79 Questions
What is the difference between disease and infection?
Disease involves signs and symptoms, while infection may be clinically unapparent.
What does colonization refer to?
Introduction and growth of an organism in or on body tissues.
What does tropism mean?
The predilection to infect specific cells, tissues, or organs.
What defines viremia?
Presence of virions in the blood.
What is the term for a viral infection where the virus is unable to successfully replicate and produce progeny virions within the host?
Non-productive infection
Which stage of viral disease involves transmission and is responsible for contagion?
Incubation period
In viral disease progression, what is the first stage characterized by colonization of the body and cells?
Acquisition and infection
What is the term for a type of cancer that can be caused by some strains of human papillomavirus?
Squamous cell carcinoma
Which phase of viral disease progression comes after the prodromal phase and involves either recovery or establishment of chronic infection?
Acute phase
What is responsible for general, non-specific symptoms such as fever and malaise during the first stage of viral disease?
The virus
Which stage of viral disease progression can result in smoldering or relapsing infections?
Persistent infections
What refers to the development of disease from a virus' capacity to alter cell cycle regulatory processes?
Pathogenesis
Which factor can make it easier for viruses to cause infection and disease?
Decrease in immune system response
What stage of viral disease involves immune responses that can either limit the disease or contribute to it?
Immune responses
Which pattern of viral disease progression involves acquisition and multiplication of a pathogen followed by clearance of the infection by the host's immune system?
Acute disease pattern
In which phase does transmission occur in viral disease progression?
Acquisition and infection
What is the process by which mutations are frequently introduced during viral replication?
Antigenic shift
What are immune-privileged sites in the body?
CNS, eyes, testicles
What are gene products of a virus called?
Toxins
What factor can influence the pathogenicity of a virus related to host susceptibility?
Age
How can the skin and mucosa help prevent viral infections?
By producing inhibitory molecules
What is the role of acute phase proteins in response to viral infections?
Induce fever and inflammation
What are danger-associated molecular patterns (DAMPs) typically released upon?
Cell death
Which type of cell death results in less inflammation due to intracellular membrane fragmentation?
Apoptosis
What type of receptors stimulate interferon gene expression in infected cells?
Pattern recognition receptors (PRRs)
What is one reason some viruses may inhibit MHC class I receptor expression?
To signal infection to natural killer cells
How do type I interferons induce an antiviral state in infected cells?
Through autocrine and paracrine signaling
Which interferons are more specific to single stranded RNA viruses through toll-like receptors TLR7 and TLR8?
Type III interferons
What does the term 'viral load' refer to?
The amount of virus in the blood
What does the term 'latent infection' refer to?
Persistent infection characterized by the presence of an intact viral genome
What is the main characteristic of an acute infection?
Self-limiting infection with a rapid onset and resolution
What is invasiveness in the context of viruses?
Capacity of a virus to enter and cause tissue damage
What does 'cytopathic effect' refer to?
Morphological change to cells due to viral infection
What is a quasispecies?
Mixture of viruses derived from a common ancestral virus in a host
What defines an abortive infection?
Viral infection that does not lead to the production of progeny virions
What are host defenses?
Mechanisms used by the body to fight infections
What is meant by 'transformation' in the context of viral infections?
Process through which healthy cells become cancerous
What is 'host damage' in the context of viral infections?
The loss of cellular, tissue, organ, or system function due to an infection
What is a 'slow infection'?
Infection with long symptom incubation period followed by rapid death
What is the definition of a virus?
An infectious agent capable of multiplying inside a living cell
What does the term 'Host' refer to in the context of infectious diseases?
An animal or plant that nourishes and supports a parasite
Which virus is typically transmitted through sexual contact?
Human Herpesvirus 2
What is the primary difference between DNA viruses and retroviruses?
DNA viruses produce a DNA copy when invading a cell while retroviruses produce RNA copies
What is the meaning of 'Viral Titer'?
The concentration of virus particles in a solution
Which virus causes chickenpox in children and shingles in adults?
