World Conference on Disaster Reduction / The Fight Against Polio / Prostate Cancer
This is SCIENCE IN THE NEWS, in VOA Special English. I'm Sarah Long. And I'm Bob Doughty. On our program this week: a progress report on efforts to stop the disease polio and we answer a listener's question about a common kind of cancer.
But first, scientists are examining ways of improving their ability to estimate the effects of underwater earthquakes. Today, we look one system already in use.
Scientists did not expect the powerful earthquake that caused huge, destructive waves in the Indian Ocean last month. This is because technology for measuring motion has never been placed on the floor of Indian Ocean.
Yet, experts have been watching for earthquakes in the Pacific Ocean for more than fifty years. An international warning system was established there in nineteen sixty-five. The system has its headquarters in the American state of Hawaii.
Scientists there listen to sound waves directed at the ocean floor for possible earthquakes and underwater motion. They also watch water levels at more than one hundred water stations across the Pacific Ocean. If destructive waves are discovered, warning information is sent to more than one hundred places across the Pacific. Experts believe that establishment of similar warning systems in other areas could help to save many lives.
Last month, an earthquake in the Indian Ocean caused a series of events that killed more than one hundred sixty thousand people. The earthquake struck in waters near the Indonesian island of Sumatra on December twenty-sixth. The earthquake was one of the strongest earthquakes ever measured. It had a rating of nine on the Richter scale, the leading measure for earthquake strength.
The Indian Ocean earthquake created huge shock waves, or tsunami. The tsunami struck Sumatra and two groups of Indian islands in less than an hour. A short time later, the deadly waves reached Sri Lanka and Thailand. Several hours later, the waves reached coastal areas of eastern Africa. Officials say this was enough time to warn countries of possible danger.
Scientists usually know within minutes after an underwater earthquake if it was large enough to create tsunami waves. Yet, warnings are worthless without a local civil defense system to receive and act on them. Affected areas may lack the communications systems needed to warn people quickly.
A tsunami warning system for South Asia is one subject to be discussed this week at the World Conference on Disaster Reduction in Kobe, Japan. Germany, Japan and the United States have each offered to create a tsunami warning system in the Indian Ocean.
The Bush Administration will present a plan to deploy scientific equipment throughout the Pacific, Indian and Atlantic Oceans and the Caribbean Sea. The equipment would send messages from the ocean floor to devices floating on top of the water. The information would then be sent by satellite to scientists.
The World Health Organization says the number of people infected with polio rose almost thirty percent last year. W.H.O. officials say there were one thousand one hundred seventy polio cases worldwide in two thousand four. That compares with seven hundred eighty-four infections in two thousand three.
Ninety percent of the people infected last year live in three countries -- Nigeria, India, and Pakistan. In fact, Nigeria had sixty-five percent of all polio cases.
Anti-polio campaigns were halted in northern Nigeria after Islamic leaders expressed concern about the safety of polio vaccines. Vaccines help the body's natural defenses recognize and fight disease.
Polio is a disease that can make people unable to move their arms or legs. It also can kill people. The virus spreads very quickly among people who have not been given vaccines.
Recently, a polio vaccination campaign re-started in Nigeria. However, there are already new cases of polio, both in and out of the country. W.H.O. officials say the virus has spread to nearby countries, including Benin, Chad, Ghana and Togo. W.H.O. officials say conflicts in Ivory Coast and Sudan also affected efforts to stop the disease.
The American performer Jerry Orbach died last month. He was sixty-nine years old. The cause of death was prostate cancer. A listener in Viet Nam wrote to ask us for information about prostate cancer. Than Nguyen wants to know what causes the disease and how it is treated.
Only males have prostate glands so only males get prostate cancer. The gland is a part of the reproductive system. It is involved in the production and storage of semen, the male reproductive fluid. Semen is used to fertilize a female's egg.
A normal prostate is about the size of a small ball or walnut. A cancer can make the prostate larger. This can cause pressure on the bladder and restrict the release of liquid wastes. An enlarged prostate can affect a man's ability to have sex. It also can cause pain in the lower back, hips and upper part of the legs.
The American Cancer Society estimates that about one in six men in the United States will get prostate cancer. But, the group says only one man in thirty-two will die from it. Prostate cancer is common in older men.
The National Cancer Institute says more than seventy percent of men with the disease are sixty-five years of age or older. However, most prostate cancer grows slowly. So, many patients die of other causes instead of the disease.
Scientists do not know the exact cause of prostate cancer. But they have found things that can influence its development. The World Health Organization says the foods a man eats may affect his chances of developing the disease. Prostate cancer appears more common in communities where animal fat, red meats, and high-fat milk products are a major part of the diet.
W-H-O officials say about two hundred fifty thousand people die each year from prostate cancer. They say the death rate is about ten times higher in Europe and North America than in Asia.
The Prostate Cancer Foundation says prostate cancer is the most common cancer in the United States. The group also says it is the second leading cause of cancer deaths among American men.
The American Cancer Society reports that prostate cancer is more common among African-Americans than among white Americans. Also, African Americans are two times as likely as whites to die from it. The group says exercise might help reduce the risk of prostate cancer. Also, men with fathers or brothers who have had the disease are more likely to get it than those without such a family history.
There are many things to consider when choosing a treatment for prostate cancer. Some cancers grow so slowly they never cause any major problems in a lifetime. In these cases, a man's doctor might suggest simply watching for changes in the growth.
More rarely, a doctor may perform an operation to remove the prostate. This is a complex surgery that can last as long as four hours.
A third kind of treatment is radiation. High energy x-rays can be used to kill cancer cells in the prostate. A doctor also may place small radioactive seeds in the prostate to kill the cancer. Doctors have greater control with this method so there is less risk of damage to healthy tissue.
Cancer that has spread beyond the prostate gland may require a more aggressive treatment known as hormonal therapy. A doctor may operate to remove the man's sex organs, or testicles. The testicles are the main producer of male hormones called androgens. The doctor may advise the patient to use drugs that can cut off the body's androgen supply.
Doctors say one of the most important ways for men to reduce their risk of death from prostate cancer is to find the disease early. There are two ways to discover the disease before any signs of it appear. A doctor will examine the prostate grand using his fingers. He will feel for any hardness or growth.
A doctor also may test a man's blood to measure levels of a protein called prostate-specific antigen. An injured or disease prostate often expels P.S.A. The higher the P.S.A. level, the greater the chance that the patient has prostate cancer.
This program was written by Karen Leggett, Jill Moss and Caty Weaver. Cynthia Kirk was our producer. And, our engineer was Dwayne Collins. I'm Sarah Long. And I'm Bob Doughty. Join us again next week for SCIENCE IN THE NEWS in VOA Special English.