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77 Cards in this Set
- Front
- Back
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Picornavirus
General Characteristics |
ss(+) RNA, non-enveloped
icosahedral capsid 1. Enteroviruses= acid stabile 2. Rhinoviruses= acid labile |
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Rhinovirus
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Picornavirus= ss(+) RNA, nonenveloped, icosahedral capsid
-->acid labile, URT infection -->killed by CITRIC ACID -->many serotypes make Ab resistance pointless -->optimal temperature for replication is 33C BINDING= use ICAM as viral receptor, endocytosis REPLICATION= creation of a long polypeptide in the cytoplasm RELEASE= using hte lytic cycle |
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Rhinovirus
Pathobiology |
URI with maximal replication at 33C
-->viral binding to ICAM in the respiratory epithelium -->local inflammation induces increased ICAM expression ---------> increased viral spreading -->use of lytic cycle for viral release -->secondary bacterial sinusitis common |
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Enteroviruses
General Characteristics |
Picronavirus= ss(+)RNA non enveloped with icosahedral capsid
-->acid-stable with Tmax= 37C 1. Poliovirus 2. Cocksackie virus 3. Echovirus 4. Hepatitis A 5. Numbered Enteroviruses |
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Most common cause of aseptic meningitis in the US:
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Enterovirus
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Salk Vaccine
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formalin inactivated poliovirus
(Enterovirus < Picornavirus) aka: eIPV (Enhances Intramuscular Polio Vaccine) intramuscular administration -->no local mucosal IgA (poor protection in gut) -->no chance of reversion |
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Sabin Vaccine
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live attenuated vaccine
administered orally -->development of local mucosal IgA -->reversion in 1:3 million cases with PARALYTIC POLIO -->because of local IgA, capable of interrupting ongoing fecal-oral transmission |
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Four outcomes of Polio infections:
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1. Asymptomatic
2. Abortive: nausea, vomiting, febrile 3. Nonparalytic polio: aseptic meningitis, still neck, fever 4. Paralytic: flaccid paralysis, painful muscle spasms |
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Poliovirus
Pathogenesis |
Oral-->Fecal Transmission
1. Replication in the oropharyngeal and sm. intestine mucosa 2. Replication in lymphoid tissue (tonsils, Peyer's patches) 3. Viral spread via viremia or retrograde movement in neurons (preference for motor neurons in anterior horn) 4. Paralysis via death of motor neurons (motor paralysis); Flaccid paralysis from invasion of the brain stem 5. Virus is shed in feces for months following infection. |
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What vaccine against polio is preferred for erradication?
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Sabin (Oral Polio Vaccine)
-->stimulation of local mucosal IgA will interrupt the fecal-oral transmission (virus shed in feces months following infection) -->co-infection with other enteroviruses hinders immunization -->risk of reversion in 1:3 million cases -->cannot be administered to immunocompromised -->must be kept cool |
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Post-Paralytic Syndrome
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years following initial polio infection
presents as muscle wasting |
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Paralytic Poliomyelitis
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more common in adults than children
febrile, aseptic meningitis, may or may not involve brain-stem (flaccid paralysis) |
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Causes of paralysis in polio:
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Muscular Paralysis: death of motor neurons--> prefer motor neurons in the anterior horn of spinal cord
Flaccid Paralysis: invasion of the brain stem; very rarely affects te brainstem |
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Bulbar Poliomyelitis
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flaccid paralysis from viral invasion of the brain stem
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Norovirus
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Calciviridae family
ss(+)RNA, non-enveloped, icosahedral capsid 10 prominent spikes w/ 32 depressions (EM) |
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Calciviridae family
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Norovirus
ss(+)RNA, non-enveloped, icosahedral capsid |
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Most common cause of non-bacterial gastroenteritis
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Norovirus < Calcivirus
ss(+)RNA, non-enveloped, icosahedral capsid |
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Norovirus
Transmission/Epidemiology |
most common cause of non-bacteriat gastroenteritis
fecal-->oral route (frequently with contaminated seafood or water) person to person typical outbreaks: group settings, schools, cruise ships excretion in stool for weeks following infection |
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Norovirus
Pathogenesis |
oral-->fecal route: contaminated seafood or water
person to person -->infection of intestinal mucosal cells -->sudden onset diarrhea and vomiting (no blood or WBC) -->viral shedding in feces for weeks following infections |
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Reoviridae
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Rotavirus< Reoviridae
dsRNA, non-enveloped, icosahedral capsid 11 segments packages RdRP ENTRY: proteolytic cleavage of capsid, genome into cytoplasm REPLICATION: RdRP makes viral mRNA; viral mRNAs may be used as template to make new genomes |
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Most common cause of GI infection in children
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Rotavirus
dsRNA, icosahedral capsid, non-enveloped |
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What GI virus packages RdRP?
