Lab Diagnosis & Prevention of Enterovirus在线视频

Poliovirus infection
脊髓灰质炎病毒感染

Poliovirus shows tissue tropism by specifically
脊髓灰质炎病毒有组织嗜性

combining with neural cells.
特异性的结合神经细胞

It recognizes a receptor present on the anterior horn cells
病毒能识别脊髓前角细胞

of the spinal cord, dorsal root ganglia, and motor neurons.
背根神经节和运动神经元上的受体

On combination at these sites, the poliovirus causes
脊髓灰质炎病毒结合在这些位点后会引起

destruction of the motor neurons, anterior horn, and brain stem.
运动神经元、前角和脑干的破坏

The destruction of motor neurons in the spinal cord
对脊髓中运动神经元的破坏

results in flaccid paralysis (poliomyelitis).
会导致弛缓性麻痹(脊髓灰质炎)

Paralysis is not caused by the virus infecting the muscles.
症状并不是由于肌肉被感染引起的

There are three poliovirus types, with 85% of the cases
脊髓灰质炎病毒有三型

of paralytic polio caused by type 1.
85%的病例是由1型引起的

The poliovirus also infects the brain stem,
脊髓灰质炎病毒也会感染脑干

causing bulbar poliomyelitis associated with respiratory paralysis.
导致与呼吸麻痹有关的延髓脊髓灰质炎

Do you remember the iceberg concept?
你还记得冰山概念吗？

Asymptomatic illness is far more common than clinically manifestation.
无症状感染者远比有临床表现的病例更常见

At least 90% of poliovirus infections are asymptomatic.
至少有90%的脊髓灰质炎病毒感染是无症状的

Abortive poliomyelitis occurs in approximately 5% of infected people.
大约5%的感染者出现顿挫型脊髓灰质炎

The patient has only the minor illness,
病人只有一些轻微的症状

characterized by fever, malaise, drowsiness, headache, nausea,
如发烧、不适、嗜睡、头痛、恶心

vomiting, constipation, and sore throat in various combinations.
呕吐、便秘和咽痛等不同症状

Nonparalytic poliomyelitis or aseptic meningitis occurs
1%至2%的脊髓灰质炎病毒感染者

in 1% to 2% of patients with poliovirus infections.
会出现非麻痹性脊髓灰质炎或无菌性脑膜炎

The patient with the nonparalytic form has stiffness
非麻痹性脊髓灰质炎的患者会感到

and pain in the back and neck.
背部和颈部的僵直和疼痛

Paralytic polio, the major illness,
麻痹性脊髓灰质炎是主要的疾病类型

occurs in 0.1% to 2.0% of persons with poliovirus infections
发生在0.1%至2.0%的脊髓灰质炎病毒感染者身上

and is the most severe outcome.
它也是脊髓灰质炎病毒导致的最严重疾病

Patients & asymptomatic carriers both can be
患者和无症状携带者都可能是

the source of the infection.
传染源

Outbreak of Poliomyelitis
脊髓灰质炎的爆发

The Polio is a disease with long history.
脊髓灰质炎是一种历史悠久的疾病

The wall painting shows an ancient Egyptian with polio.
这幅壁画展示了一位患有小儿麻痹症的古埃及人

The disease is first described by Michael Underwood in 1789.
1789年Michael Underwood首次描述了本病

A severe outbreak in the U.S. in 1952,
在1952年美国爆发的一次严重疫情中

there were 21, 000 paralytic cases reported.
报告了21，000例瘫痪病例

If there were 21, 000 paralytic cases,
如果那年有21000个瘫痪病例

how many polio infectors that year?
那有多少感染者呢？

Yes, about 1000 times of the paralytic cases, maybe 21 million.
没错，大约是瘫痪病例的1000倍，可能会是2100万人感染

Most of them were asymptomatic.
大部分感染者无症状

And now, global eradication in near future.
现在，脊髓灰质炎病毒将在不久的将来从全球消灭

Questions are how can we eradicate an infectious disease in the world?
问题是我们如何才能消灭一种传染病？

