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

Viruses I - RNA and V. Hepatitis - KMS Flashcards

(101 cards)

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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
What strange histological finding should you associate with the Paramyxovirus family?
Syncytia! Produce multinucleated giant cells (syncytia) via a cell fusing factor
26
What is the point of the fusion protein for the Paramyxovirus family?
Fuses virus envelope to cell membrane
27
What surface glycoprotein is present in the Paramyxovirus family?
single surface HN glycoprotein with both hemagglutinin and neuraminidase activity - this protein is lacking in metapneumovirus though
28
What pathology does human metapneumovirus cause?
Common cold, bronchiolitis and pneumonia in children and adults
29
How is an infection of human metapneumovirus dx'ed? How is it treated?
PCR - definitive Also consider clinical presentation, obviously. Treatment consists of supportive care.
30
What is the genetic makeup of parainfluenza viruses? Is it enveloped? How many serotypes?
-ssRNA, enveloped 4 serotypes, 1 and 2 are more severe
31
What tissues do parainfluenza viruses invade?
Local infection of ciliated respiratory epithelium
32
How widespread/common is infection from parainfluenza viruses?
Pretty common - cause of 30-40% of acute respiratory infection in infants and children
33
What are the symptoms of parainfluenza infection?
Mild cold-like to life-threatening (croup, bronchiolitis, pneumonia) Most common cause of croup laryngotracheobronchitis (barking cough, steeple sign)
34
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?
seal bark cough = laryngotracheobronchitis = parainfluenza infection Steeple sign on CXR - swelling and possible obstruction of airway in laryngotracheal region
35
What is the transmission of parainfluenza virus?
Droplet
36
How do you Dx and treat a suspected parainfluenza infection?
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
37
What is the genetic makeup of respiratory synctial virus (RSV)? Is it enveloped?
-ssRNA, enveloped
38
What tissues does RSV infect?
Local infection in ciliated epithelia (upper or lower respiratory tract), nose, eye and mouth - can proceed into bronchioles, as per Dr. Gomez
39
What types of illness does RSV cause?
•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
40
How common is infection and reinfection with RSV? How does it affect adults versus children/babies?
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
41
How do you Dx an RSV infection?
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
How do you care for an RSV infection?
•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
What is the genetic makeup of the Mumps virus? Is it enveloped?
-ssRNA, enveloped
44
How is the Mumps virus spread?
Enters from salivary secretions (intimate contact) via the pharynx or conjunctiva
45
What tissues does the Mumps virus infect?
viremia targeting: **glandular** (salivary glands, testes, ovaries, pancreas) **nerve tissue** (causing aseptic meningitis and encephalitis)
46
An active Mumps infection will target glandular and nerve tissue. What sequelae can develop?
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
What is the epidemiology of the Mumps virus? (How widespread, hosts, reservoirs, etc.)
* 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
How do you Dx a Mumps infection? When is it contagious?
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
What is the treatment for a Mumps infection? How long is the patient contagious?
•Rx –Supportive care and isolation * Disease is contagious just before and after the symptoms * Incubation period is 18-21 days
50
How is infection with the mumps virus prevented?
•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
What is the genetic makeup of the measles virus? Is it enveloped?
-ssRNA, enveloped
52
What tissues does the measles virus infect?
•Enters oropharynx from human secretions - followed by viremia to: skin mucosae CNS lymphatic & respiratory systems
53
What symptoms, from mild to horrifying, can present when someone has a measles virus infection?
* **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
What is the epidemiology of the measles virus?
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
How is a Dx of measles virus infection made? What histological findings should you expect?
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
How is a measles infection treated?
* Rx – Supportive, intramuscular immunoglobulin and isolation * Contagious up to 4 days post rash
57
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?
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
How is measles infection prevented?
- Immunize MMR live vaccine at 12-15 months and 4-6 years
59
What is the genomic makeup of hepatitis A? Is it enveloped? Classification?
+ssRNA, naked Pico**rna**viridae
60
What is the clinical presentation of a hepatitis A infection?
•Subclinical to fulminant hepatitis with rare chronic state in immunocompromised
61
What is the mode of transmission for hepatitis A?
Fecal oral route
62
How is a Dx made of a hepatitis A infection?
•Dx: Clinical presentation and or serology
63
What relevant serology findings should you expect for a hepatitis A infection?
