RNA Viruses Flashcards
1
Q
what is the smallest RNA virus
A
picornavirus
2
Q
What is the structure of picornavirus
A
Naked, + icosahedral ssRNA
3
Q
Where does picornavirus replicate?
A
cytoplasm
4
Q
what is the picornavirus capsid made of?
A
60 copies of NON-GLYCOSYLATED proteins
5
Q
how does picornavirus enter the cell?
A
receptor-mediated endocytosis
6
Q
What does a + genome mean?
A
the genome acts as mRNA
7
Q
What does a - genome mean?
A
the genome is complementary to the mRNA that will eventually be made
8
Q
What are picornaviruses released from the cell?
A
cell lysis
9
Q
What does poliovirus use as a receptor?
A
PVR/CD155
10
Q
What do most other picornaviruses use as a receptor?
A
ICAM-1
11
Q
What part of the picornavirus capsid binds to the receptor?
A
canyon region
12
Q
What else can bind to the picornavirus canyon regions?
A
Antibodies to neutralize virus
13
Q
What is unique about the protein made by picornavirus?
A
It is translated as 1 protein, and cleaved by a VIRAL PROTEASE
14
Q
What are (-) copies made by picornaviruses?
A
complementary template used to make more copies of the viral genome
15
Q
What is found at the 5’ end of picornavirus RNA?
A
VPg
16
Q
What is cleaved terminally in picornavirus replication? what is made?
A
VP0 –> VP2 and 4 mature particles
17
Q
What is VPg?
A
virally encoded protein that acts as a 5’ cap; guides translation and packaging of proteins
18
Q
How is picornavirus transmitted?
A
Fecal-oral
Respiratory droplets
19
Q
What is unique about rhinoviruses?
A
They are LABILE at acidic pH; like the upper airway
20
Q
What is unique about the other enteroviruses?
A
STABLE at acidic pH, like the GI tract
21
Q
What are the examples of the picornavirus family?
A
Poliovirus Enterovirus Rhinovirus Coxsackie A and B Hepatitis A
22
Q
What is the most common cause of the common cold ?
A
Rhinovirus
23
Q
Where do enteroviruses replicate?
A
mucosa and lymphoid tissue of tonsils and pharynx
M cells and lymphocytes of Peyer’s patches
Enterocytes of intestinal mucosa
24
Q
What causes the spread of virus to secondary tissues?
A
Primary viremia
25
What determines the degree of paralysis in paralytic polio?
the type of neurons affected and degree of damage
26
Who is more severely affected by paralytic polio?
the young and elderly
27
What are the effects of spinal cord involvement in paralytic polio?
paralysis of limbs or complete flaccid paralysis
28
What is affected in bulbar paralysis?
cranial nerves and the respiratory center in the medulla
29
Where is replication of poliovirus restricted to?
GI tract
30
What are the symptoms of poliovirus?
Could be asymptomatic
Could range from mild fever w/ diarrhea to FLACCID PARALYSIS
31
What does poliovirus infect?
ANTERIOR horn cells of the spinal cord and the MOTOR cortex
32
What are the vaccines for polio?
Salk -Inactivated vaccine (intramuscular)
Sabin- Live attenuated (oral) [CAN REVERT]
33
How many doses of polio vaccine are given?
4
34
What does coxsackie A cause?
herpangina
| Hand, foot, and mouth disease
35
What is herpangina?
painful ulcers found in the mouths of young children
36
What is hand, foot, and mouth disease?
vesicular lesions of the hand, feet, and mouth
37
What does echovirus cause?
aseptic meningitis
38
What does parechovirus cause?
GI and respiratory infection
encephalitis, myocarditis
39
What does kobuvirus cause?
GI infections
40
What does coxsackie B cause?
myocardial and pericardial infections
41
When does enterovirus aseptic meningitis normally occur?
Summer and early fall
42
What is the most common cause of viral meningitis?
Enteroviruses
43
Most common culprits of viral conjunctivitis?
