Viral Disease Flashcards

1
Q

viruses damage host cells by

A

entering the cell and replicating at the host expense

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2
Q

Steps in virus infection and replication

A
  1. attachment to host cell
  2. host cell penetration
  3. viral uncoating
  4. viral replication
  5. re-assembly of virions
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3
Q

Attachment to host cell involves

A

viral tropisms

special enzymes or promotor elements in host cells

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4
Q

Examples of viral tropisms

A

HIV - CD4
EBV - complement CD21 receptor on macrophages
rabies - acetylcholine receptor
rhinoviruses - ICAM-1

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5
Q

types of viral infections

A

abortive; latent; persistent

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6
Q

Mechanisms of host cell death

A
  1. inhibition of host RNA, DNA, protein synthesis
  2. viral proteins damage host membrane integrity or promote cell fusion
  3. replicate and lyse host cells
  4. antiviral host responses with recognition of viral antigens on infected host cell
  5. secondary infections due to suppression of host immune response
  6. secondary loss of cells dependent on infected cells
  7. transformation by oncogenic virus resulting in neoplasia
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7
Q

Acute viral infections are generally controlled by

A
cell-mediated (CD8) responses to virally infected cells;
restricted to viral antigen + MHC class I molecules
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8
Q

antibody serves two purposes

A
  1. to control blood borne dissemination (viremia)

2. control reinfection (protective immunity) - often by interfering with attachment or viral release

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9
Q

Vaccination can induce

A

either a humoral or cell-mediated response

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10
Q

antigenic shift

A

recombination of RNA segments with those of animal viruses to cause changes in hemagglutinin and neuraminidase (pandemics)

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11
Q

antigenic drift

A

mutations of hemagglutinin and neuraminidase that allow virus to escape host antibodies (epidemics)

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12
Q

isotype shift of antibody from IgM to IgG is indicative of

A

prior infection with or without current infection
IgM = recent infection
IgG = prior infection

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13
Q

antiviral functions of antibody

A

neutralization (prevent attachment/interfere with viral uncoating)
opsonization
complement-mediated cell and/or virion lysis

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14
Q

role of antibody in disease states

A
  1. immune complex reactions - arthralgias/glomerulonephritis

2. may enhance cell uptake and promote infection

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15
Q

epithelial necrosis and sloughing

A

influenza

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16
Q

inclusion bodies

A

CMV, adenovirus

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17
Q

syncytial cells

A

measles, herpes viruses, retroviruses

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18
Q

blisters

A

discohesion of epithelial cells as with herpes virus, varicella-zoster

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19
Q

dysplastic changes to neoplastic transformation

A

papillomavirus

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20
Q

CMV inclusions

A

distinct intranuclear and ill-defined cytoplasmic inclusions

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21
Q

Herpes, varicella inclusions

A

Cowdry type A intranuclear inclusion bodies

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22
Q

Rabies

A

Negri bodies; cytoplasmic inclusion bodies

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23
Q

Papillomavirus

A

koilocytes

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24
Q

Hepatitis

A

Councilman bodies (necrotic cells)

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25
Q

Measles

A

Warthin-Finkeldey giant cells with intracytoplasmic and intranuclear inclusion bodies

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26
Q

Adenovirus

A

smudge cells and Cowdry type A intranuclear inclusion bodies

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27
Q

reactive lymphoid hyperplasia

A

EBV (B cells), measles (giant cells), mumps

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28
Q

infection spread by food/water

A

Hepatitis A

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29
Q

infection spread by aerosolized droplets

A

influenza, adenovirus, rhinovirus

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30
Q

infection spread by cells or body fluids

A

EBV, HIV, herpes etc

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31
Q

Respiratory viruses

A
  1. adenovirus
  2. rhinovirus
  3. influenza
  4. measles
  5. RSV
  6. coronavirus
  7. CMV
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32
Q

GI viruses

A
  1. poliovirus
  2. coxsackie
  3. echovirus
  4. rotavirus
  5. Hep A/B/C
  6. Norwalk agent
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33
Q

Encephalitis/Hemorrhagic fever viruses

A
  1. Rubella
  2. Yellow Fever
  3. Dengue
  4. Hanta
  5. Mumps
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34
Q

Vesicular viruses

A

HSV1
HSV2
Varicella-Zoster
smallpox

35
Q

Proliferative/Oncogenic viruses

A
  1. EBV
  2. Papillomavirus
  3. HIV
  4. HTLV
36
Q

Neurotropic viruses

A
  1. HSV 1
  2. HSV 2
  3. Varicella Zoster
  4. Rabies
37
Q

DNA viruses

A
  1. Herpes (1-8)
  2. Adenovirus
  3. hepatitis B
  4. Pox
  5. papilloma/JC
  6. parvovirus
38
Q

RNA viruses

A
  1. Enteroviruses (polio, coxsackie, echo, hep A)
  2. Reo - rotavirus
  3. coronavirus
  4. Toga - rubella
  5. Flavi - yellow fever, dengue, hep C
  6. Orthomyxo - influenza
  7. Paramyxo - measles, mumps, RSV
  8. Hanta
  9. Filo - ebola
  10. Rhabdo - rabies
39
Q

Retro viruses

A

HTLV

HIV

40
Q

polio

A

enterovirus
infects tissues in oropharynx
secreted into saliva/swallowed
multiplies in intetinal mucosa and lymph nodes
1% invades CNS to replicate in motor neurons of spinal cord/brain stem

