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56 Cards in this Set

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Picornaviruses - size
very small - 25-30 nm in diameter
Picornaviruses - capsid
naked icosahedral
Picornaviruses - genome
(+) ssRNA
def - Pico RNA Virues
very small RNA viruses
Are Picornaviruses tough? How do they fair in the environment?
very tough and resistant viruses, persist in environment.

exception - rhinovirus
What are the three Picornavirus family members significant to human disease?
1) Enterovirus
2) Rhinovirus
3) Heparnavirus
Where do Picornaviruses replicate, and how are they spread to target organs?
replicate at site of primary infection, spread by viremia
What is the major protective immune response to Picornaviruses?
antibody
Where do Enteroviruses replicate?
replicate in gut (but DO NOT cause gastroenteritis)
Where do Rhinoviruses replicate?
limited to upper respiratory tract
Rhinoviruses cannot live in the stomach because they are ____ ____.
acid labile
Most enteroviruses show strong cell ____.
tropism
Most picornavirus infections are ____, although virus shedding does occur.
asymptomatic
What is the prototype enterovirus?
poliovirus
Polivirus has a narrow tissue range as the ____ binds to a host receptor found mostly on ____ tissues.
VAP, neural
Describe the general migration of poliovirus
Initial infection in oropharynx and tonsils. Virus travels through blood and crosses blood brain barrier. Virus can also travel through skeletal nerves to the brain.
What are they three types of poliovirus infection (from most common to least common).
1) Asymptomatic (90%)
2) Abortive poliomyelitis (minor illness, 5%)
3) Paralytic polio (major illness, 0.1 - 2.0%)
Is the damage done by paralytic polio through direct or indirect pathology?
direct --> the more neurons infected, the greater the disease
Poliovirus laboratory diagnosis.
CSF has lymphatic pleocytosis, no neutrophils.
Can you culture enteroviruses?
yes
Rhinoviruses cannot live in the stomach because they are ____ ____.
acid labile
Most enteroviruses show strong cell ____.
tropism
Most picornavirus infections are ____, although virus shedding does occur.
asymptomatic
What is the prototype enterovirus?
poliovirus
Polivirus has a narrow tissue range as the ____ binds to a host receptor found mostly on ____ tissues.
VAP, neural
Describe the general migration of poliovirus
Initial infection in oropharynx and tonsils. Virus travels through blood and crosses blood brain barrier. Virus can also travel through skeletal nerves to the brain.
What are they three types of poliovirus infection (from most common to least common).
1) Asymptomatic (90%)
2) Abortive poliomyelitis (minor illness, 5%)
3) Paralytic polio (major illness, 0.1 - 2.0%)
Is the damage done by paralytic polio through direct or indirect pathology?
direct --> the more neurons infected, the greater the disease
Poliovirus laboratory diagnosis.
CSF has lymphatic pleocytosis, no neutrophils.
Can you culture enteroviruses?
yes
Pleconaril
Poliovirus
blocks penetration
only works in first 48 hours of infection
Poliovirus vaccines incorporate ____ strains of poliovirus
three
Which immunoglobulins are important for blocking viremia?
IgG and IgA
What are the most common symptoms of coxsackievirus infection?
Most are asymptomatic, some produce mild upper respiratory illness or flu-like symptoms.
Coxsackie A viruses are associated with ____ ____.
vesicular lesions
Coxsackie B viruses are associated with ____ and ____.
myocarditis, pleurodynia
Herpangina
Oral vesicular disease caused by Coxsackievirus Type A.
Not related to herpes.
Symptoms include vesicular lesions in throat, fever, sore throat, anorexia, vomiting.
Hand Foot and Mouth Disease
Caused by Coxsackievirus A16.
First lesions appear in the oral cavity, later small lesions appear on the hands, feet and mouth.
Resolves in a few days.
Viral Meningitis
Acute febrile illness, may be accompanied by rash or petechiae.
Caused by Coxsackievirus A or B and some Echoviruses.
Low neutrophil count in CSF.
Common Cold (of the Coxsackie variety...)
Cold-like symptoms produced by several types of Coxsackievirus (A21, A24) and Echovirus (11, 20).
How are coxsackievirus and echovirus transmitted?
these highly resistant virions are transmitted by fecal oral means
How can serology confirm infection with coxsackievirus and echovirus?
showing presence of IgM or a fourfold increase in IgG

**great number of serotypes makes serology difficult.
How many serotypes of rhinovirus?
>120
Rhinovirus - Clinical Symptoms
sneezing, rhinitis, nasal obstructions, sore throat, headache, malaise
flu-like symptoms due to IFN
not distinguishable from common cold caused by enterovirus, coronavirus or adenovirus
How is rhinovirus transmitted?
aerosolized droplets, contact or fomites
Is rhinovirus pathology indirect, direct or both?
both

KR
Caliciviridae
*characteristics similar to picornaviruses
Virons are non-enveloped and very small (27 nm in diameter)
Genome is linear (+) ssRNA
Describe calcivirus capsid structure.
*differ from picornavirus
Norwalk-like virus are round with a ragged outline, others have a variety of indentations or star shapes.
Are calciviruses durable?
yes
Calcivirus pathology
Act by direct pathology
Disrupt function of (or lyse) brush border epithelial cells in the intestine
Blocks proper absorption of water and nutrients --> GASTROENTERITIS
Calicivirus Epidemiology
Cause outbreak as single source transmissions (food, water, shellfish)
Fecal-oral route.
Norwalk-like Virus
primary cause of food and water-borne viral gastroenteritis in the USA
Norwalk-like Virus pathology & Symptoms
Typical pathology of caliciviruses
Symptoms develop after 1-3 d incubation, normally lasting 2-3 d
Low grade fever, vomiting, diarrhea (not bloody), headache
Generally mild and self-limiting.
Can NLV be grown in culture?
no
How is NLV detected in a lab?
can be directly detected in stool by antibody
IEM
Serology and RT-PCR, esp in outbreaks
receives sensations of pain, touch, pressure, and temperature
primary somatosensory cortex