Coxsackie A24
| Enterovirus 70
44
Most common culprits of hand,foot,and mouth disease?
Coxsackie A16
| Enterovirus 71
45
How are enteroviruses diagnosed?
Antibodies(IgG or IgM) or viral RNA through RT-PCR
46
What do rhinoviruses attach to on the cell?
ICAM-1
47
Where is a rhinovirus infection most commonly found?
UPPER Respiratory tract
48
What mediates rhinovirus immunity?
IgA (can have re-infection)
49
How many Hep A serotypes are there?
ONE
50
How is Hep A transmitted?
Fecal-oral
51
Where does Hep A replicate?
enteric mucosa
52
When do Hep A symptoms arise?
AFTER excretion
53
What is a prodrome?
set of early symptoms that may indicate a disease is present before specific symptoms arise
54
What is part of the prodrome of Hep A?
Dark urine, clay colored stool
55
What are symptoms of the icteric stage of Hep A?
jaundice, pruritis, tender hepatomegaly
56
What is unique about Hep A infections?
Most will be ASYMPTOMATIC
57
What labs can diagnose acute Hep A infections?
Increased ALT
| + IgM anti Hep A test
58
Needed for Hep A diagnosis?
Hep viral serologies, liver ultrasound
59
Where is Hep A primarily found?
Developing countries
60
What is the vaccine for Hep A?
Inactivated whole virus vaccine
61
What viruses cause Gastroenteritis?
Caliciviruses
Astroviruses
Rotaviruses
Adenoviruses
62
What is the structure of the calicivirus
Naked, + icosahedral ssRNA
63
What is the primary agent responsible for most acute dirrheal diseases in adults and children?
Norovirus
64
Where is calicivirus commonly found?
Cruise ships and day care (causing DIARRHEA)
65
How is norovirus transmitted?
person to person
Fecal-oral
aerosol transmission from vomiting
66
What is unique about the virus particles of noroviruses?
Not many are needed to infect!
67
What is the pathogenesis of noroviruses?
infection of epithelial cells in the stomach/intestine leads to maldigestion
68
What is unique about astroviruses?
it cannot be grown on cell culture
69
What is the structure of reoviruses?
Naked, + icosahedral dsRNA
70
What are the 2 types of reovirus?
Rotavirus
| Colorado tick fever
71
What is the leading cause of severe acute gastroenteritis in children worldwide?
Rotavirus
72
How many rotavirus serotypes are there?
5 (G1, G2, G3, G4, G9)
73
How is rotavirus transmitted?
Fecal-oral (VERY STABLE)
74
What does rotavirus replicate?
villous epithelium of the small intestine
75
What is an important treamtent for rotaviruses
REHYDRATION THERAPY
76
How is rotavirus diagnosed?
detection of virus particles or viral antigens in stool
77
What are vaccines for rotavirus?
RotaTeq and Rotarix (both oral live virus vaccine)
78
Antibodies to what are important for rotavirus protection?
VP7 and VP4
79
What has rotavirus vaccines been associated with?
intussusception
80
What are the symptoms of Colorado tick fever?
fever, headache, sever myalgia
81
How many segments does Colorado tick fever have?
12 dsRNA segments
82
What is the structure of Hep E?
Naked, + icosahedral ssRNA
83
How is Hep E transmitted?
fecal-oral
84
What is a major cause of acute hepatitis worldwide?
HEV
85
What is Hep E primarily associated with?
poor sanitation
86
What kind of disease is Hep E?
ACUTE only
87
Who is most likely to have fulminate symptoms from Hep E?
pregnant women
88
Hep E symptoms are most common among who?
adolescents, young adults, and pregnant women
89
What is IgG associated with?
long term immunity
90
What is IgM associated with?
acute infection
91
What is IgA associated with?
mucosal immunity
92
What are some viruses causing CNS disease and hemorrhagic fever?
