VIRUS Flashcards

1
Q

What are the DNA viruses?

A

poxvirus
adenovirus
herpes virus
hepadna viruses
papova viruses

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2
Q

What virus is under poxvirus?

A

variola
vaccinia

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3
Q

What type of virus is viriola?

A

DNA poxvirus

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4
Q

What type of virus is vaccinia?

A

DNA poxvirus

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5
Q

What illness does variola cause?

A

smallpox

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6
Q

What type of infection does variola cause?

A

systemic infection with vesicular rash affecting:
face
arms
legs

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7
Q

Describe the mortality of variola virus.

A

high mortality rate

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8
Q

What is vaccinia virus used for?

A

immunize against smallpox

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9
Q

What is vaccinia derived from?

A

cowpox

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10
Q

What virus is used to immunize against small pox?

A

vaccinia

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11
Q

What type of capsid do adenoviruses have?

A

icosahedral

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12
Q

What illness does adenovirus cause?

A
  • upper respiratory tract infections
  • latent infections in tonsils and adenoids
  • tumors on injection into hamsters, rats or mice
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13
Q

What are the viruses under herpes virus?

A

Herpes simplex virus - HSV1 and HSV2
Varicellazoster VSV
Cytomegalovirus CMV
Epstein-Barr Virus EBV

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14
Q

What type of capsid do HSV1 and HSV2 have?

A

enveloped
icosahedral

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15
Q

What type of herpes is HSV1?

A

oral

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16
Q

What type of herpes is HSV2?

A

genital

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17
Q

What illness does HSV1 cause?

A

infection of oral membranes in children.

individual retains the HSV1 DNA in the trigeminal nerve ganglion for life after primary infection

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18
Q

What nerve is the HSV1 retained after primary infectopm?

A

trigeminal nerve ganglion

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19
Q

Describe HSV1 reinfection.

A

50% of developing cold sores triggered by:
UV sunlight
viral infection

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20
Q

What is the percentage of HSV1 infection.

A

> 80% infection by adolescence

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21
Q

What type of capsid do varicella zoster virus have?

A

enveloped
icosahedral

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22
Q

What illness does varicella zoster virus cause?

A

human herpes virus 3

chickenpox- children
shingles- adults

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23
Q

Where is the VZV retained after infection?

A

dormant in any dorsal root ganglion of the CNS

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24
Q

What type of capsid do cytomegalovirus have?

A

enveloped
icosahedral

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25
Q

What virus causes human herpes virus 5?

A

CMV cytomegalovirus

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26
Q

What illness does cytomegalvirus cause?

A

human herpes virus 5
- subclinical infection generally acquired in childhood
- induce congenital abnormalities in pregnancy

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27
Q

What illnesses does the cytomegalovirus cause in immunocompromised pts?

A

pneumonia
hepatitis
encephalitis

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28
Q

What complications can CMV cause in pregnancies?

A

congenital abnormalities in fetus

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29
Q

Where is the CMV retained after infection?

A

50% of adults in WBC

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30
Q

What virus causes human herpes virus 4?

A

epstein-barr virus

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31
Q

What type of capsid does the epstein-barr virus have?

A

enveloped
icosahedral

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32
Q

How does the EBV infection occur?

A

salivary exchange

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33
Q

What illness does EBV cause?

A

human herpes virus 4

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34
Q

Mechanism of EBV in children.

A
  • commonly asymptomatic but virus stays in latent form in lymphocytes
  • the infection is delayed until adolescence = then causes mononucleosis
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35
Q

What does mononucleosis cause?

A

fever
pharyngitis
adenopathy

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36
Q

How does EBV present in tropical Africa?

A

severe EBV infection causes predisposes children to:
malignant factal tumors - Burkitt’s lymphoma
> must be co0infected with malaria

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37
Q

How does EBV present in china?

A

EBV with consumption of fish may trigger nasopharyngeal carcinoma in adults

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38
Q

What is required for EBV to cause illness?

A

aquisition of viral gene followed by:
environmental/dietary exposure to chemical carcinogens

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39
Q

What type of capsid does the Hepatitis B virus have?

A

spherical
enveloped
icosahedral

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40
Q

Describe the genetic material in HBV.

A

partial double-stranded DNA

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41
Q

How does HBV manifest in South-East Asia and Africa?

A

most children infected by prenatal transmission

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42
Q

How does HBV manifest in the Western world?

A

contact with contaminated blood
sexual intercourse

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43
Q

What can chronic infections with HBV progress to?

A

hepatocellular carcinoma
liver cancer

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44
Q

How can liver cancer due to HBV be triggered?

A

high alcohol consumption
smoking
exposure to fungal toxin - alflatoxin

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45
Q

What virus is under papovavirus?

A

human papilloma virus

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46
Q

What type of capsid does the papovavirus virus have?

A

naked
icosahedral

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47
Q

What cancer is HPV associated with?

