XIII - Virology Flashcards Preview

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Flashcards in XIII - Virology Deck (366):
1

Size of Viruses

20-300 nm

2

All viruses have a _____ coat.

protein coat (capsid), lipoprotein envelope in some

3

Virus capsids are composed of

repeating capsomeres

4

All helical viruses are

enveloped

5

Icosahedral (spherical) viruses can be enveloped or

naked

6

Viral Proteins

surface proteins, DNA or RNA polymerases, matrix protein, antigenic (serotypic) variants

7

Viral Proteins: Attachment to host cell receptors

surface protein

8

Viral Proteins: Interaction between nucleocapsid and envelope

matrix protein

9

Viral Proteins: Evasion of host defenses

antigenic (serotypic) variants

10

Lipid membrane derived from the host cell, acquired as the virus exits from the cell in a process called budding

viral envelope

11

All enveloped viruses acquire their envelope from plasma membrane except

herpesvirus - nuclear membrane

12

Enveloped viruses are _____ stable and _____ inactivated.

less stable, easily inactivated

13

Naked Viruses

RNA - Calici, Picorna, Reo, DNA - Parvo, Adeno, Papilloma, Polyoma

14

Purified nucleic acids of most dsDNA (except poxviruses and HBV) and (+) strand genome ssRNA viruses are

infectious

15

Naked nucleic acids of (-) strand ssRNA and dsDNA viruses are

not infectious

16

Naked nucleic acids of (-) strand ssRNA and dsDNA viruses require

enzymes contained in the complete virion

17

Infectious particles composed entirely of protein which case transmissible spongiform encephalopathies, highly resistant to inactivation, do not elicit an inflammatory response or an antibody response

Prions

18

Prion Proteins: Non-pathogenic

alpha-helix

19

Prions Proteins: Pathogenic

beta-pleated sheet

20

All viruses are haploid except

retroviruses

21

Genomes of RNA viruses can either have positive or negative

polarity

22

Some RNA viruses have a _____ genome.

segmented genome

23

Viruses with Segmented Genomes

Bunyavirus, Orthomyxovirus (influenza), Arenavirus, Reovirus

24

Must transcribe negative strand to positive, virion brings its own RNA-dependent polymerase

Negative-Strand RNA Viruses

25

Negative-Strand RNA Viruses

Arenavirus, Bunyavirus, Paramyxovirus, Orthomyxovirus, Filovirus, Rhabdovirus

26

Viral Genetics: Mutations can produce

antigenic, drug-resistant or attenuated variants

27

Viral Genetics: Causes epidemics

genomic reassortment

28

Viral Genetics: One virus produces a protein that can be used by another virus

complementation

29

Viral Genetics: Two different viruses infect the same cell

phenotypic mixing

30

Virus Life Cycle

attachment → penetration → uncoating → biosynthesis → maturation → release

31

Viral Growth Curve: A single virus particle infects a cell

Phase 0 - Entry

32

Viral Growth Curve: Virus decreases in number but continues to function

Phase 1 - Decline

33

Viral Growth Curve: No virus is detectable inside the cell

Phase 2 - Eclipse Period

34

Viral Growth Curve: Dramatic increase in amount of detectable viruses

Phase 3 - Rise Period

35

Viral Growth Curve: Amount of detectable viruses reach a plateau

Phase 4 - Latent Period

36

Viral Growth Curve: Marked derangement of cell function leading to lysis and cell death, remarkable amplification in number of viral particles

Phase 5 - Cytopathic Effect

37

Outcomes of Viral Infection: Visual or functional change in infected cells

Cytopathic Effect

38

Outcomes of Viral Infection: Oncogenic viruses induce transformation and unrestrained growth

Malignant Transformation

39

Outcomes of Viral Infection: Infected cells appear normal but are producing large numbers of progeny viruses

Commensal Symbiosis

40

Virulence Factors: Bind cytokines and block their ability to interact with receptors on their intended targets

Cytokine Decoys

41

Virulence Factors: Reduce the expression of antigen presenting cells and inactivate complement

Virokines

42

Viruses: Virulence Factors

antigenic variants of surface proteins, cytokine decoys, virokines

43

Persistent Viral Infections: Produce viruses for long periods of time, can serve as a source of infection for others

Carrier State

44

Persistent Viral Infections: Not producing virus at present but can be reactivated at a subsequent time

Latent Infections

45

Persistent Viral Infections: Long incubation period (years)

Slow Virus Infections

46

Viruses: Presumptive Identification

cytopathic effect, hemadsorption, interference, decrease in acid production (phenol red)

47

Presumptive Identification of Viruses: Attachment of RBCs to the surface of infected cells

hemadsorption

48

Presumptive Identification of Viruses: Disturbance with CPE by another virus

interference

49

Presumptive Identification of Viruses: Decrease in acid production by infected, dying cells

phenol red

50

Viruses: Definitive Diagnosis

complement fixation, hemagglutination inhibition, neutralization, fluorescent-antibody assay, radioimmunoassay, Enzyme-Linked Immunosorbent Assay (ELISA)