Togaviruses
Flaviviruses
Bunyaviruses
Arenviruses
93
What are arboviruses?
arthropod-borne viruses
94
What is the structure of togaviruses?
Enveloped, + icosahedral ssRNA
95
How do togaviruses enter the cell?
receptor-mediated endocytosis
96
What are the genuses of togaviruses?
Alphaviruses and Rubiviruses
97
Where do alphaviruses replicate?
cells of arthropod vectors and vertebrae host
98
What is the natural host of alphaviruses?
mammal or bird
99
How are alphaviruses transmitted?
FEMALE mosquitos
100
Where is the alphavirus transmitted from?
salivary gland of mosquito to capillary bed
101
Types of alphaviral encephalitides
Easter, Western, and Venezueland equine encephalitits
102
How are arboviruses diagnosed?
virus specific IgM and neutralizing antibodies in serum or CSF
103
What is the most severe equine encephalitis?
EASTERN
104
What is the reservoir of VEE? for EEE and WEE?
Rodents. Birds
105
What is Chickungunya Fever virus?
debiliating illness with high fever, petechial or maculopapular rash, headache, fatigue, nausea, vomiting, muscle and joint pain
106
Where does Chickungunya fever virus replicate?
fibroblasts, skeletal muscle progenitor cells, myofibers
107
Most common lab finding of Chikungunya?
elevated creatinine, AST, and ALT
108
What is the treatment for Chikungunya fever virus?
There is none.
109
How is Chikungunya transmitted?
mosquitoes (A. aegypti, A albopictus)
110
How is Chikungunya diagnosed?
Serological IgM/IgG
| RT-PCR
111
What is the structure of flaviviruses?
Enveloped, + icosahedral ssRNA
112
What kinds of diseases do flaviviruses cause?
encephalitis and hemorrhagic fevers
113
What flaviviruses cause hemorrhagic fever?
Dengue
| Yellow fever
114
How is yellow fever transmitted?
mosquitos
115
What are the symptoms of yellow fever?
MOstly asymptomatic
Can have flu-like symptoms with jaundice, GI hemorrhage, and BLACK vomit
116
What is the vaccine for yellow fever?
Live attenuated 17D vaccine
117
What is the most widespread arbovirus in the world?
Dengue fever
118
How many serotypes of Dengue fever are there?
4. multiple reinfections possible
119
How is Dengue fever transmitted?
mosquitos
120
What are the symptoms of Dengue fever?
severe headache, muscle and joint pain, leukopenia, thrombocytopenia
121
Where does Dengue fever replicate?
mononuclear cells
122
What is a nickname for Dengue fever?
Breakbone fever
123
What is Dengue Hemorrhagic fever?
occurs with re-infection with a different Dengue fever serotype
124
What is the treatment for Dengue Hemorrhagic fever?
Treat the symptoms.
IV fluids, electrolytes, Oxygen, rehydraton
125
What are some Flaviviruses that cause encephalitis?
```
Powassan virus
STL encephalitis
West Nile fever
Japanese B encephalitis
Murray valley fever
```
126
What is unique about Powassan virus?
it is TICK borne
127
What is POW encephalitis associated with?
long-term morbidity
128
Clinically, West nile virus can be what?
Non-neuroinvasive or neuroinvasive
129
How can West nile be transmitted from human to human?
Blood transfusions
Transplanted organs
Breast milk
Transplacentally
130
What test is used by blood banks to check for West Nile?
Nucleic acid Amplification Test
131
How can West Nile be diagnosed?
testing serum/CSF for WNV specific IgM antibodies
| viral cultures and RT-PCR
132
What is the treatment for West nile?
There is no treatment.
133
What are some arbovirus Bunyaviruses?
California encephalitis virus and RIft valley fever
134
How is California encephalitis transmitted?
mosquitoes
135
How is Rift valley fever transmitted?
mosquitoes and sandflies
136
What does Hantavirus cause?
