VIRUS Flashcards
(145 cards)
1
Q
What are the DNA viruses?
A
poxvirus
adenovirus
herpes virus
hepadna viruses
papova viruses
2
Q
What virus is under poxvirus?
A
variola
vaccinia
3
Q
What type of virus is viriola?
A
DNA poxvirus
4
Q
What type of virus is vaccinia?
A
DNA poxvirus
5
Q
What illness does variola cause?
A
smallpox
6
Q
What type of infection does variola cause?
A
systemic infection with vesicular rash affecting:
face
arms
legs
7
Q
Describe the mortality of variola virus.
A
high mortality rate
8
Q
What is vaccinia virus used for?
A
immunize against smallpox
9
Q
What is vaccinia derived from?
A
cowpox
10
Q
What virus is used to immunize against small pox?
A
vaccinia
11
Q
What type of capsid do adenoviruses have?
A
icosahedral
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
13
Q
What are the viruses under herpes virus?
A
Herpes simplex virus - HSV1 and HSV2
Varicellazoster VSV
Cytomegalovirus CMV
Epstein-Barr Virus EBV
14
Q
What type of capsid do HSV1 and HSV2 have?
A
enveloped
icosahedral
15
Q
What type of herpes is HSV1?
A
oral
16
Q
What type of herpes is HSV2?
A
genital
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
18
Q
What nerve is the HSV1 retained after primary infectopm?
A
trigeminal nerve ganglion
19
Q
Describe HSV1 reinfection.
A
50% of developing cold sores triggered by:
UV sunlight
viral infection
20
Q
What is the percentage of HSV1 infection.
A
> 80% infection by adolescence
21
Q
What type of capsid do varicella zoster virus have?
A
enveloped
icosahedral
22
Q
What illness does varicella zoster virus cause?
A
human herpes virus 3
chickenpox- children
shingles- adults
23
Q
Where is the VZV retained after infection?
A
dormant in any dorsal root ganglion of the CNS
24
Q
What type of capsid do cytomegalovirus have?
A
enveloped
icosahedral
25
What virus causes human herpes virus 5?
CMV cytomegalovirus
26
What illness does cytomegalvirus cause?
human herpes virus 5
- subclinical infection generally acquired in childhood
- induce congenital abnormalities in pregnancy
27
What illnesses does the cytomegalovirus cause in immunocompromised pts?
pneumonia
hepatitis
encephalitis
28
What complications can CMV cause in pregnancies?
congenital abnormalities in fetus
29
Where is the CMV retained after infection?
50% of adults in WBC
30
What virus causes human herpes virus 4?
epstein-barr virus
31
What type of capsid does the epstein-barr virus have?
enveloped
icosahedral
32
How does the EBV infection occur?
salivary exchange
33
What illness does EBV cause?
human herpes virus 4
34
Mechanism of EBV in children.
- commonly asymptomatic but virus stays in latent form in lymphocytes
- the infection is delayed until adolescence = then causes mononucleosis
35
What does mononucleosis cause?
fever
pharyngitis
adenopathy
36
How does EBV present in tropical Africa?
severe EBV infection causes predisposes children to:
malignant factal tumors - Burkitt's lymphoma
> must be co0infected with malaria
37
How does EBV present in china?
EBV with consumption of fish may trigger nasopharyngeal carcinoma in adults
38
What is required for EBV to cause illness?
aquisition of viral gene followed by:
environmental/dietary exposure to chemical carcinogens
39
What type of capsid does the Hepatitis B virus have?
spherical
enveloped
icosahedral
40
Describe the genetic material in HBV.
partial double-stranded DNA
41
How does HBV manifest in South-East Asia and Africa?
most children infected by prenatal transmission
42
How does HBV manifest in the Western world?
contact with contaminated blood
sexual intercourse
43
What can chronic infections with HBV progress to?
hepatocellular carcinoma
liver cancer
44
How can liver cancer due to HBV be triggered?
high alcohol consumption
smoking
exposure to fungal toxin - alflatoxin
45
What virus is under papovavirus?
