TEXT E Rabies is an ordinarily
infectious disease of the central nervous system, caused by a virus and, as a
rule, spread chiefly by domestic dogs and wild flesh-eating animals. Man and all
warm-blooded animals are susceptible to rabies. The people of ancient Egypt,
Greece and Rome ascribed rabies to evil spirits because ordinarily gently and
friendly animals suddenly became vicious and violent without evident cause and,
after a period of maniacal behaviour, became paralysed and died.
Experiments carried out in Europe in the early nineteenth century of
injecting saliva from a rabid dog into a normal dog proved that the disease was
infectious. Preventive steps, such as the destruction of stray dogs, were taken
and by 1826 the disease was permanently eliminated in Norway, Sweden and
Denmark. Though urban centres on the continent of Europe were cleared several
times during the nineteenth century, they soon became reinfected since rabies
was uncontrolled among wild animals. During the early stages of
the disease, a rabid animal is most dangerous because it appears normal and
friendly, but it will bite at the slightest provocation. The virus is present in
the sailvary glands(腺) and passes into the saliva so that the bite of the
infected animal introduces the virus into a fresh wound. If no action is taken,
the virus may become established in the central nervous system and finally
attack the brain. The incubation(潜伏期) period varies from ten days to eight
months or more, and the disease develops more quickly the nearer to the brain
the wound is. Most infected dogs become restless, nervous, and irritable and
vicious, then depressed and paralysed. With this type of rabies, the dog’s death
is inevitable and usually occurs within three to five days after the onset of
the symptoms. Anti-rabies vaccine(疫苗) is widely used nowadays in
two ways. Dogs may be given three-year protection against the disease by one
powerful injection, while persons who have been bitten by rabid animals are
given a course of daily injections over a week or ten days. The mortality rate
from all types of bites from rabid animals has dropped from 9% to 0.5%. In rare
cases, the vaccine will not prevent rabies in human beings because the virus
produces the disease before the person’s body has time to build up enough
resistance. Because of this, immediate vaccination is essential for anyone
bitten by an animal observed acting strangely and the animal should be captured
circumspectly, and examined professionally or destroyed. According to the passage, which of the following is NOT role
A．Animals will be paralysed and died after being infected with rabies. B．In 19th century, Europeans were reinfected with rabies for the uncontrolling of wild animals. C．All dogs were killed in Europe in the early 19th century. D．The saliva of a rabid dog is infectious.