virology 2 Flashcards

1
Q

viral epidemiology

A

diseases in population(s) developed before recognition of a causative agent
three interdependent terms define increasing size of population

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2
Q

enzootic

A

multiple, continuous transmission, disease presence in a defined population/region/time

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3
Q

epizootic

A

peaks in incidence exceeding the endemic baseline
nature and degree of expected damage defines whether it is call epidemic (high damage)

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4
Q

panzootic

A

worldwide epidemics

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5
Q

rate

A

disease in population
number of cases/population
different diseases, different rates

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6
Q

incidence or attack rate

A

number of cases over number of subjects over period of time (case:population ratio)
acute, short duration diseases
denominator: population in a time frame: thus person-years or subject-weeks

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7
Q

prevalence

A

insidious onset with unknown initial date
chronic long duration diseases
no time parameters only number of cases in defined number of subject

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8
Q

Data

A

acquisition difficult, incomplete and inaccurate; computation easier

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9
Q

surveillance

A

continuous reporting, reportable diseases

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10
Q

serological survey

A

antibody, clinical disease-silent, subclinical infection
not informative on current infections

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11
Q

prospective studies

A

tracking events that are supposed to happen in the future
placebo and treatment groups
number of subjects depending on incidence
very expensive

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12
Q

retrospective studies

A

cost-effective
only needing limited numbers of subjects

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13
Q

incubation period

A

moment of infection to onset of clinical signs
variable

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14
Q

generation time

A

from moment of infection to first day virus shedding
mostly shorter than incubation period
influence in spreading disease

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15
Q

period of infectivity

A

from first day to last day of virus shedding
may or may not be longer than clinical signs
great influence in spreading disease
chronic viral diseases
distinction between these time periods is difficult
little correlation among disease, generation time, infectivity

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16
Q

modes of transmission by virus

A

horizontal transmission
vertical transmission
zoonotic transmission
vector-borne transmission
iatrogenic
nosocomical

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17
Q

horizontal

A

with or without vector, between the same or different host species
common vehicle: water, feed
airborne: droplets, aerosols

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18
Q

direct contact:

A

licking, rubbing, biting, sexual contact
suitable for transmission of enveloped virus
lipid easier to inactivate

19
Q

indirect contact

A

fomites, eating, bedding, vehicles, surgical instruments, needles
non-enveloped virus-usually use this route of transmission

20
Q

vertical transmission

A

movement of virus from parents to their offspring during gestation via placenta, perinatally, colostrum, milk

21
Q

germline transmission

A

virus integrated into genome of ovum, transcription and replication in offspring
pass from generation to generation

22
Q

biological vector

A

virus replicate, magnify in vectors efficient transmission

23
Q

mechanical vector

A

no virus replication in vector not efficient for transmission

24
Q

zoonotic transmission

A

viral diseases transmissible under natural conditions from vertebrate animals to humans

25
Q

iatrogenic

A

patient to patient transmission under veterinary care during the interactions between the vet and the animals

26
Q

nosocomial

A

transmission occurs while the animals are in hospital or clinic under the care of veterinarians

27
Q

acute infection

A

rapid production of infectious viruses
rapid resolution and elimination of infection by host
acute infections do not always produce disease

28
Q

persistent infection

A

infection not cleared efficiently
virus particles are produced for long period of time either continuously or intermittently for months or years

29
Q

chronic infection

A

persistent infections that are eventually cleared

30
Q

Latent infection

A

persistent infections that last the life of the host

31
Q

latency

A

viral genomes integrated into cellular genomes, not expressed
no infectious progeny

32
Q

Routes of shedding

A

skin
repiratory secretion
saliva
feces
genital secretions
urine
milk
no shedding

33
Q

skin

A

not a major route
contact, abrasion, wound

34
Q

respiratory secretion

A

very important
numerous disease, local, systemic
shedding occur before, during after clinical signs

35
Q

saliva

A

salivary gland, oral cavity
rabies, FIV

36
Q

Feces

A

GI tract virus
many also without intestinal signs

37
Q

genital secretion

A

sexual activity, semen, mucus

38
Q

urine

A

rinderpest, FMD, canine hepatitis in kidney
hantaviruses: mice to human

39
Q

milk

A

not an important route
mammary gland replication
caprine arthritis encephalitis

40
Q

no shedding

A

not all virus replications end with shedding
encephalitis (CNS) retrovirus (germ line)

41
Q

host range

A

receptors on animal tissue/cells
susceptible for wide range of infections or restricted infections

42
Q

susceptibility

A

ability to become infected

43
Q

permissivitiy

A

ability to replicate and produce progeny viruses