Japanese researchers are genetically changing mosquitoes so that they become carriers of a vaccine （疫苗）that could vaccinate millions for free. The researchers have already genetically changed a mosquito species so that its saliva （唾液） contains a protein that acts as a vaccine against leishmaniasis （利什曼病），a deadly disease that leads to terrible skin problems. The team confirmed that mice bitten by the genetically engineered mosquito developed an antibody to the disease, meaning they had built up immunity （免疫力）.
"You would be vaccinated without even noticing. You wouldn't need any drug and you wouldn't need to show up at a fixed place for mass vaccinations," said Shigeto Yoshida, the associate professor who has led the research. "Repeated bites would only strengthen the immunity."
"Similarly the mosquitoes could be used to help treat malaria （疟疾）， perhaps a decade from now," said the malaria expert.
Nearly one million people die each year from malaria-most of them are children-mainly in Africa and Asia, according to the World Health Organization. Now a problem is that no effective vaccine exists. "There is a treatment that works, but it is beyond the reach of people who need to worry about food for tomorrow," Yoshida said.
However, Yoshida expects that the genetically-engineered mosquito will finally help wipe out the deadly disease in the developing world. "Technically speaking, I believe it's a matter of 10 years or so,but it's not clear whether society would accept it," he said.
Another problem is that the genetically-engineered mosquito may still pick up and spread the infected blood of a person who has already caught malaria. Yoshida's team is hoping it can solve this problem by developing a mosquito species that kills the malaria virus inside its own body.



How have scientists turned mosquitoes into carriers of a vaccine？ ______

A. By changing their genes.
B. By killing the virus in their bodies.
C. By letting them bite mice.
D. By injecting vaccines into their bodies.

Which of the following is NOT an advantage of using mosquitoes as vaccine carriers？ ______

A. It's free of charge.
B. It's convenient.
C. It's more effective.
D. It's unnoticeable.

What can we infer from the last two paragraphs？ ______

A. People welcome the idea of using mosquitoes to treat malaria.
B. Mosquitoes carrying vaccines may still spread malaria.
C. It is not long before people will use mosquitoes to get rid of malaria.
D. A mosquito can kill the malaria virus inside its own body.

The main purpose of the passage is to ______ .

A. introduce a possible solution to malaria
B. encourage people to use mosquitoes to fight against diseases
C. show that Japan has very advanced technology
D. call on people to help people suffering from malaria in Africa and Asia