VOA健康报道2024--Why Is Polio Still a Problem?

Polio was driven out of much of the world more than 30 years ago after a series of successful vaccination¹ campaigns. But the viral disease is still spreading in a small number of nations.

The recent discovery of the first polio case in Gaza in 25 years led world health officials to set new goals to get rid of the disease in all areas.

What is polio?

Polio is an infection caused by a virus that mostly affects children under the age of five. Most infected people do not have any symptoms. But some can experience a high body temperature, headaches, vomiting³ and stiffness of the backbone⁴, or spine⁵.

The World Health Organization (WHO) says polio can affect the nervous system and cause paralysis⁶ within hours. The U.N. agency estimates 1 in 200 polio cases results in permanent paralysis, usually of the legs. Among children who are paralyzed, up to 10 percent die when their breathing muscles stop working.

The virus spreads from person to person, entering the body though the mouth. It is most often spread through contact with the waste from an infected person. Sometimes, it is also passed through water or food.

How bad was polio in the past?

Polio has existed for hundreds of years. The Associated Press says that Ancient Egyptian writings show children using sticks to walk and having wasted legs or arms, suggesting the effects of polio.

Before the first vaccine⁷ was developed in the 1950s, polio was among the world's most feared diseases. A 1916 outbreak in New York killed more than 2,000 people. The worst recorded U.S. outbreak in 1952 killed more than 3,000 people. Many who survived polio suffered lifelong effects, including paralysis and deformed⁸ limbs. Others whose breathing muscles were paralyzed required specialized⁹ lung treatments.

When did the campaign to destroy polio begin?

The WHO passed a resolution in 1988 calling for polio to be eradicated¹¹, or destroyed, worldwide. The effort followed a successful campaign against smallpox¹² eight years earlier.

The WHO's first plan was to eradicate¹⁰ polio by 2000. The U.N. agency cooperated with the U.S. Centers for Disease Control and Prevention, UNICEF and Rotary¹³ International. The campaign centered on increasing the production of a vaccine and launching vaccination efforts. As a result, polio cases dropped by more than 99 percent.

Afghanistan and Pakistan are the only countries where the spread of polio has never been stopped. There have also been outbreaks in several other countries, mostly in Africa. The WHO and its partners now aim to eradicate polio by 2026.

Why have efforts to fight polio taken so long?

Health experts say stopping polio outbreaks requires vaccinating¹⁴ at least 95 percent of the world's population. Vaccinating people is more difficult in nations that have conflicts or weak health systems.

The vaccine given by mouth does not cost a lot to manufacture and is better at preventing infection. But it contains weakened, live polio virus. In rare cases, the vaccine can spread or cause polio in unvaccinated people. In even rarer cases, live virus from the vaccine can mutate into a new form that could start new outbreaks.

Health officials have become more successful at reducing the number of cases caused by the natural polio virus. The majority of infections in the world today are related to the vaccine.

Scott Barrett is a professor at Columbia University in New York City who has studied polio eradication¹⁵. He told the AP, "The problem with trying to eradicate polio is that the need for perfection is so great and there are so many weak links." He added that while the technical ability to destroy polio exists, "We live in a vastly imperfect world."

Words in This Story

symptom - n. a physical feeling or problem that suggests a person has a particular sickness

vomit² -v. to expel what is in the stomach through the mouth

stiffness -n. a difficulty in either slowness or pain in moving a part of the body

paralysis - n. being unable to move all of part of the body because of sickness or injury

eradicate -v. to completely remove or destroy

mutate - v. to cause a gene¹⁶ to change and create an unusual characteristic in a plant or animal

perfection -n. a state in which no error or fault exists

vastly - adv. to a very large extent

1 vaccination   

n.接种疫苗，种痘

参考例句：

• Vaccination is a preventive against smallpox.种痘是预防天花的方法。
• Doctors suggest getting a tetanus vaccination every ten years.医生建议每十年注射一次破伤风疫苗。

2 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。

3 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。”

4 backbone   

n.脊骨，脊柱，骨干；刚毅，骨气

参考例句：

• The Chinese people have backbone.中国人民有骨气。
• The backbone is an articulate structure.脊椎骨是一种关节相连的结构。

5 spine   

n.脊柱，脊椎；(动植物的)刺；书脊

参考例句：

• He broke his spine in a fall from a horse.他从马上跌下摔断了脊梁骨。
• His spine developed a slight curve.他的脊柱有点弯曲。

6 paralysis   

n.麻痹(症)；瘫痪(症)

参考例句：

• The paralysis affects his right leg and he can only walk with difficulty.他右腿瘫痪步履维艰。
• The paralysis affects his right leg and he can only walk with difficulty.他右腿瘫痪步履维艰。

7 vaccine   

n.牛痘苗，疫苗；adj.牛痘的，疫苗的

参考例句：

• The polio vaccine has saved millions of lives.脊髓灰质炎疫苗挽救了数以百万计的生命。
• She takes a vaccine against influenza every fall.她每年秋季接种流感疫苗。

8 deformed   

adj.畸形的；变形的；丑的，破相了的

参考例句：

• He was born with a deformed right leg.他出生时右腿畸形。
• His body was deformed by leprosy.他的身体因为麻风病变形了。

9 specialized   

adj.专门的，专业化的

参考例句：

• There are many specialized agencies in the United Nations.联合国有许多专门机构。
• These tools are very specialized.这些是专用工具。

10 eradicate   

v.根除，消灭，杜绝

参考例句：

• These insects are very difficult to eradicate.这些昆虫很难根除。
• They are already battling to eradicate illnesses such as malaria and tetanus.他们已经在努力消灭疟疾、破伤风等疾病。

11 eradicated   

画着根的

参考例句：

• Polio has been virtually eradicated in Brazil. 在巴西脊髓灰质炎实际上已经根除。
• The disease has been eradicated from the world. 这种疾病已在全世界得到根除。

12 smallpox   

n.天花

参考例句：

• In 1742 he suffered a fatal attack of smallpox.1742年，他染上了致命的天花。
• Were you vaccinated against smallpox as a child?你小时候打过天花疫苗吗？

13 rotary   

adj.(运动等)旋转的；轮转的；转动的

参考例句：

• The central unit is a rotary drum.核心设备是一个旋转的滚筒。
• A rotary table helps to optimize the beam incidence angle.一张旋转的桌子有助于将光线影响之方式角最佳化。

14 vaccinating   

给…接种疫苗( vaccinate的现在分词 )； 注射疫苗，接种疫苗

参考例句：

• At first blush, vaccinating the wolves against rabies seems a simple solution. 乍一看来，为狼群注射防狂犬病疫苗是一种简单的办法。
• Also vaccinating children against misers (measles) has saved many lives. 还有，给儿童进行疫苗接种防止麻疹也挽救了许多生命。

15 eradication   

n.根除

参考例句：

• The eradication of an established infestation is not easy. 根除昆虫蔓延是不容易的。
• This is often required for intelligent control and eradication. 这经常需要灵巧的控制与消除。

16 gene   

n.遗传因子，基因

参考例句：

• A single gene may have many effects.单一基因可能具有很多种效应。
• The targeting of gene therapy has been paid close attention.其中基因治疗的靶向性是值得密切关注的问题之一。