Viruses Flashcards
1
Q
Which herpes viruses cause meningitis/encephalitis?
A
HSV 1&2 VZV EBV CMV
2
Q
Which paramyxoviruses cause meningitis/encephalitis?
A
Mumps Mealses
3
Q
Which enteroviruses cause meningitis/encephalitis?
A
Polio Coxsackie Echovirus
4
Q
Which arboviruses cause meningitis/encephalitis?
A
Eastern equine
Western equine
Venezuelan equine
California encephalitis
La Crosse virus
St. Louis encephalitis
West Nile
Powasson
5
Q
Which arenavirus causes meningitis/encephalitis?
A
LCMV (lymphocytic choriomeningitis virus)
6
Q
Name 3 other viruses that cause meningitis/encephalitis.
A
HIV Adenovirus Rabies
7
Q
LP shows PMNs + glucose < 34
A
Bacterial
8
Q
LP shows lymphocytes + glucose 70
A
Virus (CSF glucose normally 2/3 of plasma so 70 is normal)
9
Q
LP shows lymphocytes + glucose < 34
A
Fungus
10
Q
CSF protein > 220
A
Bacterial
11
Q
List some complications of meningitis
A
Death,hydrocephalus, deafness, seizures, herniation More common with bacterial etiologies
12
Q
How could you be >99% certain a CSF infection is bacterial?
A
Presence of ONE of the following: Protein > 220 Glucose < 34 WBC > 2000 PMNs > 1180
13
Q
MCC viral meningitis? 2nd? Third?
A
Enteroviruses (Coxsackie, polio, echo) Mumps (before MMR) HSV2, HIV, VZV
14
Q
Recurrent viral meningitis
A
HSV 1 or 2
15
Q
URI followed by nuchal rigidity, HA, fever, lumbago, malaise
A
Viral meningitis
16
Q
MCC sporadic encephalitis in the US?
A
HSV
17
Q
When does viral meningitis usually resolve?
A
10-14 days
18
Q
MCC epidemic encephalitis in US?
A
St. Louis encephalitis
19
Q
What two classical scenarios suggest recurrent bacterial meningitis in a kid or adult?
A
Kid - ear infections then meningismus Adult - head trauma then meningismus
20
Q
Route of enteroviruses?
A
Fecal-oral
21
Q
Which virus can quickly seed the meninges?
A
HIV
22
Q
MCC arboviral-induced pediatric encephalitis in the US?
A
La Crosse virus (bunyaviridae)
23
Q
A patient presents with fever, HA, nuchal rigidity, and the following findings on LP:
Protein - 200
Lymphocytes - 100
PMNs - 1
Glucose - 67
Dx?
A
HSV encephalitis
(CSF characteristic of aseptic meningitis + Mollerat cells**, which are **activated monocytes)
24
Q
Several family members present to the ED with fever, nuchal rigidity, HA, and a history of URI. Most likely agents?
A
Enteroviruses (Coxsackie, echo, polio) - tend to run in families
25
MCC viral encephalitis? 2nd? 3rd? Most serious?
Arboviruses (St. Louis, West Nile, La Crosse, etc)
HSV-1 - most serious
Enteroviruses (echo, coxsackie, polio)
26
When do arbovirus infections tend to occur?
Spring, summer, early fall
(When ticks and mosquitos are prevalent)
27
Who is most likely to become infected with an arbovirus?
Children and elderly
28
Which symptoms suggest encephalitis over meningitis?
Confusion, seizures, coma, death
(Both can have fever, HA, lethardy, prodromal URI)
29
A patient presents with fever, HA, lethargy, and confusion. First step in managment?
Empirical antiobiotics and acyclovir
(This could be either bacterial or viral encephalitis; if it's HSV-1 encephalitis, it needs to be treated immediately)
30
Describe postinfectious/post-vaccinial immune-mediated encephalitis
AKA subacute sclerosing panencephalitis
Follows measles infection/vaccination in infancy
Antibodies attack myelin basic protein/oligodendrocytes and neurons (**_pan_**encephalitis)
Slowly progressive with neuro signs developing years later
31
Tx for HSV-1? CMV?