51

Virus Serologic Tests: Finding an antibody in one who previously had none

seroconversion

52

Virus Serologic Tests: Ig in current infection

IgM

53

Virus Serologic Tests: Ig that can be from previous infection

IgG

54

Gold Standard in Viral Dagnosis

viral DNA/RNA

55

Vaccines: Induce humoral and cell-mediated immunity but may revert to virulence on rare occasions, dangerous to give to immunocompromised patients or their close contacts

Live-Attenuated Vaccines

56

Only live-attenuated vaccine that may be given to HIV (+) patients

MMR

57

Live-Attenuated Vaccines

yellow fever, chicken pox (VZV), polio (Sabin's), MMR

58

Vaccines: Induce only humoral immunity but are stable

Killed Vaccines

59

Killed Vaccines

rabies, influenza, polio (Salk's), hepatitis A

60

Recombinant Vaccines

Hepatitis B (HBsAg), HPV (6, 11, 16, 18)

61

Hepatitis Virus: A

Picornaviridae

62

Hepatitis Virus: B

Hepadnaviridae

63

Hepatitis Virus: C

Flaviviridae

64

Hepatitis Virus: D

not classified

65

Hepatitis Virus: E

Caliciviridae

66

DNA Viruses

Hepadna, Herpes, Adeno, Pox, Parvo, Polyoma, Papilloma

67

All DNA viruses have dsDNA except

Parvovirus - ssDNA

68

All DNA viruses have linear DNA except

Papilloma, Polyoma, Hepadna

69

All DNA viruses are icosahedral except

Poxvirus - complex symmetry

70

All DNA viruses replicate in the nucleus except

Poxvirus - cytoplasm, Guarnieri bodies

71

Naked DNA Viruses

Parvovirus, Adenovirus, Human Papillomavirus

72

Naked DNA Viruses: Respiratory, transplacental, non-oncogenic, no vaccine

Parvovirus

73

Naked DNA Viruses: Respiratory, fecal-oral, non-oncogenic, vaccine available

Adenovirus

74

Naked DNA Viruses: Sexual, skin contact, oncogenic, vaccine available

Human Papillomavirus

75

Naked virus with icosahedral symmetry, ssDNA genome, one serotype

Parvovirus B19

76

Parvovirus: Transmission

respiratory droplets, transplacental

77

Parvovirus: Infections

Erythema Infectiosum (5th Disease), Aplastic Crisis, Fetal Infections, Arthritis, Chronic B19 Infection

78

Bright red cheeks (slapped cheeks), fever, coryza, sore throat

Erythema Infectiosum (5th Disease) - Parvovirus B19

79

Transient but severe aplastic anemia in children, sickle cell anemia, thalassemia, spherocytosis

Aplastic Crisis - Parvovirus B19

80

Parvovirus Fetal Infections: 1st Trimester

fetal death

81

Parvovirus Fetal Infections: 2nd Trimester

hydrops fetalis

82

Viral immune-complex arthritis of small joints

Parvovirus Arthritis

83

Chronic Parvovirus B19 infection causes _____ in immunodeficient patients.

pancytopenia

84

Naked virus, dsDNA, icosahedral nucleocapsid, only virus with fiber (penton), 41 antigenic types, Cowdry type B intranuclear inclusions

Adenovirus

85

Adenovirus: Transmission

aerosol droplet, fecal-oral, direct contact

86

Adenovirus: URT

pharyngitis, conjunctivitis, coryza

87

Adenovirus: LRT

bronchitis, atypical pneumonia

88

Adenovirus: GIT

acute gastroenteritis

89

Adenovirus: GUT

hemorrhagic cystitis

90

Adenovirus: Histopathology

Cowdry type B intranuclear inclusions

91

Naked virus with circular dsDNA, icosahedral nucleocapsid, at least 100 types

HPV

92

HPV: Transmission

sexually, direct contact

93

Infect squamous cells and induce formation of cytoplasmic vacuole (koilocytes), genes E6 & E7

HPV

94

HPV: Encode proteins that inactivate tumor suppressor genes

genes E6 & E7

95

HPV: Skin and plantar warts

HPV 1-4

96

HPV: Genital warts (condyloma acuminata), respiratory tract

HPV 6 & 11

97

Most common viral STD

HPV

98

HPV: Carcinoma of cervix, penis, anus

HPV 16, 18, 31, 33

99

HPV: Treatment for Genital Warts

Podophyllin

100

HPV: Treatment for Skin Warts

Liquid Nitrogen

101

HPV: Treatment for Plantar Warts

Salicylic Acid

102

HPV: Prevention

vaccine for HPV 6, 11, 16, 18, 9-26 y.o.