Hemorrhagic fever and pulmonary syndrome
137
When does California encephalitis peak?
summer months
138
Influenza is a member of what family?
Orthomyxovirus
139
What is the structure of orthomyxoviruses?
Enveloped, - HELICAL segmented ssRNA
140
What are the major types of influenza
A, B, C
141
How many gene segments do Influenza A and B have?
8
142
What proteins are found in the surface of the influenza virus?
Hemagglutinin and Neuraminidase
143
What is significant about the M2 protein?
Needed to get the genome OUT
144
What does hemagglutinin bind?
sialic acid
145
How many HA subtypes are there?
18
146
What is HA1 used for?
attachment
147
What is HA2 used for?
fusion
148
What is neuraminidase used for?
cleaving sialic aicd during release of viruses
149
Hemagglutinin is a...
TRIMER
150
Neuraminidase is a...
TETRAMER
151
Which part of the orthomyxovirus is a target for drugs?
Neuraminidase
| Tamiflu, Relenza
152
Where is HA0 protein cleaved?
Respiratory epithelium
153
What causes the conformational rearrangement in HA
pH drop in the endosome
154
Where are alpha (2,3) linkages cleaved?
LOWER Respiratory tract
| avian influenza virus
155
Where are alpha(2,6) linkages cleaved?
UPPER Respiratory tract (human influenza virus)
156
What is unique about the HA protein?
high degree of variability
| virus in is NOT the same virus out
157
Where does the HA variability come from?
No exonuclease activity in RNA polymerase
158
What is a quasi-species?
not a clone, but a mixture that undergoes selection, has a variety of genotypes
159
Where does orthomyxovirus replicate?
Nucleus ( in order to use the 5' caps of host mRNA)
160
How is orthomyxovirus transmitted?
large-particle respiratory droplets
161
Where does influenza multiply?
ciliated respiratory epithelium cells
162
Where is the influenza virus limited?
respiratory tract
163
What is a complication of influenza infection?
invasive bacterial superinfection
164
What is unique about the association between bacterial pathogens and influenza?
Bacterial pathogens can readily adhere to the surface of influenza-infected cells
165
What does recovery from influenza infection begin with?
IFN production
166
When does influenza peak?
winter months
167
What is shift?
SUDDEN, emergence of NEW subtypes
Little or no herd immunity
168
What is drift?
INCREMENTAL, emergence of VARIANT subtypes
Mutations cause evasion of herd immunity
169
What was the most devastating outbreak in human history?
Spanish Flu
170
Is drift or shift associated with increasing the world death rate?
SHIFT.
171
What percentage of the population gets the flue each year?
5-20%
172
What are the influenza vaccines?
Inactivated injection
| Live attenuated nasal spray
173
Which influenza vaccine is QUADRIVALENT only?
Nasal spray
174
Influenza vaccines are normally grown in what?
eggs
175
What influenza vaccine is okay for people with egg allergies?
Trivalent vaccine grown in cell culture
176
Who is the high dose trivalent vaccine used for?
the elderly (4x antigen)
177
Who is the nasal spray vaccine recommended for?
Healthy people 2 through 49 that are not pregnant
178
How do zanamivir and oseltamivir work?
inhibits neuraminidase
179
What is another name for zanamivir?
Relenza
180
What is another name for oseltamivir?
tamiflu
181
How do amantidine and rimantidine function?
target the M2 ion channel and block fusion
182
How is influenza diagnosed?
By looking at the viral antigens
183
What are some complications of influenza vaccines?
Guilian-Barre syndrome
| Reye's syndrome
184
Which bird flu has never been detected in peopl?
H7N9
185
What would cause bird flu to become a Human pandemic virus?
Better binding by HA
Better replication
Better processing of viral RNAs and proteins
Person-person transmission
186
What is a necessary precondition for a virus to be pandemic?
PERSON TO PERSON TRANSMISSION
187
What is the structure of paramyxoviruses?