Acyclovir
Ganciclovir
32
A 30 year old presents to the ED with high fever, HA, N/V, confusion, and focal seizures. MRI shows this finding. Dx?
HSV encephalitis
(Shows **_temporal lobe necrosis_**)
33
A 30 year old presents to the ED with high fever, HA, N/V, confusion, and focal seizures with spike and wave changes in the temporal lobe. What do you expect to see in the CSF?
_RBC's_
Lymphocytes
Normal glucose
(These symtpoms with temporal lobe involvement suggests HSV encephalitis; the characterisitc finding in the CSF is RBC's due to temporal necrosis)
34
Who gets acute HSV encephalitis? Reccurent?
Acute - newborns, usually HSV-2
Recurrent - adults, usually HSV-1
35
Prognosis of HSV encephalitis if treated? Untreated?
Good, curable
70% fatality if untreated
36
Which are the togaviruses/alphaviruses? Flaviviridae? Bunyaviruses?
Togaviruses/alphaviruses - Eastern equine, Western equine, Venezuelan equine, Rubella
Flaviviridae - St. Louis encephalitis, West Nile, yellow fever virus, Dengue virus, pestiviruses, hepaciviruses
Bunyaviruses - La Crosse virus, California virus
37
Flaviviruses are (enveloped, nonenveloped) (segmented, nonsegmented) (+, -, ambisense) (DNA, RNA)
Enveloped nonsegmented + RNA
38
With regards to replication cycle, the flaviviruses (SLE, West Nile, JE) are similar to ______ except:
Picornaviruses (rhinovirus, enterovirus) except flaviviruses have a 5' cap
39
Describe the replication cycle of the flaviruses (SLE, WN, JE)
1. Enter cell via receptor-mediated endocytosis
2. Virions released in a pH-dependent fusion event
3. + genome translated in nucleus into single polyprotein
4. Polyprotein cleaved in nucleus via viral and host proteases
5. Virions assemble in intracellular organelles
6. Enveloped viruses released at cell surface
40
(T/F): Flaviviruses lyse host cells
(T/F): Humans are the primary host for flaviviruses
Both false
(Transmitted from wild birds --\> mosquitos --\> back to birds and incidentally to humans)
41
Describe the disease course of the flaviruses (SLE, WN, JE)
Mosquito bites human and releases flavivirus
Day 2-3 = Replicates at inoculation site - PRIMARY VIREMIA
Day 3-7 = Replicates in RES - flu-like symptoms
SECONDARY VIREMIA
Encephalitis (SLE, JE), hepatitis (WN), DSS/DHI (Dengue virus)
42
Which demographic of patients would experience a secondary viremia with the flaviruses (SLE, WN, JE)?
Elderly, infants, immunocompromised
(Most infections do not progress past the initial flu-like symptoms phase; with continued replication, secondary viremia results)
43
Geography of St. Louis virus infections?
North, South, Central America
(In N. America, especially Colorado, Florida, Texas, and Arkansas)
44
Three illnesses caused by SLE?
Febrile HA
Aseptic meningitis
Encephalitis
45
Describe the progression of symptoms of SLE
1. 4-21 days post exposure = flu-like symptoms (most people don't progress from here)
2. 1-4 days later = meningeal and encephalopathic symptoms
46
Prognosis of SLE infection?
Low mortality rate but if patient has a fatal infection, 50% die within first week and 80% die within two weeks
47
Tx SLE?
No vaccine or anti-viral proven effective
Control mosquito population
48
Where is West Nile virus found?
US, Africa, West Asia, Europe, Middle East
49
\_\_\_% of people infected with West Nile virus get severely ill
1%
50
Most West Nile fatalities occur in what demographic?
Elderly
51
Tx West Nile?