A

cervical carcinoma

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48
Q

Describe mechanism of HPV infection.

A

multiply in epithelial cells of skin and mucous membrane
causes warts

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49
Q

How did cervical cancer cases decrease?

A

effective HPV vaccine design
successful vaccination program

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50
Q

What kind of virus is HPB?

A

hepadna virus

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51
Q

What illness does hepadna virus cause?

A

hepatitis B

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52
Q

What are the viruses under myxoviruses?

A

influenza virus

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53
Q

What type of virus is the influenza virus?

A

myxovirus

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54
Q

What type of capsid does the influenza virus have?

A

enveloped
helically symmetric capsid

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55
Q

Describe the genetic material in influenza virus.

A

segmented RNA

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56
Q

What spikes are on the envelop of the myxovirus?

A

hemagglutinin
neuraminidase

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57
Q

Where does the influenza virus go in the body?

A

multiplies in the cells lining the upper respiratory tract

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58
Q

What adaptation is influenza capable of?

A

extensive antigentic variation - alter antigens that human does not have effective immunity against

the new antigenic types can cause influenza pandemics

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59
Q

What type of capsid does the mumps virus have?

A

enveloped
helical capsid

60
Q

What type of virus is the mumps virus?

A

paramyxovirus

61
Q

What viruses are under paramyxoviruses?

A

mumps virus
measles virus

62
Q

Describe the manifestation of mumps virus infection.

A

children:
produce characteristic swelling of-
parotid salivary glands
submaxillary salivery glands

adults: neurological complications (meningitis)

63
Q

What type of capsid does the measles virus have?

A

enveloped
helical capsid

64
Q

Describe the manifestation of measles virus infection.

A

very common childhood fever

65
Q

Describe the immunity against measles after infection.

A

lifelong immunity
second attacks are very rare

66
Q

What viruses are under rhabdoviruses?

A

rabies virus

67
Q

What type of capsid does the rabies virus have?

A

bullet-shaped
enveloped
helical capsid

68
Q

What are the hosts of rabies?

A

very wide host range

infects all mammals: especially-
dogs
cats
cattle

69
Q

What is the incubation of rabies virus?

A

extremely varies:
6 days to 1 year

70
Q

What is the mechanism of action of rabies virus?

A
  • virus remains localized at the wound site of entry for a while
  • passes along nerve fibers to CNS
  • produces fatal encephalitis
71
Q

What type of virus is the rabies virus?

A

rhabdovirus

72
Q

What virus is under the reovirus?

A

rotavirus

73
Q

Describe the structure of rotavirus.

A

segmented, double-stranded RNA

inner core is surrounded by two concentric icosahedral shells

74
Q

How does the rotavirus spread?

A

poor water supplies when standards of egeneral hygiene are low

75
Q

What illness does rotavirus cause?

A

gastroenteritis in infants

76
Q

What is the mortality rate of rotavirus?

A

Cause millions of deaths each year in developing countries

77
Q

What viruses are under picornaviruses?

A

poliovirus
rhinovirus
hepatitis A virus

78
Q

Describe the capsid of picornaviruses.

A

naked
icosahedral

79
Q

What entervirus is commonly found in the gut?

A

poliovirus

80
Q

Where is the poliovirus commonly concentrated in?

A

gut

81
Q

What is the site of multiplication of poliovirus?

A

lymphoid tissue of alimentary tract

82
Q

What illness does poliovirys cause?

A

rare systemic infections

rare neurological conditions like:
encephalitis
poliomyelitis

83
Q

What type of illnesses does the rhinoviruses cause?

A

common cold

84
Q

Why is it difficult to prepare rhinovirus vaccines?

A

because there are over 100 antigenically distinct types of rhinovirus

85
Q

Where is the rhinovirus commonly concentrated in?

A

watery nasal secretions

86
Q

How is hepatitis A virus spread?

A

oral-faecal route (esp in children) as HAV is associated with:
contaminated sewage

87
Q

What type of hepatitis is the infectious hepatitis?

A

hepatitis a virus

88
Q

What viruses are under togaviruses?

A

rubella

89
Q

What type of virus is rubella?

A

togavirus

90
Q

Describe the capsid of rubella.

A

spherical
enveloped
icosahedral

91
Q

What illness is caused by rubella in children?

A

german measles

92
Q

What illness is caused by rubella during preganancy?

A

severe multiple congenital abnormalities, if contracted in early pregnancy

93
Q

What are the congenital abnormalities are caused by rubella?

A

deafness
blindness
heart disease
mental retardation

94
Q

What viruses are under flaviviruses?

A

yellow fever virus
hepatitis C virus HCV
dengue virus

95
Q

Describe the capsid of flaviviruses.

A

spherical
enveloped

96
Q

How is yellow fever virus spread?

A

mosquito bites

97
Q

What species of mosquitos cause yellow fever?

A

Aedes
Haemogogus

98
Q

What organ is the main target of the yellow fever virus?

