Virology Flashcards

You may prefer our related Brainscape-certified flashcards:
1
Q

What are the components of a Virion?

A
  • Genome: DNA or RNA (Instructions to clone itself)
  • Protein coat: Protection, Facilitates attachment, and Antigens
  • May contain enzymes needed for transcription (e.g. polymerase)
  • No energy source
  • No metabolic processes
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
2
Q

What are viral spikes or glycoproteins?

A
  • Protein (or protein + glycogen) that are antigens

- Responsible for different viral serotypes (viral subcategories)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
3
Q

What is the difference between a naked and an enveloped virus?

A
  • Enveloped has outer lipid bilayer

- Naked survive better in the environment (i.e. not as sensitive to heat, drying, alcohol, etc)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
4
Q

What is the difference between positive and negative stranded viral RNA?

A
  • Positive stranded can immediately be translated into protein.
  • Negative stranded must be transcribed into a positive RNA strand prior to being translated. Virus can have it own enzyme to transcribe negative stranded to positive stranded
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
5
Q

What is unique about retroviruses?

A

Even though they are positive stranded RNA virus they cannot be immediately translated. They use virion reverse transcriptase to copy RNA to DNA, which is then incorporated into the host genome

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
6
Q

What are the (+) RNA Naked viruses?

A
  • Calici (Norwalk)
  • Hep E
  • Reov (Rotavirus) Double Stranded
  • Picorna (Polio, Echo, Rhino, Cox, Hep A)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
7
Q

What are the (+) RNA Enveloped viruses?

A
  • Corona (viral pharyngitis)
  • Retro (HIV) Reverse- transcribed
  • Flavi (Westnile, Hep. C, Dengue, Yellow fever)
  • Toga (Rubella, Alpha, Rubi)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
8
Q

What are the (-) RNA enveloped viruses?

A
  • Bunya
  • Paramyxo (Mumps and Morbilli –> Measles)
  • Orthomyxo (Influenza A, B, C)
  • Rhabdo (Rabies)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
9
Q

What are the Naked DNA viruses?

A
  • Parvo (B19 –> Fifths Disease) Single Stranded
  • Adeno
  • Papilloma
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
10
Q

What are the Enveloped DNA viruses?

A
  • Hepadna
  • Herpos (Varicella + Herpes Zoster, Herp 6 or 7 –> Roseola)
  • Pox (Small pox)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
11
Q

What is unique about DNA viruses?

A
  • DNA must first be transcribed into RNA, then translated into proteins (They make mRNA using host RNA polymerase)
  • Positive strand is read and transcribed into mRNA
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
12
Q

What is unique about a Prion?

A
  • Composed entirely of protein
  • No DNA or RNA
  • Disrupts neuron function by converting normal cells into –> B-pleated sheets
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
13
Q

Describe Viral Transmission

A

1-Attachment to host cell: Virion surface proteins attach to receptor proteins on the cell surface
2-Penetration/Entry: Naked viruses engulfed by vesicle
Enveloped viruses undergo fusion
3-Uncoating to release the genome: Low vesicle pH uncoats virion. Rupture or fusion SEE PICTURE
4-Gene expression: Virus specific mRNA synthesis
Synthesis of viral proteins
5-Genome replication: DNA viruses replicate in the nucleus using host cell DNA-dependent RNA polymerase
Exception = poxviruses – cytoplasm
RNA viruses replicate in the cytoplasm
6-Assembly:
Viral nucleic acid packaged within capsid proteins
Rupture of cell membrane releasing assembled virions (usually naked viruses)
OR
Budding process (enveloped viruses)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
14
Q

What happens to host cells when they become infected with a virus?

A
  • Death: Macromolecular synthesis inhibited
  • Fusion of cells to form multinucleated cells: Due to cell membrane changes
  • Malignant transformation: Unrestrained growth, Prolonged survival, Morphologic changes
  • No effect
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
15
Q

What are the stages of a viral infection?

A
  • Incubation: Asymptomatic
  • Prodromal: Non-specific symptoms
  • Specific-illness: Characteristic symptoms and signs
  • Recovery: Illness wanes
  • Persistence (sometimes): Chronic carrier state, latent infection
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
16
Q

List the Viral Infection Diagnostic procedures.

A
  • Cell culture – presumptive diagnosis
  • Definitive identification – uses known antibody with various tests
  • Microscopic identification
  • Serologic procedures
  • Viral antigens
  • Viral nucleic acids
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
17
Q

Define Cell culture diagnosis.