Enveloped, - helical ssRNA
188
Who is mostly affected by Respiratory syncytial virus?
infants and elderly
189
Who is mostly affected by parainfluenza?
young children (Croup)
190
What does metapneumovirus cause?
acute respiratory disease
191
What is the structure of RSV?
enveloped w/ 2 envelope glycoproteins
192
What is the G glycoprotein of RSV for?
Attachment
193
What is the F glycoprotein of RSV for?
Fusion
194
What is the single most important cause of respiratory diseases in infancies?
RSV
195
What does RSV infect?
Upper and lower respiratory tract
196
RSV is localized where?
Respiratory epithelium
197
What drug is targeted as the F protein of RSV
Palivizumab
198
What does Palivizumab target?
F protein of RSV
199
How many parainfluenza serotypes are there?
4
200
What is unique about each of the 4 parainfluenza serotypes?
There are antigenically stable.
201
What are parainfluenza viruses?
Enveloped paramyxoviruses with HA and NA on the SAME SPIKE
202
Parainfluenza viruses can cause what kind of illness?
Upper and Lower respiratory illnesses
203
Which parainfluenza viruses are most often associated with croup?
HPIV-1 and HPIV-2
204
What is HPIV-3 associated with?
bronchitis, bronchiolitis, and pneumonia
205
RSV is more associated with what disease?
Bronchiolitis
206
Parainfluenza is more associated with what disease
Croup
207
How is parainfluenza transmitted?
Person to person
208
What is another name for measles?
Rubeola
209
What is another name for mumps?
epidemic parotitis
210
What type of vaccine is the MMR vaccine?
Live attenuated
211
Where does measles replicate?
upper respiratory tract
212
Symptoms of measles
Cough, Coryza, Conjunctivitis, Koplik's spots on buccal mucosa
213
How is mumps transmitted?
Respiratory transmission
214
Where does mumps initally replicate?
Respiratory tract epithelium and local lymph nodes
215
Where does mumps disseminate to?
salivary glands and CNS
216
What are some complications of mumps?
meningitis, encephalitis, pancreatitis, orchitis, oophoritis
217
What is orchitis?
most common complication in postpubertal males. Inflammation of epididymis
218
What is the structure of togaviruses?
Enveloped, + icosahedral ssRNA
219
How is Rubella transmitted?
respiratory droplets
| Transplacentally
220
Where does rubella replicate? Where does it disseminate?
Upper respiratory tract
Lymphoid tissue, skin, organs
221
When during pregnancy is fetus at risk for rubella damage?
1st trimester
222
What is the treatment for measles, mumps, and rubella?
There is no treatment, BUT THERE IS A VACCINE MMR
223
What are some zoonotic paramyxoviruses?
Hendra and Nipah
224
What is the structure of a coronavirus?
Enveloped, + ssRNA, w/ spike-like glycoproteins
225
What are some examples of zoonotic coronaviruses?
SARS, MERS
226
What are the 2 main virusese of the Rhabdovirus family?
Rabies and Vesicular Stomatitis virus
227
What is the structure of a rhabdovirus?
Enveloped, - helical ssRNA with a bullet-shaped capsid
228
Where does rabies multiply?
brain
229
What are the phases of a rabies infection?
Prodrome
Neurologic
Comatose
230
What is the treatment for rabies?
THERE IS NO ANTIVIRAL TREATMENT, BUT THERE IS A VACCINE
231
What is the rabies vaccine?
Human Diploid Cell Vaccine (inactivated, gives active immunity)
232
When is it best to vaccinate someone for rabies?
When they think they have been exposed to it
233
How is rabies transmitted?
saliva of infected animals through a bite
234
How is rabies diagnosed?
Watching for clinical changes in the animal
Negri bodies in the brain (cytoplasmic inclusions)
235
How is rabies diagnosed in humans?
RT-PCR of saliva
anti-rabies Abs in serum/spinal fluid
biopsy of hair follicles from nape of neck
236
What is the Rabies prophylactic treatment?