41
Q

Upper respiratory viral syndromes

A

adenovirus
rhinovirus
echovirus
coronavirus

42
Q

Lower respiratory viral syndromes (pneumonias)

A

influenza
parainfluenza
RSV

43
Q

GI tract/liver viral syndromes

A

rotavirus
norwalk agent
hepatitis

44
Q

rhinovirus

A

binds to ICAM-1
confined to URT, needs cooler environment
hypersecretion due to bradykinins and inflammatory response
over 100 serotypes

45
Q

echovirus and coxsackie viruses

A

oral/fecal spread
organisms disseminate in blood stream after proliferation in lymphoreticular tissues
respiratory disorders primarily

46
Q

coronavirus

A

second most common cause of common cold
profuse nasal discharge
little effect on lower respiratory tract

47
Q

hemagglutinin binds

A

sialic acid-containing proteins and lipids on most cells and mediates entry into cell

48
Q

neuraminidase plays a role in

A

releasing virus from host cells

49
Q

Type A influenza major cause of

A

pandemic and epidemic flu infections

50
Q

Type B and C infect

A

mostly children

51
Q

pathology of influenzae

A

mucosal hyperemia with lymphomonocytic and plasmacytic infiltration of submucosa; hypersecretion

52
Q

influenzae can also cause

A

interstitial myocarditis

associated with Reye’s syndrome

53
Q

most deaths with pneumonia are due to

A

secondary bacterial pneumonias

54
Q

parainfluenza

A

effects mostly children; mostly localized to URT except in infants where more serious lower respiratory infections occur

55
Q

RSV

A

most common cause of viral pneumonia in children

56
Q

adenovirus

A

common cause of acute respiratory disease and pnemonia in military recruits
COWDRY TYPE A INTRANUCLEAR INCLUSIONS
epithelial necrosis with sloughing

57
Q

other important forms of viral pneumonias

A

herpes viruses including chickenpox (varicella)
CMV
herpes simplex

58
Q

rotavirus

A

usually acute/self-limited, infectious diarrhea

major cause of diarrhea in infants/older children and adults are resistant to infection

59
Q

Norwalk agent

A

epidemic viral gastroenteritis

naked icosahedryl nucleocapsids which cannot grow in cultured cells

60
Q

HSV type I

A

gingivostomatitis, cold sores

61
Q

HSV type II

A

genital herpes

62
Q

HSV type I is major infectious cause of

A

corneal blindness
also cause of fatal sporadic encephalitis
causes disseminated disease in immunosuppressed

63
Q

pathology of HSV I and II

A

fever blisters and cold sores in skin and mucous membranes
inclusion-bearing multinucleated syncytia (TZANCK PREP)
blisters associated with edema and ballooning degeneration

64
Q

Congenital infection (TORCH syndrome):

A

generalized lymphadenopathy, splenomegaly, necrotic foci throughout; corneal lesions, CNS damage (deafness, ataxia)

65
Q

Epstein-Barr

A

benign, self-limited, lymphoproliferative disease
fever, generalized lymphadenopathy, splenomegaly, sore throat
atypial lymphocytes on blood smear

66
Q

EBV binds

A

to complement receptor on epithelial cells and B cells

67
Q

When EBV infects B cells it causes

A

proliferation, lymphadenopathy, and polyclonal non-specific antibody synthesis

68
Q

EBV immune response involves

A

heterophil anti-sheep red blood cell Abs used for diagnostic testing

69
Q

latent EBV infection associated with

A

Burkitt’s lymphoma and nasopharyngela carcinoma

70
Q

Diagnosis dependent on

A
  1. atyp8ical lymphocytes
  2. positive heterophil reaction
  3. specific antibodies for EBV antigens
71
Q

HTLV associated with

A

T cell lymphomas

72
Q

CMV characteristics

A

disseminated infection in imunosuppressed individuals and neonates characterized by large purple nuclear inclusions; focal necrosis with little inflammation

73
Q

CMV infections in neonates from

A

intrauterine, perinatal and mother’s milk

devastating disease in neonates

74
Q

In infants, CMV manifests as

A
hemolytic anemia
jaundice
thrombocytopenia
purpura
hepatosplenomegaly
deafness
chorioretinitis
brain damage/encephalitis
75
Q

most common opportunistic viral disease in AIDS patients

A

CMV

76
Q

CMV infection in AIDS most always accompanied by

A

Pneumocystic carinii

77
Q

HPV

A

proliferative lesions including common warts, plantar warts and cervical dysplasia
transmitted by direct contact
initially infect basal cells

78
Q

Rabies

A

negri bodies, secreted in saliva

79
Q

yellow fever and dengue

A

mosquito-borne (aedes aegyptii)

80
Q

Ebola

A

filamentous mammalian viruses; neg. sense ssRNA

81
Q

Manifestations of ebola

A

multihemorrhagic manifestations with DIC, shock
hepatic involvement
visceral organ necrosis
organ damage not sufficient to kills

82
Q

Ebola death from

A

hemorrhage, shock, fluid loss

83
Q

hanta virus

A

acute hemorrhagic pulmonary syndrome

fever, acute respiratory distress, hemorrhages, DIC

84
Q

West Nile Virus

A

birds serve as major reservoir
transmitted by mosquitoes to birds and mammals
headahce, myalgia
meningitis/encephalitis/meningoencephalitis