Supportive
(No vaccine or antivirals)
52
Alphaviruses (WEE, EEE, VEE) are (enveloped, nonenveloped) (segmented, nonsegmented) (+, -, ambisense) (DNA, RNA)
Enveloped
Nonsegmented
+ RNA
53
Difference between rubivirus and alphaviruses? (besides disease)
Humans are only known reservoir for rubella
54
Alphaviruses (WEE, EEE, VEE) replicate in:
Muscles and fibroblasts
55
Alphaviruses (WEE, EEE, VEE) disease prevalence corresponds to:
Prevalence of insect vector
56
The severity of alphavirus WEE, EEE, VEE) infection depends on:
Age and dose
57
Describe the replication process of the alphaviruses (WEE, EEE, VEE)
1. Receptor-mediated endocytosis
2. pH-dependent uncoating in lysosome
3. Polyprotein translated and cleaved into non-structural proteins
4. NSP's form - strand complementary RNA
5. - strand serves as template for genomic RNA
6. Another polyprotein translated and cleaved into structural proteins
7. Virions assembled in intracellular organelles
8. Bud from cell surface
58
Describe the disease progression of the alphaviruses (WEE, EEE, VEE)
Low grade viremia within 24 hours
Febrile illness for ~ 2 weeks
Abrupt onset of encephalitis - confusion, dizziness, vomiting, increasing loss of consciousness
50-80% die within 2-3 days
59
An adult infected with an alphavirus (WEE, EEE, VEE) would experience \_\_\_, while a child or elderly patient might experience \_\_\_\_
Mild febrile illness
Encephalitis
60
Which of the alphaviruses (WEE, EEE, VEE) has a vaccine? Who gets it?
VEE
Lab workers and military
61
Bunyaviridae (La Crosse virus, California encephalitis virus) are (enveloped, nonenveloped) (segmented, nonsegmented) (+, -) (RNA, DNA)
Enveloped segmented - RNA
62
Bunyaviridae (La Crosse virus, California encephalitis virus) vs. influenza
Both are segmented and can undergo reassortment but bunyaviridae replicate only within the cytoplasm and its mRNA do not get spliced
63
Why are bunyaviridae (La Crosse virus, California encephalitis virus) unique among - RNA viruses?
Their genes are found on 2-3 separate RNA segments
64
Describe the disease progression of Bunyaviridae (La Crosse virus, California encephalitis virus)
SIMILAR TO FLAVIVIRUS
Mosquito bites kid
2-3 days = replication at innoculation site
4-21 days = flu-like symptoms = PRIMARY VIREMIA
Most cleared by RES
If replication continues = encephalitis = SECONDARY VIREMIA
65
(T/F): Many kids die of Bunyaviridae (La Crosse virus, California encephalitis virus) infection and those who don't have severe neurological sequelae
False
(Most recover completely with \<1% fatality)
66
Rabies is (enveloped, nonenveloped) (segmented, nonsegmented) (+, -, ambisense) (DNA, RNA)
Enveloped, nonsegmented - RNA
67
Rhabdoviruses vs. paramyxoviruses
Rhabdoviruses (rabies) uses single G protein to enter cell in a pH-dependent manner without forming syncytia
Paramyxoviruses (measles and mumps) use one protein (F) for fusion and another for attachment and form syncytia
68
Describe the disease progression of rabies
2-10 days after exposure = prodromal stage = fever, chills, HA, malaise
Months-years after exposure = acute neurological phase = dumb or furious rabies
2-7 days after that = coma
3-30 days after coma = death
69
Where is rabies found in highest concentrations in the body?
Submaxillary salivary gland (mechanism of spread via bites)
70
Where in the brain does rabies predominate?
Limbic system, hypothalamus, midbrain
71
Describe how rabies spreads from bite site to salivary gland
Local replication in muscle
Spreads up peripheral sensory nerve to dorsal root ganlia
Replicates in DRG
Spreads up spinal cord to brain
Spreads via efferent nerves to submaxillary salivary glands
Replicates to high concentrations
72
Why do rabies patients exhibit hydrophobia?
Protective airway response
73
Three things to do when someone presents with an animal bite
1. Wash wound
2. Anti-rabies IgG into wound site
3. 5 rounds of rabies vaccine
74
Is the rabies vaccine activated or inactivated?
Inactivated (cell culture)
75
Arenaviruses (LCMV) are (enveloped, nonenveloped) (segmented, nonsegmented) (+, -, ambisense) (DNA, RNA)
Enveloped segmented ambisense RNA
76
What is contained within the arenavirus (LCMV) virions?
