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Flashcards in Microbiology: Virology-1 Deck (160):
1

Questions

Answers

2

What does a naked icosahedral virus have?

hexagon shape, nucleocapid (outer part) and nucleic acid in the middle

3

What does a enveloped icosahedral virus have?

Envelope: Lipid bilayer with surface proteins in them
then a capsid with nucleic acids in the middle
hexagon shape

4

What does an enveloped helical virus have?

circular in shape
envelope: lipid bilayer with surface proteins in it
matrix or core protein surrounding nucleic acid and nucleocapsid protein

5

Viral tropism for specific tissues is dependent on what?

Viral encoded envelope glycoproteins

6

The exchange of genes between 2 chromosomes by crossing over within regions of significant base sequence homology

Recombination

7

What causes influenzae pandemics?

High-frequency recominbation

8

When viruses with segmented genomes exchange segments.

Reassortment ex. influenza virus

9

When 1 of 2 viruses that infect the cell has a mutation that results in a nonfunctional protein. The nonmutated virus complements the mutated one by making it a functional protein.

Complementation

10

When does phenotype mixing occur?

With simultaneous infection of a cell with 2 viruses. Genome of virus A can be partially or completely coated (forming pseudovirion) with the surface protein from virus B. Type B protein coat determines the infectivity of the phenotypicially mixed virus. The progeny from the infection have a type A coat that is encoded by its type A genetic material!

11

What are live attenuated vaccines?

induce humoral and cell-mediated immunity but have reverted to virulence on rare ocasions

12

Killed vaccines do what?

Induce only humoral immunity, but are stable - don't revert

13

Do you need a booster for live attenuated viral vaccines?

NO

14

Who can't get live attenuated vaccines?

ICH or close relatives - because they can revert and infect the patient

15

What are live attenuated viral vaccines?

"Live! See small yellow chickens get vaccinated with Sabin's and MMR"

Smallpox, yellow fever, chicken pox (VZV), Sabin's polio virus, MMR (measles, mumps, rubella)

16

What is the only live attenuated viral vaccine that you can give to HIV positive patients?

MMR

17

What viral vaccines are killed?

"RIP Always"
Rabies, Influenza, Salk Polio, HAV

18

What are Recombinant vaccines?

HBV (antigen = recombinant HBsAg), HPV (types 6, 11, 16, and 18)

19

All of the DNA viruses are what?

1. Double stranded DNA except Parvoviridae
2. Linear except papilloma, olyoma, and hepadnaviruses (circular)

20

All of the RNA viruses are what?

Single stranded RNA except Reoviridae (it is double stranded)

21

What viral genomes are infectious?

purified nucleic acids of most dsDNA (except poxvirus and HBV) and positive strand ssRNA (mRNA) viruses are infectious

22

What naked viral genomes are not infectious?

Naked nucleic acids of negative strand ssRNA and dsRNA viruses are not infectious. They require enzymes contained in the complete virion

23

What are viruses ploidy?

All viruses are haploid (with one copy of DNA and one copy of RNA) except retroviruses, which have 2 identical ssRNA molecules (diploid)

24

Where do DNA viruses replicate?

In the nucleus except (poxvirus)

25

Where do RNA viruses replicate?

In the cytoplasm (except influenza and retroviruses)

26

What type of viruses won't have phospholipids on the outside?

naked viruses

27

Which viruses are naked?

"Naked CPR and PAPP smear"
Calicivirus
Picornavirus
Reovirus
Parvovirus
Adenovirus
Papilloma
Polyoma

28

Where do enveloped viruses get their envelopes from?

The plasma membrane when they exit a cell. Exceptions are herpesvirus, which acquire envelopes from nuclear membrane

29

Which virus gets its envelope from the nuclear membrane?

Herpesvirus

30

DNA enveloped viruses

Herpesviruses (HSV types 1 and 2, VZV, CMV, EBV), HBV, smallpox virus

31

DNA nucleocapsid viruses

Adenovirus, papillomaviruses, parvovirus

32

RNA enveloped virus

Influenza virus, parainfluenza virus, RSV, measles virus, mumps virus, rubella virus, rabies virus, HTLV, HIV

33

RNA nucleocapsid (naked) virus?

