43 Questions
What factors can promote viral disease?
Poor nutritional status, virulence
How does malnutrition affect the body's ability to fight disease?
Makes the immune system less effective
What can make some individuals more prone to infection and disease?
Expression of specific MHC-I alleles
Do all viral infections result in disease?
Not necessarily
What is the main difference between a productive viral infection and a non-productive or abortive viral infection?
Progeny virions are produced in a productive viral infection.
How can non-productive infections by viruses lead to disease?
By transforming host epithelial cells.
Which virus is an example of a non-productive infection leading to disease?
Human papillomavirus
What can cause disease in immunocompromised hosts in the case of BK virus?
Reactivation of infection in immunocompromised hosts
What is the pathogenesis of cervical carcinoma caused by some human papillomavirus types?
Alteration of host cell cycle regulatory processes
Why do some productive infections only cause disease in immunocompromised hosts?
Reactivation of infection in immunocompromised hosts
What is a crucial requirement for a virus to overcome host defenses?
Avoiding local and systemic antiviral defenses
How can damage occur to the host during a viral infection?
By transforming healthy cells into virally infected cells
What determines the outcome of a viral infection in a host?
The balance between factors that promote disease and those that guard against it
What can lead to direct cell/tissue/organ/system destruction during a viral infection?
Changes in cellular functions/characteristics of virally infected cells
What distinguishes the first pattern of persistent infection from the acute infection?
The pathogen remains and keeps multiplying at a low level
Which virus is an example of a pathogen that remains latent and can reactivate to cause recurring disease?
Human herpesvirus 4 (Epstein-Barr virus)
What characterizes the cyclic, or periodic, disease pattern of infection?
Recurring disease separated by asymptomatic periods
Which virus is an example of a pathogen that causes both varicella (chickenpox) and later in life, zoster (shingles)?
Human herpesvirus 3 (varicella-zoster virus)
Which viruses are typical examples of pathogens with a continuous buildup after recovery leading to recurring disease?
HIV-1, HIV-2, & HTLV-1
What is characteristic of prion diseases in terms of the accumulation of pathogens?
Continuous buildup in the absence of an acute phase
What is the stage responsible for viral amplification and spread to secondary site(s) of infection?
Incubation period
Which stage is responsible for limiting disease and/or contributing to disease?
Immune responses
When can transmission of a viral disease occur?
Between stage 2 and past stage 7
Which phase is usually associated with characteristic signs and symptoms of the disease?
Symptomatic phase
In which stage can symptoms linger and wane?
Resolution of disease
What do you call infections that can go completely undetected during some or all of the stages?
Subclinical infections
Which pattern is characterized by the acquisition of a pathogen that multiplies to the extent of causing disease and is then completely eliminated by the host’s immune system?
Acute disease pattern
Which type of infection occurs without overt disease due to the host’s immune system clearing the pathogen prior to the appearance of symptoms?
Asymptomatic infection
What are examples of infections that fall into the category of acute subclinical or asymptomatic infections?
Rhinoviruses, rotaviruses, and noroviruses
What type of progression does Hepatitis B virus present when the acute disease is resolved?
Self-limited, acute progression when the virus is cleared by the host’s immune system
What type of individuals does BK virus cause disease in?
Immunocompromised or immunosuppressed individuals only
Which of the following factors can tip the balance in favor of illness or exacerbate it?
Healthy nutritional status
What is the main outcome of a productive viral infection?
Virion production
Which haplotypes are more prone to infection and disease with some agents than others?
HLA-B0027 or HLA-B0057 MHC-I alleles
What can lead to disease in immunocompromised hosts in the case of BK virus?
Infection or reactivation of the virus
What is the characteristic of infections that fall into the category of acute subclinical or asymptomatic infections?
They are completely undetected during some or all of the stages
What distinguishes the first pattern of persistent infection from the acute infection?
The pathogen is completely eliminated by the immune system in acute infection
What can cause direct destruction to cell/tissue/organ/system during a viral infection?
$Human$ papillomavirus$ infection
What determines whether a viral infection will yield progeny virions or not?
$The$ replicative cycle
What can make it easier for some individuals to get infected and suffer from disease?
Haplotypes, immunodeficiencies
What are the examples of factors guarding from disease?
$Physicochemical$ barriers, behaviors, innate and adaptive immunity, healthy nutritional status, genotype of an individual
What is irrelevant when considering viruses from a viral perspective?
The production of progeny virions
What is one possible outcome from a viral perspective?
The replicative cycle determining the outcome
Test your knowledge of the factors influencing the outcome of viral infections, including viral strain, host tropism, immune responses, and nutritional status. Explore the interplay between factors promoting disease and those guarding against it.
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