Download GMS 6121 Exam 1: Viral Entry, Infection, and Outcomes and more Quizzes Virology in PDF only on Docsity!
GMS 6121 EXAM 1 MODULE 4.1 TO 4.
(EU) QUESTIONS WITH ACCURATE
ANSWERS 100% VERIFIED ALREADY
GRADED A+
"What is the most common route of viral entry? - CORRECT ANSWER=> Respiratory tract" "Why do viruses like the respiratory track? - CORRECT ANSWER=> huge absorptive area huge turnover, ventilation rate" "What are some barriers to infection that the respiratory tract has? - CORRECT ANSWER=> barriers: mechanical = single layer of epithelial cells = all mucosal layers, trap viruses bc tight junction proteins with neighbors, ciliary action, sneezing and coughing to clear material cellular = macrophages in alveoli, phagocytosis humoral = IgA, secreted into lumen of resp tract" "How does a virus enter through the respiratory track? - CORRECT ANSWER=> via aerosolized droplets from cough or sneeze, or contact with saliva" "T/F: the further down a virus travels down the resp tract the less severe - CORRECT ANSWER=> False the further down the resp tract the more severe upper = sinusitis, pharyngitis, laryngitis lower = bronchitis, pneumonia" "What is the second most common site of infection? - CORRECT ANSWER=> GI Tract" "What are some evolved mechanism that GI tract viruses have acquired to infect the hostile environment? - CORRECT ANSWER=> infective mechanisms: Reoviruses: require proteases for entry; use microbiota to enhance infection Noroviruses: extremely stable at large pH range, use IgA to facilitate uptake by intestinal epithelial cells, use microbiota to enhance infection Coronavirus: enveloped = exception to rule; resistance mechanisms not clear overall theme is exploitation of microbiota"
"What are some barriers to infection that the GI tract has? - CORRECT ANSWER=> extremely hostile environment, acidic, intestines alkaline, digestive enzymes, bile detergents, mucous, IgA" "Why do viruses like the GI track? - CORRECT ANSWER=> easily intro through food or water contents always in motion, good opportunity for virus to contact host cells" "What is a major portal for pathogen entry in the GI tract? - CORRECT ANSWER=> M cells in small intestine in order to respond to pathogens as well as food antigens and commensal bacteria takes up material from gut lumen specialized epithelial cells = M cells transferred from gut lumen to immune nodules called peyer's patches" "Describe urogenital tract as entry: barriers to infection: _____ Virus entry:_____ Some viruses produce ____ lesions (HPV) Some viruses spread from _____ tract (HIV, HSV) - CORRECT ANSWER=> barriers to infection: mucous, low pH Virus entry: minute abrasions from sexual activity Some viruses produce local lesions (HPV) Some viruses spread from urogenital tract (HIV, HSV)" "Describe eye as entry: Barrier:___ Virus entry:___ localized infection: ________ Disseminated infection: spread to ____(HSV-1) - CORRECT ANSWER=> Barrier: blinking
"T/F: In an abortive infection, the cell is damaged, killed, or transformed but progeny virus is made - CORRECT ANSWER=> F: In an abortive infection, the cell is damaged, killed, or transformed but no progeny virus is made" "What are the three types of persistent infections? - CORRECT ANSWER=> Chronic, latent, and recurrent infections" "What kind of infection is being described; no cell death and cells are not altered significantly in their growth habits? A)Cell Death B)Abortive Infection C)Persistent infection D) Transformation - CORRECT ANSWER=> C)Persistent infection" "Fill in the blank: Persistent infection types:
- _____infections = constant production of virus, very long incubation before disease
- _____ infections = no progeny produced but genome is maintained. Small number of proteins produced to maintain genome. May have constant low-level reactivation that is pathogenically silent
- ______infections = reactivation of latent virus, e.g., stress causing a cold sore - CORRECT ANSWER=> Fill in the blank: Persistent infection types:
- Chronic infections = constant production of virus, very long incubation before disease
- Latent infections = no progeny produced but genome is maintained. Small number of proteins produced to maintain genome. May have constant low-level reactivation that is pathogenically silent
- Recurrent infections = reactivation of latent virus, e.g., stress causing a cold sore" "What are the patterns of disease(acute, chronic, latent)? - CORRECT ANSWER=> Acute is short but highest amount of virus in tissues Chronic is next highest virus in tissues then tapers off Latent is an S-curve, constantly up and down" "What kind of infection is being described below?
