VOA科学技术2023--Letting Mosquitoes Bite You for Science

Letting Mosquitoes Bite You for Science

It is lunchtime. And mosquitoes find their way to Ella Branham's arm at a Salt Lake City lab in the American state of Utah.

"They're not very aggressive and they're kind of picky eaters," said Branham. She breathed into a glass tank to attract the insects to the carbon dioxide in her breath. "So I'll be feeding them with my arm."

Branham had volunteered to let the South American mosquitoes, called sabethes cyaneus, feed on her blood. She is doing so to help produce eggs and maintain the colony for education and research at the Salt Lake City Mosquito Abatement² District.

The district is one of many mosquito control areas around the United States that seek to control one of the world's deadliest animals. Mosquitoes are expected to strengthen as climate change creates a warmer and wetter environment.

Mosquitoes can carry viruses including dengue, yellow fever, chikungunya and Zika. They are especially threatening to public health in Asia and Africa but are closely watched in the United States. Local agencies reported more than 1,100 cases of West Nile virus in 2022, says the U.S. Centers for Disease Control.

Most humans who get West Nile show no symptoms. But for some, it can cause vomiting⁴, fever and in rare cases seizures⁵ or meningitis. Over roughly the last 25 years, nearly 3,000 deaths and more than 25,000 hospitalizations connected to West Nile were reported throughout the U.S., mostly in August.

West Nile deaths have been reported this year in states including Texas and Colorado. Mosquitoes are also thought to have caused malaria⁶ infections of people in Maryland, Florida and Texas.

Ary Faraji is a disease expert and the director of the Salt Lake City Mosquito Abatement District. He said the mosquito season is starting earlier and lasting⁷ longer as the climate has warmed. The district used to shut down each year in mid-September, but that has gotten later and later. Last year, district workers were still setting and checking traps until late November.

And this year, workers estimated that there were five times as many mosquitos in May compared to the average year. There was an unusually snowy winter in Salt Lake City and a very rainy spring that left more water for mosquitoes to breed in.

That is where the health threat comes in. While both males and females feed on sugar or nectar throughout their lives, females require blood to provide nutrition to their eggs.

The workers, including scientists and students, use drones, boats and vehicles to trap, sort and test mosquitos for viruses. Their work considers how things like weather systems and population growth will affect the spread of disease.

The more people there are close to a lot of mosquitos, the higher the chance of spread, Faraji said. The wetland areas surrounding Utah's Great Salt Lake are problematic, he added.

Though dangerous, mosquitoes are also important to ecosystems⁹ throughout the world. Some serve as pollinators or food sources to fish, birds and frogs.

"We try to maintain a balance and suppress them to the point that they're not negatively affecting communities," Faraji said. "Taking them away would definitely negatively impact our ecosystem⁸ overall."

Words in This Story

abate¹ — v. to become weaker

district — n. an area established by a government for official government business

symptom — n. a change in the body or mind which indicates that a disease is present

vomit³ — n. to have the food, liquid, etc., that is in your stomach come out through your mouth because you are sick

breed — v. to produce offspring by sexual reproduction

pollinator — n. to give pollen¹⁰ from another plant of the same kind so that seeds will be produced

negative — adj. harmful or bad

1 abate   

vi.(风势，疼痛等)减弱，减轻，减退

参考例句：

• We must abate the noise pollution in our city.我们必须消除我们城里的噪音污染。
• The doctor gave him some medicine to abate the powerful pain.医生给了他一些药，以减弱那剧烈的疼痛。

2 abatement   

n.减(免)税，打折扣，冲销

参考例句：

• A bag filter for dust abatement at the discharge point should be provided.在卸料地点应该装设袋滤器以消除粉尘。
• The abatement of the headache gave him a moment of rest.头痛减轻给他片刻的休息。

3 vomit   

v.呕吐，作呕；n.呕吐物，吐出物

参考例句：

• They gave her salty water to make her vomit.他们给她喝盐水好让她吐出来。
• She was stricken by pain and began to vomit.她感到一阵疼痛，开始呕吐起来。

4 vomiting   

吐

参考例句：

• Symptoms include diarrhoea and vomiting. 症状有腹泻和呕吐。
• Especially when I feel seasick, I can't stand watching someone else vomiting." 尤其晕船的时候，看不得人家呕。”

5 seizures   

n.起获( seizure的名词复数 )；没收；充公；起获的赃物

参考例句：

• Seizures of illicit drugs have increased by 30% this year. 今年违禁药品的扣押增长了30%。 来自《简明英汉词典》
• Other causes of unconsciousness predisposing to aspiration lung abscess are convulsive seizures. 造成吸入性肺脓肿昏迷的其他原因，有惊厥发作。 来自辞典例句

6 malaria   

n.疟疾

参考例句：

• He had frequent attacks of malaria.他常患疟疾。
• Malaria is a kind of serious malady.疟疾是一种严重的疾病。

7 lasting   

adj.永久的，永恒的；vbl.持续，维持

参考例句：

• The lasting war debased the value of the dollar.持久的战争使美元贬值。
• We hope for a lasting settlement of all these troubles.我们希望这些纠纷能获得永久的解决。

8 ecosystem   

n.生态系统

参考例句：

• This destroyed the ecosystem of the island.这样破坏了岛上的生态系统。
• We all have an interest in maintaining the integrity of the ecosystem.维持生态系统的完整是我们共同的利益。

9 ecosystems   

n.生态系统( ecosystem的名词复数 )

参考例句：

• There are highly sensitive and delicately balanced ecosystems in the forest. 森林里有高度敏感、灵敏平衡的各种生态系统。 来自《简明英汉词典》
• Madagascar's ecosystems range from rainforest to semi-desert. 马达加斯加生态系统类型多样，从雨林到半荒漠等不一而足。 来自辞典例句

10 pollen   

n.[植]花粉

参考例句：

• Hummingbirds have discovered that nectar and pollen are very nutritious.蜂鸟发现花蜜和花粉是很有营养的。
• He developed an allergy to pollen.他对花粉过敏。