You are right,the vaccine.
你说得对，疫苗

What make us have the confidence to eradicate the polio?
是什么让我们有信心消灭脊髓灰质炎？

Key facts about poliomyelitis in WHO website.
世卫组织官网上关于脊髓灰质炎的关键点

Let's see the highlighted numbers.
首先让我们看一些数字

Polio (poliomyelitis) mainly affects children under 5 years of age.
脊髓灰质炎(小儿麻痹症)主要影响5岁以下的儿童

1 in 200 infections leads to irreversible paralysis.
每200例感染中就有一例导致不可逆的瘫痪

Among those paralysed,
在那些瘫痪者中

5% to 10% die when their respiratory muscles become affected.
有5%到10%的人因影响到呼吸肌而死亡

Host response to poliovirus mostly depends on the humoral immunity.
宿主对脊髓灰质炎病毒的反应主要依赖于体液免疫

Both the serum and secretory antibodies play
血清和分泌性抗体

an important role in providing protection against poliomyelitis.
都在预防脊髓灰质炎方面发挥重要作用

Serum IgM antibodies appear within a week of infection.
血清IgM抗体在感染后一周内出现

IgG antibodies, which develop subsequently, persist lifelong.
随后产生的IgG抗体会在体内终生存在

Secretory IgA antibodies provide mucosal immunity
分泌型IgA通过

against the virus by preventing intestinal infections
阻止经肠道感染和阻止病毒释放

and by preventing shedding of virus.
从而发挥粘膜免疫作用

Cell-mediated immunity plays little or very insignificant role
细胞介导的免疫反应

in the immunity against poliovirus.
抵抗脊髓灰质炎病毒的作用很小

The host immunity is permanent and type-specific.
免疫是持久的和特异的

The virus in the brain and spinal cord is not influenced
血液中高滴度的抗体无法清除

by high titers of antibodies in the blood,
大脑和脊髓中的病毒

so polio vaccine should be given before infection.
因此脊髓灰质炎疫苗应该在感染前注射

Summary of pathogenesis and immunity of poliovirus infection.
脊髓灰质炎病毒感染的发病机制和免疫小结

Source of infection: patients & asymptomatic carriers.
传染源:患者和无症状携带者

Route of transmission: fecal-oral route.
传播途径:粪口传播

Season: summer and fall.
季节:夏秋季

Immunity: permanent, type-specific.
免疫性质:持久，特异性

The virion of enterovirus.
肠道病毒的病毒体

Enterovirus is a member of the family Picornaviridae.
肠道病毒属于小RNA病毒科

"Pico" means "One-trillionth (10¯¹²)"; very small
“Pico”表示“10¯¹²”；非常微小

Then "rna", refers to RNA virus
“rna”,表示RNA病毒

"-viridae", the family name.
“-viridae”，是病毒科

It is a very small RNA virus family.
小RNA病毒科是微小的RNA病毒家族

Picornaviridae contains 9 genera, including Enterovirus,
包含9个属，包括肠道病毒

Rhinovirus,Hepatovirus, and so on.
鼻病毒，嗜肝病毒，等

Rhinoviruses can cause common cold,
鼻病毒会引起普通感冒

including more than 100 anti-genic types.
包括100多种血清型

They are labile at acidic pH and the optimum growth
它们在酸性条件下不稳定

temperature is 33°C, which are different from enteroviruses.
最佳生长温度为33°C，这一点有别于肠道病毒

The enteroviruses are very resistant to harsh environmental
肠道病毒对恶劣环境（例如污水和胃肠道的环境）

conditions (sewage systems) and the conditions in the
有很强的抵抗力

gastrointestinal tract,
这使它们能够通过

which facilitates their transmission by the fecal-oral route.
粪口途径传播

Hepatitis A virus was originally classified as
甲型肝炎病毒最初被归类为

enterovirus type 72 but now assigned to a separate genus.
肠道病毒72型，但现在被纳入一个单独的属

Diagram again, picornaviruses are +ssRNA viruses, very small.
这张示意图显示，小RNA病毒是+ssRNA病毒，非常小