human papilloma virus
46
What type of capsid does the papovavirus virus have?
naked
icosahedral
47
What cancer is HPV associated with?
cervical carcinoma
48
Describe mechanism of HPV infection.
multiply in epithelial cells of skin and mucous membrane
causes warts
49
How did cervical cancer cases decrease?
effective HPV vaccine design
successful vaccination program
50
What kind of virus is HPB?
hepadna virus
51
What illness does hepadna virus cause?
hepatitis B
52
What are the viruses under myxoviruses?
influenza virus
53
What type of virus is the influenza virus?
myxovirus
54
What type of capsid does the influenza virus have?
enveloped
helically symmetric capsid
55
Describe the genetic material in influenza virus.
segmented RNA
56
What spikes are on the envelop of the myxovirus?
hemagglutinin
neuraminidase
57
Where does the influenza virus go in the body?
multiplies in the cells lining the upper respiratory tract
58
What adaptation is influenza capable of?
extensive antigentic variation - alter antigens that human does not have effective immunity against
the new antigenic types can cause influenza pandemics
59
What type of capsid does the mumps virus have?
enveloped
helical capsid
60
What type of virus is the mumps virus?
paramyxovirus
61
What viruses are under paramyxoviruses?
mumps virus
measles virus
62
Describe the manifestation of mumps virus infection.
children:
produce characteristic swelling of-
parotid salivary glands
submaxillary salivery glands
adults: neurological complications (meningitis)
63
What type of capsid does the measles virus have?
enveloped
helical capsid
64
Describe the manifestation of measles virus infection.
very common childhood fever
65
Describe the immunity against measles after infection.
lifelong immunity
second attacks are very rare
66
What viruses are under rhabdoviruses?
rabies virus
67
What type of capsid does the rabies virus have?
bullet-shaped
enveloped
helical capsid
68
What are the hosts of rabies?
very wide host range
infects all mammals: especially-
dogs
cats
cattle
69
What is the incubation of rabies virus?
extremely varies:
6 days to 1 year
70
What is the mechanism of action of rabies virus?
- virus remains localized at the wound site of entry for a while
- passes along nerve fibers to CNS
- produces fatal encephalitis
71
What type of virus is the rabies virus?
rhabdovirus
72
What virus is under the reovirus?
rotavirus
73
Describe the structure of rotavirus.
segmented, double-stranded RNA
inner core is surrounded by two concentric icosahedral shells
74
How does the rotavirus spread?
poor water supplies when standards of egeneral hygiene are low
75
What illness does rotavirus cause?
gastroenteritis in infants
76
What is the mortality rate of rotavirus?
Cause millions of deaths each year in developing countries
77
What viruses are under picornaviruses?
poliovirus
rhinovirus
hepatitis A virus
78
Describe the capsid of picornaviruses.
naked
icosahedral
79
What entervirus is commonly found in the gut?
poliovirus
80
Where is the poliovirus commonly concentrated in?
gut
81
What is the site of multiplication of poliovirus?
lymphoid tissue of alimentary tract
82
What illness does poliovirys cause?
rare systemic infections
rare neurological conditions like:
encephalitis
poliomyelitis
83
What type of illnesses does the rhinoviruses cause?
common cold
84
Why is it difficult to prepare rhinovirus vaccines?
because there are over 100 antigenically distinct types of rhinovirus
85
Where is the rhinovirus commonly concentrated in?
watery nasal secretions
86
How is hepatitis A virus spread?
oral-faecal route (esp in children) as HAV is associated with:
contaminated sewage
87
What type of hepatitis is the infectious hepatitis?
hepatitis a virus
88
What viruses are under togaviruses?
rubella
89
What type of virus is rubella?
togavirus
90
Describe the capsid of rubella.
spherical
enveloped
icosahedral
91
What illness is caused by rubella in children?
german measles
92
What illness is caused by rubella during preganancy?
severe multiple congenital abnormalities, if contracted in early pregnancy
93
What are the congenital abnormalities are caused by rubella?
deafness
blindness
heart disease
mental retardation
94
What viruses are under flaviviruses?
yellow fever virus
hepatitis C virus HCV
dengue virus
95
Describe the capsid of flaviviruses.
spherical
enveloped
96
How is yellow fever virus spread?
mosquito bites
97
What species of mosquitos cause yellow fever?
