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PBD II > Viruses I - RNA and V. Hepatitis - KMS > Flashcards

Viruses I - RNA and V. Hepatitis - KMS Flashcards

1
Q

What mechanism do viruses have for energy production?

A

They don’t.

As obligate intracellular parasites, they pirate the resources of the host.

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2
Q

Will a single stranded, positive sense RNA virus need special viral proteins in order to infect the host cell once it gains entry? What viral enzyme must it synthesize to proliferate?

A

+RNA = positive reading frame

Viral genome in this case is much like host cell mRNA, and can start hijacking host transcription machinery immediately.

+RNA viruses must make an RNA-dependent RNA polymerase enzyme in order to make new copies of their genome and proliferate

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3
Q

Will a negative sense single stranded RNA virus need to have special viral enzymes in the viral particle in order to infect the host cell once it gains entry?

A

(-) RNA virus will need to be packaged with a viral RNA dependent RNA polymerase in order to make copies of its genome with the right reading frame - positive sense RNA copies. Once these copies are made, they can be fed into the host cell’s transcription machinery.

(Enzyme must be packaged into the virus, virus cannot establish infection or replicate until it makes RNA that can work with the host cell machinery.

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4
Q

Retroviruses have what kind of genetic material in the viral particle? What enzymes does this type need in order to infect a cell?

A

(diploid) positive sense RNA

Retroviruses will need to have reverse transcriptase enzyme packaged in the viral particle in order to make a DNA copy of its genome

Virus will also need integrase enzyme in order to insert the DNA copy of its genome into the host cell DNA

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5
Q

What viral families are non-enveloped? Which are enveloped?

A

Non-enveloped:

Picornaviruses

Caliciviruses

Reoviruses

Papovaviruses

Adenoviruses

Parvoviruses

Enveloped: everything else

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6
Q

What 4 viruses are associated with illness in the respiratory system?

A

Adenovirus

Rhinovirus

Influenze viruses A, B

Resp. Synctial Virus (RSV)

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7
Q

What 8 viruses are associated with infections of the digestive system?

A

Mumps virus

Rotavirus

Norovirus/Norwalk

Hepatitis A, B, C, D, and E

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8
Q

What 5 viruses are associated with systemic infections with skin eruptions?

A

Measles virus

Rubella virus

Varicella-Zoster virus (VZV)

Herpes Simplex virus 1 (HSV1)

Herpes Simplex virus 2 (HSV2)

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9
Q

What 3 viruses are associated with systemic infection with hematopoietic disorders?

A

Cytomegalovirus (CMV)

Epstein-Barre Virus (EBV)

HIV-1 and HIV-2

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10
Q

The Orthomyxovirus family causes what disease?

A

Influenza

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11
Q

Orthomyxoviruses have what kind of genetic material? Are they enveloped?

A
  • ssRNA, enveloped

(will be packaged with a viral RNA-dependent RNA polymerase)

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12
Q

What determines the viral types of the Influenza genus?

A

Nucleoprotein antigen determines virus type A, B or C

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13
Q

What Influenza viral type can cause the most severe disease? Least severe?

A

A is most severe

B is middling

C is least severe

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14
Q

What Influenza viral type has an animal reservoir?

A

Type A

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15
Q

What are 2 important markers on the Influenza envelope? Why are these important?

A

2 surface glycoproteins:

(H) - hemagglutinin - mediates attachment to respiratory mucosa and RBCs

(N) - neuraminidase - mucus liquifaction leading to local viral spread

Changes in surface antigens/glycoproteins produce new strains of Influenza, and can lead to pandemics

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16
Q

What is the difference between antigenic drift versus antigenic shift in the case of Influenza?

A

Antigenic drift - mutations in RNA leading to minor changes in the antigenic character of H and N surface glycoproteins

  • cause of yearly epidemics

Antigenic shift - rearrangement of genome segments leading to major changes in the antigenic character of the H and N molecules

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17
Q

What are some major flu pandemics that have happened? What were the surface glycoprotein variants, and year of outbreak?

(This card might not be high yield, more of a CYA)

A

1957 Asian flu H2N2

1968 Hong Kong flu H3N2

1977 Russian flu H1N1

2009 Swine flu H1N1

Next pandemic? Avian flu - 1997 H5N1 or H7N9

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18
Q

How do you diagnose an influenza infection?

