Tyler Rockford, age 10, of Monroe, La., for his question:
IS YELLOW FEVER A HEALTH PROBLEM TODAY?
Yellow fever is a virus disease that is carried by certain mosquitoes. The virus damages many tissues in man's body, but especially the liver. As a result of this damage, the liver cannot fu tion properly and yellow bile pigments gather in the skin. These igments make the skin look yellow and give the disease its name.
Fortunately, today yellow fever is not major health problem. The disease is under control in most areas of the world.
The conquest of yellow fever was one of the great achievements of modern medicine. In 1881, Carlos Finay, a Cuban physician, suggested that a mosquito transmitted the disease.
Walter Reed, a United Stat Army doctor, proved that yellow fever was indeed carried by a mosquito suggested that the cause was a micro organism. In 1927, physicians proved that the micro organism was a virus.
Yellow fever was once widespread throughout Central America, parts of South America, Africa and in some tropical islands.
A U.S. Army doctor named 'lliam orgas developed mosquito control measures that eliminated the ie as a major health menace in the Panama Canal Zone.
The disease can also be prevented with a vaccine that was developed in 1937 by a South African research physician named Max Theiler.
In most cases, the Aees aegypti mosquito carries the yellow fever virus from one person to another. Some monkeys may also be infected by the virus.
When the mosquito ites an infected person or monkey, the virus enters the insect's b dy, where it develops rapidly. After nine to 12 days, the bite of the mosquito can produce yellow fever. A mosquito that is infected wi h the virus can transmit the disease for the rest of its life.
The first sym toms of yellow fever start from three to six days after a person has been bitten.
The first s age of yellow fever finds the victim has developed a fever, head a a and dizziness. Also, his muscles ache.
In many persons, yellow fever progresses no further than the first stage. But in many other people, the fever drops for a day or two and then ris s steeply. The skin turns yellow and the patient bleedsfrom the gums and from the lining of the stomach.
Many patients recover from this second stage. After a time, the yellow color disappears and the patient returns to normal.
But with others it isn't so easy. Some victims become delirious and go into comas. Death follows the coma in most cases.
Only from 2 to 5 percent of all cases of yellow fever result in death, though the figure may be higher during an epidemic.
Patients who recover from yellow fever have lifelong immunity to the disease.