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Flashcards in Virology Deck (109):
1

What is virology?

the study of viruses and viral disease

2

What is a virologist?

someone who studies viruses

3

T or F: Viruses cause high rates of morality and morbidity in animals and birds?

True

4

T or F: Viruses cause financial loss to livestock and poultry industries

True

5

T or F: Some viruses are zoonotic ?

True

6

Are viruses non living?

yes

7

What does a viruses contain?

nucleic aicd genome (DNA or RNA) surrounded by a protein coat (capsid) and in some cases a lipid envelope

8

T or F: Viruses posses standard cellular organelles?

False, THEY DONT

9

Can viruses make energy or proteins by themsleves?

no

10

T or F: Viruses are obligate intracellular parasites?

true, they hack the cell machinery

11

Do viruses have the capability to multiply by division?

No

12

How does a viruses reproduce?

by an assembly line in which various parts come together from different parts of the host cell to form new virus particles

13

What is a capsid?

protein shell of a virus that encases/envelopes the viral nucleic acid or genome

14

What is a capsid made up of?

capsomeres held together by non covalent bonds

15

What is nucleocapsid?

capsid + virus nucleic acid

16

T or F: some viruses have additional layer known as envelope

True

17

What is a envelope of a viruses made up of?

lipid bilayer derived from host cell

18

T or F: Glycoproteins are present on the surface of the envelope, and often appear as spikes

True

19

T or F: Naked viruses have only protein capsid enclosing nucleic acid?

true

20

T or F: Enveloped viruses have an additional lipid layer enclosing the protein capsid enclosing nucleic acid?

True

21

What is pleomorphism?

the ability of some viruses to alter their shape of size

22

Does RNA have double-stranded and single stranded RNA

yes

23

Does DNA have double-stranded and single stranded DNA

Yes

24

What is virus replication?

attachment, penetration, uncoating, release in large numbers, assembly and maturation and synthesis of viral nucleic acid and protein

25

How are viruses classified?

the international committee on taxonomy of viruses

26

How are virsues transmitted?

direct contact, indirect, and common vehicle transmission

27

What is common vehicle transmission?

food borne or feces borne

28

What is vertical transmission?

infection that is transferred from mother to embryo, newborn

29

How does one diagnose viruses?

gross evaluation and histopathology

30

How do you detect viruses?

cultivation and isolation on tissue culture or inoculation in eggs

31

What is serology of viruses?

ELISA, viral antigen to host antibody, florescent antibody staining and immunohistochemical staining

32

What is RT-PCR

Reverse transcription polymerase chain reaction

33

How does one treat viral infections?

antiviral drugs, immune system stimulation

34

How does one prevent viral infections?

vaccinations, live attenuated, non-replicating, recombinant DNA, disinfectants and hygiene

35

What is an all in, all out management system?

animal houses are emptied, cleaned and disinfected between batches of animals

36

What is culling?

killing of animals to control viruses spread

37

What is pathogenicity?

the ability of a virus to cause disease in a host

38

What is pathogenesis?

manner of development of a disease

39

What is avirulent?

not harmful to the host

40

T or F: virulence is not an absolute property, but depends on many variables

True

41

What are factors related to a virus?

genetic variation, route of entry in host, affinity to host, dose of infection, immuno evasion

42

What are factors related to the host?

host species, host immunity, host physiological factors, fever

43

What are some other factors of virulence?

environment and dual infections

44

How does one measure a virus?

lethal dose 50: the dose of a virus required to cause death to 50% of animals

45

What is a route of entry for a virus?

skin, transcutaneous injection, mucous membranes, gastrointestinal tract, respiratory tract

46

What is viremia?

presence of virus in the blood

47

How does a virus spread into the bloodstream?

subepitheial tissue/ lymphatics and direct injection

48

What is secondary viremia?

virus has replicated in major organs and once more entered into circulation

49

What is a disseminated infection?

spreads beyond the primary site of infection

50

What is a systemic infection?

number of organs and tissues are infected

51

How does a viruses spread via nerves?

peripheral nerves, through receptor neurons, blood brain barrier

52

What is a nuerotropic virus?

viruses that can infect neural cells

53

What is tropism?

a affinity of a virus for a particular host tissue

54

What is a pantropic virus?

can replicate in more than one host organ/tissue

55

What is virus-cell interactions?

inhibition of host/cell nucleic acid or transcription
inhibition of protein synthesis
toxic viral infections
interference with cellular membrane function

56

T or F: cell lysis following virus replication allows release of new viruses?