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Rotavirus (Reoviridae):
dsRNA, icosahedral, non-enveloped |
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Rotavirus
Pathogenesis |
Fecal-->oral route
-->infection mainly in the DUODENUM, with intestinal villi blunting and atrophy -->mucosa fails to absorb water, leading to watery diarrhea and severe dehydration -->use of NSP4 enterotoxin: induces watery diarrhea associated with Ca2+-dependent transepithelial secretion |
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Rotavirus Enterotoxin
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NSP4 enterotoxin
-->induce watery diarrhea via Ca2+-dependent transepithelial secretion |
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GI infection with dsRNA segmented genome
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Rotavirus
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Rotavirus
General Characteristics |
11 segmented ds RNA virus packaging RdRP
icosahedral and non-enveloped infects the mucosal epithelium of hte duodenum--> causes villi blunting MOST COMMON CAUSE OF VIRAL GI INFECTIONS IN CHILDREN |
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Protective immunity against Rotavirus
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Hemmaglutinin
protective Ab |
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Rotavirus
Attachment |
binds to the Beta-adrenergic receptor (mucosal epithelium of duodenum)
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Rotavirus
Assembly and Release |
-->structural proteins assemble around the (-)RNA
--> (+)RNA strand follows RELEASE VIA LYSIS |
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Rotavirus
Vaccine |
-->both are live attenuated with insertion of human proteins to bovine strain
RotaTeq: five strains of Rotavirus Rotarix: single most common strain |
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Only dsRNA viruses:
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Reoviruses> Rotaviruses
-->packages RdRp -->11 segments -->non-enveloped |
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Rotavirus
Diarrhea |
non inflammatory
non-bloody |
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Norovirus
Diarrhea |
no WBC
no blood sudden onset with vomiting |
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Coxsackievirus
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Picornavirus> Coxsackievirus
ss(+)RNA, icosahedral, non-enveloped |
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Most common causes of aseptic meningitis
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90%= coxsackievirus + echovirus
BOTH are Enterovirus < Picornovirus also: Mumps |
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Causes of palm/sole rashes
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Bacterial endocarditis (with splenic and pulmonary emboli, Rots spots-->retinal hemorrage)
syphyllis Rocky Mt. Spotted Fever coxsackie virus measles (lesser) |
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Coxsackie A
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Picornavirus family
ss(+)RNA, non-enveloped, icosahedral 1. herpangia 2. hand-foot-mouth disease ALL: aseptic meningitis, URI, febrile rashes |
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Coxsackie B
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Picornavirus
ss(+)RNA, non-enveloped, icosahedral 1. polydynia 2. myocarditis, pericarditis ALL cause: asepric meningitis, febril rashes, URI |
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Fever, sore throat, vesicles in the oropharynx
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Herpangia < Coxsackie A < Picornavirus
ss(+)RNA, icosahedral capsid, non-enveloped (also hand-foot-mouth) |
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vesicular rash on palms and feet, ulcerations in mouth
mainly children |
Hand-Foot-Mouth
Coxsackie A < Picornavirus (also herpangia) |
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fever, severe pleuritic-type chest pain
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Pleurdynia
Coxsackie B < Picornavirus ss(+)RNA, icosahedral, non-enveloped -->pain caused by infection of hte INTERCOSTALS (also, myocarditis and pericarditis) |
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Coxsackievirus
Transmission and Pathogenesis |
TRANSMISSION: aerosols and fecal-->oral
Coxsackie A= predilection for skin and mucous membranes Coxsackie B= many tissue types |
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Enteric Adenoviruses 40 and 41
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non-enveloped icosahedral viruses
dsDNA gastroenteritis in children, usually in daycare settings |
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Astroviruses
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ss(+)RNA, non-enveloped
star-like appearance (EM) same replicative cycle as picornaviruses and calciviruses |
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Enterovirus 70
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main cause of hemmoragic conjuctivities
Picornavirus= ss(+)RNA, packages protease |
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Most common cause of hemmoragic conjunctivitis
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Enterovirus 70
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ss(+) RNA, enveloped
URI/LRI virus |
Coronavirus
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Enterovirus 71
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causes viral meningitis and encephalitits
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Enterovirus 72
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same as Hepatitis A virus
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Why does Rotavirus have to carry own RdRP?
