Influenza—What We Know Now
IT IS 1997. A scientist sits in the small Eskimo village of Brevig on the frozen tundra of the Seward Peninsula of Alaska. In front of him is the exhumed body of a young woman that he and four Eskimo helpers have dug out of the permafrost. She fell victim to the flu back in 1918 and has lain there, frozen, ever since.
What good can come from examining her now? The scientist hopes that the flu-causing agent is still in her lungs and that through the use of advanced genetic techniques, it can be isolated and identified. Why might that knowledge prove helpful? To answer, we need to understand a little more about how viruses work and what makes them so dangerous.
A Virus That Can Be Deadly
Today we know that influenza is caused by a virus and that it can be spread from person to person in respiratory secretions expelled by coughing, sneezing, and talking.* It is present worldwide even in the Tropics, where it can strike year-round. In the Northern Hemisphere, flu season runs from November to March; and in the Southern Hemisphere, from April to September.
Influenza type A, the most dangerous type of flu virus, is small in size compared with many viruses. It is usually spherical, with projections from its surface. When this virus infects a human cell, it reproduces so rapidly that often within about ten hours, a swarm of between 100,000 and a million new influenza virus “copies” explode from the cell.
The scary characteristic of this simple organism is its ability to change quickly. Because the virus reproduces so rapidly (far faster than the HIV virus), its many “copies” are not exact. Some are different enough to escape the immune system. That is why we face different flu viruses every year, which present a new set of antigens—substances that test our immunity. If the antigen changes sufficiently, our immune system has little defense against it and there is risk of a pandemic.
Furthermore, flu viruses also infect animals, and therein lies a problem for humans. The pig, it is believed, can be a host for viruses that infect such birds as chickens and ducks. But it can also be the host for other viruses that infect humans.
Therefore, if a pig becomes infected by both types of viruses—one sort that infects animals and another sort common to humans—the genes of the two strains can get mixed together. The result can be a totally new strain of influenza, one to which humans have no immunity. Some feel that farming communities where poultry, swine, and people live in close proximity—as is often the case in Asia, for example—are likely sources of new flu strains.
Why Did It Become So Virulent?
The question is, What could have caused the flu virus of 1918-19 to turn into a pneumonia-causing killer of young people? Though none of the live virus is left from that time, scientists have long felt that if they could find a frozen specimen of it, they might be able to isolate intact RNA and discover what made this strain so lethal. Actually, to some extent they have succeeded.
Thanks to the frozen Alaskan specimen described at the outset of this article, a team of scientists has been able to identify and sequence most of the genes of the 1918-19 flu virus. However, scientists have still not figured out what caused that flu to be such a killer. Apparently, though, this strain was a relative of a flu virus that infects both pigs and birds.
Could It Come Back?
According to many experts, it is not a question of if such a vicious flu virus will return but of when and how it will return. In fact, some expect a significant new influenza outbreak every 11 years or so and a severe one approximately every 30 years. According to these predictions, mankind is overdue for another pandemic.
The medical journal Vaccine reported in 2003: “It has been 35 years since the last influenza pandemic, and the longest interval between pandemics recorded with certainty is 39 years.” The article continued: “The pandemic virus may emerge in China or a nearby country and could include surface antigens or virulence factors derived from animal influenza viruses.”
The Vaccine article predicted concerning the virus: “It will spread rapidly throughout the world. Several waves of infection will occur. Morbidity will be extensive in all age groups, and there will be widespread disruption of social and economic activity in all countries. Excess mortality will be evident in most if not all age groups. It is unlikely that health care systems in even the most economically developed countries will be able to adequately cope with the demand for health care services.”
Just how alarming is such a scenario? John M. Barry, author of the book The Great Influenza, provides this perspective: “A terrorist with a nuclear weapon is every national politician’s nightmare. A new influenza pandemic should be.”
What Treatments Are Available?
You may ask, ‘Aren’t there effective treatments now?’ The answer involves both good news and bad. Antibiotics can cut the mortality from secondary bacterial pneumonias, and certain medications can be effective against some flu strains. There are immunizations that can be helpful in combating a flu virus if the correct strains of it are identified and if the immunizations can be produced in time. Such is the good news. The bad?
The history of flu immunizations—from the ill-fated swine flu episode of 1976 to the production shortage of 2004—has been spotty. Even though medical science has realized momentous advancements since World War I, doctors still do not know of any cure for a powerful virus.
Hence, there is this disquieting question: Could there be a repeat of 1918-19? Note what is said in a paper from London’s National Institute for Medical Research: “In some ways, conditions prevail as they did in 1918: there is a huge volume of international travel due to the development of transport, there are a number of war-zones with their inherent problems of malnutrition and poor hygiene, the world population has grown to six and a half billion and a greater proportion of this population is living in urban situations many of which have decaying infrastructures in terms of waste disposal.”
Concludes a well-respected U.S. authority: “Put simply, each year brings us closer to the next pandemic.” Does all this mean, though, that the future is bleak, even hopeless? No!
The book Viruses, Plagues, and History notes: “Italians introduced the term influenza in about 1500 for diseases attributed to the ‘influence’ of the stars.”
[Picture on page 8]
New flu strains can get their start in farming communities
BAY ISMOYO/AFP/Getty Images
[Picture on page 8, 9]
Influenza type A virus
© Science Source/Photo Researchers, Inc
[Picture on page 9]
Researchers have examined specimens of the 1918-19 virus
© TOUHIG SION/CORBIS SYGMA