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2nd year - Microbiology > Semester 2 - Hepatitis Virus and Retroviruses > Flashcards

Semester 2 - Hepatitis Virus and Retroviruses Flashcards

(72 cards)

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1
Q

What are hepatitis viruses?

A

A group of viruses causing infection and inflammation of the liver (hepatotrophic virus). They have diversity of nucleic acid composition, structure, and families of origin

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2
Q

What are the human pathogens of hepatitis viruses?

A 
Hep A - Picornavirus (+ssRNA)
Hep B - Hepadnavirus (+dsDNA-RT)
Hep C - flavivirus (+ssRNA)
Hep D - deltavirus (-ssRNA)
Hep E - hepevirus (+ssRNA)
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3
Q

What are some characteristics of Hepatitis A

A

(+)ssRNA, nonenveloped picornavirus

Protein synthesis followed by proteolytic cleavage

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4
Q

What are the clinical features of Hep A?

A

Range from mild to severe
Sudden onset of fever, malaise, anorexia, abdominal discomfort
10% patients have recurrent illness for 6-9 months following infection

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5
Q

How is Hep A transmitted?

A

Contaminated food/water

Associated with travellers

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6
Q

How long is the incubation period of Hep A?

A

2-3 weeks

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7
Q

How is Hep A treated?

A

Treatment supportive
Vaccine preventable (inactivated) - combo A/B
Heat food/water to >85 Celsius for more than 1 minute or chlorinate

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8
Q

What are some characteristics of Hepatitis B?

A

Hepadnavirus
Class VII - dsDNA genome with an RNA intermediate
Encodes a reverse transcriptase enzyme

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9
Q

What are the clinical features of Hep B?

A

Mild fever, dark urine, nausea, anorexia
Vomiting, diarrhea, jaundice (hyperbilirubinemia)
Chronic infection may lead to cirrhosis and liver cancer

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10
Q

How is Hep B transmitted?

A

Blood products and bodily fluid

Sexual transmission

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11
Q

How long is the incubation period for Hep B?

A

Variable (weeks to months)

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12
Q

How is Hep B treated?

A

Nucleotide analogs, RT inhibitors, IFN

Vaccine-preventable (subunit) - combo vaccine

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13
Q

What are some characteristics of Hep C?

A

Non-A, non-B hepatitis
Flavivirus family (+ssRNA, envoloped)
Gene expression via single polyprotein translation followed by proteolytic cleavage

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14
Q

What is the leading cause of liver cancer and liver transplantation woldwide?

A

Hep C

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15
Q

What are the clinical features of Hep C?

A

Fever, fatigue, nausea, vomiting
Dark urine, grey coloured feces, jaundice
Chronic infection leads to liver pathology (failure, cancer)

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16
Q

How long is the incubation period of Hep C?

A

2-6 months

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17
Q

How is Hep C transmitted?

A

Infected blood products

Sexual transmission

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18
Q

How is Hep C treated?

A

IFN and ribavarin

There is no vaccination against HCV

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19
Q

What are characteristics of Hep D?

A

Deltavirus, requires HBV to replicate viral genome
(-)ssRNA, enveloped
It is NOT a virus. Satellite virus, virusoid, subviral particle

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20
Q

What is a viroid?

A

A subviral pathogen in plants (no proteins expressed)

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21
Q

What is a virusoid?

A

Expresses viral protein (HDV)

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22
Q

What is a satellite virus?

A

Requires another virus for its own replication

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23
Q

What is the nuclear antigen often associated with?

A

HBV patients with severe liver disease

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24
Q

What is the life cycle of Hep D?

A

Only infects cells that are also infected with HBV: coinfection occurs simultaneously, superinfection occurs following a primary infection
Replication occurs in the nucleus? - uses cellular RNA polyperases I, II and III, utilizes HBV polymerase enzymes