A

Classic flu Sx in winters, current epidemiology

Also: serology, PCR, culture

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19
Q

What is the treatment for the flu?

A

Mostly supportive

Rx: Neuraminidase inhibitors

  • oseltamivir - Tamiflu
  • zananivir - Relenza
  • IV peramivir - Rapivab
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20
Q

What could happen when aspirin is given to people/children <19 years with acute febrile illness?

A

Reye’s syndrome

  • Aspirin or salicylates given to person
  • Results in fatty liver and cerebral edema; can cause permanent brain/organ damage, liver problems, death
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21
Q

How are flu epidemics and pandemics prevented?

A

Yearly inactivated vaccines, generally given in the fall

Based on an epidemiological ‘forecast’ of the flu strains likely to be troublemakers in the flu season ahead

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22
Q

The flu is generally a mild and self-limiting disease. Why is it so problematic for immunocompromised people?

A

Infection can potentially compromise host further

  • paves way for secondary infections, bacterial superinfections that could be much worse
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23
Q

What kind of genetic material does the Paramyxovirus family have? Envelope?

A

-ssRNA

enveloped

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24
Q

What 5 clinically important viruses are included in the family Paramyxovirus?

A

Parainfluenza

Mumps

Measles

Respiratory Synctial Virus (RSV)

Human metapneumovirus

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25
Q

What strange histological finding should you associate with the Paramyxovirus family?

A

Syncytia!

Produce multinucleated giant cells (syncytia) via a cell fusing factor

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26
Q

What is the point of the fusion protein for the Paramyxovirus family?

A

Fuses virus envelope to cell membrane

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27
Q

What surface glycoprotein is present in the Paramyxovirus family?

A

single surface HN glycoprotein with both hemagglutinin and neuraminidase activity

  • this protein is lacking in metapneumovirus though
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28
Q

What pathology does human metapneumovirus cause?

A

Common cold, bronchiolitis and pneumonia in children and adults

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29
Q

How is an infection of human metapneumovirus dx’ed? How is it treated?

A

PCR - definitive

Also consider clinical presentation, obviously.

Treatment consists of supportive care.

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30
Q

What is the genetic makeup of parainfluenza viruses? Is it enveloped? How many serotypes?

A

-ssRNA, enveloped

4 serotypes, 1 and 2 are more severe

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31
Q

What tissues do parainfluenza viruses invade?

A

Local infection of ciliated respiratory epithelium

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32
Q

How widespread/common is infection from parainfluenza viruses?

A

Pretty common - cause of 30-40% of acute respiratory infection in infants and children

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33
Q

What are the symptoms of parainfluenza infection?

A

Mild cold-like to life-threatening (croup, bronchiolitis, pneumonia)

Most common cause of croup laryngotracheobronchitis (barking cough, steeple sign)

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34
Q

A young child presents with a recent Hx of febrile illness and a loud, barking cough like a seal. What do you suspect is causing the infection? What do you expect to see on a CXR?

A

seal bark cough = laryngotracheobronchitis = parainfluenza infection

Steeple sign on CXR - swelling and possible obstruction of airway in laryngotracheal region

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35
Q

What is the transmission of parainfluenza virus?

A

Droplet

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36
Q

How do you Dx and treat a suspected parainfluenza infection?

A

Dx - symptoms, then isolation of virus or serology

Rx - supportive care, isolation (keep kid home from day care or school)

contagious for 3-16 days

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37
Q

What is the genetic makeup of respiratory synctial virus (RSV)? Is it enveloped?

A

-ssRNA, enveloped

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38
Q

What tissues does RSV infect?

A

Local infection in ciliated epithelia (upper or lower respiratory tract), nose, eye and mouth

  • can proceed into bronchioles, as per Dr. Gomez
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39
Q

What types of illness does RSV cause?

A

•Major cause of bronchiolitis and pneumonia in infants (#1 cause in age < 6 months)

Severe disease may present as bronchiolitis, pneumonia or croup

Reinfection in adults usually involves the upper respiratory tract (common cold

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40
Q

How common is infection and reinfection with RSV? How does it affect adults versus children/babies?