103

Only causes disease in immunocompromised hosts, causes progressive multifocal leukoencephalopathy (PML) in AIDS patients

JC Polyoma Virus

104

Demyelinating disease that affects oligodendrocytes characterized by deficits in speech, coordination and memory, AIDS patients

Progressive Multifocal Leukoencephalopathy (PML)

105

Only causes disease in immunocompromised hosts, causes hemorrhagic cystitis and nephropathy in patients with solid organ (kidney) and bone marrow transplants

BK Polyoma Virus

106

Enveloped DNA Virsues

HSV, VZV, EBV, CMV, HHV

107

Herpesviruses

CMV, HSV, EBV, VZV

108

Enveloped virus, icosahedral nucleocapsid, linear dsDNA, vesicle filled with virus particles and cell debris, multinucleated giant cells on Tzanck smear, large, pink-purple intranuclear inclusions (Cowdry type A)

Herpes Simplex Virus

109

Herpes Simplex Virus: Transmission

HSV 1 - saliva, direct (above umbilicus), HSV 2 - sexual, transvaginal (below umbilicus)

110

Herpes Simplex Virus: Site of Latency

HSV 1 - trigeminal ganglia, HSV 2 - lumbosacral ganglia

111

HSV: Gingivostomatitis, herpes labialis (lips), keratoconjunctivitis, temporal lobe encephalitis, herpetic whitlow (fingers), herpes gladiatorum (trunk)

HSV 1

112

HSV: Genital herpes (painful anogenital vesicles), neonatal herpes (contact within birth canal), aseptic meningitis

HSV 2

113

Herpes Simplex Virus: Treatment

Acyclovir

114

Needs virus kinase to be activated, analogue of guanine, shortens duration of lesions, reduces the extent of shedding of the virus, no effect on the latent sate

Acyclovir

115

Enveloped virus, icosahedral nucleocapsid, linear dsDNA, infects URT, hematogenous spread to the skin, becomes latent in the dorsal root ganglia, may reactivate as zoster, multinucleated giant cells with intranuclear inclusions

Varicella-Zoster Virus

116

Varicella-Zoster Virus: Transmission

respiratory droplets, direct contact with lesions

117

Varicella-Zoster Virus: Diseases

Varicella, Zoster, Ramsay Hunt Syndrome

118

VZV: Incubation period of 14-21 days, vesicular centrifugal rash in different stages (dewdrop on a rose petal), pneumonia, encephalitis, Reye's Syndrome

Varicella

119

Aspirin in Pediatric Cases

Kawasaki, ARF, JRA

120

VZV: Painful vesicles along dermatomal distribution, debilitating pain (postherpetic neuralgia)

Zoster

121

VZV: Involvement of geniculate ganglion causes facial nerve paralysis

Ramsay Hunt Syndrome

122

Varicella-Zoster Virus: Site of Latency

dorsal root ganglia

123

Varicella-Zoster Virus: Treatment

Acyclovir - moderate to severe (shortens duration of lesions)

124

Enveloped virus, icosahedral nucleocapsid, linear dsDNA, cultured in shell tubes, (-) neutrophil test

Cytomegalovirus

125

Cytomegalovirus: Transmission

body fluids, transplacental, organ transplant

126

Immediate early proteins, giant cells with owl's-eye nuclear inclusions

Cytomegalovirus

127

Cytomegalovirus: Translated from premade mRNAs, impair assembly of the MHC class I-viral peptide complexes

Immediate Early Proteins

128

Cytomegalovirus: Diseases

congenital CMV, heterophil (-) mononucleosis, systemic CMV

129

Most common cause of congenital abnormalities

Cytomegalovirus

130

Microcephaly, seizures, deafness, jaundice, purpura (blueberry muffin), most common when mother is infected in the 1st trimester

Congenital CMV

131

Fever, lethargy, abnormal lymphocytes in peripheral blood smears

Heterophil (-) Mononucleosis

132

Pneumonitis, hepatitis, colitis, retinitis in HIV

Systemic CMV

133

Cytomegalovirus: Treatment

Gancyclovir (resistant to Acyclovir), Foscarnet - retinitis

134

Enveloped virus, icosahedral nucleocapsid, linear dsDNA, infects mainly lymphoid cells (B-cells → Downey cells), elicits specific antibodies and nonspecific heterophil antibodies

Epstein-Barr Virus

135

Epstein-Barr Virus: Transmission

saliva

136

Kissing Disease

Epstein-Barr Virus

137

Epstein-Barr Virus: Diseases

Infectious Mononucleosis, malignancies

138

Fever, sore throat, lymphadenopathy, splenomegaly, splenic rupture

Infectious Mononucleosis

139

Epstein-Barr Virus: Malignancies

Burkitt's Lymphoma (Africans), B-cell Lymphomas, Nasopharyngeal CA (Chinese), Hairy Leukoplakia (AIDS)

140

Malignancy of vascular endothelial cells, flat to nodular dark purple skin lesions at multiple sites

Kaposi's Sarcoma (Human Herpesvirus 8)