A

Virus growth produces characteristic cytopathic effect (CPE)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
18
Q

Describe serologic procedures.

A

Antibody titer in acute-phase and convalescent-phase (10-14 days later) compared (4-fold higher = infected)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
19
Q

What are the different types of vaccination immunity

A

1) Active immunity
- Attenuated live virus – greater, longer lasting protection
- Killed virus
- Subunit vaccines – contain purified viral proteins
2) Passive immunity
- Preformed antibody administered in immune globulins
3) Herd immunity – “community immunity”

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
20
Q

What are some challenges that arise with viral disease control?

A
  • Difficult to obtain selective toxicity against the virus since replication so closely involved with normal synthetic processes of the cell
  • Extensive viral replication occurs during the incubation period
  • Drug-resistant viral mutants
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
21
Q

What are the respiratory illnesses?

A
  • Common cold (Rhinoviruses)
  • Viral pharyngitis
  • Influenza
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
22
Q

Common Cold Infectious agent…

A
  • Rhinoviruses (30-50% case): Picornavirus family

- Naked (+) RNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
23
Q

Common Cold transmission…

A
  • Hosts: humans and chimps
  • Entry point: URT
  • Droplets (direct & indirect)
  • Peaks: early fall or spring
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
24
Q

Common Cold Signs/symptoms…

A
  • Incubation: 2-4 days
  • Duration: 1 week
  • sneezing, nasal discharge, sore throat, cough, headache
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
25
Q

Viral pharyngitis infectious agents…

A

Multiple!!… Coronavirus

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
26
Q

Viral pharyngitis signs and symptoms…

A
  • Headache, malaise, +/- fever, sore throat

- Nasal congestion, coryza, hoarseness, sinus discomfort/tenderness, ear pain, cough

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
27
Q

Influenza infectious agents…

A
  • Influenza A, B, C: Orthomyxovirus family
  • Enveloped (–) RNA
  • 2 glycoproteins
  • Hemagglutinin (H1, H2, H3)
  • Neuraminidase (N1, N2)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
28
Q

Describe antigenic shift vs drift

A

Drift: mutations
Shift: animal –> human… causes re-assortment of genome segments (big change!!) (H1N1)

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
29
Q

Influenza transmission…

A
  • Host: Humans
  • Influenza A: mammals and birds
  • Influenza B: seals
  • Influenza C: pigs, dogs
  • Entry point: respiratory tract
  • Direct droplet spread
  • Peak: winter months
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
30
Q

Influenza signs and symptoms…

A
  • Incubation: 2 days
  • Duration: acute phase 3-5 days. Normal in 2-6 weeks
  • Abrupt onset: FACTS
  • F - fever
  • A - aches (aka myalgias)
  • C - chills
  • T - tiredness
  • S - sudden onset
  • 6-12 hrs later respiratory signs (dry, nonproductive cough)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
31
Q

Influenza prevention…

A

Antivirals
- Neuraminidase inhibitors: block the enzyme so it can’t release/spread/infect
- Viral protein M2 inhibitor: block uncoating/assembly
Vaccines
- Killed (inactivated): virions/split subunits made of hemagglutinin antigens
- Live attenuated: antibodies form 2 weeks after vaccination

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
32
Q

Influenza complications…

A
  • Pneumonia
  • Bacterial superinfection
  • Reye’s syndrome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
33
Q

What are the Exanthem viruses?

A
  • Varicella (Chickenpox)
  • Herpes zoster (Shingles)
  • Measles
  • Roseola
  • Rubella
  • Fifth disease
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
34
Q

Varicella (Chickenpox) infectious agents…

A
  • Varicella zoster virus: Herpesvirus family
  • Enveloped DNA
  • Single serotype
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
35
Q

Varicella (Chickenpox) transmission…

A
  • Host: humans
  • Respiratory droplets and direct contact w/lesions
  • Mucosa of URT
  • blood –> skin
  • Sensory neurons: travels to dorsal root ganglia then becomes latent
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
36
Q

Varicella (Chickenpox) signs and symptoms…

A
  • Incubation: 14-21 days
  • Prodrome: fever & malaise
  • Papulovesicular rash in trunk and spreads to head/extremities
  • Pruritis (itchy skin): Papule, Blister, Ulser
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
37
Q

Varicella (Chickenpox) Prevent/Control…

A
  • Diagnosed with Tzanck smear
  • Antivirals: acyclovir, Foscarnet, Famciclovir, Valacyclovir
  • Live, attenuated vaccines
  • Varicella
  • Zoster (14x more virus)
  • varicella-zoster immune globulin
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
38
Q