True

57

What is apoptosis?

process of programmed cell death, cell suicide

58

What is an oncovirus?

causes cancer

59

What is a persistent infection of a virus?

not immediate death of a host cell, remain latent in host cell for long periods

60

T or F: Viruses cause immunosupression?

True

61

T or F: Shedding of infectious virons is crucial to the maintenance of infection in populations?

True

62

T or F: acute infections is intensive shedding over short periods of time?

True

63

T or F: persistent infections can shed at lower titers for months to years?

True

64

What are warts?

benign skin growths that appear when a virus infects the top layer of the skin

65

What is erythema?

reddening of the skin

66

What does a virus in the respiratory tract cause?

inflammation
obstruction of air passages
hypoxia and respiratory distress

67

What does a virus in the central nervous system cause?

bursting (lytic) infections of neurons
neuronal necrosis
killing of phagocytic cells
inflammatory cels around blood vessels

68

What is progressive demyelination?

canine distemper, damaged nerve, scarred myelin

69

What does damage to endothelium cause?

hemorrhages

70

What is an teratogenic viruses?

cause developmental defects of embryo or fetus in utero infections

71

What is the latent period of infectious disease?

microbe is replicating but not yet enough for the host to be infectious

72

What is the incubation period of infectious disease?

microbe is replicating but host has no symptoms

73

What is communicable disease?

disease caused by agent capable of transmission by direct, airborne or indirect routes from infected person, animal or plant

74

What is a reservoir?

habitat in which infectious agent lives and grows

75

T or F: pathogens can escape immunity so that animals become susceptible again?

True

76

T or F: pathogens can evade immunity, allowing reinfection to occur after a short period of time

True

77

T or F: all sick animals are reservoirs?

False

78

What is vertical transmission of pathogens?

from host to its offspring, possibility through placenta or during parturition

79

What is horizontal transmission of pathogens?

from reservoir to new host
direct and indirect

80

What is a vehicle for pathogens?

inanimate object which serves to communicate disease

81

What is a vector?

a living organism that serves to communicate disease

82

What are fomites?

object that can be contaminated and transmit disease on a limited scale

83

What is a mechanical vector?

agent does not multiply or undergo part of its life cycle while in vector

84

What is a biological vector?

agent undergoes changes in vector

85

What are determinants of emergence?

type of agent
host susceptibility
pathogenetic distance
contact frequency

86

What is pathogenic adaption?

increased antibiotic resistance
increased virulence

87

What factors increase transmission of a pathogen?

increasing abundance of host
increasing pathogen prevalence
increasing contact

88

What is prevention of infectious disease?

inhibiting the introduction or establishment of a disease into an area, herd or individual

89

T or F: Rinderpest is only animal disease that has been eradicated?

True

90

What does eradication of a infectious disease involve?

complete elimination of the pathogen from a defined region

91

What is primary prevention?

avoid occurrence of disease by health promotion or specific protection

92

What is secondary prevention?

primary prevention failed
minimize damage
early diagnosis

93

What is tertiary prevention?

both primary and secondary failed
rehab

94

What is farm biosecurity?

external ( leaving) and internal (spread)
all measures taken to minimize the risk of introduction and spread of agent

95

What is the purchasing policy?

closed herd system
reduce number of new animals
vaccination and health status of new animals
quarantine new animals

96

How does one remove infected individuals from a herd?

testing and slaughter

97

What is mass therapy?

eliminate pathogen from herd

98

What is biological control of an infection?

introducing a predator

99

What is the difference between isolation and quarantine?

isolation is ill with disease
quarantine is exposed to disease

100

What is chemoprophlaxis?

use of antimicrobal drugs
prevent infection

101

What are the four W's of immunization?

Where
When
Who
Why

102

What are features of a safe vaccine?

safe to use
effective against different strains
few side effects
low in cost
benefit outwieghs risk

103

Where does the World Animal health publication come from?

world organization for animal health OIE

104

What are sentinel labs?

direct contact with patients

105

What is infected premises?

confirmed positive cases
infected zone surrounds this

106

What is contact premises?

may have been exposed to infection

107

What is a buffer zone?

surrounds infected zone

108

What is one health?

healthy people, healthy environment, healthy animals

109

How to protect livestock from wildlife?

separate livestock from wildlife
vector control
wildlife population control