Virus infects, genetically alters cell, result is abnormal growth - CORRECT ANSWER=> Transformation" "What are the four types of abnormal growth in Transformation? - CORRECT ANSWER=> Loss of contact inhibition Loss of polarization Immortalization Disruption of cell cytoskeleton" "Fill in the blank: What are the mechanisms that a virus will use to transform a cell? ____ viral oncogene derived from cellular gene (ex: block a cellular tumor suppressor gene) ___ into host chromosome(disrupt cell cycle regulatory genes) Hep C Virus: leads to liver cancer, but whether it does so by transforming cells is unclear. 2 options: occurs during injury/regeneration of liver, or virus itself causes cancer - CORRECT ANSWER=> Fill in the blank: What are the mechanisms that a virus will use to transform a cell? Encode viral oncogene derived from cellular gene (ex: block a cellular tumor suppressor gene) Integration into host chromosome Hep C Virus: leads to liver cancer, but whether it does so by transforming cells is unclear. 2 options: occurs during injury/regeneration of liver, or virus itself causes cancer" "What is the term for the the spectrum of tissues infected by a virus (e.g an enteric virus replicates in the gut but not the lungs) - CORRECT ANSWER=> Tissue Tropism" "The tropism of some viruses is limited whereas other viruses can replicate in many organs. What is this known as? - CORRECT ANSWER=> Pantropic" "Fill in the blank: What are the determinants of viral tropism (Tissue tropism) Determinants:
- ______ to permissive cell
- Presence of appropriate cell surface ____
- Presence of _____host factors required for virus replication
- Absence of ______antiviral mediators - CORRECT ANSWER=> Fill in the blank: What are the determinants of viral tropism (Tissue tropism)
"What are the three ways that viruses spread via hematogenous spread? - CORRECT ANSWER=> Enter directly via capillaries Replicating in endothelial cells Vector bite (insect)" "Hematogenous spread: Viruses in extracellular fluid can be taken up by ____ capillaries (more permeable then circulatory capillaries) then spread to blood Once in blood, virus has access to almost ___ tissues Can occur cell-associated or as ___ virus particles - CORRECT ANSWER=> Hematogenous spread: Viruses in extracellular fluid can be taken up by lymphatic(more permeable then circulatory capillaries) capillaries then spread to blood Once in blood, virus has access to almost all tissues Can occur cell-associated or as free virus particles" "Term: _____viremia Occurs when primary viremia has resulted in infection of additional tissues via bloodstream, in which the virus has replicated and once more entered the circulation - CORRECT ANSWER=> Secondary viremia" "Term: _____viremia Initial spread of virus in the blood from the first site of infection - CORRECT ANSWER=> Primary viremia" "Term: _____viremia Results from virus introduced into blood without replication; virus does not replicate until it reaches target organ ex: direct inoculation of arbovirus into blood from insect bite - CORRECT ANSWER=> Passive viremia" "Term: _____viremia Virus replication occurs preceding viremic phase ex: virus replicates in mucosal epithelium, resulting in virus being introduced into bloodstream - CORRECT ANSWER=> Active viremia"
"In cell-associated hematogenous spread, it may replicate in _____ cells (dendritic cells, macrophages, lymphocytes). May _____to RBC's or platelets without replicating - CORRECT ANSWER=> In cell- associated hematogenous spread, it may replicate in migratory cells (dendritic cells, macrophages, lymphocytes). May adhere to RBC's or platelets without replicating" "Neural spread-via peripheral nerve T/F: Certain viruses spread from primary site of infection by entering local nerve endings - CORRECT ANSWER=> True" "What does it mean when a virus spreads via peripheral nerve? - CORRECT ANSWER=> Neuron to Neuron" "How does Neural spread- via peripheral nerve work? - CORRECT ANSWER=> 1. Uptake at Axon
- Transport
- Replication
- Transsynaptic spread
- Transport
- Replication" "Fill in the blank (Neural spread- via peripheral nerve): For some viruses, neural spread is a definitive characteristic of ______(rabies, HSV) For others viruses, invasion of CNS is an infrequent _____from normal replication & hematogenous spread (polio, reovirus) - CORRECT ANSWER=> Fill in the blank (Neural spread- via peripheral nerve): For some viruses, neural spread is a definitive characteristic of pathogenesis (rabies, HSV) For others, invasion of CNS infrequent diversion from normal replication & hematogenous spread (polio, reovirus)" "What does it mean when a virus spreads hematogenously (neural spread)? - CORRECT ANSWER=> Spread from the bloodstream to neural tissue" "What are the three ways a virus spreads hematogenously (neural spread)? - CORRECT ANSWER=> Replication in endothelial cells Transcytosis Tracking lymphocyte or monocyte" "T/F: Cytokines decreases permeability of viral spread - CORRECT ANSWER=> False Cytokines increases permeability of viral spread" "the skin is the most common site of viral infections - CORRECT ANSWER=> false"
"What is tamiflu? - CORRECT ANSWER=> targets influenza neuraminidase, inhibits permissive cell = supports influenza infection after budding to leave host cell, virion remains stuck, encodes neuraminidase to cleave sialic acid and release tamiflu binds neuraminidase so virions cannot spread" "Why study viral pathogenesis? 1)By understanding the interaction of viruses with host cells, one can identify targets for _____drugs 2)By understanding how viruses interact with the immune system, one can identify target for _____ 3)By identifying viral ____factors (i.e. live attenuated vaccines) or antigenic ____(i.e. subunit vaccines), one can design efficacious vaccines - CORRECT ANSWER=> 1)By understanding the interaction of viruses with host cells, one can identify targets for antiviral drugs 2)By understanding how viruses interact with the immune system, one can identify target for immunomodulation 3)By identifying viral virulence factors (i.e. live attenuated vaccines) or antigenic epitopes (i.e. subunit vaccines), one can design efficacious vaccines" "What are points of viral entry? - CORRECT ANSWER=> anywhere they can come into contact with host from external environment skin eyes (conjunctiva) along any exposed mucosal surfaces = GI, urogenital, resp" "Describe the skin as a barrier - CORRECT ANSWER=> Barriers to infection: the outer layer of dead keratinized cells cannot support viral infection Virus entry: in order to infect, must break/puncture to reach live layers epithelium= needle punctures, abrasions, insect/animal bites severity depends on how deep virus is deposited upper layer is devoid of lymphatics or blood vessels, stays confined lower layers are highly vascularized ex. herpes-, pox-, papilloma-, arbo- viruses (carried in insect vector)"
