美国英语听力80篇2 Lesson22
22) West Nile Fever
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 2,000 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 was first 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 500,000,000 people around the world each year are infected with sicknesses carried by mosquitoes,
These include dengue fever, malaria,yellow fever and brain fevers such as West Nile.
More than 2,000,000 people die of these diseases, many of them young children.
One example of the increase in these diseases is dengue fever.
In the 1950s, the serious form of the disease infectedabout 1,000 people each year.
Today, more than 500,000 people are infected each year.
About 24,000 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.