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segmented dsRNA
host cell cannot replicate the (-)RNA strand |
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Poliovirus Serotypes
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3--> vaccine protects against all three
Ab against one non-protective against the others |
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Coxsackie B
Transmission |
aerosols
fecal-->oral |
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What GI infection may be spread via aerosols
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Coxsackie B
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Sapovirus
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another Calcivirus causeing more gastroenteritis
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Calcivirus strains
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Norovirus
Sapovirus |
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Hepatitis Strains and Genomic Characteristics
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Hep.A= Picornavirus ( ss(+)RNA ), non-enveloped
Hep. B= Hepadenavirus (DNA) enveoped Hep. C= Flavivirus ( ss(+)RNA ) enveloped Hep. D= Deltavirus (ss(-)RNA circular), eveloped Hep. E= Caliciviridae (ss(+)RNA) non-envelope |
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Name the families of te Hepatitis viruses:
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A= Picornavirus
B= Hepadenavirus C= Flavivirus D=Delta virus E=Calicivirus |
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Which Hep. virus is Flavivirus?
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Hep. C
ss(+)RNA, enveloped |
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Process of breakign down heme:
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Heme-------(heme oxygenase)----->biliverdin
biliverdin----------(biliverdin reductase)------------>bilirubin bilirubin conjugates to albumin, carried to liver |
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Pre-hepatic Jaundice
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jaundice before the liver
EXCEED ABILITY OF LIVER OT PROCESS BILIRUBIN hemolytic disease hemmorage |
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Hepatic Jaundice
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pathology within the liver
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Post-Hepatic Jaundice
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aka. OBSTRUCTIVE JAUNDICE
blockage of the bile disposal 1. pale stools 2. dark urine |
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LFT enzymes to watch:
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ALT: specific to liver, elevated with damage
AST: non-specific to liver (also blood cells, cardiocytes, skeletal muscle) ALP: non-specific to liver (also placenta, kidney, bone, bile duct) --->used to ID bile obstruction or infiltrative diseases GGT: used to indicate sub-clinical cases of liver damage --->good to ID recent alcohol abuse |
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LFT enzyme to ID obstruction of bile duct:
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ALP
non-specific to the liver (also in bone, placenta, kidney, bile duct) |
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LFT enzyme to indicate sub-clinical cases of liver damage
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GGT
may indicate recent alcohol abuse |
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Urine color
Jaundice |
Normal urine: urochrome, and light yellow
Jaundice= bilirubin and dark orange/brown |
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Hepatitis A
Pathogenesis |
infection of intestinal mucosa
spreads to liver via low level viremia CTL response is the main cause of symptoms |
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Hepatitis A
Diagnoses |
IgM
elevated tranaminase dark urine pale stool |
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another name for Hep. A
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Enterovirus 72
(Picornavirus--> ss(+)RNA ) |
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most common presentations for Hep A.
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children in boarding schools or camps
contaminates oysters |
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Hep B. virus
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Hepadenavirus--> partially dsDNA circular genome
enveloped with icosahedral capsid -->packages DdDP |
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Hep. B Genome
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partially dsDNA circular
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HbCAg
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core antigen of Hep. B
forms nucleocapsid core of virus |
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HBeAg
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e antigen of the HBV
important for transission of HBV secreted into blood |
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Dane Particles
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HBV infections
complete enveloped viral particles (opposed to the spherical and filamentous capsid) |
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HBsAg
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HBV diagnositc determinant and immunization
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Serotypes for HBV
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four serotypes determined by group-specific antigens
adw adr ayw ayr |