Varicella (Chickenpox) complications…

A
  • Varicella pneumonia
  • Encephalitis
  • Reye’s syndrome
  • Postherpetic neuralgia(Shigls)
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
39
Q

Herpes Zoster (Shingles) signs and symptoms…

A

-Painful vesicles along course of sensory nerve of the head or trunk

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
40
Q

Measles Infectious agents

A
  • Morbillivirus: paramyxovirus fam.
  • Enveloped (–) RNA
  • 2 envelope spikes
  • Hemagglutinin
  • Cell fusing & hemolytic activity
  • single serotype
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
41
Q

Measles Transmission

A
  • Host: humans
  • Person-to-person contact through respiratory droplets
  • URT –> Mucosal epithelium
  • Epidemics: winter & spring as well as unimmunized/ partially immunized
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
42
Q

Measles Signs and symptoms

A

Incubat: 7-18 days (usually 9-11)

  • Fever, cough, coryza, conjunctivis
  • 1-3 days later: KOPLIK SPOTS lasting 1-2 days
  • 1 day later: rash (head trunk/extremities) lasting 3-5 days
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
43
Q

Measles prevention/control

A
  • Live attenuated vaccine

- Immune serum globulin

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
44
Q

Measles complications

A
  • Varicella pneumonia
  • Encephalitis
  • Reye’s syndrome
How well did you know this?
1
Not at all
2
3
4
5
Perfectly
45
Q

Roseola infectious agents

A
  • Hum. herpesvirus 6 or 7: Herpesvirus family

- Enveloped DNA

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
46
Q

Roseola transmission

A

-Mainly through saliva

How well did you know this?
1
Not at all
2
3
4
5
Perfectly
47
Q

Roseola signs and symptoms

A
  • Fever x3 days

- Faint maculopapular rash spreading from trunk –> extremities

48
Q

Mumps infectious agents

A
  • Mumps virus: Paramyxovirus fam.
  • Enveloped (–) RNA
  • 2 envelope spikes
  • single serotype
49
Q

Mumps transmission

A
  • Host: humans
  • Droplets or DC w/ fomites
  • URT: blood –> saliv. glands (testes, ovaries, pancreas, meninges)
50
Q

Mumps signs and symptoms

A
  • Incubation: 18-21 days
  • Duration: 1 week
  • Prodrome: fever, malaise, anorexia
  • Tender salivary gland swelling
  • Peak: late winter, early spring
51
Q

Mumps control/prevention

A

Live, attenuated vaccine

52
Q

Mumps complications

A
  • Orchitis in post-pubertal males

- Meningitis

53
Q

Rubella - “german” measles infectious agent

A
  • Rubella virus: Togavirus family
  • Enveloped (+) RNA
  • 2 envelope glycoproteins
  • single serotype
54
Q

Rubella - “german” measles transmission

A

Host: humans

  • Respiratory droplets
  • URT: Blood lymph tissue, skin, organs
  • Transplacental spread to fetus = congenital rubella
55
Q

Rubella - “german” measles signs and symptoms

A
  • Incubation: 14-21 days
  • Duration: 1-3 days
  • Low grade fever, upper respiratory sxs, lymphadenopathy
  • W/in 24 hours faint, macular rash to head, neck and trunk as well as petechial lesions over soft palate
56
Q

Rubella - “german” measles control/prevention

A

-Live, attenuated vaccine

57
Q

Rubella - “german” measles complications

A
  • Arthritis (days – 3 weeks)
  • Thrombocytopenic purpura
  • Encephalitis
58
Q

Fifth disease – erythema infectiosum infectious agent

A
  • Parovirus B19: Parvovirus family

- Naked single strand DNA

59
Q

Fifth disease – erythema infectiosum transmission

A
  • Host: humans
  • Respiratory or DC w/fomite
  • Blood or blood products
  • Vertical transmission
  • Winter to early summer
60
Q

Fifth disease – erythema infectiosum signs and symptoms

A

Incubation: 4-12 days

  • Duration: 1-2 weeks
  • Fever, malaise, headache, myalgias, pruritis
  • CHARACTERISTIC ‘BLUSH’ RASH: confluent, indurated rash to face
  • 1-2 days later macular, reticular rash to arms and legs
  • Lymphadenopathy, splenomegaly, mild leukopenia, anemia
61
Q

Fifth disease – erythema infectiosum control/prevention

A

Immunogloblin may be useful (immunodeficiency)

62
Q

Fifth disease – erythema infectiosum complications

A
  • Hepatitis
  • Thrombocytopenia
  • Nephritis
  • Encephalitis
  • In pregnancy: profound anemia of fetus
63
Q

What are the gastrointestinal virus infections?