Varicella-Zoster Virus
What does 'Recurrent Disease' refer to?
A disease that reappears after being dormant for an extended period
'MOI' stands for:
Multiplicity of Infection
What does 'Prion Disease' result from?
Incorrect folding of prion proteins in the brain
Which virus typically causes cold sores and fever blisters around the mouth?
Human Herpesvirus 1
What is the primary function of the immune system?
To protect the body from foreign substances and pathogens
What is the significance of 'Endothelial Transmigration'?
The process of leukocytes passing from blood to tissues through endothelial cells
What is the role of the E7 protein in cervical/anal/oropharyngeal carcinoma caused by human papillomavirus?
Promoting tumor formation
How does human herpesvirus 8 contribute to Kaposi Sarcoma?
Promoting cell growth
What are viroceptors?
Viral homologs of host cytokines or chemokines
What two roles does the E6 protein play in cervical/anal/oropharyngeal carcinoma caused by human papillomavirus?
Degrading p53 and inactivating a cell cycle inhibitor
What role does the HBV X protein play in hepatocellular carcinoma?
Activating transcription of cell genes
How does persistent hepatitis B or C virus infection contribute to hepatocellular carcinoma?
Leading to liver inflammation and increased hepatocyte proliferation
What are some examples of mechanisms that increase viral virulence?
Altering viral replication and host defense mechanisms
What percentage of cases of Endemic Burkitt Lymphoma are caused by the translocation of the c-myc gene?
80%
Do all viruses require dividing cells to access the cell's replication machinery?
No, some viruses can integrate their DNA into the host cell's genome.
What are interferons?
A family of cytokines produced in response to viral infection
What is genetic drift?
A process causing random changes in viral genes over time
Which proteins impede (-)ssRNA virus replication, particularly during an influenza infection?
Mx proteins
What is the purpose of APOBEC proteins upon viral infection?
Contribute to viral genome degradation
What is the role of caspase 1 in the immune response to viral infections?
Activating pro-IL-18 into its biologically active form
What stimulates an increase in cellular concentrations of 2’-5’-oligo(A) synthetase and RNase L for virus replication control?
Type 1 interferons
Which cells are activated by IL-18 in acquired responses to promote action against viruses and cancer cells?
NK cells and macrophages
What is the primary function of monocyte-derived phagocytic cells in the immune response?
Destroying pathogens and antigen presentation
Which receptor helps macrophages recognize a virus's own antigens in biology?
Toll-like receptor
'Pattern recognition receptors' (PRRs) play a critical role in biology by helping to recognize:
-ssRNA virus's own antigens
Which immune cell type is responsible for directly targeting and destroying harmful cells in cell-mediated immunity?
Memory T lymphocytes
Which cell surface protein is critical in presenting antigens to CD8+ T cells in order to activate them?
MHC-I
What type of white blood cell is responsible for modifying viral genomes and inhibiting viral replication?
APOBEC enzymes
Which cytokines trigger the differentiation of naive T cells into TH1 cells that help activate CD8+ T cells?
IL-12 & IFN-γ
What is the function of antibody-dependent cell cytotoxicity (ADCC) in the immune response against viruses?
NK cells recognize and remove infected cells
Which type of lymphocyte secretes cytokines to enhance the activity of immune cells involved in cell-mediated immunity?
TH1 cells
What is the primary function of neutralization by immunoglobulins in response to viruses?
"Blocking" viruses from infecting other cells
"Cross-presentation" involves the acquisition of exogenous antigens by a cell for presentation to which type of immune cell?
CD8+ T cells
"Persistent infection" occurs when a virus continues to replicate in the body and can potentially lead to what kind of illness?
"Chronic" illness
Test your knowledge on important interferon-induced genes that help contain viral infections, such as class I major histocompatibility complex (MHC) molecules and type I interferons. Learn about the role of IFNAR in signaling for the expression of ISGs. Explore the concept of GDP recycling for protein synthesis.
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