A

Extremely common, reinfection common

Worldwide, winter epidemics yearly

Reinfection in adults usually involves the upper respiratory tract (common cold)

Major cause of bronchiolitis and pneumonia in infants (#1 cause in age < 6 months)
Severe disease may present as bronchiolitis, pneumonia or croup

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41
Q

How do you Dx an RSV infection?

A

Strongly suspect in infants with lower respiratory tract infection.
Contagious about 4-5 days after the symptoms, so consider keeping children away from other children

Adults - usually presents as a cold

42
Q

How do you care for an RSV infection?

A

•Rx - Supportive care and isolation

For sick infants consider Palivizumab - monoclonal antibody against F-protein

(Used in the prevention of RSV infections - F-protein is the factor that Paramyxovirus family viruses use to fuse virus envelope with host cell membrane. Could also slow spread of virus in vulnerable patients.)

43
Q

What is the genetic makeup of the Mumps virus? Is it enveloped?

A

-ssRNA, enveloped

44
Q

How is the Mumps virus spread?

A

Enters from salivary secretions (intimate contact) via the pharynx or conjunctiva

45
Q

What tissues does the Mumps virus infect?

A

viremia targeting:

glandular (salivary glands, testes, ovaries, pancreas)

nerve tissue (causing aseptic meningitis and encephalitis)

46
Q

An active Mumps infection will target glandular and nerve tissue. What sequelae can develop?

A

Asymptomatic in about 35%

Glands:
Painful enlargement of the salivary glands
Pancreatitis
Epididymoorchitis in males, which can cause sterility

Nerve:
Can produce transient high frequency deafness

47
Q

What is the epidemiology of the Mumps virus? (How widespread, hosts, reservoirs, etc.)

A
  • Found worldwide
  • Epidemics every 2-7 years
  • Humans only host

Generally more rare in countries with high vaccination rates - usually prevented by MMR

  • babies can receive passive immunization from mom- IgA passed in breast milk, in utero, etc.
  • children will usually only get mild form if vaccinated, as per Dr. Gomez
48
Q

How do you Dx a Mumps infection? When is it contagious?

A

Does your patient resemble a bull frog?

  • Dx- Classic clinical symptoms
  • Disease is contagious just before and after the symptoms
  • Incubation period is 18-21 days
  • Serology, viral cultures and PCR also available
49
Q

What is the treatment for a Mumps infection? How long is the patient contagious?

A

•Rx –Supportive care and isolation

  • Disease is contagious just before and after the symptoms
  • Incubation period is 18-21 days
50
Q

How is infection with the mumps virus prevented?

A

•Prevention - Immunize with MMR live vaccine at 12-15 months and 4-6 years

Physicians can enhance immunity conferred from vaccine and reduce feelings of burnout by punching Andrew Wakefield and/or Jenny McCarthy in the face.

51
Q

What is the genetic makeup of the measles virus? Is it enveloped?

A

-ssRNA, enveloped

52
Q

What tissues does the measles virus infect?

A

•Enters oropharynx from human secretions

  • followed by viremia to:

skin

mucosae

CNS

lymphatic &

respiratory systems

53
Q

What symptoms, from mild to horrifying, can present when someone has a measles virus infection?

A
  • Koplik spots of mouth precede T-cell mediated rash
  • Usually have fever, maculopapular rash, +/- conjunctivitis that can lead to blindness, and sometimes pneumonia
  • Inclusion body encephalitis and/or with chronic infection

subacute sclerosing panencephalitis (SSPE)

54
Q

What is the epidemiology of the measles virus?

A

Extremely contagious!

Epidemics every 2-4 years in unvaccinated population of developed countries (93.3% vaccinated = herd immunity)
•Limited to humans and monkeys

•#1 cause of vaccine preventable deaths and illnesses

55
Q

How is a Dx of measles virus infection made? What histological findings should you expect?

A

Dx -Typical clinical symptoms
Measles-specific IgM or viral RNA by PCR

multinucleated measles giant cells (Warthin-Finkeldey cells) with cytoplasmic and nuclear viral inclusions

56
Q

How is a measles infection treated?

