Transcript  Human enterovirus Viruses of causing acute gastroenteritis Chapter 21

Chapter 21
Human enterovirus
Viruses of causing acute gastroenteritis
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)
1.Biological properties
of enterovirus
 Shape and structure
•d=24~30 nm, spherical and
naked virus with icosahedral
nucleocapsid
•genome:+ssRNA
polyprotein
↓
VP1~VP4 and functional protein
衣壳蛋白(VP1与受体结合)
 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)
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
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
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)
⑷ Enterovirus 71 (neurotropic virus)
---cause viral CNS disease (such as aseptic
meningitis and encephalitis and so.on) and
HFMD(hand-foot-and-mouth disease,手足口病)
3.Immunity of enteroviruses
--- lifelong type-specific immunity
( neutralizing antibody )
4.Laboratory diagnosis
of enteroviruses
Isolation and identification of virus (CPE)
Detection of viral antibody and RNA
5. Specific prevention of poliovirus
 Artificial active immunity
均为三价混合疫苗；但
•IPV ( Salk vaccine) OPV与疫苗相关麻痹型脊髓
•OPV(Sabin vaccine ) 灰质炎(VAPP)发生有关
 Artificial passive immunity
---Viruses of causing
acute gastroenteritis
Rotavirus (RV)
Other acute gastroenteritis virus
(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
appearance of a “wheel”
 code for 6 structural
proteins(VP1-4,6,7) and 5
non-structural proteins
(NSP1~NSP5)
3.Pathogenicity
 Source of infection
 Route of transmission
 The main viral cause
of acute gastroenteritis
• group A: main pathogen of acute
gastroenteritis in infants (6个月~2岁)
• group B (or ADRV)
cause epidemic diarrhea in adult
• group C: cause human or animal
sporadic diarrhea
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)
2.Other acute gastroenteritis virus
Cause viral gastroenteritis by fecaloral 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)
→5岁以下小儿腹泻
*“classic” calicivirus (Classified as HuCV)
• Astrovirus
‫٭‬主要引起5岁以下小儿腹泻(5%~20%为隐性感染)
‫٭‬冬季流行