Exam I (Virology IP6)

A

rotaviruses, coronaviruses, parvovirus, pestivirus, and canine distemper V can all cause (A/B/C/D) disease

A. gastrointestinal

B. respiratory

C. CNS

D. reproductive

B

feline calicivirus, BRSV in bovids, PRRSV in swine, and influenza viruses can all cause (A/B/C/D) disease

A. gastrointestinal

B. respiratory

C. CNS

D. reproductive

C

prions, rabies, and arboviruses can cause (A/B/C/D) disease

A. gastrointestinal

B. respiratory

C. CNS

D. reproductive

D

viruses can undergo mutations which can result in the following, except:

A. change in host range

B. altered disease causing properties

C. multiple new serological strains

D. makes epidemiological tracking of the virus impossible

mutation

______________ of viral genes occurs to a greater or lesser extent with ALL viruses and these can result in infection and disease in new host species (new host range)

transferred

influenza viruses and parvoviruses are examples of viruses that were ______________ between hosts to gain new host ranges

travel

increased ___________ and increased density of populations results in increased exposure to novel viruses

contact

___________ between host + virus, infection of the host, amplification of the virus, and creation of new variants helps increase viral host range

replication

some viral mutations may confer a _______________ advantage in the host that aids in infection and causing disease (e.g. receptor or viral protein change)

cell

increased severity of viral disease can occur by mutations that result in infection of a new ________ type (e.g. original only infects GI cells, novel variant can infect macrophages)

effects

increased severity of disease can occur by mutations that result in different __________ upon infected cells (e.g. persistent/latent vs. non-latent virus)

replicate

virulence is often related to increased ability to __________ within host cells

false (usually not)

true/false: many viral mutations make obvious or dramatic changes in disease or host range

true (i.e. they are all equally virulent)

true/false: no evidence suggests any of the 3 variants of canine parvovirus is more virulent than the others

mutations

__________ of viral genes are used in epidemiological studies to track spread of viruses in host populations

surface proteins

mutation of viral genes for _____________ _______________ may be responsible for the large number of serologically distinct strains of many viruses

false (only detects feline enteric coronavirus, FIP caused by its mutated form that isn't detectable by PCR because each cat's mutation is unique)

true/false: PCR is very effective in diagnosing feline infectious peritonitis (FIP)

antibodies

why do puppies still get parvovirus despite being vaccinated against it? maternal ___________ interfere with vaccine effectiveness of the puppies

lymphosarcoma

bovine leukemia virus often causes the development of _______________ in multiple organs of cattle

immunocytochemistry

most effective method used to diagnose feline infectious peritonitis (FIP), canine parvovirus, and canine coronavirus enteritis?

virus

any of a large group of submicroscopic infectious agents that are usually regarded as nonliving, extremely complex molecules that typically contain a protein coat, genetic material, are obligately intracellular

true

true/false: herpesviruses infect practically every species we study

C

herpesviruses are (A/B/C/D) viruses

A. non-enveloped DNA

B. non-enveloped RNA

C. enveloped DNA

D. enveloped RNA

virions

viruses' vehicle for transmission (the infectious particles)

false (they usually hijack host cell replication machinery)

true/false: viruses often encode their own replication machinery

false (can be either DNA or RNA, but not both)

true/false: it is possible for viruses to have both a DNA and RNA genome

capsid

outer shell of viral proteins that surrounds the viral genome

envelope

the viral (capsid/envelope) is derived from host cell membranes

peplomeres

virus-specified glycoproteins important in host cell attachment are embedded in the envelope; these are called _______________

budding

the process by which the envelope is acquired from the host cell membrane is called _______________

true (envelope sensitive to heat, drying, detergents, etc)

true/false: viruses with an envelope do not survive as long in the environment as non-envelope viruses

capsid

the viral (capsid/envelope) is resistant to drying, heat, detergents, acids, and proteases

capsid

a virus with a (capsid/envelope) is more likely to be involved in fomite transmission of a virus

enveloped

(enveloped/non-enveloped) viruses do NOT kills cells in order to spread

non-enveloped (via lysis)

(enveloped/non-enveloped) viruses KILL cells in order to spread

inclusion bodies

nuclear or cytoplasmic aggregates of viral substances that typically represent sites of viral multiplication

true

true/false: both enveloped and non-enveloped viruses can form inclusion bodies

membrane fusion (or hemifusion state)

type of virus entry where the cell membrane is punctured and made to further connect with the unfolding viral envelope

pore mediated penetration

type of non-enveloped virus entry where their genome is injected into host cytoplasm by creating a pore in the cell cell membrane

nucleus

most DNA viruses replicate in the ___________ of the cell

poxviruses

DNA viruses that are the EXCEPTION and replicate in the cytoplasm (instead of the nucleus)

cytoplasm

RNA viruses replicate in the _____________ of the cell

RNA

(RNA/DNA) viruses have a higher rate of mutation and are more error-prone with their replication

provirus

retroviruses replicate in the nucleus and are integrated into host DNA as a ____________

pathogenesis

the study of infection and spread of viruses in the animal and mechanisms by which disease is produced

pathogenic virus

a virus capable of inducing disease or lesions

virulence

a measure of the ability of a virus to produce disease in the host

false (can only replicate, not produce disease; wild type causes disease)

true/false: a modified live vaccine can cause disease in the host

true

true/false: an animal may or may not have the disease when shedding the virus

birds (>mosquitos as vector> horses)

reservoir for equine encephalitis virus and west nile virus

horizontal transmission

most important route of transmission for most viruses; includes direct contact, indirect contact, and vectors

direct contact

virus transmission between co-habitating animals (e.g. respiratory route including aersol, droplets, etc)

indirect contact

virus transmission from contaminated fomites or the environment

vectors

virus transmission through mechanical or biological means

vertical transmission

virus transmission from parent to offspring via the germplasm, egg, placenta, or milk