1 dose of immunoglobulins and 4 doses of rabies vaccine over a 14-day period
237
How is Human Diploid Cell Vaccine made?
in tissue culture using normal human WI-38 fibroblasts. The rabies virus is then inactivated
238
What is the only non-arboviric Bunyavirus?
Hantavirus
239
How many segments does Hantavirus have?
3
240
What are the 2 different manifestations of hantavirus?
Hemorrhagic fever w/ renal syndrome
Hantavirus pulmonary syndrome
241
What hantavirus type causes Hemorrhagic fever w/ renal syndrome
Old world Hantaviruses
242
What hantavirus type causes hantavirus pulmonary syndrome?
New World Hantaviruses
243
Where is hantavirus found in infected rodents?
urine and feces (rodents are not sick)
244
How is hantavirus transmitted?
aerosolized rodent excreta
245
How is Hantavirus pulmonary syndrome caused?
an inflammatory response against infected tissues
246
What is the structure of an arenavirus?
Enveloped, - helical segmented ssRNA
247
What is unique about arenaviruses?
they have TWO separate nucleocapsids surrounding the 2 segments of RNA
248
What are some diseases caused by arenaviruses?
Lymphocytic choriomeningitis virus and Hemorrhagic fevers
249
Where are arenaviruses shed?
urine and droppings of infected hosts
250
How are arenaviruses transmitted?
contact with excretions of infected rodents
| some person-person transmission
251
How does LCMV present?
aseptic meningitis, encephalitis, or meningioencephalitits
252
A transplacental LCMV infection is associated with what?
congenital hydrocephalus
Chorioretinitis
mental retardation
253
What is the primary host of LCMV?
Mus musculus (house mouse)
254
What disease does Lassa virus cause?
African Hemorrhagic fever (Lassa fever)
255
What disease does junin virus cause?
Argentine hemorrhagic fever
256
What disease does Machupo virus cause?
Bolivian hemorrhagic fever
257
What disease does Guanarito virus cause?
Venezuelan hemorrhagic fever
258
What disease does sabia cause?
Brazilian hemorrhagic fever
259
What groups are particularly at risk of death with arenavirus hemorrhagic fevers?
Fetuses with transplacental infections and women in the 3rd trimester
260
What are some symptoms of arenavirus hemorrhagic fever?
```
fever
hemorrhagic manifestations
hepatitis
shock
neurological manifestations
```
261
What is the last ditch effort against RNA viruses?
Ribavarin
262
What is the structure of a fillovirus?
Enveloped, - helical ssRNA
263
What are some examples of filoviruses?
Ebola, Marburg
264
What is the most likely reservoir of ebola?
fruit bats
265
Most likely source of zoonotic ebola infection
bushmeat
266
What are the first symptoms of filovirus infection?
sudden onset of flu-like symptoms
267
What cells are infected by filovirus infection?
lymphoid and endothelial cells
268
What causes death in a filovirus infection?
hypovolumic shock, multi-organ failure
269
What is the pathogenicity of RNA viruses associated with?
cross species jump
270
What is the most likely reason for virus spread?
increased, rapid, international travel
271
What is the structure of a flavivirus?
Enveloped, +icosahedral ssRNA
272
What family is Hep C a part of?
Flavivirus
273
What does HCV exist as?
A quasispecies
274
Where is antigenic variation predominnat in HCV
envelope glycoprotein E2
| enables escapes and persistant infection
275
What is the most common chronic blood-borne infection in the US?
HCV infection
276
Who is Hep C screening recommended for?
People born between 1945-1965
| History of IV drug use
277
How is HCV transmitted?
Percutaneous exposures to infectious blood sex(infrequent)
| Trans-placentally
278
What are some symptoms of an acute HCV infection?
fever, fatigue, dark urine, clay-colored stool, abdominal pain, loss of appetite, nausea, vomiting, joint pain, and jaundice
279
Where does the initial replication of HCV occur?
monocytes, B ant T cells
280
What is unique about HCV disease?