Enteroviruses (poliovirus, coxsackievirus, echovirus, HAV), rhinovirus, reovirus (rotavirus)

34

All DNA viruses

HHAPPPPy
Hepadna
Herpes
Adeno
Pox
Parvo
Papilloma
Polyoma

35

All DNA viruses are dsDNA except

parvo (ssDNA)

36

All DNA viruses are linear except

papilloma and polyoma (circular, supercoiled) and hepadna (circular, incomplete)

37

All DNA viruses are icsahedral except

pox (complex)

38

All DNA viruses replicate in the nucleus except

pox (carries own DNA dependent RNA polymerase)

39

What are the different herpesviruses? What are their characteristics?

HSV-1, HSV-2, VZV (HHV-3), EBV (HHV-4), CMV (HHV-5), HHV-6, HHV-7, HHV-8

dsDNA with an envelope

40

what causes oral (and some genital) lesions, keratoconjunctivitis?

HSV-1
dsDNA, with an envelope

41

What does HSV-2 cause? What is its characterisitcs?

genital (and some oral) lesions
dsDNA with an evelope

42

VZV - characteristics and what does ti cause?

chickenpox, shingles, zoster
dsDNA (linear), with an envelope

43

CMV

dsDNA (linear), with an envelope
infection in ICH, especially in transplant recipients, congenital defects

44

HHV-6

dsDNA (linear), with an envelope
causes roseola (exanthem subitum)

45

HHV-7

dsDNA (linear), with an envelope
clinically insignificant

46

HHV-8

dsDNA (linear) with an evelope
causes Kaposi's sarcoma - associated with herpesvirus (KSHV)
common in HIV patients

47

Who commonly gets HHV-8 and how?

HIV patients from sexual contact

48

What is it and what causes it? High fevers for several days that can cause seizures, followed by a diffuse macular rash

Roseola - caused by HHV-6
*they don't know how it is spread

49

What does Hepadnavirus cause? What are it's characterisitcs?

HBV (hepatitis B): acute or chronic hepatitis, vaccine available, not a retrovirus but has reverse transcriptase
dsDNA (partial circular), with an envelope

50

What is not a retrovirus but has transcriptase?

HBV (Hepatitis B virus) Hepadnavirus
dsDNA (partial circular), with an evelope

51

What does Adenovirus cause? What is its characteristics?

dsDNA (linear), does not have an envelope
causes febrile pharyngitis - sore throat
Pneumonia, and Conjunctivitis - "pink eye" (watery)

52

What causes febrile pharyngitis - sore throat, pneumonia, and conjunctivitis (watery pink eye)

Adenovirus - dsDNA (linear) with an envelope

53

What viral family causes B19 virus?

Parvovirus - ssDNA linear (-), with no envelope

54

What is the smallest DNA virus?

Parvovirus - causes B19
ssDNA linear (-), with no envelope

55

What does B19 virus cause?

1. aplastic anemia in sickle cells patients
2. "slapped cheeks" rash - erythema infectiosum (fifth's disease) *rash spares nasolabial folds - lace like rash on trunk and extremities
3. RBC destruction in fetus leads to
hydrops fetalis and death

56

Papillomavirus characteristics and what does it cause?

dsDNA (circular), with no envelope
causes HPV

57

What can HPV cause?

genital warts, CIN, cervical cancer

58

What does Polyomavirus cause? What is its characteristics?

dsDNA (circular), with no envelope
cause JC virus - progressive multifocal leukoencephalopathy (PML) (headaches, vision loss, memory problems, clumsiness, aphasia) in HIV patients

59

What are the two families that are considered papovavirus?

Papillomavirus, Polyomavirus

60

What is the largest DNA virus - what is its characteristics and what does it cause?

Poxvirus - dsDNA (linear), with an envelope
causes smallpox - now eradicated, could be used in germ warfare, vaccina (cowpox) - milkmaid's bilsters, and molluscum contagiosum (

61

Most common cause of sporatic enchephalitis in the US what is the characteristics of the disease?

HSV-1
dsDNA (linear), with an envelop virus part of herpesvirus family

62

What can HSV-1 cause?

gingivostomatitis, keratoconjunctivitis, temporal lobe encephalitis, herpes labialis

63

What is the route of transmission of HSV-1?

Respiratory secretions, saliva

64

What does HSV-2 cause? How is it transmitted?

Herpes genitalis, neonatal herpes
transmitted via sexual contact, perinatal

65

What does VZV cause? How is it transmitted?

chickenpox, shingles (varicella-zoster), encephalitis, pneumonia
transmitted in respiratory secretions

66

What virus remains dormant in trigeminal and dorsal root ganglia?