A
  • Rotavirus
  • Norwalk virus
  • Hepatitis A, B, C, D, E
64
Q

Rotavirus infectious agents

A
  • Rotavirus: Reoviridae family

- Naked double strand RNA

65
Q

Rotavirus transmission

A
  • Host: humans, animals (calves, mice, piglets, foals) but no interspecies spread
  • Fecal-oral route
  • Localize in duodenum and proximal jejunum
  • cooler months
66
Q

Rotavirus signs and symptoms

A
  • Incubation: 1-3 days
  • Duration: vomiting 1-3 days; diarrhea 4-8 days
  • Abrupt onset of vomiting, then hours later watery/brown stools
  • Low grade fever
67
Q

Rotavirus control/prevention

A
  • live, oral rotavirus vaccine

- rigorous hygiene measures

68
Q

Rotavirus complications

A

Dehydration

69
Q

Norwalk virus infectious agents

A
  • Norovirus: Calciviridae family
  • Naked (+) RNA
  • 4 serotypes
70
Q

Norwalk virus transmission

A
  • Fecal-oral

- Consumption of contaminated food, water, uncooked shellfish & other foods

71
Q

Norwalk virus signs and symptoms

A
  • Incubation: 10-51 hours
  • Abrupt onset vomiting & diarrhea
  • Duration: 1-2 days
72
Q

Norwalk virus control/prevention

A

Hygiene

73
Q

Norwalk virus complications

A

Dehydration

74
Q

Hepatitis A infectious agent

A
  • Hepatitis A: Picornaviridae family

- Naked (+) RNA

75
Q

Hepatitis A transmission

A
  • Host: humans, primates

- Fecal-oral (contaminated food, water)

76
Q

Hepatitis A signs and symptoms

A
  • Incubation: 15-45 days
  • Duration: days-weeks
  • Fever, anorexia, nausea, RUQ pain, jaundice, dark urine, clay-colored stools, hepatomegaly
77
Q

Hepatitis A control/prevention

A
  • Avoidance of exposure
  • Passive immunity- immune serum globulin
  • Active immunization – killed HAV vaccine
78
Q

Hepatitis B infectious agent

A
  • Hepadnaviridae agent
  • Enveloped, DNA (partially double stranded)
  • 4 serotypes
79
Q

Hepatitis B transmission

A
  • Host- humans

- Vertical, parenterally, sexual contact

80
Q

Hepatitis B signs and symptoms

A
  • Incubation: 30-180 days (avg 10 wks)
  • Duration: several months
  • Fatigue, anorexia, nausea, RUQ pain/fullness, +/- arthralgias, rash, clay colored stools, dark urine, jaundice
81
Q

Hepatitis B control/prevention

A
  • Interferon and nucleoside and nucleotide analogs
  • Hep B immune globulin
  • Recombinant vaccine
82
Q

Hepatitis B complications

A

-Fulminant hepatitis leading to liver necrosis & death; chronic hepatitis associated with cirrhosis, liver failure, HCC

83
Q

Hepatitis D infectious agents

A

-Enveloped RNA

84
Q

Hepatitis D transmission

A

-Requires Hep B surface antigen for transmission

85
Q

Hepatitis D signs and symptoms

A
  • Simultaneous D & B infection – looks like HAV or HBV

- Chronic HBV with superimposed hep D – jaundice relapse & high risk chronic cirrhosis

86
Q

Hepatitis D control/prevention

A
  • Interferon and nucleoside and nucleotide analogs
  • Hep B immune globulin
  • Recombinant vaccine
87
Q

Hepatitis D complications

A

-Progressive liver disease, chronic cirrhosi

88
Q

Hepatitis C infectious agents

A
  • Flaviviridae family
  • Enveloped (+) RNA
  • 11 genotypes, multiple subtypes
89
Q

Hepatitis C transmission

A
  • Hosts: humans

- Parenterally, may be sexually transmitted

90
Q

Hepatitis C signs and symptoms

A
  • Incubation: 6-12 weeks
  • Asymptomatic
  • Chronic carrier state in 85%
  • 10-18 years to develop chronic hepatitis
91
Q

