Brainscape's Knowledge GenomeTM


Top Flashcards (Certified)
All Flashcards

3. Mondays > 302 How viruses cause disease > Flashcards

302 How viruses cause disease Flashcards

1
Q

How many people were living with HIV in 2021?

A

38.4 million

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What type of virus is HIV?

A

A retrovirus

Family: Retrovirdae
Subfamily: Orthoretroirnae
Genus: Lentivirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the zoonic origin of HIV-1?

A

Chimpanzees and gorillas

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the zoonic origin of HIV-2?

A

Sooty mangabeys (a monkey)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What are SIV’s?

A

Simian immunodeficiency viruses

They naturally infect a wide range of African nonhuman primates and are the souse of HIV-1 and HIV-2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the 4 genetically distinct groups HIV-1 is subdivided into?

A

M, N, O, and P

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the 9 distinct groups that HIV-2 is subdivided into?

A

A-I

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What is the global distribution of HIV subtypes?

A

M has a global distribution

N, O, and P and HIV-2 are confined to West central Africa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the 9 distinct genotypes of HIV-1 group M?

A

A-D, F-H , J, K

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the different sub-subtypes of HIV-1 group M?

A

A1-A4, F1, F2

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What are CRF’s?

A

Circulating recombinant forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What are URF’s?

A

Unique recombinant forms

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

How do CRF’s and URF’s form?

A

Through recombination of different subtypes

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

Which area in the world has the highest HIV-1 genetic diversity?

A

Central Africa

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

Describe the structure of the HIV-1 virus

A

100nm in diameter
gp120 and gp41 membrane proteins

Has an envelope (outer membrane), matrix, viral capsid, 2 identical molecules of ssRNA, RT, and IN

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

What is RT in viruses?

A

Reverse transcriptase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

What is IN in viruses?

A

Integrase

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

What is integrase in viruses?

A

It’s the viral enzyme that catalyses the integration of virally derived DNA into the host cell DNA in the nucleus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

Describe the HIV life cycle

A
  1. Attachment and fusion into the host cell and uncoating once inside the host cell
  2. Reverse transcription
  3. Integration
  4. Transcription
  5. Translation into proteins that assemble into a virus
  6. Budding and maturation of the virus
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

At which part of the HIV life cycle do attachment inhibitors work on?

A

On the attachment part

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

At which part of the HIV life cycle do fusion inhibitors work on?

A

The fusion and uncoating part

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

What is the risk of transmission of HIV through different methods?

A

Blood transfusion 90%
Mother to child 23%
Drug injection equipment 0.63%
Percutaneous needle stick injections 1.4%
Insertive anal intercourse 011%
Receptive penile-vaginal intercourse 0.08%
Insertive penile-vaginal intercourse 0.04%

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

What are risks that increase HIV transmission?

A

-Other STI’s because there a higher number of target cells
-High viral load

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Why can’t antiretroviral treatment (ART) eliminate infection?