Vaccinated person: +/- for anti-HAV IgG Previous hepatitis A infection: + for anti-HAV IgG Acute hepatitis A infection: + for anti-HAV IgM
64
How is hepatitis A infection prevented?
Hepatitis A vaccine - 2 doses hygeine
65
What is the genomic makeup of hepatitis B? Is it enveloped? Classification?
dsDNA, enveloped Hepa**dna**viridae
66
What is the clinical presentation of a hepatitis B infection?
* 1.Chronic persistent: Generally asymptomatic with a mild elevation of ALT * 2.Chronic active: Jaundice, elevated liver enzymes, cirrhosis, +/- hepatocellular carcinoma
67
What is the mode of transmission for hepatitis B?
Parenteral, STI (Sexually Transmitted Infection)
68
What is the incubation period for hepatitis B?
60-180 days
69
What kind of virus is hepatitis B?
Hepatitis B = Dane particle - Oncogenic transforming virus
70
How is a hepatitis B infection Dx'ed?
Clinical presentation and serology: ## Footnote 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
What is the expected serology of someone who is the recipient of the Hepatitis B vaccine?
B Vaccine: + HBsAb IgG
72
What is the expected serology of someone who has had a previous hepatitis B infection?
Previous B: -HBsAg, + HBcAb IgG, +/-HBcAb IgM, + HBsAb IgG, +/- Anti-HBe
73
What is the expected serology of someone who is in a hepatitis B infection "window"?
B “window”: + HBcAb IgM, +/- HBsAb IgG, +/- Anti-HBe
74
What is the expected serology of someone who is in an acute hepatitis B infection?
Acute B: + HBsAg, + HBcAb IgG, + HBcAb IgM, + anti-HBe
75
What is the expected serology of someone who is in a chronic hepatitis B infection?
Chronic B: + HBsAg, + HBcAb IgG, +/- anti-HBe
76
What is the expected serology of someone who is in a chronic hepatitis B & D superinfection?
Chronic B + D Superinfection: + HBsAg, + HBcAb IgG, +/- HBcAb IgM, - HBsAbIgG, + anti-HDV
77
What is the expected serology of someone who is in a hepatitis B & D coinfection?
B & D Co-infection: + HBsAg, + HBcAb IgG, + HBcAb IgM, + anti-HDV
78
How is a hepatitis B infection treated?
Supportive care Nucleoside analogs and interferon for chronic hepatitis B
79
How is a hepatitis B infection prevented?
Safe needle and sex practices Maternofetal/vertical infection prevention 3 doses hepatitis B vaccine
80
What is the genetic makeup of hepatitis C? Is it enveloped?
Flaviviridae +ssRNA, enveloped
81
What is the mode of transmission for hepatitis C?
sex, parenteral
82
What is the incubation period for hepatitis C?
28-112 days
83
What hepatitis viruses are carrier states and asymptomatic infections common?
Hepatitis B, C, and D
84
What happens with a chronic persistent hepatitis C infection?
•1.Chronic persistent: Generally asymptomatic with a mild elevation of serum alanine transaminase (ALT)
85
What happens with a chronic active hepatitis C infection? What characteristics of the hepatitis C virus cause some of the more disastrous outcomes?
•2.Chronic active: Jaundice with elevated liver enzymes, cirrhosis and **hepatocellular carcinoma** Hepatitis C- Oncogenic transforming virus
86
What are some medications that are helpful in controlling a hepatitis C infection?
•Rx – Harvoni (ledipasvir + sofosbuvir) or Sovaldi (sofosbuvir)+other antivirals (ribavirin)
87
How is a Dx of a hepatitis C infection made?
* Dx: Clinical presentation and or serology (more on next slide) * C: Anti hepatitis C antibodies and HCV-RNA
88
What is the expected serology for a prior hepatitis C, acute C, and chronic hepatitis C infection?
Prior C: + anti-HCV Acute C: + anti HCV, + HCV-RNA Chronic C: + anti HCV, + HCV-RNA
89
What is the genetic makeup of a hepatitis D virus? Envelope?
-ssRNA (circular) hepatitis B envelope
90
How is the hepatitis D virus transmitted?
parenteral, sex
91
Hepatitis D is unusual because it needs other entities in order to establish an infection. What does it need?
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
What are the symptoms of a hepatitis D infection?
•Presents with acute liver inflammation/failure, and jaundice
93
How is a Dx of a hepatitis D infection made?
Dx: Clinical presentation and or serology •D: Anti-delta antibodies (Anti-HDV)
94
How is a **hepatitis C** infection treated?
Ribavirin (guanosine analog), protease NS3 inhibitors and interferon for chronic hepatitis C
95
How is hepatitis D infection prevented?
safe sex and needle practices prevention of vertical transmission
96
What is the genetic makeup of a hepatitis E virus? Envelope? Classification?
Hepeviridae +ssRNA **Naked - not enveloped**
97
What pathology does hepatitis E cause? Where is it common?
* Subclinical to fulminant hepatitis with rare chronic state in immunocompromised * Worldwide but more common in Asia and Africa
98
How is a Dx of a hepatitis E infection made?
Clinical presentation and serology: •E: Anti hepatitis E antibodies and HEV-RNA
99
How is hepatitis E infection prevented?
Usually transmitted via fecal-oral route, so hygeine is key
100
What is the expected serology of a hepatitis E infection?
+ anti-HEV HEV RNA
101
In the interest of avoiding stupid rote memorization, what do the markers in hepatitis B serology tests actually mean?
**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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