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Chapter 21

Viruses Associated with Enteric Infections. Chapter 21. 肠道感染病毒. Human enterovirus. Viruses of causing acute gastroenteritis. Hnman enteroviruses. Poliovirus. (types 1~3). Coxsackievirus. • group A : types 1~22, 24 • group B : types 1~6. Enteric cytopathogenic human

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Chapter 21

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  1. Viruses Associated with Enteric Infections Chapter 21 肠道感染病毒 • Human enterovirus • Viruses of causing acute gastroenteritis

  2. Hnman enteroviruses Poliovirus (types 1~3) Coxsackievirus •group A : types 1~22, 24 •group B : types 1~6 Enteric cytopathogenic human orphan(ECHO) virus (31 types) New enteroviruses (types 68~71)

  3. 1.Biological properties of enterovirus  Shape and structure •d=24~30 nm, spherical and naked virus withicosahedral nucleocapsid •genome:+ssRNA polyprotein ↓ VP1~VP4 and functional protein 衣壳蛋白(VP1与受体结合)

  4. Type-specific antigen •D(density)/N(native) antigen•C (coreless) antigen  Rresistance (stronger) (pH3~9稳定,污水和粪便中可存活数月) Cultivation •primary cell culture----CPE •animal inoculation (A1,A19,A22)

  5. 2.Pathogenicity of enteroviruses Replicate in the intestinal tract and spread through bloodstream to target organs (通常有二次病毒血症) Via fecal-oral route cause a variety of diseases or syndromes ---from subclinical infection to severe infection of CNS (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

  6. ⑴ Poliovirus (neurotropic virus) ---pathogen of poliomyelitis(脊髓灰质炎或小儿麻痹症) •source of infection(patients and carrier) • cause poliomyelitis by fecal-oral route •clinical findings of poliomyelitis *subclinical infection(90%) *abortive infection (5%) *nonparalytic poliomyelitis/aseptic meningitis(1-2%) *paralytic poliomyelitis(0.1%-2%) nonparalytic : paralytic=100~1000 : 1

  7. ⑵Coxsackievirus and ECHO virus ---cause a variety of diseases or syndromes(such as aseptic meningitis and encephalitis and so.on)(P275~276表) ⑶ Enterovirus 71 ----The main cause of acute hemorrhagic conjunctivitis (AHC) •initial site of infection and route of transmission •E70,CA24 and Ad3,7→AHC (急性出血性结膜炎)

  8. ⑷ Enterovirus 71 (neurotropic virus) ---causeviral CNS disease (such as aseptic meningitis and encephalitis and so.on) and HFMD(hand-foot-and-mouth disease,手足口病) 3.Immunityof enteroviruses ---lifelong type-specific immunity ( neutralizing antibody )

  9. 4.Laboratory diagnosis of enteroviruses (CPE) • Isolation and identification of virus • Detection of viral antibody and RNA 5.Specific prevention of poliovirus Artificial active immunity Artificial passive immunity 均为三价混合疫苗；但OPV与疫苗相关麻痹型脊髓灰质炎(VAPP)发生有关 •IPV ( Salk vaccine) •OPV(Sabin vaccine )

  10. Gastroenteritis Virus ---Viruses of causing acute gastroenteritis • Rotavirus (RV) • Other acute gastroenteritis virus

  11. Rotavirus (轮状病毒) 1.Shape of virion ---d=60-80nm, spheric and naked virus with double-shelled capsid 2.Genome consists of 11 segments of ds-RNA code for 6 structural proteins(VP1-4,6,7) and 5 non-structural proteins (NSP1~NSP5) appearance of a “wheel”

  12. 3.Pathogenicity Source of infection Route of transmission  The main viral cause 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 (6个月~2岁) (or ADRV)

  13. 4.Diagnosis of infection Detection of viral particle and viral antigen (EM,ELISA) PAGE & RT-PCR (聚丙烯酰胺凝胶电泳)

  14. 2.Other acute gastroenteritis virus Cause viral gastroenteritis by fecal- oral route EAd-40, 41 and 42型是引起婴儿病毒性腹泻的第二位病原体 Including: •Enteric adenovirus •Calicivirus ٭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 *SRSV (small round structured virus) *“classic” calicivirus (Classified as HuCV) →5岁以下小儿腹泻 •Astrovirus ٭主要引起5岁以下小儿腹泻(5%~20%为隐性感染) ٭冬季流行

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