Mosquitoes carry malaria (疟疾), which kills thousands of people each year. Now some researchers are trying to use genetic engineering to make the annoying insects into partners in the fight against the disease.
For years, public health officials have tried to limit the disease by controlling mosquito populations. “But that approach is temporary,” says Anthony James, a professor of biology and genetics at the University of California, Irvine, “Because mosquitoes are extremely tough little insects, and their populations can quickly rebound.”
Therefore, James and his colleagues want to try a different approach: making mosquitoes themselves into malaria-fighting warriors, which is a complete departure from traditional ways of controlling malaria.
To understand how it works, it helps to understand the life cycle of malaria. The malaria pathogen (病原体) is a parasite (寄生虫) that grows inside humans. It’s passed via mosquitoes that move from person to person, sucking blood. “If we can make the mosquitoes difficult for the pathogens to survive, we can wipe out the disease,” he says. But making mosquitoes uninviting to malaria is a tough job.
To solve the problem, the team used a gene-editing technique called CRISPR. They started with genes from mice, whose immune systems do fight human malaria, engineered those genes, and then gave them to the mosquitoes.
It turned out the malaria-fighting antibodies which gene-edited mosquitoes produced worked very well. They reduced the number of parasites in the mosquito before they were passed to a human host.
James’ team are now working on planning a field trial, which he hopes could be conducted on an island or in another isolated location.
But genetically changing wild animals does not sit well with environmentalists. “There’s no need to engineer a mosquito,” says Dana Perls, senior program manager for the emerging technology program at the non-profit Friends of the Earth. Perls points out that naturally occurring methods for reducing malaria appear to be showing promise, as does a new vaccine (疫苗) against the disease. “Why take unnecessary risks and release a species that can’t be recalled once it’s released into the wild?” she asks.
【小题1】What can we know from the second and third paragraphs?A.Mosquitoes reproduce quickly. |
B.Mosquitoes depart from malaria. |
C.Mosquitoes are malaria-fighting warriors. |
D.Mosquitoes’ populations are under control. |
A.Mice. | B.Parasites. | C.Mosquitoes. | D.Gene-edited mosquitoes. |
A.Tolerant. | B.Favorable. | C.Objective. | D.Disapproving. |
A.Limiting Malaria by Controlling Mosquito Populations |
B.Controlling Malaria by editing Mosquitoes’ genes |
C.Curing Malaria with Gene-edited Mosquitoes |
D.Preventing Malaria with a new vaccine |
Mental health matters. Many of us will experience a mental health issue in our lifetime. One of the most common is stress.
Another common mental health problem is anxiety. Like stress, feeling anxious is a normal reaction to certain situations — such as taking a test, going to an interview, worrying about a loved one — but more severe anxiety can have a huge impact on daily life and is a long-term condition.
If you recognize any of the signs of a mental health issue, you should seek help from a professional.
There are some more serious mental health disorders too, and it is important that these are diagnosed (诊断) properly.
A.Exercise can relieve depression, anxiety and stress. |
B.It is a natural reaction to feel under pressure or threat. |
C.Thinking positively is the key to lowering anxiety level. |
D.We all suffer from a low mood by events in our lives sometimes. |
E.There are plenty of options, from talking therapies (疗法) to medication. |
F.In these cases, better talk to your medical team about the treatment. |
G.Feeling anxious all the time makes it hard for you to relax or enjoy life. |
French baby-milk maker Lactalis and health authorities have ordered a major international recall ( 召回) of several food products for babies. The Lactalis Group is one of the world’s largest manufacturers of dairy products. It said French health officials warned the company that 26 babies had been sickened with salmonella (沙门氏菌) since December 1,2017.
The French Ministry of the Economy ordered the suspension of marketing and export of several baby products made at a Lactalis factory in Craon, France. It said all the products were manufactured after February 15, 2017, the French health ministry’s website says the recall affects nine countries in four continents: Britain and Greece in Europe; Morocco and Sudan in Africa; Peru and Colombia in South America; and Pakistan, Bangladesh and China in Asia. The United States, a major market for Lactalis products, is not affected.
A company spokesman told the Associated Press Monday that the recall is “precautionary (预防的)” and involves “several million” products. Lactalis noted in a statement that the 26 cases of infection were linked to products with the brand names Picot SL, Pepti Junior 1 , Milumel Bio 1 and Picot Riz. The statement included an apology and provided financial support to the families whose children were sickened. The company said it had taken measures to clean the area of the factory where the bacteria spread.
Infection with salmonella can cause sickness. Signs of infection include abdominal ( 腹 部 ) pain , diarrhea ( 腹泻) and higher-than-normal body temperature. The sickness is more dangerous among some populations, including the very young.
The Lactalis Group is a privately-held company. Its headquarters is in western France. Lactalis has 75, 000 employees in 85 countries and earnings of about 17 billion euros a year. Its famous brands include President and Galbani cheeses, as well as Parmalat milk.
【小题1】Why are the dairy products of Lactalis ordered to be returned?A.Because they may have been polluted by salmonella. |
B.Because they have claimed the lives of some babies. |
C.Because their marketing strategy has been adjusted. |
D.Because they are being boycotted by consumers. |
A.26 baby cases have been found by now. |
B.The symptoms include a high body temperature. |
C.The very young tend to suffer less. |
D.Nine countries were infected, including America. |
A.Recalling the products made before Feb.15, 2017. |
B.Cleaning all the areas of the relevant factories. |
C.Pausing the promotion of products in Australia. |
D.Covering the medical expenses of the sick children. |
A.A book review. |
B.A research paper. |
C.A news report. |
D.A doctor’s diary. |
When it comes to medical care, many patients and doctors believe “more is better.” But what they do not realize is that overtreatment—too many scans, too many blood tests, too many procedures—may bring harm. Sometimes a test leads you down a path to more and more testing, some of which may be attacking, or to treatment for things that should be left out.
Terrence Power, for example, complained that after his wife learned she had Wegener’s disease, an uncommon disorder of the immune system(免疫系统), they found it difficult to refuse testing recommended by her doctor. The doctor insisted on office visits every three weeks, even when she was feeling well. He frequently ordered blood tests and X-rays, and repeatedly referred her to experts for even minor complaints. Even when tests came back negative, more were ordered, and she was hospitalized as prevention when she developed a cold. She had as many as 25 doctor visits during one six-month period. The couple was spending about $30,000 a year for her care.
After several years of physical suffering and near financial ruin from the medical costs, the couple began questioning the treatment after discussing with other patients in online support groups. “It’s a really hard thing to determine when doctors have crossed the line,” Mr. Power said. “You think she’s getting the best care in the world, but after a while you start to wonder: What is the purpose?” Mr. Power then spoke with his own primary care doctor, who advised him to find a new expert to oversee Mrs. Power’s care. Under the new doctor’s care, the regular testing stopped and Mrs. Power’s condition was stable. Now she sees the doctor only four or five times a year.
【小题1】What is the main idea of this passage?A.Treatments do not always cause harmful side effects. |
B.Patients tend to believe more testing is better treatment. |
C.Too much medical care may not be beneficial to patients. |
D.Doctors generally recommend office visits that are necessary. |
A.She had to be hospitalized for three weeks whenever she had a cold. |
B.When test results showed she was fine, her doctor still ordered more tests. |
C.She did not have any insurance, so she became penniless. |
D.Her doctor asked her to consult other experts for her complaints. |
A.construct | B.improve | C.catch | D.attack |
A.After knowing about other patients’ treatment. |
B.After analyzing the results of her blood tests. |
C.After curing Mrs Power of her illness. |
D.After the new expert’s testing |
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