Influenza Pandemic of 1957
Influenza Pandemic of 1957
Disease History, Characteristics, and Transmission
Introduction
The 1957 influenza pandemic was the second-greatest influenza pandemic in the twentieth century. It killed approximately one to two million people worldwide, including about 70,000 in the United States. The first influenza pandemic of the twentieth century, in 1918– 19, killed between 20 and 100 million people worldwide and about 675,000 in the United States; the third, in 1968, killed about 700,000 people worldwide and 34,000 in the United States. Influenza (“flu” for short) is a viral infection of the respiratory system that is spread either by contact or by droplets of mucus or saliva ejected into the air by a cough or sneeze. Symptoms of flu include cough, muscle aches, vomiting, loss of appetite, fever, and, in extreme cases, death. Flu pandemics tend to occur every 10 or 11 years, but most are not as severe as those of 1918, 1957, and 1968.
Disease History, Characteristics, and Transmission
The flu that caused the 1957 pandemic is called Asian flu because it was first detected in China in February, 1957. United States government experts could not decide at first whether a 1918-style disaster was in the making and did not want to alarm the public, so the Surgeon General recommended that flu vaccinations be given only through ordinary doctor-patient channels. The pandemic did spread through the United States, however, starting in the late spring and peaking in October 1957. A second wave of infections, mostly affecting the elderly, occurred in January and February 1958. About 69,800 people died of the Asian flu in the United States (In a typical year, as of the early 2000s, about 36,000 people die of flu each year in the United States. However, the U.S. population was much smaller in 1957, so the death rate from the pandemic was relatively much higher.) Flu costs billions of dollars even in a non-pandemic year because of hospitalizations and lost work time.
WORDS TO KNOW
CAPSID: The protein shell surrounding a virus particle.
MUTATION: A mutation is a change in an organism's DNA that occurs over time and may render it less sensitive to drugs which are used against it.
PANDEMIC: Pandemic, which means all the people, describes an epidemic that occurs in more than one country or population simultaneously.
REASSORTMENT: A condition resulting when two or more different types of viruses exchange genetic material to form a new, genetically different virus.
VIRION: A virion is a mature virus particle, consisting of a core of ribonucleic acid (RNA) or deoxyribonucleic acid (DNA) surrounded by a protein coat. This is the form in which a virus exists outside of its host cell.
Influenza is caused by a virus. Viruses are tiny clusters of molecules called virions or virus particles. Each influenza virion consists of an out shell or capsid made of proteins (a kind of complex molecule used by all living things) and an inner core of RNA (ribonucleic acid). A virion attaches to a cell using capsid proteins. It then injects its RNA into the cell. The cell's mechanisms cannot tell viral RNA from its own RNA, and manufacture proteins according to the instructions in the viral RNA. These molecules assemble themselves into new virus particles. New influenza viruses escape from the host cell by budding off from the cell membrane.
There are three types of flu, namely influenza A, B, and C. Influenza A viruses are also called avian viruses because they live in birds as well as in human beings. The 1957 flu virus was an influenza A virus. Influenza A viruses are given code names to distinguish them. These names are based on two of the 11 proteins found in the capsid, hemagglutinin (HA) and neuraminidase (NA). HA and NA each occur in a variety of forms which are given numbers by biologists. A virus having a type 2 HA protein and a type 2 NA protein is an H2N2 virus. The virus that caused the 1957 pandemic was an H2N2 virus.
Mutations (changes) occur in viral RNA, changing the capsid proteins in new viruses. When enough of these changes happen, the immune system's memory of its previous encounter with flu is no longer useful; the new, changed virus is not recognized as soon as it appears, and so has a chance to cause an infection before the body destroys it. Viruses can also change by reassortment. Reassortment can happen when two different types of virus infect the same cell at the same time. The new viruses that the cell manufactures may contain RNA from both types. The 1957 H2N2 virus probably arose through reassortment of a virus originating in birds (an avian influenza) and a virus already easily transmitted among humans.
Scope and Distribution
Today, the strain of H2N2 influenza A virus that caused the 1957 pandemic exists only in laboratory cultures. Other H2N2 viruses exist in the wild.
Treatment and Prevention
No antiviral drugs existed in 1957. A vaccine was created for this flu but was not available to most people. Treatment, as for the common cold, consisted mostly of rest, fluids, and staying warm. Antibiotics—drugs that kill only bacteria—are sometimes given to flu patients to fight secondary bacterial infections but do not treat the flu itself.
Today, vaccination remains the first line of defense against any flu outbreak, but several antiviral drugs are available. Efforts are sometimes made to prevent the origin of 1957-type flu viruses by preventing people who have virus infections from working around or slaughtering birds while sick. The goal is to lessen the chances that reassortment will occur in cells infected by an avian virus from the birds and a virus already easily transmitted among humans.
Impacts and Issues
Unlike the Spanish flu pandemic of 1918–1920, international strategies to report and respond to pandemic threats gave many nations advance warning of the new pandemic. Soon after the virus was identified in China, several nations were able to develop and produce vaccines to stem the spread of the illness. In addition to limited vaccination programs, many of the same quarantine techniques that were used to combat the 1918 pandemic were used again in 1957. Since children and families with young children were disproportionately affected, many schools and libraries closed temporarily to prevent the spread of the flu within local communities. Such measures helped limit the spread of the flu among children, but the disease reemerged in early 1958. Most of the victims of the “second wave” of the pandemic were elderly.
In 2005, it was found that quality-control kits containing live Asian flu virus had been sent to 6,000 labs in 19 countries. To prevent the reintroduction of the 1957 pandemic flu virus into the general population, efforts were overseen by the World Health Organization (WHO) to track down and destroy all the virus samples. No outbreak occurred.
See AlsoAvian Influenza; H5N1; Influenza; Influenza Epidemic of 1918; Influenza, Tracking Seasonal Influences and Virus Mutation; Viral Disease.
BIBLIOGRAPHY
Books
Goldsmith, Connie. Influenza: The Next Pandemic? New York: Twenty-First Century Books, 2006.
Periodicals
Altman, Lawrence K. “Flu Samples, Released in Error, Are Mostly Destroyed, U.S. Says.” New York Times. April 22, 2005.
Check, Erika. “Heightened Security After Flu Scare Sparks Biosafety Debate.” Nature. 432 (2005): 943.
Ferguson, Neil M. “Ecological and Immunological Determinants of Influenza Evolution.” Nature. 4222 (2003): 428-433.
Laver, Graeme and Elspeth Garman. “The Origin and Control of Pandemic Influenza.” Science. 293 (2001): 1776–1777.
Web Sites
National Vaccine Program Office, United States Department of Health and Human Services. “Pandemics and Pandemic Scares in the 20th Century.” <http://www.hhs.gov/nvpo/pandemics/flu3.htm#10> (accessed January 23, 2007).
U.S. Department of Health and Human Services. “PandemicFlu.org/AsianFlu.org.” August 24, 2006 <http://www.pandemicflu.gov> (accessed January 25, 2007).
The White House (U.S. Government). “National Strategy for Pandemic Influenza.” November 1, 2005 <http://www.whitehouse.gov/homeland/pandemic-influenza.html> (accessed January 23, 2007).
Larry Gilman