SCIENCE IN THE NEWS #2069 - DigestBy StaffThis is Steve Ember.And this is Sarah Long with SCIENCE IN THE NEWS, a VOA Special English program about recent developments in Science. Today, we tell about diseases spread by mosquitoes. We tell about the eye disease glaucoma. We tell about human ancestors that walked on their knuckles. And we tell about famous ancient documents called the Dead Sea Scrolls.
Last summer, Americans in the eastern state of New York were threatened by a disease never before seen in the country -- West Nile Fever. The disease usually is not serious in people. But it can cause swelling of the brain. The disease killed seven people and made sixty-two others sick in and around New York City. Today, officials say more than two-thousand other people could also have been infected, but showed little or no signs of being sick. The West Nile virus also killed thousands of birds in the area.
West Nile Fever is carried by birds. The disease is then passed to mosquitoes when the insects bite birds that have the virus. People become infected when mosquitoes bite them.When the disease first was discovered in New York, health officials immediately began efforts to kill mosquitoes. They hoped the threat would end when the mosquitoes became inactive during the winter. Last month, however, they reported that the virus has survived. Health officials found inactive mosquitoes still infected with the disease. And they found a bird killed by the disease.
This year, health officials have started a campaign in the eastern United States to teach people how to prevent being bitten by mosquitoes. Health officials say this could be the start of an infectious disease danger in the United States that has been present for years around the world.
The World Health Organization says five-hundred-million people around the world each year are infected with sicknesses carried by mosquitoes. These include dengue (den-gay) fever, malaria, yellow fever and brain fevers such as West Nile. More than two-million people die of these diseases, many of them young children.One example of the increase in these diseases is dengue fever. In the Nineteen-Fifties, the serious form of the disease infected about one-thousand people each year. Today, more than five-hundred-thousand people are infected each year. About twenty-four-thousand people die of the disease each year. The W-H-O organized a campaign to kill the mosquitoes that carry the sickness. But experts say it was stopped too soon. As a result, dengue fever has spread through North and South America. The mosquito that carries dengue fever has been found in eleven states in the United States.
There is no medicine to prevent dengue and West Nile fevers. Health experts say everyone should take steps to prevent mosquito bites. These include removing containers of water where mosquitoes could lay their eggs. Wearing clothing that covers the arms and legs. And using chemicals to kill insects on the body and on material that covers beds.
((MUSIC BRIDGE))Sixty-seven million people around the world cannot see because they suffer the eye disease glaucoma. The disease prevents the clear liquid in the eye from flowing normally in and out of the eye. This results in an increase in pressure in the eye that damages the optic nerve. The optic nerve carries images from the eye to the brain.
The first sign of glaucoma is usually a very small loss of vision at the outside edges of the eye. Experts say most people do not know they have glaucoma until it causes a real loss of sight. Doctors now treat glaucoma with eye medicines or an operation.
A new discovery about the disease was reported in the publication "Archives of Ophthalmology." Robert Weinreb (WINE-reb) is an eye doctor and researcher at the University of California. He and others have long suspected that glaucoma patients also suffer damage to nerves deep within their brains. He says the new study shows damage to the part of brain known as the lateral geniculate nucleus.Doctor Weinreb and scientists from other universities studied the brains of monkeys suffering glaucoma. They examined special pictures taken of the insides of the monkeys' brains. They also studied similar pictures of the brains of healthy monkeys. The researchers counted each nerve cell in the lateral geniculate nucleus area of the brains. This showed that the monkeys with glaucoma had lost about forty percent of the nerve cells in this area of the brain.
The researchers say future work will involve studying the brains of people with glaucoma. They want to learn what causes the disease and find which areas of the brain it damages. The researchers say this discovery could lead to new ways to protect the nerve cells in the eye and the brain.
((MUSIC BRIDGE))For years, many scientists have considered walking on two legs as one sign of being human. Early humans were not thought to have used their knuckle bones or other parts of their hands in walking. Now, however, American scientists have found evidence that humans developed from creatures that walked on their knuckles, much like gorillas and chimpanzees do today. Researchers Brian Richmond and David Strait are from the George Washington University in Washington, D. C. They say they made their discovery almost by accident during a visit to the Smithsonian Institution in Washington. They compared old reports about the biology of apes with a copy of the wrist bone from Lucy, the most famous fossil remains of an early form of human. Their findings are reported in the publication Nature.
The researchers examined how the wrist structure of chimpanzees and gorillas differs from other apes. They also examined the wrist bones from Lucy and another human-like creature that lived in Africa more than three-million years ago.The researchers say the ancient creatures had the same wrist structure as modern chimpanzees and gorillas. They found structures in the wrist bones that restricted the movement of the wrist.
However, the researchers do not believe the creatures used their knuckles in walking because they had longer legs than the apes. The researchers say a creature with longer legs would have a difficult time supporting its weight on its lower legs and hands at the same time. They suggest that the wrist structure for knuckle-walking may have developed even earlier - as much as five-million years ago.
David Strait says the development of walking upright required major changes in the structure of the early human ancestors. He says there must have been a good reason for making those changes. The exact reasons, however, remain a mystery.
((MUSIC BRIDGE))Many people are visiting a museum in Chicago, Illinois to see ancient documents called the Dead Sea Scrolls. The world famous writings will be shown at the Field Museum of Natural History until the middle of June. Museum officials say it is the most extensive exhibit of the Dead Sea Scrolls in North America. Officials in Israel lent the documents to the museum.
The Dead Sea Scrolls were written in what is now Israel more than two-thousand years ago. They represent the oldest surviving copies of the Old Testament of the Bible. The Jewish and Christian religions consider the Bible to be holy. The scrolls were discovered in Nineteen-Forty-Seven near Qumran, along the northwest shore of the Dead Sea.Experts say some of the writings describe the laws and beliefs of the people who wrote them. Many experts believe the writers were from a group called the Essenes, who lived in Qumran. Other experts believe the scrolls were written in Jerusalem and hidden in caves near Qumran to protect them from invading Roman forces.
The Field Museum exhibit contains parts of fifteen of the ancient documents. They include five documents that have never been shown outside Israel. The exhibit also has eighty ancient objects from settlements near Qumran. They include containers, money and shoes.
This SCIENCE IN THE NEWS program was written by Nancy Steinbach and George Grow. This is Sarah Long.And this is Steve Ember. Join us again next week for more news about science in Special English on the Voice of America.