VZV - Herpesvirus dsDNA (linear) with an envelope

67

What does EBV cause? How is it spread?

Infectious mononucelosis, Burkitt's lymphoma, and nasopharyngeal carcinoma
transmission: respiratory secretions, saliva

68

What does CMV cause? How is it transmitted?

congenital infection, mononucelosis (negative monospot), pneumonia, infected cells have Owl's eye appearance
transmitted: congenital, tarnsvusion, sexual contact, saliva, urine, transplant

69

What does HHV-6 cause? How is it transmitted?

Roseola: high fevers for several days that can cause seizures, followed by a diffuse macular rash
transmision: not determined

70

How do you identify HSV?

Tzank test: a smear of an opened skin vesicle to determine multinucleated giant cells. Used to assay HSV-1, HSV-2, VZV

71

intranuclear Cowdry A inclusions seen in what?

HSV-1, HSV-2, VZV
Herpesvirus
dsDNA (linear), with an envelope

72

What are the 1 most common causes of focal brain lesions in HIV positive patient?

Toxoplasmosis and CNS lymphoma

73

What does mononuclosis infect?

B cells!

74

fever, hepatosplenomegley, pharyngitis, and lymphadenpathy

Mono - EBV

75

lymphadenpathy in posterior cervical nodes +hepatosplenomegly

EBV
mono

76

What is the peak incidence of mono?

15-20 year olds - most common during peak kissing years (the kissing disease)

77

What type of T cells do you see in mono?

Abnormal circulating cytotoxic T cells (atypical lymphocytes)

78

What cancers are EBV associated with?

Hodgkin's lymphoma, Burkitts lymphoma (kids in africa), nasopharyngeal carcinoma

79

What has a negative monospot test?

CMV

80

What has a positive monospot test?

EBV

81

What does a positive monospot test mean?

Heterophil antibodies detected by aggluination of sheep RBC
heterophil (means the antibodies react across species lines)
*mix patients serum and sheep RBC - if agglutination occurs - test is positive!

82

What viruses are in the family reovirus? What are the characteristics?

Reovirus (colorado tick fever) and Rotavrius (#1 cause of fatal diarrhea in children)
dsRNA (linear 10-12 segments) with no envelope, icosahedral (double)

83

What viruses are in the family picornaviruses? What are the characteristics?

Poliovirus
Echovirus (aseptic meningitis)
Rhinovirus (common cold)
Coxsackievirus - aseptic meningitis, herpangina - febrile pharyngitis, hand, foot, and mouth disease, myocarditis
HAV - acute viral hepatitis
ssRNA (linear), icosahedral with no envelope

84

What viruses are in the family Hepevirus? What are the characterisitcs?

HEV
ssRNA (linear), icosahedral with no envelope

85

What viruses are in the family Caliciviruses? What are the characterisitics?

Norwalk virus - viral gastroenteritis
ssRNA, linear, icosahedral, with no envelope

86

What viruses are in the family flaviviruses? What are the characterisitcs?

HCV
yellow fever
dengue
St. Louis encephalitis
West nile virus
ssRNA, linear, icosahedral with a capsule

87

What are the viruses in the family togaviruses? What are the characterisitcs?

Rubella (german measles), Eastern equine encephalitis, Western equine encephalitis
ssRNA linear, icosahedral, with an envelope

88

What are the viruses in the family retrovirus? What are the characteristics?

HIV, HTLV (T-cell leukemia)
they have reverse transcriptase
ssRNA, linear, icosahedral and with an envelope

89

What are the viruses in the family coronaviruses? What are the characteristics?

coronavirus - common cold and SARS
ssRNA, linear, helical with a capsule

90

What are the viruses in the family Orthomyxoviruses? What are the characteristics?

Influenza virus
ssRNA linear (-), 8 segments, helial with an envelope

91

What are the viruses in the family paramyxoviruses? What are the characteristics?

PaRaMyxovirus
Parainfluenzae (croup)
RSV (bronchiolitis in babies; rx. ribavirin)
Rubeola (measles)
Mumps
ssRNA, linear (-) (nonsegmented)
helical with an envelope

92

What viruses are in the Rhabdovirus family? What are the characteristics?