A
  • Rx – Supportive, intramuscular immunoglobulin and isolation
  • Contagious up to 4 days post rash
57
Q

You are a physician and are lucky enough to practice in an area with high compliance to vaccination schedules. What threshold is needed for ‘herd immunity’ to measles virus? Should measles virus still be on your ‘radar’ as a source of morbidity and mortality for your patients?

A

herd immunity to measles - need 93.3% of pop. vaccinated (Colorado vaccination rate = 86%)

Individual cases of measles can still pop up, even in well-vaccinated populations

58
Q

How is measles infection prevented?

A
  • Immunize MMR live vaccine at 12-15 months and 4-6 years
59
Q

What is the genomic makeup of hepatitis A? Is it enveloped? Classification?

A

+ssRNA, naked

Picornaviridae

60
Q

What is the clinical presentation of a hepatitis A infection?

A

•Subclinical to fulminant hepatitis with rare chronic state in immunocompromised

61
Q

What is the mode of transmission for hepatitis A?

A

Fecal oral route

62
Q

How is a Dx made of a hepatitis A infection?

A

•Dx: Clinical presentation and or serology

63
Q

What relevant serology findings should you expect for a hepatitis A infection?

A

Vaccinated person: +/- for anti-HAV IgG

Previous hepatitis A infection: + for anti-HAV IgG

Acute hepatitis A infection: + for anti-HAV IgM

64
Q

How is hepatitis A infection prevented?

A

Hepatitis A vaccine - 2 doses

hygeine

65
Q

What is the genomic makeup of hepatitis B? Is it enveloped? Classification?

A

dsDNA, enveloped

Hepadnaviridae

66
Q

What is the clinical presentation of a hepatitis B infection?

A
  • 1.Chronic persistent: Generally asymptomatic with a mild elevation of ALT
  • 2.Chronic active: Jaundice, elevated liver enzymes, cirrhosis, +/- hepatocellular carcinoma
67
Q

What is the mode of transmission for hepatitis B?

A

Parenteral, STI (Sexually Transmitted Infection)

68
Q

What is the incubation period for hepatitis B?

A

60-180 days

69
Q

What kind of virus is hepatitis B?

A

Hepatitis B = Dane particle - Oncogenic transforming virus

70
Q

How is a hepatitis B infection Dx’ed?

A

Clinical presentation and serology:

B Vaccine: + HBsAb IgG

Previous B: -HBsAg, + HBcAb IgG, +/-HBcAb IgM, + HBsAb IgG, +/- Anti-HBe

B “window”: + HBcAb IgM, +/- HBsAb IgG, +/- Anti-HBe

Acute B: + HBsAg, + HBcAb IgG, + HBcAb IgM, + anti-HBe

Chronic B: + HBsAg, + HBcAb IgG, +/- anti-HBe

Chronic B + D Superinfection: + HBsAg, + HBcAb IgG, +/- HBcAb IgM, - HBsAbIgG, + anti-HDV

B & D Co-infection: + HBsAg, + HBcAb IgG, + HBcAb IgM, + anti-HDV

71
Q

What is the expected serology of someone who is the recipient of the Hepatitis B vaccine?

A

B Vaccine: + HBsAb IgG

72
Q

What is the expected serology of someone who has had a previous hepatitis B infection?

A

Previous B: -HBsAg, + HBcAb IgG, +/-HBcAb IgM, + HBsAb IgG, +/- Anti-HBe

73
Q

What is the expected serology of someone who is in a hepatitis B infection “window”?

A

B “window”: + HBcAb IgM, +/- HBsAb IgG, +/- Anti-HBe

74
Q

What is the expected serology of someone who is in an acute hepatitis B infection?

A

Acute B: + HBsAg, + HBcAb IgG, + HBcAb IgM, + anti-HBe

75
Q

What is the expected serology of someone who is in a chronic hepatitis B infection?

A

Chronic B: + HBsAg, + HBcAb IgG, +/- anti-HBe

76
Q

What is the expected serology of someone who is in a chronic hepatitis B & D superinfection?

A

Chronic B + D Superinfection: + HBsAg, + HBcAb IgG, +/- HBcAb IgM, - HBsAbIgG, + anti-HDV

77
Q

What is the expected serology of someone who is in a hepatitis B & D coinfection?

A

B & D Co-infection: + HBsAg, + HBcAb IgG, + HBcAb IgM, + anti-HDV

78
Q

How is a hepatitis B infection treated?