141

Kaposi's Sarcoma: Treatment

surgical excision, radiation

142

Only disease that has been eradicated from Earth

Smallpox (Variola Virus)

143

Largest virus, brick-shaped poxvirus, Guarnieri bodies (intracytoplasmic eosinophilic inclusions)

Smallpox (Variola Virus)

144

Smallpox: Transmission

aerosol, contact

145

Smallpox: Incubation Period

7-14 days

146

Smallpox: Findings

prodrome of fever and malaise followed by centrifugal rash

147

Pinkish, papular skin lesions with an umbilicated center, Henderson-Peterson bodies (intracytoplasmic eosinophilic inclusions)

Molluscum Contagiosum

148

Molluscum Contagiosum: Transmission

direct contact

149

Molluscum Contagiosum: Treatment

Cifodivir

150

Enveloped virus, incomplete circular dsDNA

Hepadnaviridae (Hepatitis B)

151

Hepatitis Types: Asymptomatic

Hepatitis A

152

Hepatitis Types: Blood-borne

Hepatitis B

153

Hepatitis Types: Chronic, cirrhosis, carcinoma, carriers

Hepatitis C

154

Hepatitis Types: Enteric, expectant mothers, epidemics

Hepatitis E

155

Hepatitis Types: Enteric infections

Hepatitis A & E

156

Hepadnaviridae: Transmission

blood, birth, sexual

157

Hepadnaviridae: Virulence Factors

HBsAg - surface antigen, HBcAg - core antigen, HBeAg - e antigen

158

Only DNA virus that produces DNA by reverse transcription with mRNA as template

Hepadnaviridae (Hepatitis B)

159

Hepadnaviridae causes hepatocellular injury due to

immune attack (HBV has no cytopathic effect)

160

Hepadnaviridae: Incubation Period

10-12 weeks

161

Fever, anorexia, jaundice, dark urine, pale feces, elevated transaminase levels, cirrhosis, hepatocellular CA, autoimmune vasculitides (polyarteritis nodosa)

Hepadnaviridae (Hepatitis B)

162

Hepatitis B Complications: Functional renal failure from hepatic injury in the abscence of renal pathology

Hepatorenal Syndrome

163

Hepatitis B Complications: Vascular dilatations cause overperfusion relative to ventilation leading to V/Q mismatch and hypoxemia

Hepatopulmonary Syndrome

164

Hepatitis B Complications

hepatorenal syndrome, hepatopulmonary syndrome, portal HPN, hepatic encephalopathy

165

Hepadnaviridae: Treatment

Interferon α, Lamivudine

166

Hepadnaviridae: Prevention

vaccination - first vaccine to prevent human cancer

167

All RNA viruses have ssRNA except

Reovirus, Rotavirus (dsRNA)

168

All RNA viruses replicate in the cytoplasm except

Influenza, Retrovirus (nucleus)

169

Picornaviridae

Polio, Echo, Rhino, Coxsackie, Hepatitis A

170

Naked nucleocapsid, ssRNA with (+) polarity, oral-fecal transmission, replicates in motor neurons in the anterior horn of the spinal cord causing paralysis

Poliovirus

171

Host range is limited to primates due to the binding of the viral capsid protein to a receptor found only on primate cell membranes

Poliovirus

172

Has 3 serologic (antigenic) types based on different antigenic determinants on the outer capsid proteins

Poliovirus

173

Poliovirus: Diseases

asymptomatic, abortive poliomyelitis, non-paralytic poliomyelitis, paralytic poliomyelitis

174

Poliovirus: Most common clinical form, mild, febrile illness, headache, sore throat, nausea, vomiting

abortive poliomyelitis

175

Poliovirus: Aseptic meningitis

non-paralytic poliomyelitis

176

Poliovirus: Flaccid paralysis, permanent motor nerve damage

paralytic poliomyelitis

177

Poliovirus: Histopathology

Cowdry type B intranuclear inclusions

178

Poliovirus: Prevention

killed vaccine (Salk, IPV), live-attenuated vaccine (Sabin, OPV)

179

Polio Vaccine: Interrupts transmission

live-attenuated vaccine (Sabin, OPV)

180

Polio Vaccine: Induces humoral IgG

killed vaccine (Salk, IPV), live-attenuated vaccine (Sabin, OPV)

181

Polio Vaccine: Induces intestinal IgA

live-attenuated vaccine (Sabin, OPV)

182

Polio Vaccine: Affords secondary protection by spread to others

live-attenuated vaccine (Sabin, OPV)

183

Polio Vaccine: Interferes with replication of virulent virus in gut

live-attenuated vaccine (Sabin, OPV)

184

Polio Vaccine: Reverts to virulence

live-attenuated vaccine (Sabin, OPV)

185

Polio Vaccine: Co-infection with enteroviruses may impair immunization

live-attenuated vaccine (Sabin, OPV)