2 RNA segments + host ribosomes
77
Describe the replication strategy of arenaviruses
pH-dependent endocytosis
NP and L mRNA translated from genome from short and long segments, respectively
NP and L proteins promote translation
Polymerase produces full-length + sense antigenome for both segments
+ sense antigenome used as template for glycoprotein mRNA
Assembly and budding
78
How are arenaviruses (LCMV) transmitted?
Inhalation of aerosolized rodent excreta or saliva
79
Describe the disease progression of the arenaviruses (LCMV)
Primary viremia = fever, HA, N/V
10 days later = aseptic meningitis sometimes with DEAFNESS
80
Prognosis of arenavirus (LCMV) infection
1/3 asymptomatic, 1/2 get prodrome but don't progress
Most who do get the meningitis recover without neuro problems but occasional deafness during meningeal phase
81
MC neuro infection of HIV patients?
Toxoplasmosis
82
A patient mentions during a routine physical in May that he needs a 90 day prescription for his blood pressure medication rather than his usual 30 day as he will be traveling to India for a couple months on a work trip. You should recommend vaccination against:
Japanese encephalitis
(Vaccine available for people travelling to Asia, eastern Soviet Union, India for \> 1 month especially during the summer months when mosquitos are cray cray)
83
A 30 yo male on long-term corticosteroids presents to the ED with high fever, confusion, tremor, HA, N/V, and convulsions. His wife reports that he has "the flu" that started when they returned from a trip along the Mississippi-Ohio river basin about two weeks ago. Dx?
St. Louis encephalitis
(Flu-like symptoms followed by encephalopathic symptoms + Mississippi-Ohio river basin = SLE)
84
An 86 yo woman presents to the ED in a very confused state with a high fever. Her caretaker states she had been running a fever for over a week then woke up that morning with confusion, vomiting, and dizziness. Dx?
Alphaviruses (WEE, EEE, VEE)
(Age of patient + history of fever for over a week then abrupt onset of encephalitis)
85
A 50 yo male presents to the ED with HA, muscle pain, and the rash shown below. A few days later he comes back with confusion, neck stiffness, high fever, severe HA, convulsions, and tremors. Dx?
West Nile meningoencephalitis
(Rash with flu-like sx is characteristic of West Nile)
86
Which viruses are associated with a high mortality rate?
HSV, alphaviruses (EEE. WEE, VEE), rabies
87
Sudden deafness
Arenavirus (LCMV)
88
An 11 year old presents in the ED with fever, severe HA, vomiting, tremor, and a history of seizure. His mother notes that he returned home from visiting family in Southeast Asia about a week ago. She denies rash prior to these symptoms. They declined vaccines recommended by their PCP for religous reasons. Dx?
Japanese encephalitis virus
89
Not transmitted by mosquitos
Arenavirus (LCMV; aerosolization of rodent feces/saliva)
Rabies (bites)
90
An 8 year old returning home one week ago from summer camp complains of fever for 2-3 days duration, N/V, HA, and fatigue. His mother brings him to the ED after he experiences a seizure. Dx?
La Crosse virus
(MCC pediatric encephalitis, seizures common with LCV, summer camp = mosquitos)
91
For which two viruses do horses routinely get vaccinated?
Alphaviruses (WEE, EEE, VEE)
West Nile virus
92
Which virus(es) have hemagluttinin on the caspid?
Togavirdae (Rubella, EEE, WEE, VEE)
93
Which encephalopathic virus(es) can undergo reassortment?
Bunyaviridae (La Crosse virus, California encephalitis virus)
(Segmented genome)
94
No vaccine available for:
West Nile
La Crosse
California encephalitis
WEE
EEE
HSV
LCMV
95
Vaccines ARE available for:
Rubella
ZEE (lab workers, military only)
Rabies
96
Dx?
Rabies
(Bullet-shaped morphology)
97
Multiple RNA segments
Bunyaviridae (La Crosse, California encephalitis)
Arenavirus (LCMV)
98
Segmented genomes
Bunyaviridae
Arenavirus
99
A researcher working on Alzheimer's progression in a rat model develops a HA, fever, and N/V. About 10 days later, she experiences nuchal rigidity, worsened HA, and sudden deafness. Dx?
LMCV meningitis
(Rats, sudden deafness, meningitis 10 days after prodrome)
100
101
102
103
104
