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

Semester 2 - Hepatitis Virus and Retroviruses Flashcards

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
Q

What are the clinical features of a Hep D infection?

A

Associated with increased severity of HBV disease. Treatment/prophylaxis is to treat/prevent HBV infection

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26
Q

What are some characteristics of Hep E?

A

(+)ssRNA, non-enveloped

Enteric

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27
Q

How is Hep E trasmitted?

A 
Fecal-oral - contaminated water, pork/deer meat)
Blood products (rare)
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28
Q

What are the clinical features of a Hep E infection?

A

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

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29
Q

What is the incubation period of Hep E?

A

3-8 weeks

30
Q

What is the treatment for Hep E?

A

Supportive

No vaccine currently approved in North America

31
Q

What are some nutritional factors regarding liver health?

A

Alcohol

Medications

32
Q

What are predisposing conditions regarding liver health?

A

Obesity
Diabetes
Toxin exposure

33
Q

What are some characteristics of retroviruses?

A

Class VI Baltimore ssRNA-RT
Diploid genome
Characteristic Gag, Pol, Env genes

34
Q

What is a Gag gene?

A

Structural

35
Q

What is a Pol gene?

A

Enzymatic (RT, integrase, protease)

36
Q

What is an Env gene?

A

Envelope glycoproteins

37
Q

What are human pathogens of retroviruses?

A 
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
Q

Who discovered HIV?

A

Luc Montangier and Robert Gallo
Patient 0 - 1981
Lentivirus family (Lenti=slow)

39
Q

Where does HIV infect?

A

CD4 cells (T-cells, macrophages)

40
Q

What are the clinical features of an acute HIV infection?

A

Patients may experience generalized symptoms - fever, myalgia, lymphadenopathy
Generally undiagnosed at this stage

41
Q

What are the clinical features of a chronic HIV infection?

A

Immune compromise, decreasing CD4+ count, increasing opportunistic infection

42
Q

What characterizes AIDS?

A

WBC count below 200 c/ul blood, AIDS-defning illness (Kaposi’s sarcoma, candidiasis, pneumocystis pneumonia)

43
Q

How many stages of infection of HIV are there?

A 
4
Organization dependent (WHO, CDC etc)
44
Q

What is stage 1 of HIV infection?

A

Persistent generalized lymphadeonopathy

45
Q

What is stage 2 of HIV infection?

A

mild clinical symptoms, CD4+ <500c/ul

46
Q

What is stage 3 of HIV infection?

A

ARC

Advanced symptoms, CD4+ <350c/ul

47
Q

What is stage 4 of HIV infection?

A 
AIDS
Opportunistic infection (AID-defining illness), CD4+ <200c/ul
48
Q

What is HIV encephalopathy?

A

AIDS dementia complex
One of the few diseases associated directly with HIV infection
Infection of macrophages and microglia, release of neurotoxins

49
Q

What are complications of HIV CNS invasion?

A

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
Q

What is the treatment for HIV encephalitis?

A

Antiretroviral therapy slows development/progression of AIDS dementia complex in HIV (+) individuals

51
Q

How is HIV diagnosed?

A

Serology 6-12 weeks post-exposure

52
Q

How is HIV transmitted?

A

Sexual transmission
mother-to-child transmission (gestation, delivery, or breastmilk)
Needle-sharing, blood transfusion

53
Q

What is the treatment/prevention of HIV?

A

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
Q

How is an HIV infection initiated?

A

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
Q

What does X4-tropic HIV infect?

A

T-cells

56
Q

What does R5-tropic HIV infect?

A

Macrophages

57
Q

What is transmigration?

A

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
Q

What is transcytosis

A

?? Good question

59
Q

What factors are associated with virulence?

A

Mutation
Immune cell attack
Chronicity and mildness of symptoms
Accessibility to treatment, prevention, and education

60
Q

Are there vaccines for HIV?

A

No, but in development

61
Q

What are elite controllers?

A

long-term non-progressors

Aka patients who are positive for HIV but don’t progress to AIDS

62
Q

What are ND approaches to antivirals/antimicrobials?

A

Astragalus, goldenseal, licorice root, garlic

St. John’s Wort (inactivates p24?)

63
Q

What is nutritional support for HIV patients?

A

Whole food diet, avoid processed foods and refined carbs

Vit A, B, C, E, K, folic acid, biotin, Mg, Mn, omega 3

64
Q

What are immune boosting herbs?

A

Garlic
Ginseng
Echinacea

65
Q

What are some other alternative therapies to consider with HIV?

A

Acupuncture
Oxygen therapy
Mind/body therapy

66
Q

Where is HTLV-1 endemic to?

A

Carribean, Africa, Southern Japan

67
Q

Where does HTLV-1 infect?

A

Spinal cord leading to myelopathy and spreads to peripheral nerves

68
Q

What is HAM/TSP?

A

HTLV-associated myelopathy/tropical spastic paraperesis

Acute infection is asymptomatic, symptoms may appear following infection

69
Q

What are the clinical features of HAM/TSP?

A

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
Q

What are the clinical features of a chronic HAM/TSP infection?

A

Associated with adult T-cell leukemia

71
Q

What are some characteristics of HTLV-2?

A

70% homology to HTLV-1

Associated with HAM/TSP

72
Q

What are some characteristics of human endogenous retroviruses?

A 
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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