Chapter 21 Chapter 21

Human enterovirusHuman enterovirusViruses of causing acute gastroenteritisViruses of causing acute gastroenteritis

PoliovirusPoliovirus

CoxsackievirusCoxsackievirus• group A : types 1~22, 24 • group B : types 1~6

Enteric cytopathogenic human Enteric cytopathogenic human orphan(ECHO) virusorphan(ECHO) virus

New enterovirusesNew enteroviruses

(types 1~3)

(31 types)

(types 68~71)

of enterovirusof enterovirus Shape and structureShape and structure •d=24~30 nm, spherical and naked virus with icosahedral nucleocapsid

polyproteinpolyprotein ↓ ↓ VP1~VP4 and functional protVP1~VP4 and functional proteinein

衣壳蛋白衣壳蛋白 (VP1(VP1 与受体结合与受体结合 ))

•genome:+ssRNA

1.Biological properties1.Biological properties

Cultivation

RresistanceRresistance (stronger)(pH3~9(pH3~9 稳定稳定 ,, 污水和粪便中可存活数月污水和粪便中可存活数月 ))

Type-specific antigenType-specific antigen• D(density)/N(native) antigen • C (coreless) antigen

• primary cell culture----CPE • animal inoculation (A1,A19,A22)

2.Pathogenicity of enteroviruses2.Pathogenicity of enteroviruses Replicate in the intestinal tract and Replicate in the intestinal tract and spread through bloodstream to target spread through bloodstream to target organsorgans

Via fecal-oral route cause a variety Via fecal-oral route cause a variety of diseases or syndromes of diseases or syndromes ( 夏秋季为主要流行季节 )

不同肠道病毒可引起相同的临床症状 , 同一种病毒可引起几种不同的临床疾病 P275~276 表

( 通常有二次病毒血症 )

---from subclinical infection to severe infection of CNS

• source of infectionsource of infection (patients and carrier)

• cause poliomyelitis by fecal-oral routecause poliomyelitis by fecal-oral route• clinical findings of poliomyelitisclinical findings of poliomyelitis

⑴ ⑴ Poliovirus (neurotropic virus)

*subclinical infection(90%) *abortive infection (5%) *nonparalytic poliomyelitis/aseptic meningitis(1-2%) *paralytic poliomyelitis(0.1%-2%)

nonparalytic : paralytic=100~1000 : 1nonparalytic : paralytic=100~1000 : 1

---pathogen of poliomyelitis---pathogen of poliomyelitis( 脊髓灰质炎或小儿麻痹症 )

⑵ ⑵Coxsackievirus and ECHO virusCoxsackievirus and ECHO virus

⑶ ⑶ Enterovirus 71Enterovirus 71

---cause a variety of diseases or syndr---cause a variety of diseases or syndromesomes (such as aseptic meningitis and encephalitis and so.on) (P275~276P275~276 表表 ))

••initial site of infection and route of transmission ••E70,CA24 and Ad3,7→AHC ( 急性出血性结膜炎 )

----The main cause of acute hemorr----The main cause of acute hemorrhagic conjunctivitis (AHC)hagic conjunctivitis (AHC)

⑷ ⑷ Enterovirus 71Enterovirus 71

--- lifelong type-specific immunity ( neutralizing antibody )

---causecause viral CNS diseaseviral CNS disease (such as aseptic meningitis and encephalitis and so.on) and HFMDHFMD(hand-foot-and-mouth disease, 手足口病 )

3.3.ImmunityImmunity of enterovirusesof enteroviruses

(neurotropic virus)

4.4.Laboratory diagnosis Laboratory diagnosis of enteroviruses of enteroviruses

4.4.Laboratory diagnosis Laboratory diagnosis of enteroviruses of enteroviruses Isolation and identification of virus Isolation and identification of virus Detection of viral antibody and RNADetection of viral antibody and RNA

5.5. Specific prevention of Specific prevention of poliovirus Artificial active immunity

Artificial passive immunity

••IPV ( Salk vaccine) IPV ( Salk vaccine) ••OPV(Sabin vacciOPV(Sabin vaccine ) ne )

均为三价混合疫苗；但均为三价混合疫苗；但OPVOPV 与疫苗相关麻痹型脊髓与疫苗相关麻痹型脊髓灰质炎灰质炎 (VAPP)(VAPP) 发生有关 发生有关

(CPE)(CPE)

---Viruses of causing ---Viruses of causing acute gastroenteritisacute gastroenteritis

Rotavirus (RV)Rotavirus (RV)Other acute gastroenteritis virus Other acute gastroenteritis virus

1.Shape of virion1.Shape of virion---d=60-80nm, spheric and naked virus with double-shelled capsid

2.Genome 2.Genome

appearance of a “wheel”appearance of a “wheel”

(( 轮状病毒轮状病毒 ))

consists of 11 segments of ds-RNA

code for 6 structural proteins(VP1-4,6,7) and 5 non-structural proteins (NSP1~NSP5)

3.Pathogenicity3.Pathogenicity Source of infection Source of infection Route of transmission Route of transmission The main viral cause The main viral cause of acute gastroenteritis of acute gastroenteritis • • group A: main pathogen of acute

gastroenteritis in infants•• group B cause epidemic diarrhea in adult •• group C: cause human or animal sporadic diarrhea

(or ADRV)(or ADRV)(6(6 个月个月 ~2~2 岁岁 ))

4.4. Diagnosis of infectionDiagnosis of infection4.4. Diagnosis of infectionDiagnosis of infection

Detection of viral particle Detection of viral particle and viral antigenand viral antigen (EM,ELISA) PAGE & RT-PCRPAGE & RT-PCR( 聚丙烯酰胺凝胶电泳 )

Including:Including: ••Enteric adenovirusEnteric adenovirus ••CalicivirusCalicivirus

Cause viral gastroenteritis by fecal- Cause viral gastroenteritis by fecal- oral routeoral route

**SRSV SRSV (small round structured virus)(small round structured virus)

**“classic” calicivirus “classic” calicivirus (Classified as HuCV)(Classified as HuCV)

٭ 其原型病毒为 Norwalk 病毒٭ 无菌性胃肠炎暴发流行最重要病原体٭ 流行季节 : 冬季٭ 可累及任何年龄组

→→55 岁以下小儿腹泻岁以下小儿腹泻

٭ 主要引起 5 岁以下小儿腹泻 (5%~20% 为隐性感染 )٭ 冬季流行

2.Other acute gastroenteritis virus2.Other acute gastroenteritis virus

EAd-40, 41 and 42EAd-40, 41 and 42 型是引起型是引起婴儿病毒性腹泻的第二位病原体

•• AstrovirusAstrovirus