Lec 28 MMR Flashcards

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1
Q

What are symptoms of measles?

A
  • rash covering childs arm and stomach

- lasts ~4 days

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2
Q

What are characteristics of measles virus?

A
  • paramyxovirus family
  • negate strand
  • non-segmented
  • RNA
  • 6 genes encoding 8 proteins
  • enveloped
  • lipid envelope has viral H and F glycoproteins
  • nucleocapsid contains viral RNA, N, P, and L
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3
Q

What are the 3 proteins encoded by measles P gene? and their roles?

A

P/C/V
P = phosphoprotein required for polymerase activity
V = accessory protein blocks innate immune response
C = accessory protein blocks innate immune response

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4
Q

What is the measles replication cycle?

A

attachment: by H protein binds CD46, SLAM, Nectin 4
fusion: mediated by F protein

replication and transcription: cat by vRNA dependnent RNA polymerase [L and P], occurs in cytoplasm

budding: mediated by M protein

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5
Q

What mediates measles attachment?

A

H protein

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6
Q

what mediated measles fusion?

A

F protein

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7
Q

what mediates measles replication and transcription?

A

L and P proteins

– viral RNA dependent RNA polymerase

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8
Q

what mediates measles budding?

A

M protein

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9
Q

What are clinical manifestations of measles?

A
  • childhood infection spread by respiratory route
  • latent period 10-14 days –> 2-3 days of prodrome [fever, cough, conjuncitivits, coryza, kopliks spots in mouth] –> characteristic rash
  • onset of rash coincides with immune response and initiation of viral clearance
  • rash is maculopapular – fat, red area covered with small bumps
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10
Q

How is measles transmitted/spread?

A
  • transmitted via respiratory droplets entering resp tract
  • initial infaction in macrophages and dendritic cells of resp tract
  • infected cells transport virus to lymphoid tissue –> amplified –> viremia –> tissues
  • virus spread in tissues occurs via release of virus or cell-cell fusion leading to formation syncytium [giant multi-nucleated cells]
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11
Q

What are koplik’s spots?

A
  • pinpoint gray-white spots [grain of salt appearance]

- on mucous membranes

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12
Q

What are characteristics of measles rash?

A
  • maculopapular
  • beings on face –> trunk and extremities
  • fever and severe symptoms lessen as rash progresses
  • associated with beginning of cell mediated immunity
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13
Q

What are possible complications of measles?

A
  • bacterial superinfection [common]
  • immune suppression caused by infection –> TB reactivation
  • severe in immuno-compromised pts
  • postinfectious or acute disseminated encephalomyelitis [ADME]
  • subacute sclerosing panencephalitis [SSPE]
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14
Q

What are signs of bacterial superinfection in measles?

A
  • otitis media
  • mastoiditis
  • sinusitis
  • pneumonia
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15
Q

What is ADME?

A
  • acute disseminated encephalomyelitis
  • possible complication of measles
  • autoimmune demyelinating disease 3-14 days after illness onset
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16
Q

What is SSPE? signs and symptoms?

A

subacute sclerosing panencephalitis

  • rare neuro disease in children associated with measles infection
  • occurs 6-10 yrs after measles
  • most often in children with infection at < 2yrs old

signs: measles virus antibody elevated in serum and CSF, evidence of virus in glial cells and neurons
symptoms: personality change, progressive intellectual deterioration, motor and ANS dysfunction, death

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17
Q

How is measles diagnosed?

A
  • clinical findings
  • lab diagnostics:
  • — direct detection of virus antigen in epithelial cells by FAS
  • — RT-PCR detection of virus RNA
  • — serology
  • — virus isolation
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18
Q

What are the 3 symptoms that are case definition of clinical measles diagnosis?

A
  1. generalized maculopapular rash for 3 or more days
  2. fever [101 F, 38.3 C]
  3. either cough, coryza, or conjunctivitis
19
Q

How is measles transmitted?

A
  • very contagious
  • by aerosol transmition
  • humans are only host, primary children
20
Q

What is immune response to measles?

A
  • long lived immunity —> if get it once you won’t get it again
  • maternal antibodies protect for up to 6 months old
  • immune suppression during infection, cellular response clears infection
21
Q

What is treatment for measles?

A

no specific therapy

22
Q

What is the measles vaccine? who can get it?

A
  • live attenuated virus vaccine
  • administered with mumps and rubella as MMR
  • give to 12-15 mo old children, revaccination at 4-6 yrs
  • not for: pregnant, TB, immunocompromised
23
Q

What causes mumps?

A
  • mumps virus
24
Q

What are symptoms of mumps?

A
  • swelling of salivary glands [particularly parotid]
25
Q

What are viral properties of mumps virus?

A
  • paramyxovirus family [genus rubulavirus]
  • negative strand
  • non-segment
  • RNA virus
  • enveloped
26
Q

What are the virulence factors of mumps virus?

A
in envelope
- Hemagluttinin/neuraminidase [HN]
- Fusion [F]
matrix [M]
in capsid
- nucleoprotein [N]
- phosphoprotein [P]
polymerase [L]
27
Q

What is pathogenesis of mumps infection?

A
  • virus enters respiratory tract
  • virus grows in salivary glands and local lymphoid tissue
  • virus spreads to spleen and distant lymphoid tissue [at 7-10 days]
  • viremia [at 15 days]
  • virus spreads through body to glandular tissue and CNS [18 days and after]
28
Q

What are the clinical symptoms associated with mumps replicating in salivary glands?

A

fever, inflammation of lymph nodes, parotitis

29
Q

What are the clinical symptoms associated with mumps replicating in meninges?

A

meningitis [10%]

30
Q

What are the clinical symptoms associated with mumps replicating in brain?

A

encephalitis [rare]

31
Q

What are the clinical symptoms associated with mumps replicating in kidney?

A

no clinical consequences

32
Q

What are the clinical symptoms associated with mumps replicating in testis/ovary?

A

orchitis [in 20% of adult males

33
Q

What are the clinical symptoms associated with mumps replicating in mammary gland?

A

mastitis [in 10% of post-puberal femals

34
Q

What are the clinical symptoms associated with mumps replicating in pancreas/thyroid/myocardium/joints?

A

pancreatitis, thyroiditis, myocarditis, arthritis

35
Q

What are most common clinical signs of mumps?

A
  • meningitis [in 10%]
  • orchitis [testis inflamed] in 20% of adult males
  • mastitis [mammary gland inflamed] in 10% of post pubertal females
36
Q

What is mumps vaccine?

A
  • live attenuated virus vaccine
  • single serotype
  • administered as MMR
37
Q

What is epidemiology of mumps [who gets it]?

A
  • mostly children age 5-8

- outbreaks in adults in high density [military]

38
Q

How is rubella transmitted?

A

respiratory secretions

39
Q

who gets rubella?

A

both children and adults get mild disease with maculopapular rash

40
Q

What are characteristics of rubella virus?

A
  • togavirus
  • positive single strand
  • RNA
  • enveloped
  • isocahedral nucleocapsid
41
Q

What is congenital rubella syndrome

A
  • get it in early months of pregnancy
  • associated with high rate of birth defects
  • mother gets viremia, goes through placenta to fetus, fetus gets chronic infection
  • 20% chance of damage to fetus if woman infected in first trimester
42
Q

What are symptoms of congenital rubella syndrome?

A

deafness [most common]

also: cataracts, heart defect, mental retardation, microcephaly, liver/spleen damage

43
Q

What is rubella vaccine?

A
  • live attenuated
  • single serotype
  • given as MMR