Intro to Viruses Part 1 Flashcards
Unique characteristics of viruses
energy-less, composed of a capsid surrounding genetic material
Types of RNA virus genome
positive and negative stranded
Positive stranded RNA
just like mRNA, can immediately be translated
Negative stranded RNA
must be transcribed to a positive strand, carry their own RNA polymerase
DNA viruses
Herpes, Hepadna, Adeno, Papova, Parvo, Pox
Types of capsid
icosahedral, helical
Parvoviridae DNA
single stranded
Poxviridae genome
very complex, dsDNA, surrounded by structural proteins
DNA viruses with envelopes
Herpes, Hepadna, Pox
Dna viruses without envelopes
Papova, Adeno, Parvo
RNA viruses
poliovirus, coxackie, hepatitis, rhinovirus, rotavirus, yellow fever, dengue, west nile, influenza, corona
dsRNA virus
Reoviridae
nonenveloped RNA virus
picorna, calici, reoviridae
Steps of viral replication
adsorption and penetration; uncoating; synthesis and assembly of products; release of virions
Orthomyxoviridae
flu virus; fever, chills, headaches, malaise, myalgias, dry cough, sore throat, runny nose
Orthomyxoviridae structure
spherical virions, RNA strands held together with a protein; glycoproteins and M proteins surround RNA
Hemagglutinin
can attach to sialic acid receptors (present on RBCs and upper respiratory epithelium)
Neuramnidase
mucosal epithelial cells and upper respiratory tract covered with neuraminic acid which is cleaved/disrupted by neuraminidase
Types of influenza virus
A, B, C
Why do we continually get epidemics of influenza?
antigenic drift, mutations in HA or NA
Antigenic shift
complete change of HA or NA or both
Complications of influenza
viral pneumonia, lowers host defense and increases susceptibility to bacterial infections
Reye’s syndrome
severe liver and brain disease following aspirin administration in children with influenza or varicella
Diagnostic tests for influenza
virus isolation, detection of proteins, detection of nucleic acid, serological diagnosis
Clinical presentation of H5N1
occurs 2-4 days after exposure; high fever, HA, muscle aches, diarrhea, abd pain, vomiting, sore throat, rhinorrhea, cough; progresses to ARDS
Paramyxoviridae important characteristics
-RNA in a single strand, HA and NA ore on the same glycoprotein, Fusion protein
Common diseases associated with paramyxoviridae
parainfluenza, respiratory syncitial virus, metapneumovirus, mumps, measles; lungs, kids, viremia
Parainfluenza presentation
URI, rhinitis, pharyngitis, sinus congestion; croup
Respiratory Syncytial Virus presentation
no HA or NA proteins, number one cause of pneumonia in children
Metapneumovirus presentation
second most common etiology of lower resp infection in children; bronchioloitis, croup, pneumonia
Mumps presentation
replicates in upper resp tract and LN then spreads to distant organs via blood; protitis and orchitis
Measles presentation
conjunctivitis, swelling of eyelids, photophobia, hacking cough, rhinitis, malaise followed by wide spread rash (Koplik’s spots) which spreads downwards