A

liver

99
Q

What is the mechanism of action of yellow virus?

A

causes necrosis of hepatocytes that lead to:
jaundice
fever

100
Q

How is HCV spread?

A

blood transfusion
blood products

101
Q

What is the illness caused by HCV?

A

hepatitis milder than HBV

102
Q

How is dengue virus spread?

A

infected mosquito bites

103
Q

What species of mosquitos cause dengue?

A

aegypti
albopictus

104
Q

What is the most common symptom of dengue?

A

fever

105
Q

How many types of dengue virus is there?

A

1
2
3
4

106
Q

What type of virus is ebola virus?

A

filovirus

107
Q

What viruses are under filoviruses?

A

ebola virus

108
Q

Describe the capsid of filovirus.

A

long filamentous rods
enveloped
helical nucleocapsid

109
Q

Size of ebola virus capsid.

A

1000nm long
80nm in diameter

110
Q

How is ebola virus spread?

A

contact with primate bodily fluids

111
Q

What is the mortality rate of ebola virus?

A

90% fatality if haemorragic fever is manifested

112
Q

What species is ebola virus widespread amongst?

A

monkeys

113
Q

What virus is under the deltaviridae?

A

hepatitis D virus (HDV)

114
Q

What is the requirement for HDV to be replicate?

A

must be in cells co-infected with HBV

115
Q

Describe the coat of HDV.

A

spherical coat with HBV capsid

116
Q

Describe the illness caused by HDV.

A

Severe hepatitis:
satellite HDV exacerbates the pathogenic effects of HBV

117
Q

How is HDV transmitted?

A
  • mother to child
  • contact with bloof or other bodily fluids
118
Q

What are ways the HDV can spread through body fluid contact?

A

sex with infected partner
injection-drug use
needle sticks
exposure to sharp instruments

119
Q

What virus is under retroviridae?

A

human t-cell leukemia virus (HTLV-1)
human immunodeficiency virus (HIV)

120
Q

Describe the capsid of HTLV-1.

A

spherical
enveloped
icosahedral

121
Q

What type of virus is HTLV-1?

A

retroviridae

122
Q

How is HTLV-1 transmitted?

A

infected:
lymphocytes in blood
semen
breastmilk

123
Q

Describe the mechanism of action of the HTLV-1.

A
  • remain asymptomatic
  • after 10-40 years incubation in 2% of infections = adult T-cell leukemia
124
Q

What cancer does HTLV-1 cause?

A

Kaposi’s sarcoma

125
Q

What type of virus is HIV?

A

retroviridae

126
Q

What shape of core does HIV have?

A

cone-shaped

127
Q

How is HIV transmitted?

A

blood
genital secretions

128
Q

What is the principal target of HIV?

A

CD4+ T-lymphocyte cells

129
Q

What happens if T-lymphocyte numbers decrease?

A

immunodeficiency

130
Q

What other illness can HIV cause?

A

Kaposi’s sarcoma

131
Q

Describe the capsid of HIV.

A

enveloped
cone-shaped nucleocapsid

132
Q

What genetic material does HIV have?

A

two copies of positive-sense single-stranded RNA molecules

133
Q

What enzymes does HIV contain?

A

reverse transcriptase

134
Q

What projections does HIV have on the envelope?

A

70 glycoprotein spikes (GP120)

135
Q

What does the GP120 of HIV interact with?

A

CD4+ protein receptor on the T-lymphocyte

136
Q

What are the steps of HIV infecting a T-lymphocyte host cell?

A

1) virus fuses with host cell membrane by binding to CD4+ receptors
2) core of virus penetrates cell cytoplasm
3) 2 RNA molecules + reverse transcriptase is released into the cytoplasm
4) reverse transcription: RNA is copied into single-stranded DNA by reverse transcriptase
5) single-stranded DNA is duplicated to form double-stranded DNA
6) DNA moves into host cell nucleus
7) DNA is integrated into host cell chromosome by integrase enzyme
8) HIV becomes provirus

137
Q

What is the mechanism of provirus?

A
  1. lie dormant in host cell
  2. expressed, causing production of viral mRNA and proteins. This causes multiplication of virus through virions.
138
Q

What type of cistron do proviruses have?

A

polycistron

139
Q

How do virions of proviruses spread?

A

the virions bud off the infected cells

140
Q

How are the polyproteins produced by proviruses cleaved?

A

by protease enzyme

141
Q

What virus is under coronaviridae?

A

SARS-COV 2

142
Q

Describe the genetic material of SARS-COV 2

A

single-stranded
positive-sense RNA

143
Q

Describe the capsid of SARS-COV 2.

A

envelops genetic material

144
Q

What are the three structural proteins associated with SARS-COV 2?

A

S - spike protein
E - envelope protein
M - membrane protein

145
Q

What is the third zoonotic human coronavirus?

A

SARS-COV 2