Infection is usually mild and anicteric, but results in a chronic carrier state in a majority of people
281
How long is IgG anti HCV found in an infected individual?
For life.
282
What is a host factor that may improve clearance of HCV?
IL-28B gene plymorphisms
283
Chronic HCV disease has what kind of disease progression?
Insidious
284
What are some complication of chronic HCV disease?
Cirrhosis
| Hepatocellular carcinoma
285
What is the leading cause of liver transplants in the US?
Chronic HCV Disease
286
HCV is mainly an ______-mediated dissease
Immune (cytokine storm)
287
What allows HCV to escape the immune system?
Viral mutations from its quasispecies nature
288
How does HCV target the immune response?
HCV core binds host's TNF receptor
289
Are Hep C antigens for in the blood?
NO. antibodies are
290
How is HCV diagnosed?
Anti- HCV using ELISA
HCV RNA using Nucleic Acid Test
291
What are some treatments for HCV?
protease inhibitors (telaprevir, boceprevir, simeprevir)
nucleotide inhibitors (sofosbuvir)
292
What are the 4 families of retroviruses?
```
LOSE:
Lentiviruses
Oncoviruese
Spumaviruses
Endogenous retroviruses
```
293
What are human endogenous retroviruses (HERVs)?
retrovirus sequences that have been integrated into the human genome
294
Do HERVs produce infectious particles?
No. but can encode some functional proteins
295
What is HERV-W?
functional envelope protein expressed in human placenta (syncytin protein); needed for creation and maintainence of syncytiotrophoblast
296
How do retroviruses work?
they beome part of the host DNA
297
What does reverse transcriptase do?
converts ssRNA into ssDNA, and then into dsDNA
allows for integration of viral genome into host DNA
298
What is the structure of a retrovirus?
Enveloped, + icosahedral with 2 IDENTICAL COPIES of ssRNA
299
What is unique about retroviruses?
They do not directly code for protein, they will be reverse transcribed into DNA
300
What is gag for in the retroviral genome?
encodes capsid, nucleocapsid, and matrix proteins
301
What is pol for in the retroviral genome?
encodes the reverse transcriptase, protease, and intergrase
302
What is env for in the retroviral genome?
encodes surface and transmembrance proteins
303
What is LTR for in the retroviral genome?
Long terminal repeats. These bind cellular and viral transcription factors
304
Where does reverse transcriptase do its job?
Cytoplasm
305
What incorporate the newly made viral dsDNA into the host DNA
LTRs and intergrase
306
What must occur for a mature infectious virus to occur?
cleavage of gag-pol precursors on budding immature particles
307
Is the new dsDNA linear or circular before it is integrated into the host genome?
circular
308
What is a provirus?
DNA copy with LTR integrated into the host
309
What is an example of a Spumavirus?
Human foamy virus
310
Is spumavirus considered pathogenic.
Nope.
311
What are oncoviruses?
retroviruses that can immortalize or transform cells
312
What important about oncoviruses in relation to cancer?
they may contain growth-regulating oncogenes that if overproduced or altered stimulat cell growth, causing tumors
313
What is the only human oncovirus?
HTLV
314
What can HTLV-1 cause?
Adult T cell leukemia and Tropical spastic paraparesis
315
Where is HTLV-1 endemic?
Southern japan and the carribean
316
How is HTLV-1 transmitted?
Sex
mother-to-infant (breastfeeding)
[requires cell-to-cell contact]
317
What is important about Tropical Spastic Paraparesis?
It is a non-neoplatic neurologic disorder
318
What does HTLV-1 contain?
tax, binds in LTR to promote viral replication
319
What are flower cells?
multi-lobulated lymphocytes that are seen in patients with ATLL
320
In what group is HTLV-II prevalent?
IV drug users
321
How are HTLV viruses diagnoses?
ELISA to find anitbodies against viral antigens
322
What is another name for Tropical Spastic Paraparesis?