A

Supportive care

Nucleoside analogs and interferon for chronic hepatitis B

79
Q

How is a hepatitis B infection prevented?

A

Safe needle and sex practices

Maternofetal/vertical infection prevention

3 doses hepatitis B vaccine

80
Q

What is the genetic makeup of hepatitis C? Is it enveloped?

A

Flaviviridae

+ssRNA, enveloped

81
Q

What is the mode of transmission for hepatitis C?

A

sex, parenteral

82
Q

What is the incubation period for hepatitis C?

A

28-112 days

83
Q

What hepatitis viruses are carrier states and asymptomatic infections common?

A

Hepatitis B, C, and D

84
Q

What happens with a chronic persistent hepatitis C infection?

A

•1.Chronic persistent: Generally asymptomatic with a mild elevation of serum alanine transaminase (ALT)

85
Q

What happens with a chronic active hepatitis C infection? What characteristics of the hepatitis C virus cause some of the more disastrous outcomes?

A

•2.Chronic active: Jaundice with elevated liver enzymes, cirrhosis and hepatocellular carcinoma

Hepatitis C- Oncogenic transforming virus

86
Q

What are some medications that are helpful in controlling a hepatitis C infection?

A

•Rx – Harvoni (ledipasvir + sofosbuvir) or Sovaldi (sofosbuvir)+other antivirals (ribavirin)

87
Q

How is a Dx of a hepatitis C infection made?

A
  • Dx: Clinical presentation and or serology (more on next slide)
  • C: Anti hepatitis C antibodies and HCV-RNA
88
Q

What is the expected serology for a prior hepatitis C, acute C, and chronic hepatitis C infection?

A

Prior C: + anti-HCV

Acute C: + anti HCV, + HCV-RNA

Chronic C: + anti HCV, + HCV-RNA

89
Q

What is the genetic makeup of a hepatitis D virus? Envelope?

A

-ssRNA (circular)

hepatitis B envelope

90
Q

How is the hepatitis D virus transmitted?

A

parenteral, sex

91
Q

Hepatitis D is unusual because it needs other entities in order to establish an infection. What does it need?

A

Hepatitis D (delta antigen)

  • Have to have previous chronic or concurrent hepatitis B infection
  • Defective incomplete virus - needs HBsAg for its own virion coat (envelope)
92
Q

What are the symptoms of a hepatitis D infection?

A

•Presents with acute liver inflammation/failure, and jaundice

93
Q

How is a Dx of a hepatitis D infection made?

A

Dx: Clinical presentation and or serology

•D: Anti-delta antibodies (Anti-HDV)

94
Q

How is a hepatitis C infection treated?

A

Ribavirin (guanosine analog), protease NS3 inhibitors and interferon for chronic hepatitis C

95
Q

How is hepatitis D infection prevented?

A

safe sex and needle practices

prevention of vertical transmission

96
Q

What is the genetic makeup of a hepatitis E virus? Envelope? Classification?

A

Hepeviridae

+ssRNA

Naked - not enveloped

97
Q

What pathology does hepatitis E cause? Where is it common?

A
  • Subclinical to fulminant hepatitis with rare chronic state in immunocompromised
  • Worldwide but more common in Asia and Africa
98
Q

How is a Dx of a hepatitis E infection made?

A

Clinical presentation and serology:

•E: Anti hepatitis E antibodies and HEV-RNA

99
Q

How is hepatitis E infection prevented?

A

Usually transmitted via fecal-oral route, so hygeine is key

100
Q

What is the expected serology of a hepatitis E infection?

A

+ anti-HEV HEV RNA

101
Q

In the interest of avoiding stupid rote memorization, what do the markers in hepatitis B serology tests actually mean?

A

HBsAg - Hepatitis surface antigen - indicates active infection, presence of virus in blood

anti-HBs - Hepatitis B surface antigen antibody - often IgG, signals someone has recovered from Hep B infection successfully, or has had the Hep B vaccine

anti-HBc - Total Hepatitis B core antibody - present at start of infection, remains for life. Indicates previous or current infection with Hep B.

anti-HBc IgM - Ab to Hepatitis B core antigen - indicates recent/acute infection with Hepatitis B.

PBD II (18 decks)

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