Structure of picornaviruses
小RNA病毒的结构

Naked
裸病毒

28-30 nm in diameter
直径为28-30 nm

RNA core and capsid
有RNA核心和衣壳

Do you remember the homework last week?
还记得上周的作业吗？

Can you answer the questions?
能回答这些问题吗？

How many faces? 20 faces.
衣壳多少个面？20个面

What is pentamer? Five units
什么是pentamer？五聚体

How many pentamers? 12.
有多少个五聚体？12个

The Capsid of picornaviruses is icosahedral, 12 pentamers.
小RNA病毒的衣壳是二十面体，由12个五聚体构成

Viral proteins VP1-VP4
病毒蛋白VP1-VP4

VP1 binds to receptor.
VP1与受体结合

Surface proteins VP1 and VP3 are major antibody-binding sites.
表面蛋白VP1和VP3是主要的抗体结合位点

Internal protein VP4 is associated with viral RNA.
内部蛋白VP4与病毒RNA有关

The core
核心

+ssRNA, linear, infectious
+ssRNA，线性，有传染性

The naked picornaviruses genome resembles a mRNA
裸露的小RNA病毒基因组类似于一个mRNA

and is sufficient to infect a cell.
足以感染一个细胞

It has a polyA (polyadenosine) sequence at the 3′end
3’端有一个聚腺苷酸序列polyA

and a small protein, VPg (viral protein genome-linked),
5’端

attached to the 5′ end.
有VPg(病毒基因组连接蛋白)

The polyA sequence enhances the infectivity of the RNA,
polyA增强了RNA的传染性

and the VPg is important in packaging the genome into
而VPg与基因的装配

the capsid and initiating viral RNA synthesis.
和病毒RNA合成有关

The genome encodes structural and nonstructual proteins.
基因组编码结构蛋白和非结构蛋白

In addition to the capsid proteins and VPg,
除了衣壳蛋白和VPg

the picornaviruses encode at least two proteases
小RNA病毒还编码至少两种蛋白酶

and an RNA-dependent RNA polymerase.
和一种依赖RNA的RNA聚合酶

Replication
病毒复制

1. Receptor:
1.受体:

VP1 binds to the receptor,
VP1与受体结合

and the VP4 is released and the capsid weakened.
VP4被释放，衣壳松动

The genome is then injected directly across the membrane.
然后基因组直接穿过细胞膜注入细胞

2. Genome is an mRNA, can be used to translate to proteins directly.
2.基因组是一条mRNA，它可以直接用于翻译蛋白质

3. Virus replicates in cytoplasm.
3.病毒在细胞质中复制

4. Most enteroviruses are cytolytic,
4.大多数肠道病毒是溶细胞的

replicating rapidly and causing direct damage to the target cells.
它们快速复制并对靶细胞直接造成损伤

CPE (cytopathic effect)
致细胞病变效应

When the viruses are cultured in the living cells,
当病毒在活细胞中培养时

the viruses induce CPE.
病毒就会导致CPE形成

Left, normal cells
左边，是正常细胞

Right, cells infected with polio virus.
右边，是感染了脊髓灰质炎病毒的细胞

Many of the degenerated cells have fallen from the glass surface.
许多变性的细胞都从表面脱落

Summary of structure & composition of enteroviruses.
肠道病毒的结构和组成小结

Virion: Icosahedral, 28-30 nm in diameter.
病毒体：二十面体，直径28-30 nm

Composition: RNA(30%), protein(70%).
组成:RNA(30%)，蛋白质(70%)

Genome: +ss RNA, linear, infectious,
基因组:+ss RNA，线性，有传染性

contains genome-linked protein (VPg)
含有基因组连接蛋白(VPg)

Proteins: surface proteins VP1 and 3 are major antibody-binding sites.
蛋白质:表面蛋白VP1和VP3是主要的抗体结合位点

Internal protein VP4 is associated with viral RNA.
内部蛋白质VP4与病毒RNA有关

Envelope: none.
包膜:无

Replication: in cytoplasm.
复制:在细胞质中

Now have a break.
现在休息一下

We will focus on the lab test and prevention in next session.
下一节我们将重点讨论实验室检查和预防措施