186

Polio Vaccine: Can cause disease in the immunocompromised

live-attenuated vaccine (Sabin, OPV)

187

Polio Vaccine: Injection

killed vaccine (Salk, IPV)

188

Polio Vaccine: Oral

live-attenuated vaccine (Sabin, OPV)

189

Polio Vaccine: Requires refrigeration

live-attenuated vaccine (Sabin, OPV)

190

Polio Vaccine: Short immunity

killed vaccine (Salk, IPV)

191

Polio Vaccine: Long-lasting immunity

live-attenuated vaccine (Sabin, OPV)

192

Naked nucleocapsid, ssRNA, (+) polarity, classified based on pathogenicity in mice

Coxsackievirus

193

Coxsackievirus: Transmission

oral-fecal

194

Coxsackievirus A: Diseases

herpangina, hand-foot-and-mouth disease, hemorrhagic conjunctivitis, aseptic meningitis

195

Coxsackievirus B: Diseases

pleurodynia, myocarditis, pericarditis, aseptic meningitis

196

Coxsackievirus: Fever, sore throat, tender vesicles in oropharynx

herpangina

197

Coxsackievirus: Vesicular rash on hands and feet and ulcerations in the mouth

hand-foot-and-mouth disease

198

Coxsackievirus: Fever, severe pleuritic chest pain

pleurodynia

199

Coxsackievirus: Fever, chest pain, congestive failure

myocarditis, pericarditis

200

Most common cause of myocarditis and pericarditis

Coxsackievirus

201

Most common cause of aseptic meningitis

Coxsackievirus

202

Coxsackievirus, Poliovirus and Echovirus are

enteroviruses

203

Enteric Cytopathic Human Orphan

ECHOvirus

204

Virus initially not associated with any disease

Echovirus

205

Aseptic meningitis, URTI, febrile illness ± rash, infantile diarrhea, hemorrhagic conjunctivitis

Echovirus

206

Echovirus: Transmission

fecal-oral

207

Only respiratory picornavirus, causes common colds

Rhinovirus

208

Naked nucleocapsid virus, ssRNA, (+) polarity, more than 100 serotypes, affect mainly the nose and conjunctiva, replicates better at 33°C, acid-labile, host range limited to humans and chimpanzees

Rhinovirus

209

Rhinovirus: Transmission

aerosol droplets, hand-to-nose contact

210

Naked nucleocapsid virus, ssRNA, (+) polarity, frequently infects children, self-limited hepatitis, anti-HAV IgM (most important test), Enterovirus 72, has 1 serotype

Hepatitis A Virus (Picornaviridae)

211

Hepatitis A Virus: Transmission

fecal-oral

212

Hepatitis A Virus: Diagnosis

anti-HAV IgM

213

Fecal-oral transmission, no chronic carrier state, no cirrhosis, no hepatocellular CA, high mortality in pregnant women, causes hepatitis epidemics

Hepatitis E Virus (Caliciviridae)

214

Non-enveloped virus, icosahedral nucleocapsid, one piece of ssRNA, (+) polarity, sudden onset of vomiting and diarrhea accompanied by fever and abdominal cramping

Norwalk Virus/Norovirus (Viral Gastroenteritis)

215

Most common cause of non-bacterial diarrhea in adults

Norwalk Virus/Norovirus

216

Naked double-layered capsid with 10-11 segments of dsRNA, most common cause of childhood diarrhea

Rotavirus (Viral Gastroenteritis)

217

Enveloped virus, helical nucleocapsid, segmented ssRNA, (-) polarity, most common cause of respiratory tract infections

Influenza Virus

218

Influenza Virus: Major Antigens

hemagglutinin (H), neuraminidase (N)

219

Influenza Virus: Transmission

respiratory droplet

220

Influenza Virus: Worldwide epidemics (pandemics)

Influenza A

221

Influenza Virus: Major outbreaks

Influenza B

222

Influenza Virus: Mild respiratory tract infections, does not cause outbreaks

Influenza C

223

Influenza Virus: Pathogenesis

Envelope → 2 different types of spikes: hemagglutinin (H), neuraminidase (N)

224

Influenza Virus: 16 types of hemagglutinin (H), 9 types of neuraminidase (N)

Influenza A

225

Binds to the cell surface receptor (neuraminic acid/sialic acid) to initiate infection of the cell, target of neutralizing antibody

hemagglutinin

226

Cleaves neuraminic acid (sialic acid) to release progeny virus from infected cell, degrades the protective layer of mucus in the respiratory tract → enhances access to the respiratory epithelial cells

neuraminidase

227

Animal influenza viruses are the source of RNA segments that encode the antigenic _____ variants that cause epidemics among humas.

antigentic shift

228

Creation of new influenza variants

Reassortment

229

Common source of new influenza variants

aquatic birds (waterfowl)

230

Influenza "Mixing Bowl"