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25
What are the clinical features of a Hep D infection?
Associated with increased severity of HBV disease. Treatment/prophylaxis is to treat/prevent HBV infection
26
What are some characteristics of Hep E?
(+)ssRNA, non-enveloped | Enteric
27
How is Hep E trasmitted?
``` Fecal-oral - contaminated water, pork/deer meat) Blood products (rare) ```
28
What are the clinical features of a Hep E infection?
Fever, fatigue, nausea, anorexia, abdominal pain, joint pain, jaundice, dark coloured urine Generally self-limiting Pregnant women - mortality rate high during 3rd trimester Risk of fulminant hepatitis
29
What is the incubation period of Hep E?
3-8 weeks
30
What is the treatment for Hep E?
Supportive | No vaccine currently approved in North America
31
What are some nutritional factors regarding liver health?
Alcohol | Medications
32
What are predisposing conditions regarding liver health?
Obesity Diabetes Toxin exposure
33
What are some characteristics of retroviruses?
Class VI Baltimore ssRNA-RT Diploid genome Characteristic Gag, Pol, Env genes
34
What is a Gag gene?
Structural
35
What is a Pol gene?
Enzymatic (RT, integrase, protease)
36
What is an Env gene?
Envelope glycoproteins
37
What are human pathogens of retroviruses?
``` Human T cell leukemia virus (HTLV-1) HTLV-2 Human immunodeficiency virus (HIV) (HTLV-3) HIV2 = HTLV-4 HTLV-5 Human endogenous retrovirus (HERV) ```
38
Who discovered HIV?
Luc Montangier and Robert Gallo Patient 0 - 1981 Lentivirus family (Lenti=slow)
39
Where does HIV infect?
CD4 cells (T-cells, macrophages)
40
What are the clinical features of an acute HIV infection?
Patients may experience generalized symptoms - fever, myalgia, lymphadenopathy Generally undiagnosed at this stage
41
What are the clinical features of a chronic HIV infection?
Immune compromise, decreasing CD4+ count, increasing opportunistic infection
42
What characterizes AIDS?
WBC count below 200 c/ul blood, AIDS-defning illness (Kaposi's sarcoma, candidiasis, pneumocystis pneumonia)
43
How many stages of infection of HIV are there?
``` 4 Organization dependent (WHO, CDC etc) ```
44
What is stage 1 of HIV infection?
Persistent generalized lymphadeonopathy
45
What is stage 2 of HIV infection?
mild clinical symptoms, CD4+ <500c/ul
46
What is stage 3 of HIV infection?
ARC | Advanced symptoms, CD4+ <350c/ul
47
What is stage 4 of HIV infection?
``` AIDS Opportunistic infection (AID-defining illness), CD4+ <200c/ul ```
48
What is HIV encephalopathy?
AIDS dementia complex One of the few diseases associated directly with HIV infection Infection of macrophages and microglia, release of neurotoxins
49
What are complications of HIV CNS invasion?
Dementia - loss of normal functioning, require assistance for day to day tasks Progressive - one of the first signs of progression from HIV to AIDS
50
What is the treatment for HIV encephalitis?
Antiretroviral therapy slows development/progression of AIDS dementia complex in HIV (+) individuals
51
How is HIV diagnosed?
Serology 6-12 weeks post-exposure
52
How is HIV transmitted?
Sexual transmission mother-to-child transmission (gestation, delivery, or breastmilk) Needle-sharing, blood transfusion
53
What is the treatment/prevention of HIV?
HAART therapy Antiviral therapy includes RT inhibitors, nucleotide analogs, protease inhibitors Post-exposure prophylaxis - health care workers etc Pre-exposure prophylactic antivirals emerging (daily) Prevention and education!!
54
How is an HIV infection initiated?
Viral ligand gp120 Coreceptor gp41 Cellular receptor CD4 (t-cells, macrophages, DCs) Cellular co-receptors CXCR4 (Tcells), CCR5 (macrophages) DC-sign cellular receptor on DCs
55
What does X4-tropic HIV infect?
T-cells
56
What does R5-tropic HIV infect?
Macrophages
57
What is transmigration?
Intraepithelial dendritic cells bind HIV using DC-Sign HIV is internalized into early endosomes Dendritic cells that have migrated to lymph nodes transfer HIV to CD4 T cells
58
What is transcytosis
?? Good question
59
What factors are associated with virulence?
Mutation Immune cell attack Chronicity and mildness of symptoms Accessibility to treatment, prevention, and education
60
Are there vaccines for HIV?
No, but in development
61
What are elite controllers?
long-term non-progressors | Aka patients who are positive for HIV but don't progress to AIDS
62
What are ND approaches to antivirals/antimicrobials?
Astragalus, goldenseal, licorice root, garlic | St. John's Wort (inactivates p24?)
63
What is nutritional support for HIV patients?
Whole food diet, avoid processed foods and refined carbs | Vit A, B, C, E, K, folic acid, biotin, Mg, Mn, omega 3
64
What are immune boosting herbs?
Garlic Ginseng Echinacea
65
What are some other alternative therapies to consider with HIV?
Acupuncture Oxygen therapy Mind/body therapy
66
Where is HTLV-1 endemic to?
Carribean, Africa, Southern Japan
67
Where does HTLV-1 infect?
Spinal cord leading to myelopathy and spreads to peripheral nerves
68
What is HAM/TSP?
HTLV-associated myelopathy/tropical spastic paraperesis | Acute infection is asymptomatic, symptoms may appear following infection
69
What are the clinical features of HAM/TSP?
Muscle weakness, loss of sensation, pins and needles Spastic paraparesis or paraplegia Other neurological symptoms may be present - loss of hearing, loss of vision, tremor
70
What are the clinical features of a chronic HAM/TSP infection?
Associated with adult T-cell leukemia
71
What are some characteristics of HTLV-2?
70% homology to HTLV-1 | Associated with HAM/TSP
72
What are some characteristics of human endogenous retroviruses?
``` HERVs Make up 8-10% of the human genome Evolutionarily conserved - function? May play a role in anti-retroviral immunity Autoimmune diseases (multiple sclerosis) ```

2nd year - Microbiology (21 decks)

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