the 21st century, it is clear that the threat of disease has not disappeared. The relentless spread of AIDS, the appearance of drug-resistant pathogens, and the resurgence of age-old killers like tuberculosis and malaria show that the war on disease has not yet been won.
“Are we better off today than we were a century ago?” asked Nobel Prize winner Joshua Lederberg. “In most respects, we’re worse off,” he said. “We have been neglectful of the microbes, and that is a recurring theme that is coming back to haunt us.” Can the present setbacks be overcome with determined effort by medical science and all nations of the world? Will the principal infectious diseases eventually be eradicated, as smallpox was? Our final article will consider these questions.
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Triumphs Over Smallpox and Polio
At the end of October 1977, the World Health Organization (WHO) tracked down the last-known naturally occurring case of smallpox. Ali Maow Maalin, a hospital cook who lived in Somalia, did not get a severe attack of the disease, and he was well again within a few weeks. All people in contact with him were vaccinated.
For two long years, the doctors waited anxiously. A $1,000 reward was offered to anyone who could report another confirmed “active smallpox case.” Nobody successfully claimed the reward, and on May 8, 1980, WHO formally announced that “the World and all its peoples have won freedom from smallpox.” Just a decade earlier, smallpox was causing the death of about two million people a year. For the first time in history, a major infectious disease had been eliminated. *
Polio, or poliomyelitis, a debilitating childhood disease, offered the prospect of similar success. In 1955, Jonas Salk produced an effective vaccine for polio, and an immunization campaign against polio began in the United States and other countries. Later an oral vaccine was developed. In 1988, WHO launched a worldwide program to eliminate polio.
“When we began the eradication effort in 1988, polio paralysed more than 1000 children each day,” reports Dr. Gro Harlem Brundtland, then director general of WHO. “In 2001, there were far fewer than 1000 cases for the entire year.” Polio is now confined to fewer than ten countries, although more funds will be needed to help these lands finally eliminate the disease.
^ par. 28 Smallpox was the ideal disease to combat by an international vaccination campaign because, unlike diseases that are spread by troublesome vectors such as rats and insects, the smallpox virus depends on a human host for its survival.
An Ethiopian boy receives an oral polio vaccine
© WHO/P. Virot
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AIDS—The Scourge of Our Time
AIDS has emerged as a new global threat. Already, about 20 years after its identification, more than 60 million people have been infected. And health authorities warn that the AIDS pandemic is still in “an early phase.” Infection rates are “climbing higher than previously believed possible,” and the effects in the worst-hit areas of the world are devastating.
“The vast majority of people living with HIV/AIDS worldwide are in the prime of their working lives,” explains a United Nations report. As a result, it is believed that several countries of southern Africa will lose between 10 percent and 20 percent of their work force by the year 2005. The report also says: “The average life expectancy in sub-Saharan Africa is currently 47 years. Without AIDS, it would have been 62 years.”
Efforts to find a vaccine have so far proved fruitless, and only 4 percent of the six million AIDS sufferers in the developing world receive drug therapy. At present, there is no cure for AIDS, and doctors fear that most people who are infected will eventually get the disease.
T lymphocyte cells infected by the HIV virus
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A lab worker examines a challenging strain of virus