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56 Cards in this Set
- Front
- Back
Picornaviruses - size
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very small - 25-30 nm in diameter
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Picornaviruses - capsid
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naked icosahedral
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Picornaviruses - genome
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(+) ssRNA
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def - Pico RNA Virues
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very small RNA viruses
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Are Picornaviruses tough? How do they fair in the environment?
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very tough and resistant viruses, persist in environment.
exception - rhinovirus |
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What are the three Picornavirus family members significant to human disease?
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1) Enterovirus
2) Rhinovirus 3) Heparnavirus |
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Where do Picornaviruses replicate, and how are they spread to target organs?
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replicate at site of primary infection, spread by viremia
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What is the major protective immune response to Picornaviruses?
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antibody
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Where do Enteroviruses replicate?
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replicate in gut (but DO NOT cause gastroenteritis)
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Where do Rhinoviruses replicate?
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limited to upper respiratory tract
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Rhinoviruses cannot live in the stomach because they are ____ ____.
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acid labile
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Most enteroviruses show strong cell ____.
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tropism
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Most picornavirus infections are ____, although virus shedding does occur.
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asymptomatic
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What is the prototype enterovirus?
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poliovirus
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Polivirus has a narrow tissue range as the ____ binds to a host receptor found mostly on ____ tissues.
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VAP, neural
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Describe the general migration of poliovirus
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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.
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What are they three types of poliovirus infection (from most common to least common).
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1) Asymptomatic (90%)
2) Abortive poliomyelitis (minor illness, 5%) 3) Paralytic polio (major illness, 0.1 - 2.0%) |
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Is the damage done by paralytic polio through direct or indirect pathology?
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direct --> the more neurons infected, the greater the disease
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Poliovirus laboratory diagnosis.
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CSF has lymphatic pleocytosis, no neutrophils.
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Can you culture enteroviruses?
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yes
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Rhinoviruses cannot live in the stomach because they are ____ ____.
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acid labile
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Most enteroviruses show strong cell ____.
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tropism
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Most picornavirus infections are ____, although virus shedding does occur.
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asymptomatic
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What is the prototype enterovirus?
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poliovirus
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Polivirus has a narrow tissue range as the ____ binds to a host receptor found mostly on ____ tissues.
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VAP, neural
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Describe the general migration of poliovirus
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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.
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What are they three types of poliovirus infection (from most common to least common).
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1) Asymptomatic (90%)
2) Abortive poliomyelitis (minor illness, 5%) 3) Paralytic polio (major illness, 0.1 - 2.0%) |
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Is the damage done by paralytic polio through direct or indirect pathology?
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direct --> the more neurons infected, the greater the disease
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Poliovirus laboratory diagnosis.
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CSF has lymphatic pleocytosis, no neutrophils.
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Can you culture enteroviruses?
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yes
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Pleconaril
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Poliovirus
blocks penetration only works in first 48 hours of infection |
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Poliovirus vaccines incorporate ____ strains of poliovirus
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three
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Which immunoglobulins are important for blocking viremia?
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IgG and IgA
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What are the most common symptoms of coxsackievirus infection?
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Most are asymptomatic, some produce mild upper respiratory illness or flu-like symptoms.
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Coxsackie A viruses are associated with ____ ____.
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vesicular lesions
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Coxsackie B viruses are associated with ____ and ____.
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myocarditis, pleurodynia
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Herpangina
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Oral vesicular disease caused by Coxsackievirus Type A.
Not related to herpes. Symptoms include vesicular lesions in throat, fever, sore throat, anorexia, vomiting. |
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Hand Foot and Mouth Disease
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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. |
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Viral Meningitis
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Acute febrile illness, may be accompanied by rash or petechiae.
Caused by Coxsackievirus A or B and some Echoviruses. Low neutrophil count in CSF. |
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Common Cold (of the Coxsackie variety...)
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Cold-like symptoms produced by several types of Coxsackievirus (A21, A24) and Echovirus (11, 20).
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How are coxsackievirus and echovirus transmitted?
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these highly resistant virions are transmitted by fecal oral means
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How can serology confirm infection with coxsackievirus and echovirus?
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showing presence of IgM or a fourfold increase in IgG
**great number of serotypes makes serology difficult. |
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How many serotypes of rhinovirus?
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>120
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Rhinovirus - Clinical Symptoms
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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 |
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How is rhinovirus transmitted?
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aerosolized droplets, contact or fomites
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Is rhinovirus pathology indirect, direct or both?
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both
KR |
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Caliciviridae
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*characteristics similar to picornaviruses
Virons are non-enveloped and very small (27 nm in diameter) Genome is linear (+) ssRNA |
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Describe calcivirus capsid structure.
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*differ from picornavirus
Norwalk-like virus are round with a ragged outline, others have a variety of indentations or star shapes. |
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Are calciviruses durable?
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yes
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Calcivirus pathology
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Act by direct pathology
Disrupt function of (or lyse) brush border epithelial cells in the intestine Blocks proper absorption of water and nutrients --> GASTROENTERITIS |
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Calicivirus Epidemiology
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Cause outbreak as single source transmissions (food, water, shellfish)
Fecal-oral route. |
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Norwalk-like Virus
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primary cause of food and water-borne viral gastroenteritis in the USA
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Norwalk-like Virus pathology & Symptoms
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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. |
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Can NLV be grown in culture?
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no
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How is NLV detected in a lab?
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can be directly detected in stool by antibody
IEM Serology and RT-PCR, esp in outbreaks |
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receives sensations of pain, touch, pressure, and temperature
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primary somatosensory cortex
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