ACD

list the 3 letters in which virus transmission is most common/more clinically relevant:

A. respiratory route (aerosol)

B. milk

C. oral route (saliva)

D. fecal route

E. skin

F. urogenital tract

respiratory (droplets 0.01-2.0 um)

titer/load of virus, distance between animals, and air movement are important factors when considering ______________ route virus transmission

vaccination

_________________ plays a role in host defense because you may still be able to get infected but the virus won't be able to replicate as much

receptors

viruses require _____________ on the surfaces of cells to grant them entry

pH

low or high ______ in the host's stomach and small intestine respectively helps prevent virus entry and removes viruses

skin

trauma or insect bites on the _________ can be an important route of entry for some viruses

true (abortion, stillbirth, persistently infected when born, congenital abnormalities, etc)

true/false: viral transmission through the placenta can have different effects depending on timing of gestation and dam's infection/disease status

damage

canine parvovirus causes direct cell ____________ and necrosis of the crypt epithelium

transformation

some viruses cause cell _______________ with tumor production and loss of organ function (e.g. bovine leukemia virus causing lymphosarcoma)

inflammation (the cells causing it!)

sometimes the _____________ associated with the viral infection causes destruction of the cells in the vicinity of the virus

immunosuppression

some viruses cause _________________ through the destruction of lymphocytes and macrophages, predisposing the host to secondary infections

immune mediated

some viruses can cause _____________-_____________ disease in which Ag-Ab complexes accumulate in the body and wreak havoc

severity

the _______________ of the viral disease is often determined by location, the target cell's function, and ability of the affected cells to regenerate

localized infection

infection in which the viral entry, replication, lesions, and shedding occurs within the same organ system

true

true/false: the immune system's ability to fight infection & presence of susceptible cells in other tissues determines the extent of viral spread within the body

systemic infection

infection in which the virus has entered and spread to other organ systems, is being shedded and excreted in several secretions

lymph nodes

upon infecting the local site, viruses can spread via the lymphatics to infect regional ___________ ____________

primary viremia

initial entry of virus into the blood; no clinical signs, only disseminates to central organs of replication

secondary viremia

massive viral replication event after organ dissemination and leads to shedding of virus and lesions; clinical signs occur such as fever and malaise

localized

virus shedding and clinical signs occur at an earlier time point in (localized/systemic) infections

false (shedding largely ceased by time fever occurs; take diagnostic samples early!)

true/false: typically you are still actively shedding large amounts of the virus when a fever or lesions develop

true

true/false: you will want to wait a few days after the disease/fever declines to take post-infection samples for serology

depletion

__________ of susceptible cell populations is more important in localized infections where the population of host cells is more limited (e.g. enteric and respiratory tracts)

A (viruses = obligate intracellular)

which is more important in recovery from active viral infections?

A. cell-mediated immunity

B. antibody-mediated immunity

viral epidemiology

study of frequency and distribution of viral disease in a population

true

true/false: an understanding of epidemiology is necessary for the formulation of viral control measure that interrupt the spread of infection

quarantine

__________, or restriction on the movement/importation of animals and animal products during a viral outbreak, is important in stopping the spread of a virus

sanitation

incineration, disposal, disinfection, heat treatment, or burying infected animals are _______________ procedures that can limit viral spread

wildlife control (e.g. fencing, vaccinating wildlife, etc)

intended to restrict sources of infection by reducing the risk of exposure of domestic animals to reservoir hosts

vector control (e.g. spraying, insect traps, etc)

intended to reduce the risk of spread of infection by insect vectors

A

feline infectious peritonitis is an example of:

A. immune mediated disease

B. latent infection in the trigmeinal ggl.

C. induction of immunologic tolerance

D. integration of viral DNA into host genome

true

true/false: canine parvovirus is a result of a host range change in feline panleukopenia virus

replication

increased susceptibility in the host (due to age, nutrition, immune status, etc) usually correlates with increased levels of viral _________________

genetic

______________ background of the host is a major factor in determining the outcome of infection

segregate

genes determining resistance to different viruses _____________ independently of each other

receptors

susceptibility may also be associated with the presence or absence of a host cell ______________ on the target cell (e.g. with non-primates and polio)

precursor

susceptibility may be associated with transcription factors, DNA replication enzymes, and proteases that cleave ___________ proteins to their active form (e.g. influenza)

B

animals with defects in (A/B) are usually more susceptible to viral infections

A. antibody-mediated immunity

B. cell-mediated immunity

parvovirus

what is an example of a canine/feline virus that attacks particularly young animals with immature immune systems and rapidly dividing cells?

inflammation

fever inhibits viral replication by elevating body temperature and by promoting _______________

evade

evolution of viruses is driven in part by the effort of the virus to ________ the immune response

true

true/false: on a population basis, viruses and hosts are constantly evolving and adapting to survive

mutations

the outcome of infection of the host is constantly changing due to ________________ in viral genes and changes in host immune response

non-antigen

interferon, NK cells, and the mucociliary response are (antigen/non-antigen) specific responses

interferon

in many viral infections, _____________ may be more important than other mechanisms in resistance