Pigs

231

Influenza Variants: Waterfowl

H1-H16, N1-N9

232

Influenza Variants: Humans

H1-H3, N1 and N2

233

Influenza: Only a human virus (no animal source), undergoes antigenic drift, new version every year

Influenza B

234

Influenza Variants: Major changes based on the reassortment of segments of the genome RNA, causes pandemics

antigenic SHIFT

235

Influenza Variants: Minor changes based on mutations in the genome RNA

antigenic DRIFT

236

Influenza: Incubation Period

24-48 hours

237

Fever, myalgias, headache, sore throat, cough

Influenza

238

Influenza: Complications

Staphylococcal Pneumonia, Reye's Syndrome

239

Influenza: Treatment

Oseltamivir, Zanamivir, Influenza A - Amantadine, Rimantadine (Parkinson's medicine, prevents viral uncoating)

240

Influenza: Prevention

annual vaccination

241

Paramyxoviridae

Parainfluenza, RSV, Measles, Mumps

242

Paramyxoviridae: Hemagglutinin (+), Neuraminidase (-), Fusion Protein (+)

Measles

243

Paramyxoviridae: Hemagglutinin (+), Neuraminidase (+), Fusion Protein (+)

Mumps, Parainfluenza

244

Paramyxoviridae: Hemagglutinin (-), Neuraminidase (-), Fusion Protein (+)

RSV

245

Enveloped virus, helical nucleocapsid, one piece of ssRNA, (-) polarity, infects URT, spreads to reticuloendothelial cells, hematologic spread to skin, transiently depress cell-mediated immunity

Measles

246

Multinucleated giant cells (Warthin-Finkeldey bodies) form as a result of the fusion protein in the spikes - characteristic of the lesions, lifelong immunity after recovery

Measles

247

Measles rash is caused by

cytotoxic T cells, attacking the infected vascular endothelial cells in the skin

248

Measles: Shortly after the rash appears, the virus can no longer be recovered and the patient _____ spread the virus.

can no longer spread the virus

249

Measles: Incubation Period

10-14 days

250

Measles: Pathognomonic Sign

Koplik's Spots

251

Measles: Bright red lesions with white central dot on buccal mucosa

Koplik's Spots

252

Measles: Rash

face → trunk → extremities → palms/soles

253

Rash: face → trunk → extremities → palms/soles

Measles

254

Measles: Complications

encephalitis, pneumonia, subacute sclerosing panencephalitis (SSPE) or Dawson disease

255

Measles: Triad

cough, coryza, conjunctivitis

256

Measles: Prevention

live-attenuated vaccine, Vitamin A - reduces severity

257

Enveloped virus, helical nucleocapsid, one piece of ssRNA, (-) polarity, initially infects URT, spreads to local lymph nodes, hematogenous spread to parotid glands, testes, ovaries, meninges, pancreas

Mumps

258

Mumps: Transmission

respiratory droplets

259

Mumps: Incubation Period

18-21 days

260

Tender swelling of the parotid glands (parotitis) with increased pain when drinking citrus juices, orchitis, meningitis, resolves in 1 week

Mumps

261

Mumps: Prevention

live-attenuated vaccine

262

Surface spikes are fusion proteins (not hemagglutinin or neuraminidase) which causes cells to fuse, forming multinucleated giant cells (syncitia), humans are the natural hosts

Respiratory Syncitial Virus

263

Most important cause of pneumonia and bronchiolitis in infants

Respiratory Syncitial Virus

264

Severe disease in infants due to immunologic cross-reaction with maternal antibodies

Respiratory Syncitial Virus

265

Respiratory Syncitial Virus: Treatment

Ribavirin

266

Inspiratory stridor, cough, hoarseness, steeple sign (subglottic stenosis)

Laryngotracheobronchitis / Croup (Parainfluenza Virus 1 & 2)

267

Laryngotracheobronchitis: Treatment

Racemic Epinephrine

268

Bullet-shaped enveloped virus with helical nucleocapsid, one piece of ssRNA, (-) polarity

Rabies

269

Rabies: Transmission

animal bite - dog, cats, skunks, racoons, bats

270

Multiplies locally at the bite site, infects sensory neurons and moves by axonal transport to CNS

Rabies

271

Rabies: Histopathology

Negri bodies

272

Rabies: Incubation Period

2-16 weeks - depends on bite site

273

Confusion, lethargy, hypersalivation, laryngospasm, hydrophobia, invariably fatal when encephalitis develops

Rabies

274

Rabies: Treatment and Prevetion

pre- and post-exposure vaccine (only vaccine routinely used post-exposure), post-exposure Ig

275

Rabies Post-Exposure Prophylaxis: Touching or feeding animals, licks on skin

Category I - no treatment

276

Rabies Post-Exposure Prophylaxis: Nibbling of uncovered skin, minor scratches or abrasions without bleeding, licks on broken skin

Category II - vaccine

277

Rabies Post-Exposure Prophylaxis: Single or multiple transdermal bites or scratches, contamination of mucous membranes with saliva from licks, exposure to bat bites or scratches