Hepatitis C control/prevention

A
  • Interferon-α , ribavirin, HCV protease inhibitors

- No active or passive immunity

92
Q

Hepatitis C complications

A

-Cirrhosis, increased HCC risk

93
Q

Hepatitis E infectious agent

A

Naked (+) RNA

94
Q

Hepatitis E transmission

A
  • Host: humans

- Fecal-oral route

95
Q

Hepatitis E signs and symptoms

A
  • Incubation: 40 days
  • Duration: 1-2 weeks
  • Often subclinical
  • Jaundice, anorexia, hepatomegaly, N/V, fever
96
Q

Hepatitis E control/prevention

A

No active or passive immunity

97
Q

Hepatitis E complications

A

When symptomatic can be fatal (esp. in pregnancy)

98
Q

What are the Central Nervous System virus Diseases?

A
  • Enterovirus
  • Arboviruses: Meningitis & Encephalitis
  • Rabies encephalitis
99
Q

Enterovirus specific groups

A
  • Poliovirus
  • Coxsackievirus Group A
  • Coxsackievirus Group B
  • Echovirus, parechovirus & enterovirus
100
Q

Enterovirus infectious agents

A
  • Picornaviridae family

- Naked (+) RNA

101
Q

Enterovirus transmission

A
  • Fecal-oral route
  • Infects GI & upper respiratory tract
  • Spreads to target organs: CNS, heart, vascular endothelium, liver, pancreas, lungs, gonads, skeletal, muscles, synovial tissues, skin
  • Increased prevalence – summer, fall
102
Q

Enterovirus signs and symptoms

A

Incubation varies: 2-10 days

103
Q

Enterovirus control/prevention

A

Inactivated poliovirus vaccine

104
Q

Arboviruses – arthropod borne infectious agents

A
  • Togavirus: enveloped (+) RNA: Alphaviruses & rubivruses
  • Flavivirus: enveloped (+) RNA
  • Bunyavirus: enveloped (–) RNA
105
Q

Arboviruses – arthropod borne transmission

A
  • Infected blood-sucking insects (mosquitoes, ticks, sandflies)
  • Primarily occur in tropics
106
Q

Arboviruses – arthropod borne signs and symptoms

A
  • Acute febrile illness
  • Encephalitis
  • Meningitis
107
Q

Arboviruses – arthropod borne control/prevention

A

-Immunizations for yellow fever, tick-borne, and Japanese B encephalitis

108
Q

Rabies encephalitis infectious agent

A
  • Rhabdoviridae family

- Enveloped (–) RNA

109
Q

Rabies encephalitis transmission

A
  • Host: All mammals
  • Infected secretions (usually bite)
  • Site of entry: multiplies in muscle cells then travels to CNS to replicate in brain cells
110
Q

Rabies encephalitis signs and symptoms

A

-Incubation: 10 days – 1 yr
-Median survival after becoming symptomatic: 4 days, maximum 20 days
… then you are fucked

111
Q

Rabies encephalitis control/prevention

A
  • Pre-exposure: inactivated vaccine

- Post-exposure: human hyperimmune antirabies globulin plus rabies vaccine

112
Q

Human Immunodeficiency Virus (HIV-1) infectious agent

A
Retrovirus family: Lentivirus genome
-2 copies of enveloped (+) RNA
-3 enzymes essential for viral replication
1.	Reverse transcriptase: RNA --> double stranded DNA copy --> integrated into host chromosome
2.	Protease
3.	Integrase
-Envelope contains 2 viral glycoproteins
gp120 + gp41
113
Q

Human Immunodeficiency Virus (HIV-1) transmission

A

Requires intimate contact with infecting source (bodily fluid, blood)

  • Majority from sexual contact
  • Perinatal transmission
  • Virus has been detected in saliva, tears, urine but not shown to be infectious sources
  • Primarily infects and kills helper (CD4) T lymphocytes
114
Q

Human Immunodeficiency Virus (HIV-1) Infectious Cycle

A

Acute stage: 2-4 weeks after infection
- Fever, lethargy, sore throat, generalized lymphadenopathy, maculopapular rash (trunks, extremities), leukopenia
Latent stage: 7-11 years
- Asymptomatic
- Virus produced and sequestered in lymph nodes
Immunodeficiency stage (AIDS)
- Decline in CD4 cells

115
Q

Human Immunodeficiency Virus (HIV-1) control/prevent

A

Appropriate screening

  • Avoid exposure
  • Antiretrovirals
  • Pre- and post-exposure prophylaxis