A

Because it can’t eliminate the integrated viral DNA from infected cells

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
What role does the adaptive immune system play in the initial host response of HIV infection?
HIV declines after acute infection because of HIV-specific CD8+ cytotoxic T-cells Overtime, they fail to durably control the virus because HIV is able to create cytotoxic T-lymphocyte (CTL) escape mutants
26
What does CTL stand for?
Cytotoxic T-lymphocyte
27
How does HIV evade the immune response?
-Increasing glycosylation of envelope as a shielding mechanism -Evasion from cellular restriction factors (APOBEC3) -Generating cytotoxic T-lymphocyte escape mutants
28
What is pathogenesis of HIV?
-Slow depletion of circulating tissue-based CD4+ T-cells -Cause a constant state of immune-activation, activation of the endothelium and of the coagulation system -Profound alteration of lymphoid tissues -Increases plasmatic circulation of polysaccharides -Causes a proinflammatory state
29
What is the effect of slow depletion of circulating tissue-based CD4+ T-cells?
They're essential for regulating the immune response, depletion leads to immunosuppression with development of opportunistic infections and AIDS-related malignancies
30
What are AIDS-related malignancies?
Cancers that are more likely to develop with a HIV infection Eg. Kaposi sarcoma, non-Hodgkin lymphoma, cervical cancer, Hodgkin lymphoma, and cancers of the mouth, throat, liver, lung, and anus
31
What is the effect of a constant state of immune-activation, activation of the endothelium and of the coagulation system?
-There are increased proinflammatory cytokines - Low CD4/CD8 ratio -Exhaustion and senescence of T-cells and monotypes
32
What is the effect of alteration of lymphoid tissues by HIV infection?
It causes an increase in microbial translocation due to the disruption of the physiological gut barrier
33
What is the effect of Increased plasmatic circulation of polysaccharides?
It's a component of the bacterial cell wall It enhances persistent immune activation
34
What is the effect of a constant proinflammatory state on the body?
-Premature ageing observed in people living with HIV -Multiorgan disease: Premature onset of atherosclerosis and MI Neurocognitive decline Liver disease (non-fatty liver disease) Metabolic syndrome Osteoporosis Onset non-AIDS related cancers Overall increased mortality
35
What is the pathogenesis of HIV in other sites beyond the immune system?
-In the CNS, the virus can affect astrocytes via a CD4-independent mechanism -HIV can infect renal epithelial cells in the kidneys These mechanisms are the basis of the onset of HIV-associated neurocognitive disorder (HAND) and HIV-associated nephropathy (HIVAN)
36
What % of patients develop symptoms of HIV?
50-90% They're easy to miss, transient symptoms that overlap with common infections Characterised by high viral load High inflammatory response causes systemic symptoms
37
What are some viral differential diagnoses of primary HIV infection?
Epstein-Barr virus Cytomegalovirus Primary herpes simplex virus Influenza Early-stage hepatitis Parvovirus B19 Rubella
38
What is Epstein-Barr virus?
EBV can cause infectious mononucleosis (mono)
39
What is Parvovirus B19?
Most commonly causes fifth disease, a mild rash illness that usually affects children
40
What is Rubella?
AKA German measles It's a rare illness that causes a spotty rash
41
What are some bacterial differential diagnoses of HIV infection?
Streptococcal disease Secondary syphilis Lyme disease Rickettsial disease Disseminated gonococcal infection
42
What is Lyme disease?
A bacterial infection that can be spread to humans by infected ticks Rarely deadly, easily treated if diagnosed early
43
What is Rickettsial disease?
A group of bacteria that spread by the bite of an infected tick or mite Symptoms: Fever. Headache. Rash (sparse maculopapular or papulovesicular eruptions on the trunk and extremities) Muscle aches
44
What is a disseminated gonococcal infection?
AKA DGI It occurs when the sexually transmitted pathogen Neisseria gonorrhoeae invades the bloodstream and spreads to distant sites in the body
45
What are some parasitic differential diagnoses of HIV infection?
Acute toxoplasmosis
46
What is acute toxoplasmosis?
An infection with a parasite called Toxoplasma gondii People often get the infection from eating undercooked meat, having contact with cat faeces, or it can be passed to a baby during pregnancy Most people infected with the parasite do not have symptoms
47
What are some non-infectious differential diagnoses of HIV infection?
Adult Still disease Systemic lupus erythematosus Systemic vasculitis Drug reaction
48
What is Adult Still disease?
A rare type of inflammatory arthritis that features fevers, rash and joint pain
49
What is Systemic lupus erythematosus?
A chronic autoimmune disease that can cause severe fatigue and joint pain
50
What are the Fiebig stages of HIV infection?
-Eclipse: No plasmatic markers because initial replication of virus happens at the inoculation site -1 (5 days): HIV RNA becomes detectable in plasma -2 (10days): Positive p24 antigen (Ag) in plasma -3 (14 days): seroconversion (anti-HIV antibodies present) -4 (19 days): Indeterminate Western blot -5 (88 days): Reactive Western blot for p31 Ag -6 (88+ days): Reactive Western blot with positive p31 Ag
51
What is seroconversion?
When the body starts producing detectable levels of HIV antibodies
52
What is the Indeterminate Western blot in HIV?
Banding pattern on a Western blot test that failed to meet the criteria for positivity
53
What is the purpose of the Fiebig stages?
They describe the emergence of virologic and immunologic markers following infection with HIV
54
What is the definition of the AIDS stage in HIV infection?
CD4 count <200 cells/mm3 (advanced HIV infection) Onset of opportunistic infections and malignancies
55
What are some AIDS stage opportunistic infections?
-Recurrent bacterial infections usually only found among <6 years olds -Candiditis of bronchi, trachea, or lungs -Cryptococcosis (extrapulmonary) -Cytomegalovirus disease -Herpes simples (chronic ulcers >months duration, or bronchitis, pneumonitis, or oesophagitis) -Salmonella septicaemia -Toxoplasmosis of the brain -Recurrent pneumonia
56
What is a cytopathic effect of viruses?
Morphological changes of the cells caused by the infecting virus
57
Give examples of cytopathic effects of viruses
-Inhibition of cell transcription/translation -Changes in membrane permeability -Alterations of the cytoskeleton or trafficking pathways -Cell-cell fusion -Induction of apoptosis
58
What is the cytopathic effect of Venezuelan equine encephalitis virus (VEE)?
It causes a direct cytopathic effect on neurones
59
What are immune complexes?
Aggregates of viruses and antibodies that form within small blood vessels and lead to the development of inflammation (vasculitis)
60
What diseases are immune complexes responsible for?
Glomerulonephritis
61
How doe viruses promote the onset of cancer?
-Immunosuppression (Eg. HIV and Kaposi's sarcoma) -Chronic inflammation (HCV and HCC) -Cellular transformation (HPV and cervical cancer)
62
What is Kaposi's sarcoma?
A cancer caused by viral infection that affects the mouth and skin First appears as purple, red, or brown lesions on the skin

3. Mondays (126 decks)

Brainscape helps you reach your goals faster, through stronger study habits.
© 2025 Bold Learning Solutions. Terms and Conditions