Rabies
ssRNA, linear (-), helical with an envelope

93

What are the viruses in the family Filoviruses? What are the characteristics?

Ebola/Marburg - hemorrhagic fever (often fatal)
ssRNA (-) linear, helical with an envelope

94

What are the viruses in the family Arenaviruses? What are the characteristics?

LCMV - lymphocytic choriomenigitis virus
Lassa Fever encephalitis - spread by mice
ssRNA (-) circular 2 segments, helical with an envelope

95

What are the viruses in the family Bunyaviruses? What are the characteristics?

California encephalitis
Sandfly/Rift Valley fevers
Crimean-congo hemorrhagic fever
Hantavirus - hemorrhaic fever, pneumonia
ssRNA circular (-) 3 segments, helical with an envelope

96

What are the viruses in the family Deltavirus? What are the characteristics?

HDV
ssRNA (-) circular, helical with an envelope

97

What are the arboviruses?

yellow fever, dengue, St. Louis encephalitis, West nile virus, eastern equine encephalitis, western equine encephalitis, california encephalitis, Crimean-congo hemorrhagic fever

98

What are the negative stranded RNA viruses? What must they have?

*must transcribe negative strand to positive. Virion brings its own RNA dependent RNA polymerase
"Always Bring Polymerase Or Fail Replication"
Arenaviruses
Bunyaviruses
Paramyxovirus
Orthomyxovirus
Filoviruses
Rhabdoviruses
+ Delta virus

99

What viruses are segmented?

Only RNA viruses
"BOAR"
Bunyaviruses
Orthomyxoviruses
Arenaviruses
Reoviruses

100

What virus consists of 8 segments of negative stranded RNA?

Influenzae
*segments can undergo reassortment, causing antigenic shifts that lead to worldwide pandemics of the flu

101

What are the picornaviruses?

PERCH
poliovirus
Echovirus
Rhinovirus
Coxsackievirus
HAV

102

What virus is the RNA translated into 1 large polypeptide that is cleaved by proteases into functional viral proteins?

Picornavirus (PERCH)

103

Causes aseptic meningitis

Picornaviruses (except HAV and rhinovirus)

104

Most common cause of the common cold, >100 serotypes

rhinovirus - part of picornavirus family
ssRNA (+), linear, w/o an envelope

105

Virus transmitted by Aedes mosquitos? What is its reservoir?

Yellow fever virus - a flavivirus
monkey or human reservoir

106

Virus that causes high fever, black vomitus, and juandice? What can you see in the liver?

Councilman bodies (acidophlic inclusions) - yellow fever virus - in the flavivirus family

107

What is the most important global cause of infantile gasteroenteritis?

Rotavirus - in the reovirus family segmented dsRNA
*major cause of actue diarrhea in the US during the winter especially in daycares and kindergartens

108

What happens in rotavirus?

villous destruction with atrophy leads to decreased Na+ absorption and thus decreased water absorption - loose both Na+ and water

109

What family does the influenza virus belong to?

Orthomyxoviruses: enveloped, ssRNA with segmented genome

110

What antigens does the influenza virus contain?

Hemagglutinin (promotes viral entry)
Neuraminidase (promotes progeny viron release) antigens

111

People with this virus are at risk for fatal bacterial superinfection?

People with influenza virus - orthomyxovirus family

112

What virus has rapid genetic changes?

Influenza - part of orthomyxovirus family

113

Genetic shift is what and what does it cause?

Reassortment of viral genome (when human flu A virus reassembles with swine flu A virus)
causes PANDEMICS! Most deadly!

114

Genetic drift is what and what does it cause?

minor (antigenic) changes based on random mutation
cause EPIDEMICS!

115

How do you protect against influenza?

killed vaccine - available for elderly, healthcare workers each fall

116

Cause of German (3-day measles)? What are symptoms?

Rubella virus - part of togavirus family
fever, lymphadenopathy, arthralgias, fine truncal rash

117

parainfluenza

croup - seal-like barking cough - part of paramyxovirus family

118

what does paramyxovirus family include? What do they all contain?

parainfluenza, RSV, mumps, measles
*all contain surface (F) protein, which causes respiratory epithelial cells to fuse and form multinucleated cells

119

What is used in RSV to neutralize F protein?

Palivizumab

120

Koplik spots seen in what condition?