Category III - vaccine + Ig

278

Enveloped virus, helical nucleocapsid, one piece of ssRNA, (+) polarity, prominent club-shaped spikes forming a corona, 2 serotypes

Coronavirus

279

Coronavirus: Reservoir

horseshoe bat

280

Coronavirus: Intermediate Host

civet cat

281

Coronavirus: Transmission

respiratory droplets

282

Coronavirus: Diseases

common cold, Severe Acute Respiratory Syndrome (SARS)

283

SARS: Incubation Period

2-10 days

284

Atypical pneumonia rapidly progressing to ARDS, virus binds to ACE-2 receptors, non-cavitary "ground glass" infiltrates

Severe Acute Respiratory Syndrome (SARS)

285

Enveloped virus, icosahedral nucleocapsid, one piece of ssRNA, (+) polarity, flavivirus, 4 serotypes

Dengue

286

Dengue: Vector

Aedes aegypti mosquito

287

Dengue: Diagnosis

dengue IgM, tourniquet test

288

Influenza-like syndrome with maculopapular rash and severe pains in muscles and joints (breakbone fever), leukopenia, thrombocytosis, hemorrhagic shock due to cross-reacting antibody during 2nd infection

Dengue

289

Probable Dengue

endemic area, fever ± (nausea, vomiting, rash, aches/pains, tourniquet test (+), leukopenia, any warning sign)

290

Dengue: Warning Signs

abdominal pain or tenderness, persistent vomiting, clinical fluid accumulation, mucosal bleed, lethargy, restlessness, liver enlargement > 2cm, increase in Hct concurrent with rapid decrease in PC

291

Severe Dengue

severe plasma leakage (shock, fluid accumulation with respiratory distress), severe bleeding, severe organ involvement (AST or ALT ≥ 1000, impaired consciousness)

292

Dengue: Prevention

insecticides, draining stagnant water, mosquito repellant

293

Enveloped virus, one piece of ssRNA, (+) polarity, 6 serotypes, hypervariable region in envelope glycoprotein

Hepatitis C

294

Hepatitis C: Diagnosis

anti-HCV or HCV RNA

295

Most prevalent blood-borne pathogen

Hepatitis C

296

IV drug abusers, needle-stick injury, vertical transmission, sexual transmission

Hepatitis C

297

Most common needle-stick injury pathogen

Hepatitis B

298

Replication in liver enhanced by liver-specific micro-RNA, hepatocellular injury due to immune attack, alcoholism greatly enhances rate of hepatocellular CA, chronic carriage is higher than HBV

Hepatitis C

299

Hepatitis C: Incubation Period

8 weeks

300

Hepatitis C: Autoimmune Reactions

thyroiditis, autoantibodies, MPGN, porphyria cutanea tarda, DM

301

Main cause of essential mixed cryoglobulinemia

Hepatitis C

302

Hepatitis C: Treatment for Acute Disease

Interferon

303

Hepatitis C: Treatment for Chronic Disease

Peginterferon, Ribavarin

304

Hepatitis C: Treatment for Severe Disease

liver transplant

305

Most common indication for liver transplant

Hepatitis C

306

Enveloped virus, icosahedral nucleocapsid, one piece of ssRNA, (+) polarity, togavirus

Rubella

307

Rubella: Transmission

respiratory droplets, transplacental

308

Rubella: Diseases

German Measles, Congenital Rubella Syndrome

309

German Measles: Incubation period

14-21 days

310

Prodrome followed by 3-day maculopapular rash and posterior CLAD, rash (face → trunk → arms/legs), immune-complex polyarthritis in adults

German Measles (Rubella)

311

Infected during 1st trimester, PDA, congenital cataracts, sensorineural deafness, mental retardation

Congenital Rubella Syndrome

312

Rubella: Prevention

live-attenuated vaccine (should not be given to immunocompromised or pregnant patients)

313

RNA viruses with reverse transcriptase

Retroviridae

314

Converts ssRNA viral genome into viral dsDNA

reverse transcriptase

315

Enveloped virus with 2 copies (diploid) of a ssRNA, (+) polarity, most complex retrovirus, many serotypes

Human Immunodeficiency Virus (HIV)

316

HIV: Transmembrane protein (TM) which is linked to a surface protein (SU)

fusion protein (gp41)

317

HIV: Attachment protein

gp120

318

HIV: Cone-shaped, icosahedral core containing the major capsid protein

CA (p24) - diagnosis

319

HIV: Directs entry of dsDNA provirus into the nucleus and is later essential for the process of virus assembly

MA (p17)

320

HIV: RNA is tightly packed with basic protein in a nucleocapsid structure that differs in morphology among diffent retrovirus genera

NC (p7)

