Science News Digest
This is Sarah Long. And this is Bob Doughty with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in science. Today, we tell about a link between Americans who served in the Persian Gulf war and a rare disease. We tell about a new Sumatran tiger born at the National Zoo. And we tell about Seasonal Affective Disorder.
A new study has found the first likely link between Americans who served in the Persian Gulf war and a rare disease. The study found that those who served in the Gulf war were almost two times as likely as other members of the armed forces to develop amyotrophic (am-ee-oh-TRO-fik) lateral sclerosis, or A-L-S.
The United States Department of Veterans Affairs and Defense Department reported the findings.
A-L-S is a rare and deadly disease of the human nervous system. The disease destroys the nerve cells that control muscle movement. Victims lose their ability to move, speak and breathe. Scientists do not know what causes the disease. There is no effective treatment or cure. A-L-S is also called Lou Gehrig's Disease. It was named for a famous American baseball player who had the disease.
For many years, Americans who served in the Gulf war have said they developed diseases linked to their service in the war. However, there had been little scientific evidence until now.
The new study involved about two-million-five-hundred-thousand former members of the armed forces. Research scientists examined the health of about seven-hundred-thousand service members who had been deployed to the Persian Gulf area. They had served in the Allied campaign against Iraq between August, Nineteen-Ninety and July, Nineteen-Ninety-One.
The researchers also studied one-million-eight-hundred-thousand other members of the armed forces. They had served in other parts of the world during that period.
The study found forty cases of A-L-S among the veterans deployed in the Persian Gulf. About half of them have died. Scientists would expect to find thirty-three cases in a similar-sized population during the same period. Sixty-seven cases of the disease were identified among the larger control group.
Members of the Air Force who served in the Persian Gulf war were two-point-seven times more likely to develop A-L-S than members of the control group. Those in the Army were two times as likely. However, disease rates among those in the Navy and Marines who served in the Gulf war were not much different from those who had not served.
The researchers say they do not know the reason for this link or why only some groups are at higher risk for the disease.
Secretary of Veterans Affairs Anthony Principi says the new findings are of great concern and require additional study. Mr. Principi says his agency will work with other groups to find the cause, treatment and cure for A-L-S. He also said his agency will continue research on the connection between the Gulf war and other illnesses.
The Smithsonian National Zoological Park in Washington, D.C. recently showed a new baby Sumatran tiger to the public for the first time. Thousands of people are waiting in long lines to see the rare animal. He was born at the zoo September Eighteenth. Only about one-hundred-seventy Sumatran tigers live in zoos.The baby tiger is called Berani.
The name means "brave" in the Bahasa Indonesian language. Sumatran tigers come from the island of Sumatra in northern Indonesia. Like all tigers in the world, they are threatened with dying out. Fewer than five-hundred of these animals now survive in the wild in Sumatra.
Zoo scientists examined Berani for the first time two weeks after his birth. At that time, he weighed less than three kilograms. He now weighs more than ten kilograms. Zoo director Lucy Spelman says information gained from studying Berani will help zoo experts protect other Sumatran tigers.
The birth of Berani resulted from a scientifically managed reproduction plan for Sumatran tigers. The National Zoo cooperates with the American Zoo Association in this effort. Other agencies involved are the Save the Tiger Fund and the United States Fish and Wildlife Service.
Berani's mother is Soyono. His father is Rokan. The birth marked the second time in recent years that the National Zoo has welcomed Sumatran tigers. Rokan became the father of three Sumatran baby tigers in Nineteen-Ninety-Nine.
For many years, experts believed Sumatran tigers belonged to a larger scientific grouping of tigers. However, a Nineteen-Ninety-Eight study of tiger cells questioned this belief. Researchers from several areas of science made the study. The magazine "Animal Conservation" published their results.
The study reported that Sumatran tigers are unlike other tigers. Blood taken from Sumatrans showed three genetic markers not found in other kinds of tigers. Zoos throughout the world since then have increased their efforts to produce more Sumatran tigers.
Sumatrans are the smallest surviving tigers in the world. If Berani is average, he will measure about two meters when fully grown. He will weigh about one-hundred-twenty kilograms. The Sumatran has the darkest skin of any tiger. It has many black marks on its dark orange body.
Two other kinds of tigers once lived in Indonesia. However, these Javan and Balinese tigers have disappeared from Earth. In Nineteen-Ninety-Four, Indonesia developed a reproduction program aimed at saving Sumatran tigers in the wild.
Humans threaten the existence of these animals, as they threaten all tigers. Increases in human population and agriculture have robbed the tigers of places where they once lived. ((MUSIC BRIDGE))
Some people feel sad or depressed during the winter months in northern areas of the world. They may have trouble eating or sleeping. They suffer from a condition known as Seasonal Affective Disorder, or S-A-D.
Victims of S-A-D suffer its effects during the short, dark days of winter. The problems are most severe in the months when there are fewer hours of daylight. When spring arrives, these signs disappear and S-A-D victims feel well again.
The National Mental Health Association reports that S-A-D can affect anyone. However, the group says young people and women are at the highest risk for the disorder. It says an estimated twenty-five percent of the American population suffers from some form of S-A-D. About five percent suffer from a severe form of the disorder.
Many people in other parts of the world also have the condition. For example, some scientists who work in Antarctica suffer from Seasonal Affective Disorder. During the long, dark winter months there, workers have difficulty finding enough energy to do their jobs.
The idea of health problems linked to a lack of light is not new. Scientists have discussed the issue since the beginning of medicine. More than two-thousand years ago, the Greek doctor Hippocrates (hip-POCK-ra-tees) noted that the seasons affect human emotions.
Today, experts do not fully understand S-A-D. Yet they agree that it is a very real disorder. Many doctors think that a change in brain chemistry causes people to develop S-A-D. They say people with the condition have too much of the hormone melatonin in their bodies.
The pineal gland in the brain produces melatonin while we sleep. This hormone is believed to cause signs of depression. Melatonin is produced at increased levels in the dark. So, its production increases when the days are shorter and darker.
To treat the disorder, victims of S-A-D do not need to wait until spring. Experts know that placing affected individuals in bright light each day eases the condition. There are other things people can do to ease the problem. They can increase the sunlight in their homes and workplaces. They can spend more time outdoors in the fresh air during the day.
One study found that walking for an hour in winter sunlight was as effective as spending two-and-one-half hours under bright lights indoors.
This SCIENCE IN THE NEWS program was written by George Grow and Jerilyn Watson. It was produced by Caty Weaver. This is Bob Doughty. And this is Sarah Long. Join us again next week for more news about science in Special English on the Voice of America.