Rubeola (measles) a Paramyxovirus

121

Red spots with blue-white canter on buccal mucosa

Koplik spots - measles (rubeola) a paramyxovirus

122

SSPE, encephalits, giant cell pneumonia are all possible sequelae of what disease?

rubeola (measles) part of paramyxovirus family
SSPE forms years later
encephalitis 1:2000
giant cell pneumonia in ICH

123

things seen in measles?

3 C's
Cough, Conjunctivitis, Coryza
*koplik spots!
don't confuse with roseola (HHV-6)

124

Parotitis, Orchcitis, aseptic meningitis

Mumps - a paramyxovirus
can cause sterility

125

Negri bodies

rabies - rhabdovirus
cytoplasmic inclusions in neurons

126

bullet-shaped capsid, long incubation

rabies
the long incubation allows for immunization after exposure

127

progression of rabies?

fever, malise - agitation, photophobia, hydrophoia - paralysis, coma - death

128

How does rabies get into the neurons?

travels up CNS by migrating in retrograde fashion up nerve axons

129

What most common carries rabies in US?

bat, raccoon, and skunk - in the US
dog bites more common in other countries

130

How do you prevent rabies?

killed vaccine!

131

How are arboviruses transmitted?

by arthropods (mosquitos, ticks)
dengue fever, yellow fever
variant of dengue: hemorrhagic shock syndrome (from SE asia)

132

arbovirues include

flavivirus, togavirus, bunyavirus
"Fever Transmitted by Bites"

133

What are the viruses that cause lots of spots?

Rubella: togavirus: 3-day german Rubeola: paramyxovirus: measles
Roseola: Herpesvrius (HHV-6). high fevers followed by diffuse maculopapular rash
Varicella: Herpesvirus: chickenpox
Variola: Poxvirus: smallpox (no longer present outside of labs)

134

Hepatitis viruses are what? Symptoms for Hepatitis?

All RNA viruses except Hepatitis B
fever, jaundice, elevated AST and ALT

135

What Hepatitis viruses are transmitted fecal-orally?

Hepatitis A and Hepatitis B

136

What Hep virus has no carries? What is its incubation period?

Hep A - short incubation period (3 weeks)
RNA picornavirus

137

Hepatitis virus that is DNA. How is it transmitted?

Hep B (DNA Hepadnavirus)
transmitted: pareneral, sexual, maternal-fetal routes

138

How long is the incubation for Hep B? What enzymes does it have?

long (3 months)
enzymes: RNA polymerase transcribes RNA from DNA template, Reverse transcriptase transcribes DNA from RNA. the virion enzyme is a DNA dependent DNA polymerase

139

Hep virus that is an RNA flavivirus? How is it transmitted?

Hepatitis C
Transmitted: in the blood - resembles HBV in its course and severity

140

Post transfusion Hep and Hep in IV drug users?

Hep C

141

What Hepatitis can only coinfect or superinfect with Hep B?

Hep D - requires HBsAg as its envelope
superinfection if worse!

142

Hep E

RNA hepevirus - transmitted enterically and causes water-borne epidemics - resmebles HAV in course, severity and incubation

143

What Hep has a high mortality rate in pregnant women?

Hep E!

144

Hep B and C do what?

predispose a patient to chronic active hepatitis, cirrhosis, and hepatocellular carcinoma

145

Why do A and E cause GI problems?

naked viruses do not rely on an envelope, they are not destroyed in the gut

146

If someone is IgG HAVAb positive what does that mean?

Indicates prior infection; protective against reinfection

147

If someone is IgM HAVAb positive

Indicates active Hep A infection

148

HBsAg

Antigen on surface of HBV; continued presence indicates carrier state

149

HBsAb

Antibody to HBV - provides immunity to Hep B

150

HBcAg

antigen to core of HBV

151

HBcAb

positive during window peroid
IgM: indicate recent disease
IgG: chronic disease

152

HBeAg

If high: high infectivity

153

HBeAb

Antibody to e antigen; low transmissbility

154

ALT>AST

viral hepatitis

155

AST>ALT

alcoholic hepatitis

156

HBsAg +
HBsAb -
HBcAb +

acute Hep B disease

157

HBsAg -
HBsAb -
HBcAb +

window phase

158

HBsAg -
HBsAb +
HBcAb +

complete recovery

159

HBsAg +
HBsAb -
HBcAb +

chronic carrier

160

HBsAg -
HBsAb +
HBcAb -

immunized