Viral Pathogenesis II (Exam 1) Flashcards
An increased susceptibility leads to increased viral _________.
replication
List the 6 factors of a host that determines the manifestation of viral disease.
- immune status
- genetics
- age
- nutrition
- fever
- body surface barriers
Which host factor can determine the severity of viral disease by Rotavirus?
age
What two specific Rotaviruses are more severe in younger animals due to the immune maturation stage of target cells?
Canine Parvovirus
Feline Panleukopenia
Canine Parvovirus infects ________ while Feline Panleukopenia infects ________.
cardiomyocytes
cerebellar neurons
An elevated host temperature (inhibits/enhances) viral replication and (inhibits/enhances) inflammation and clearance of the virus.
inhibits
enhances
(T/F) Both the virus and the host immune system evolve in response to the other.
True
In many viral infections, _______ may be more important than other immune system resistance mechanisms.
interferons
List two parts of the innate immune response that are important in inhibiting viral replication.
interferons
cytokines
______ function in limiting viral infection of cells, as part of the innate immune system.
NK cells
Viruses evolve to turn on and off ______ of the immune system for its replication needs.
cytokines
Which virus has evolved to control cytokines to benefit in replication?
Herpes Simplex Virus
_______ are a major target cell or reservoir for viruses, specifically lentiviruses.
macrophages
________ allow for a faster and greater immune response against a virus.
vaccines
________ immunity prevents the initial entry of a virus and decreases the initial viral load in the blood.
humoral (antibody)
________ immunity functions in recovery from an established viral infection via viral lysis.
cell-mediated
If a fetus is infected by a virus early in gestation, a virus can avoid immunity by what mechanism?
tolerance
What virus infects calves early in gestation leading to tolerance and lifelong viral shedding?
BVD
Which virus infects neurons and therefore, avoids immunity by infecting an immune-privileged site?
Alpha Herpes Virus
(T/F) Viruses can evade immunity by downregulating viral proteins and surface proteins so antibody cannot bind.
False - only viral proteins (cannot downregulate surface proteins)
What type of viruses can downregulate viral proteins to evade a host’s immune system?
herpes virus (bovine 1, equine, canine, feline)
Viruses can evade the host’s T cell response by infecting cells without _________.
Class I MHC
Which two viruses evade a host’s immune system by infecting cells without MHC I (neurons) and cause a latent or persistent infection?
Alpha Herpes Virus
Canine Distemper Virus
Viruses can evade the host’s immune system by integrating their genome into the host genome. Which type of virus can do this?
retroviruses (bovine leukemia virus)
A virus can evade a host’s immune system by infecting which two immune cell types?
lymphocytes
macrophages
Which two viruses infect lymphocytes and macrophages, leading to a loss of function and evasion of the immune system?
FIV
Canine Distemper
Viruses which cause Aleutian Disease in mink and African Swine Fever in swine can evade a host’s immune system by induction of non-neutralizing _________, so the viral infection cannot be prevented.
antibody
Viruses can evade the immune system through subtle mutation of viral genes which allow for a replication and evasion advantage. What is the process called?
antigenic drift
What may be responsible for large numbers of serologically distinct strains of many viruses?
antigenic drift
What process occurs when a virus can reassort and obtain segments from two different viruses and cause severe epidemics?
antigenic shift
Antigenic shift is responsible for epidemics of what viral disease?
influenza
_________ and ________ viruses inhibit MHC function by interfering with transport or loading of MHC complex so T cells cannot recognize them.
herpes
adeno
When immune response to a viral infection causes the actual disease, this is called:
immunopathology
When a persistent virus leads the immune response to cause more damage, this process is called:
bystander effect
Distemper, Visna, Caprine Arthritis, and FIP are all examples of __________.
immunopathology
Which two viruses are examples of viruses which cause immune complex diseases?
Equine Infectious Anemia
African Swine Fever
List two viruses which cause immunosuppression, and therefore, can predispose a host to opportunistic infections.
Canine Distemper
FIV
When a virus remains for a long period without killing cells and is not eliminated by the immune system, this is called a _________ infection.
persistent
Match the virus to which cell type it causes a persistent infection in:
Alpha Herpes Virus
Lentiviruses
Retroviruses
- neurons
- lymphocytes / macrophages
- lymphocytes
(T/F) Animals with a latent, persistent viral infection will continuously shed the virus and are a source of infection for other hosts.
False - only shed during episodes or none
(T/F) Chronic viral infections can be cytopathic or immunopathologic.
True