Aedes
Haemogogus
98
What organ is the main target of the yellow fever virus?
liver
99
What is the mechanism of action of yellow virus?
causes necrosis of hepatocytes that lead to:
jaundice
fever
100
How is HCV spread?
blood transfusion
blood products
101
What is the illness caused by HCV?
hepatitis milder than HBV
102
How is dengue virus spread?
infected mosquito bites
103
What species of mosquitos cause dengue?
aegypti
albopictus
104
What is the most common symptom of dengue?
fever
105
How many types of dengue virus is there?
1
2
3
4
106
What type of virus is ebola virus?
filovirus
107
What viruses are under filoviruses?
ebola virus
108
Describe the capsid of filovirus.
long filamentous rods
enveloped
helical nucleocapsid
109
Size of ebola virus capsid.
1000nm long
80nm in diameter
110
How is ebola virus spread?
contact with primate bodily fluids
111
What is the mortality rate of ebola virus?
90% fatality if haemorragic fever is manifested
112
What species is ebola virus widespread amongst?
monkeys
113
What virus is under the deltaviridae?
hepatitis D virus (HDV)
114
What is the requirement for HDV to be replicate?
must be in cells co-infected with HBV
115
Describe the coat of HDV.
spherical coat with HBV capsid
116
Describe the illness caused by HDV.
Severe hepatitis:
satellite HDV exacerbates the pathogenic effects of HBV
117
How is HDV transmitted?
- mother to child
- contact with bloof or other bodily fluids
118
What are ways the HDV can spread through body fluid contact?
sex with infected partner
injection-drug use
needle sticks
exposure to sharp instruments
119
What virus is under retroviridae?
human t-cell leukemia virus (HTLV-1)
human immunodeficiency virus (HIV)
120
Describe the capsid of HTLV-1.
spherical
enveloped
icosahedral
121
What type of virus is HTLV-1?
retroviridae
122
How is HTLV-1 transmitted?
infected:
lymphocytes in blood
semen
breastmilk
123
Describe the mechanism of action of the HTLV-1.
- remain asymptomatic
- after 10-40 years incubation in 2% of infections = adult T-cell leukemia
124
What cancer does HTLV-1 cause?
Kaposi's sarcoma
125
What type of virus is HIV?
retroviridae
126
What shape of core does HIV have?
cone-shaped
127
How is HIV transmitted?
blood
genital secretions
128
What is the principal target of HIV?
CD4+ T-lymphocyte cells
129
What happens if T-lymphocyte numbers decrease?
immunodeficiency
130
What other illness can HIV cause?
Kaposi's sarcoma
131
Describe the capsid of HIV.
enveloped
cone-shaped nucleocapsid
132
What genetic material does HIV have?
two copies of positive-sense single-stranded RNA molecules
133
What enzymes does HIV contain?
reverse transcriptase
134
What projections does HIV have on the envelope?
70 glycoprotein spikes (GP120)
135
What does the GP120 of HIV interact with?
CD4+ protein receptor on the T-lymphocyte
136
What are the steps of HIV infecting a T-lymphocyte host cell?
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
What is the mechanism of provirus?
1. lie dormant in host cell
2. expressed, causing production of viral mRNA and proteins. This causes multiplication of virus through virions.
138
What type of cistron do proviruses have?
polycistron
139
How do virions of proviruses spread?
the virions bud off the infected cells
140
How are the polyproteins produced by proviruses cleaved?
by protease enzyme
141
What virus is under coronaviridae?
SARS-COV 2
142
Describe the genetic material of SARS-COV 2
single-stranded
positive-sense RNA
143
Describe the capsid of SARS-COV 2.
envelops genetic material
144
What are the three structural proteins associated with SARS-COV 2?
S - spike protein
E - envelope protein
M - membrane protein
145
What is the third zoonotic human coronavirus?
SARS-COV 2
