Virology II - Mclean Flashcards
(43 cards)
Picornaviridae -> 2 types.
Enterovirus
Hepatovirus
Enterovirus -> 5 viruses. Which is different?
Poliovirus
Coxsackie virus A
Coxsackie virus B
Echovirus
Rhinovirus: cannot tolerate acid. still considered an enterovirus.
Rhinovirus facts:
Rhinovirus - grow best at 33 degrees C.
Acid labile
multiply in the nasal passages
Poliovirus facts:
Hardy survivor in water sources
Pathogenesis: Transmission: ingestion
Invades brain / spinal cord (1%)
Anterior horn cells of the spinal cord
Paralysis
Poliovirus
clinical findings:
Viral ASEPTIC meningitis
progressive postpoliomyelitis muscle atrophy (muscle deteriorates after infection)
Vaccines of Poliovirus:
Killed (Salk) vaccine - main one used
Live - attenuated (Sabin) Vaccine
Herpangina:
Hand / Foot / Mouth syndrome:
IMPORTANT
BOTH FROM COXSACKIE A VIRUS:
Herpangina: ulcers / sores inside mouth. Mainly oral cavity thats affected. Have PAPULOVESICULAR LESIONS
HFM syndrome: lesions in oral cavity, hands and feet. GINGIVA NOT AFFECTED
Coxsackie Viruses:
oral related stuff
very important
Coxsackie A: Herpangina - ulcers and sores inside the mouth, **: not associated with gingivitis. mainly posterior portion of mouth
- Hand, foot, and mouth syndrome. Note: Gingiva not infected
Coxsackie B: Pleurodynia (pain when breathing - lungs affected) Myocarditis/ Pericarditis. (heart infected)
Echoviruses (Enteric Cytopathic human orphans)
classic question:
Most common cause of Viral (aseptic) meningitis
Target question:
What is the main cause of common cold?
Rhinovirus
Only enterovirus caused from inhalation. all others are ingestion.
Coronaviruses:
general features
Glycoprotein spikes (appears as a halo) in envelope
Coronaviruses:
clinical findings, comparison to rhino:
Second main cause of common cold
more nasal discharge than rhino, but less coughing than rhino.
generally limited to upper respiratory tract
SARS-CoV-2:
Can cause pneumonia, multi-organ failure, this one generally targets LOWER respiratory tract. (lungs)
Orthomyxoviridae:
Influenza found in this family.
Influenza general features:
genetic reassortment: major exchange of genetic material
antigenic shift ^
(note: antigenic drift = minor changes, like point mutations)
Structure / composition of Influenza Viruses:
Unique feature: Multiple nuclear capsids (8). Each RNA associated protein has a gene, so you have segmented genes.
Influenza A, B, C:
Only Influenza A and B cause significant human disease
Only influenza A have subtypes based on hemagglutinin and neuraminidase (outer proteins)
Typically, the inner proteins are whats responsible for different types, but for type A, outer proteins are responsible too.
Hemagglutinin and Neuraminidase
Hemagglutinin: attachment, also fuses viral envelope to host cell
Neuraminidase: Release virions from host cell, also lowers viscosity of mucus film. increases susceptibility.
Paramyxoviruses - types:
Togaviradiae:
transmitted via
Parainfluenza
Respiratory syncytial virus (RSV)
Mumps
Measles (Rubeola)
Togaviridae:
German Measles (Rubella)
Respiratory secretions
What is one of the most contagious viruses?
Measles. R0 = 18
Paramyxoviruses vs orthomyxovirus:
Hemagglutinin and Neuraminidase are on the same molecule for paramyxoviruses. They also have something called Fusion Protein (F), which promotes fusion of viral and host cell membranes.
Paramyxoviruses properties:
Croup: Barking cough due to infection / swelling of larynx
U also see lower respiratory tract infections.
Target Question:
What is the most important cause of lower respiratory tract illness in infants / young children?
Respiratory Syncytial Virus (RSV), a type of Paramyxiovirus.
Measles Oral Infection: can follow something:
Classic Question:
Koplix spots: white center, red base lesions on oral mucosa near parotid duct
These are a characteristic of MEASLES (Rubeola)
A day or so after the spots, rashes start from hairline and moves down face and neck.