321

HIV Genes: p24, p7, p17

gag

322

HIV Genes: Nucleocapsid, Matrix

gag

323

HIV Genes: Reverse transcriptase, Protease, Integrase

pol

324

HIV Genes: gp120, gp41

env

325

HIV Proteins: gag

p24, p7, p17

326

HIV Proteins: nucleocapsid

p24, p7

327

HIV Proteins: matrix

p17

328

HIV Proteins: pol

reverse transcriptase, protease, integrase

329

HIV Proteins: Transcribes RNA genome into DNA

reverse transcriptase

330

HIV Proteins: Cleaves precursor polyeptides

protease

331

HIV Proteins: Integrates viral DNA into host cell DNA

integrase

332

HIV Proteins: env

gp120, gp41

333

HIV Proteins: Attachment to CD4 protein, antigenicity changes rapidly

gp120

334

HIV Proteins: Fusion with host cell

gp41

335

HIV: Group-specific antigen, core, not known to vary, antibodies against this do not neutralize infectivity but serve as important serologic markers of infection

p24

336

HIV: Interacts with the CD4 receptor, mutates rapidly because of lack of editing, many antigenic variants, V3 - most immunogenic region, antibody neutralizes infectivity

gp120

337

HIV: Mediates fusion of the viral envelope with the cell membrane

gp41

338

HIV Genes: Activation of transcription of viral genes

tat

339

HIV Genes: Transport of late mRNAs to cytoplasm

rev

340

HIV Genes: Decreases CD4 and class I MHC proteins

nef

341

HIV Genes: Enhances hypermutation

vif

342

HIV Genes: Transport in non-dividing cells

vpr

343

HIV Genes: Enhances virion release

vpu

344

HIV: Transmission

originally from chimpanzees, transfer of body fluids, transplacental, perinatal, needlestick, sexual contact

345

Preferentially infects and kills helper (CD4) T lymphocytes, loss of cell-mediated immunity, high probability of opportunistic infections, main immune response consists of cytotoxic (CD8) T-lymphocytes

HIV

346

HIV Phases: Acquired through sexual contact, blood, perinatally

Phase 0 - Infection

347

HIV Phases: Rapid viral replication but HIV test is (-)

Phase 1 - Window Period

348

HIV Phases: Peak of viral load, (+) HIV test, mild flu-like illness lasting 1-2 weeks

Phase 2 - Seroconversion

349

HIV Phases: Asymptomatic, CD4 goes down, lasts 1-15 years

Phase 3 - Latent Period

350

HIV Phases: CD4 500-200, lasts 5 years, mild mucocutaneous, dermatologic and hematologic illness

Phase 4 - Early Symptomatic

351

HIV Phases: CD4 < 200, lasts 2 years, AIDS-defining illnesses develop

Phase 5 - AIDS

352

AIDS-Defining Illnesses: CD4 < 500

M. tuberculosis (disseminated TB), HSV (eophagitis), C. albicans (esophageal candidiasis), HHV-8 (Kaposi's sarcoma)

353

AIDS-Defining Illnesses: CD4 < 200

P. jiroveci (PCP pneumonia), T. gondii (cerebral toxoplasmosis), C. neoformans (meningoencephalitis), C. immitis (coccidioidomycosis), C. parvum (chronic diarrhea)

354

AIDS-Defining Illnesses: CD4 < 50

M. avium (invasive pulmonary disease), H. capsulatum (histoplasmosis), CMV (retinitis)

355

Most common AIDS-defining illnesses

P. carinii pneumonia (PCP), esophageal candidiasis, wasting, Kaposi's sarcoma, disseminated MAC

356

Most common among AIDS-defining illnesses

P. carinii pneumonia (PCP)

357

HIV: Presumptive Diagnosis

ELISA

358

HIV: Definitive Diagnosis

Western Blot (gp41, p24)

359

HIV: Treatment

Highly Active Antiretroviral Therapy (HAART)

360

2 nucleoside inhibitors (Zidovudine, Lamivudine) and protease inhibitor (Indinavir), immune reconstitution syndrome in patients co-infected with HBV, HCV, MAC/MAI

Highly Active Antiretroviral Therapy (HAART)

361

HIV: General Prevention

condoms, not sharing needles, proper blood disposal, post-exposure prophylaxis

362

HIV: Perinatal Prevention

perinatal prophylaxis, CS delivery, breastfeeding cessation

363

Retrovirus causing adult T-cell leukemia and a HTLV-associated myelopathy, malignant T-calls with flower-shaped nucleus

Human T-cell Lymphotropic Virus (HTLV)

364

Thread-like virus, longest virus, outbreak of hemorrhagic fever in Zaire (1976), 100% mortality rate

Ebola Hemorrhagic Fever

365

Flavivirus, bird-mosquito-man cycle, initial self-limited febrile illness with progression to neuroinvasive disease

West Nile Fever

366

Flavivirus, most common cause of epidemic encephalitis, most prevalent in SEA, transmitted by Culex mosquitoes, thalamic infarcts on CT scan

Japanese B Encephalitis