HTLV associated myelopathy (HAM)
323
How is ATLL treated?
anti-cancer therapy
324
How is HAM treated?
anti-retrovirals
325
What genomic elements is found in all retroviruses?
tax
326
How do lentiviruses progress?
slowly
327
What do lentiviruses cause?
neurological disorders and immunosuppression
328
What are some examples of lentiviruses?
HIV-1 and HIV-2
329
What is unique about the HIV virion
it has a coffin-shaped capsid
330
Which of the 2 HIV viruses is less virulent?
HIV-2
331
What parts of HIV-1 and HIV-2 cross react? What parts don't?
Caspid antigens.
Envelope antigens.
332
Which HIV virus predominates in most of the world?
HIV-1
333
How do the products of gp160 precursor protein interact?
gp120 (globular head) associates with gp41 (stem)
334
How dogp120 and gp41 interact?
noncovalently
335
How many potential N-linked glycosylation sites are there?
30-38
336
How does HIV bind?
gp120 binds to CD4, inducing a conformational change
This changes allows gp120 to bind CCR5/CXCR5
gp41 can then initiate fusion
337
How asre TAT, REV, and NEF made?
splicing
338
What is tat?
protein that is a positive regulator of transcription
339
What is rev?
protein that regulated expression of viral mRNA for structural genes
340
What is nef?
protein needed for high levels of virus associated with disease progression; down regulates CD4 and MHC class I
341
What is required for HIV-1 replication in primary cells?
vif
342
How does vif function?
inhibits APOBEC-3G
343
What is VPR's function?
down regulating response that limit viral infection
344
In what HIV type is VPU found?
HIV-1
345
In what HIV type is VPX found?
HIV-2
346
How is HIV transmitted?
sexual contact
347
What does HIV target?
Cells with CCR5 or CXCR5
| CD4 T cells, macrophages, DCs, Langerhans cells
348
What viruses are preferentially transmitted by HIV?
viruses that use the CCR5 co-receptor
349
Is it possible to get an HIV infection without the co-receptor?
no.
350
When do anti-HIV antibodies appear?
3-8 weeks after infection
351
What does diagnosis of an acute HIV infection require?
Detection of the virus using RT-PCR
352
Are antibodies found during the window period?
No
353
If someone has a positive Rapid HIV antibody test, what is the next step?
ELISA/ Western blot
354
How can mother-infant transmission of HIV occur?
In utero, at birth, through breast feeding
355
Should HIV+ mothers breastfeed?
Nah
356
How is an infant diagnosed with HIV?
PCR for viral DNA
357
What are the stages of HIV infection?
```
Primary infection
Clinical Latency
Constitutional symptoms
Opportunistic infection
Death
```
358
What occurs during the HIV primary infection?
acute drop in T cell count
| increase in HIV RNA copies
359
What occurs during the HIV Clinical latency period?
No symptoms, increase in T cells keeps HIV in check
360
What occurs during the HIV constitutional symptoms?
drop in T cell count, onset of AIDS.
| Opportunistic infection can occur
361
What is the CD4 count in Stage I?
500 cells/mL
362
What is the CD4 count in Stage II?
200-499 cells/mL
363
What is the CD4 count in Stage III?
364
What is an early stage predictor of HIV?
viral load
365
What is a most important late stage predictor of HIV?
CD4 T cell count
366
What are elite controllers?
below 50 copies/mL
no progression/pathogenesis observed for a LONG time
367
What are long term non-progressors?
Have a very low viral load
Will have a longer latency period
368
What are progressors?
have a high viral load
much shorter latency period, quickly progress to AIDS
369
What is an AIDS defining illness?
A condition that, if present, means the patient has AIDS, no matter what their CD4 count is
370
What also HIV to escape the immune response?
antigenic drift and glycosylation of gp120
371
What is the purpose of anti-retroviral therapy?
To decrease the viral load and maintain the CD4 T cell count
