Genera of Picornaviruses
EnterovirusPolio
Coxsackie A and B
Echo
Other enteroviru ses
Diseases of the human (and other) alimentary tract
(e.g. polio virus)
Rhinovirus Disease of the nasopharyngeal region (e.g. common cold virus)
Cardiovirus Murine encephalomyocarditis, Theile r's murine encephalomyelitis virus Aphthovirus Foot and mouth disease in cloven
footed animals
Hepatovirus Human hepatitis virus A Others Drosophila C virus, equine
Categories of Enteroviruses
Viral meningitis, rash,ARD 4 types(68-71) Other EnterovirusesViral meningitis, with orchitis
32 types Echioviruses
Viral meningitis, but no orchitis
6 types (B1-B6) Coxsackie B
viruses
Viral meningitis plus, rash, ARD, myocarditis, orchitis
23 types ( A1-A22, A24)
Coxsackie A viruses
Properties of enteroviru
ses
Property EnterovirusesSize (nm) Capsid
form
Polypeptide RNA type
RNA molecular weight Acid
Optimal temperature for growth (oC)
Density in caesium chloride (g/ m)
22-30
Icosahedral
Transmission
Fecal – oral route: poor hygiene, dirty diapers( especially in day-care
settings)
Ingestion via contaminated food and water
Contact with infected hands
Pathogenesis of enterovirus infection Rhino,echo, coxsackie,polio Replication in oropharynx Primary viremia
Target Tissue Secondary viremia
Skin Muscle Brain Meninges Liver
Pathogenicity(1)
ASYMPTOMATIC
All enteroviruses
PARALYSIS - permanent
Polio 1, 2, 3
Coxsackie A7
PARALYSIS - temporary
Coxsackie B1-6
MENINGITIS (aseptic)
Echo, Coxsackie A and B
Polio, Entero 71 ENCEPHALITIS
Entero 71
Pathogenicity(2)
RASH
- macular
Many enteroviruses
- vesicular - (e.g. 'Hand Foot Mouth')
Coxsackie A
SUMMER FEBRILE ILLNESS
Many enteroviruses
VESICULAR PHARYNGITIS ('Herpangina')
Coxsackie A
MYOCARDITIS
Pathogenicity(3)
EPIDEMIC MYALGIA ('Bornholm')
Coxsackie B
UPPER RESPIRATORY INFECTION (cold)
Echo, Coxsackie A
PANCREATITIS
Coxsackie B
GASTRO-ENTERITIS
Many enteroviusess
CONJUNCTIVITIS (Haemorrhagic)
Entero 70
HEPATITIS
Human diseases caused by e
nteroviruses
Polio Cox A Cox B Echo Other
Asymptomatic
infection Yes Yes Yes Yes Yes
Meningitis( 脑脑脑 ) Yes Yes Yes Yes Yes
Paralysis( 脑脑 , 脑脑 ) Yes Yes Yes Yes No
Febrile exanthems( 热
热热 No Yes Yes Yes Yes
Acute respiratory
disease No Yes Yes Yes Yes
Myocarditis( 脑脑脑 ) No Yes Yes Yes No
Immunity
Antibody is the major protective immu
ne response to the enteroviruses . Secr
etory antibody can prevent the initial e
stablishment of infection in the oropha
rynx and gastrointestinal tract, and ser
um antibody prevents viremic spread t
o the target tissue and therefore disea
se.
Laboratory Diagnosis
Culture
Serology
Poliovirus
Important Characteristics
D or N
antigen: Type specific (CFA) C or H
antigen: Common
Pathogenesis
1.
Source of infection: Apparent and subcli nical patients2.
Incubation: 7-14 daysClinical Syndromes
Asymptomatic illness: 90%
Abortive poliomyelitis, the minor illness: 5% infected people
Nonparalytic poliomyelitis or aseptic me ningitis: 1%-2% of patients with poliovir us infections.
Franklin D. Roosevelt
Born in 1882 at Hyde Park, New York--now a national historic site--he attended
Harvard University and Columbia Law School. On St. Patrick's Day, 1905, he married Eleanor Roosevelt.
Following the example of his fifth cousin, President Theodore Roosevelt, whom he greatly admired, Franklin D. Roosevelt entered public service through politics, but as a Democrat. He won election to the New York Senate in 1910. President
Wilson appointed him Assistant Secretary of the Navy, and he was the Democratic nominee for Vice President in 1920.
In the summer of 1921, when he was 39, disaster hit-he was stricken with
poliomyelitis. Demonstrating indomitable courage, he fought to regain the use of his legs, particularly through swimming. At the 1924 Democratic Convention he dramatically appeared on crutches to nominate Alfred E. Smith as "the Happy Warrior." In 1928 Roosevelt became
Governor of New York.
