Viral cycle & basics 1
Name the two types of symmetry that most viral particles can have
Icosahedral, helical
Most RNA viruses replicate in the (cytoplasm, nucleus); the major exception to this rule is the _____ family of viruses
Cytoplasm; retroviridae
How does the absence of an envelope affect release from the cell
Nonenveloped viruses typically require cell lysis for release (enveloped viruses can often bud from the membrane)
Intramolecular recombination is most common for what genomic class of virus?
Conjunctivitis in cattle - agent and gram stain/shape?
Moraxella bovis - short GNR, usually in pairs
Name two visible changes of cells in vitro that can indicate CPE
Rounding, lysis, detachment, syncytia, clumping, inclusions
Glycoproteins are most frequently found on (enveloped, nonenveloped) viruses
Enveloped (nonenveloped viruses are usually unmodified)
Name two of the primary organs from which viruses commonly establish a 2ary viremia
spleen, liver, lymph node, bone marrow
Interfering with apoptosis is more beneficial for (RNA or DNA) viruses; whereas interfering with host MHC1 and type 1 interferon synthesis is more beneficial for (RNA or DNA) viruses
apoptosis inhibition - DNA
host macromolecule inhibition - RNA
Name two classes of antibiotics with efficacy against intracellular organisms
Tetracyclines, fluoroquinolones, rifampin, chloramphenicol
What is the name of the period of time where a virus has infected/entered the cell and BEFORE any packaged viral particles have been produced (no infectious virus can be detected during this time)
Eclipse phase
How do the result of a plaque assay and the result of an HA assay differ with regards to quantifying virus?
Plaque assay - infectious virus; HA - particles able to hemagglutinate (doesn't give you # of infectious virus)
What are the two mechanisms by which a viral genome can establish latency (what form is the genome in)
Integrated & episomal
Name 3 methods for antigen detection
IFA/DFA, IHC, ELISA, Western, lateral flow assay (immunochromatography)
Which dimorphic fungus creates large spherules filled with lots of endospores?
Coccidioides immitis
Which 2 families of viruses classically cause intranuclear inclusions?
Adenoviruses, herpesviruses
RNA viruses must encode what enzyme (with the exception of one family of RNA viruses) - what is the exception?
RdRp; exception - retroviruses (RdDp 'reverse transcriptase')
Syncytia formation is characteristic for (what broad category of) viruses, and what mediates their formation?
Enveloped; fusion glycoproteins mediate formation
This subset of T cells is highly active in innate immunity (can be activated nonspecifically) and are present in very low numbers in mice, but present in fairly high #s in calves & piglets
gamma-delta T cells
Your 3 week old broiler chicks all up and die. A couple have diarrhea, and you necropsy them and find severe necrotic small intestines. You gram stain a smear and find large gram positive rods. You are most worried about:
Clostridium perfringens (A & C)
What characteristic defines a defective interfering particle? Is a high or low MOI more likely to favor DI particles being produced?
Lack complete genome; high MOI favors DI particles
Name 3 families of viruses that classically cause intracytoplasmic inclusions
Pox, paramyxo, rhabdo, reo
Name 2 of the 3 ways a virus can exit the bloodstream and invade parenchyma during viremia
1. passively move between endothelial cells
2. Infect the endothelium
3. Carried by infected leukocytes across the endothelium
Name 2 antibody tests that do not require reagents specific to the species being tested
Competitive ELISA, serum neutralization assay, HI, (AGID)
Your pet donkey that you just bought off Craigslist develops severe nasal discharge with nasal ulceration and huge mandibular LNs. You (rightly) freak out and find a gram negative rod in the discharge. Causative agent?
Burkholderia mallei (glanders)