Immunity
Lab Diagnosis
Definitive diagnosis is made by osolation of the vir us from stool, CFS, oropharyngeal secretions
Cell culture involves fibroblastic MRC-5 cells CPE is usually evident within 36 hours
Serotyping is based on neutralization of CPE by standardized antisera using
intersecting pool followed by specific sera.
ELISA IFA
Prevention
Both oral polio vaccine( OPV live, att
enuated 脑
Sabin, 1957) and inactivat
ed poliovirus vaccine(IPV 脑
Salk, 1954
) are avilable
Advantages and disadvantages of opv
Advantages
Effectiveness
Lifelong immunity
Induction of secretory antibody response similar to that of natural infection
Possibility of attenuated virus circulating in commu nity by spread to contacts (indirect immunization) (herd immunity)
Ease of administration
Lack of need for repeated boosters
Disadvantages
Risk of vaccine-associated poliomyelites in vaccine recipients or contacts
Advantages and disadvantages of
IPV
Advantages Effectiveness
Good stability during transport and in storage Safe administration in immunodeficient patie nts
No risk of vaccine-related disease Disadvantages
Lack of induction of local (gut) immunity
Need for booster vacine for lifelong immunity Fact that injection is more painful than oral a dministration
R ep o rt ed c as es p er 1 00 00 0 p o p u la ti o n 100 10 1 0.1 0.001 0.01
1950 1960 1970 1980 1990 Inactivated
(Salk) vaccine
Oral vaccine
10000 1000 100 10 1 0 R ep o rt ed c as es
1950 1955 1960 1965 1970 1975
Killed (Salk) vaccine
Total cases
R e ci p ro ca l v iru s an tib od y tit er 512 128 32 8 2 1 Serum Ig G Serum Ig G
Serum IgM Serum Ig M
Nasal and du odenal IgA Nasal Ig A Serum Ig A Serum Ig A Duodenal I gA Days Vaccination Vaccination
48 96 48 96
Coxsackie Virus
Features of coxsackievirus infect
ion in the labortory
Types Growth in MK Effect in cell culture sucking mice
Coxsackie A virus 1-24 a + Paralysi
s
Coxsackie B virus 1-6 + Spasticit y
MK , monkey kidney
Features of coxsackievirus
infection in man
Coxsackievirus A 1-24
Asptic meningitis Febrile illness Herpangina 脑脑脑脑脑脑 Hand-foot-and-mouth dise ase
Coxsackievirus B 1-6
Disease Associations
Paralytic Disease - most commonly associated with polioviruses but other enteroviruses may also be responsible, notably enterovirus 71
Meningitis - caused by all groups of enteroviruses, most commonly seen in children under 5 years of age.
Encephalitis - focal or generalized encephalitis may accompany meningitis. Most patients recover completely with no neurological deficit.
Undifferentiated febrile illness - may be seen with all groups of enteroviruses.
Hand foot mouth disease - usually caused by group A coxsackieviruses although group B coxsackieviruses and other enteroviruses have been
caused outbreaks.
Herpangina 脑脑脑脑脑脑- caused by group A coxsackieviruses.
Myocarditis - group B coxsackieviruses are the major cause of myocarditis, although it may be caused by other enteroviruses. It may present in neonates as part of neonatal infection and is often fatal. In adults, the disease is rarely fatal.
Respiratory Infections - several enteroviruses are associated with the common cold.
Rubelliform rashes - a rash disease resembling rubella may be seen with several coxsackie A, B, and echoviruses.
Neonatal Infection - some coxsackie B viruses and echoviruses may cause infection in newborn infants. The virus is usually
transmitted perinatally during the birth process and symptoms
vary from a mild febrile illness to a severe fulminating multisystem disease and death.
Conjunctivitis - associated with several types of enteroviruses, notably Coxsackie A24 and Enterovirus 70 (haemorrhagic
conjunctivitis)
Pancreatitis 脑脑脑 /Diabetes - associated with Coxsackie B virus infection. The extent of the role of the virus in diabetes is
Exanthems –
Rubelliform rashes
Hand-foot-and-mouth disease
Hand-foot-and-mouth disease: mostly coxackie A
fever, malaise, sore throat,
vesicles on bucal mucosa, tongue, hands, feet, buttocks
highly infectious
Herpangina
脑脑脑脑脑脑
Herpangina – usually coxackie A
acute onset, fever, sore throat,
dysphagia
lesions – posterior pharynx
can persist w’s
ECHO virus
Important Characteristics
Not produce diseases in suckin
g mice, rabbits, or monkeys;
Cause aseptic meningitis, infa
ntile diarrhea,
Clinical syndromes
associated with
echoviruses
Main syndromes
Aseptic meningitis Paralysis
Rash
Respiratory disease
Other features
Pericarditis 脑脑脑 and myocarditis
Illness associated with recently i
dentified enteroviruses
Enterovirus 68 Pneumonia and bronchiolitis Enterovirus 69
Isolated from an ill person in Mexico Enterovirus 70
Acute hameorrhagic conjunctivitis Enterovirus 70, 71
