Virology Flashcards
(389 cards)
1
Q
What infection in a patient with a CD4+ count <100 cells/mm3 presents with non-specific systemic symptoms and lymphadenitis?
A
Mycobacterium avium-intracellulare or Mycobacterium avium complex infection
2
Q
What is the most salient clinical difference between opportunistic infections of Candida albicans and Epstein-Barr virus?
A
White plaques are scrapable in oral thrush (Candida albicans) whereas white plaques of oral hair leukoplakia are unscrapable (Epstein-Barr virus)
3
Q
Of the dengue and Chikungunya viruses, which is more likely to cause severe clinical symptoms that could lead to death?
A
Dengue (neutropenia, thrombocytopenia, hemorrhage, shock)
4
Q
What molecular characteristic allows the hepatitis C virus (HCV) to evade host antibodies?
A
HCV lacks 3′-5′ exonuclease activity → no proofreading → antigenic variation of HCV envelope proteins and new viral mutant strains
5
Q
Which 2 RNA viruses do not replicate in the cytoplasm?
A
Retrovirus and influenza virus (retroflu is outta cyt [sight])
6
Q
What stage of hepatitis B infection does positive hepatitis B surface antigen (HBsAg), hepatitis B e antibody (anti-HBe), and hepatitis B core antibody (anti-HBc IgG) indicate?
A
Chronic hepatitis B virus (HBV) and low infectivity
7
Q
Which 3 herpesviruses are transmitted via sexual contact?
A
Herpes simplex virus-2 (HSV-2), cytomegalovirus, and human herpesvirus-8 (HHV-8)
8
Q
In patients with HIV, what virus can cause progressive multifocal leukoencephalopathy (PML)?
A
JC virus (polyomavirus, Junky Cerebrum)
9
Q
Why can hepatitis D (HDV) infection only occur in conjunction with hepatitis B (HBV) infection?
A
HDV is a defective virus so it depends on the HBV HBsAg coat for entry into hepatocytes
10
Q
If the intracellular adhesion molecule (ICAM-1) receptor is blocked, what virus will have difficulty infecting the cells?
A
Rhinovirus (binds to ICAM-1); “I CAMe to see the rhino”
11
Q
What cells are infected by the Epstein-Barr virus?
A
Infects B cells via CD21
12
Q
What possible sequela can occur in mumps, especially after puberty?
A
Sterility
13
Q
What are the symptoms associated with dengue hemorrhagic fever?
A
Dengue fever with bleeding and plasma leakage (thrombocytopenia) and extremes in hematocrit (high or low)
14
Q
Describe how the genome of progeny virus is obtained from completed partial dsDNA.
A
Host RNA polymerase transcribes mRNA from viral DNA; DNA polymerase then reverse transcribes viral RNA to DNA
15
Q
What do IgG antibodies to hepatitis B core antigen (HBcAg) signify?
A
Chronic infection or prior exposure to hepatitis B
16
Q
What is the RNA structure of the rhabdovirus?
A
Enveloped, single-stranded, negative-sense, linear RNA with a helical capsid
17
Q
What is the incubation period for Ebola?
A
Up to 21 days
18
Q
What is the pathology that leads to dengue shock syndrome?
A
Plasma leakage leading to circulatory collapse
19
Q
Compare the incubation periods of hepatitis A, B, C, and E.
A
Hepatitis A and E: short (weeks); B and C: long (months)
20
Q
What is the purpose of neuraminidase antigen on the parainfluenza viral membrane?
A
Promotes progeny virion release (neuraminadaways sends virus away)
21
Q
What is the pathophysiology of the “blueberry muffin” rash seen in congenital rubella?
A
Dermal extramedullary hematopoiesis
22
Q
What endoscopic and biopsy findings are seen in Candida albicans esophagitis?
A
White plaques on endoscopy; biopsy shows yeast and pseudohyphae
23
Q
Name 4 medically significant conditions caused by bunyaviruses.
A
Hantavirus infection (hemorrhagic fever, pneumonia), California encephalitis, Crimean-Congo hemorrhagic fever, Sandfly/Rift Valley fevers
24
Q
What predisposing factor significantly increases the risk of developing dengue hemorrhagic fever?
A
Infection with a different dengue virus serotype after initial infection (due to antibody-dependent enhancement of disease)
25
What is the route of transmission for hepatitis A?
Fecal-oral via contaminated shellfish, exposure during travel, or in daycare centers
26
Describe the symptoms caused by Zika virus infection.
Conjunctivitis, low-grade pyrexia, and an itchy rash (20% of cases)
27
What virus can act like Epstein-Barr virus (HHV-4) but have a negative monospot test?
Cytomegalovirus (HHV-5)
28
What are the 2 most common renal manifestations of hepatitis B?
Membranous glomerulonephritis \> membranoproliferative glomerulonephritis
29
What virus causes croup?
Parainfluenza virus
30
Hepatitis D virus (HDV) infection needs coinfection with hepatitis B to supply the envelope protein for HDV. What is this mechanism called?
Complementation
31
By what mechanism does rotavirus cause gastroenteritis?
Rotavirus causes destruction of the intestinal villi and atrophy → ↓ reabsorption of Na+ and loss of K+
32
What vaccine has made mumps uncommon?
MMR (measles, mumps, rubella)
33
During which phase of HIV infection does the CD8+ T-cell count decline the most rapidly?
Systemic immunodeficiency/AIDS-defining illnesses phase (associated with exhaustion)
34
Describe the progression of rabies infection.
Fever and malaise → agitation, photophobia, hydrophobia, hypersalivation → paralysis, coma → death
35
What is the RNA structure of the flavivirus?
Enveloped, single-stranded, positive-sense, linear RNA with an icosahedral capsid
36
Which 2 viruses in the picornavirus family are not enteroviruses?
Rhinovirus and hepatitis A virus (HAV)
37
What ⊕ markers are expected in a chronic hepatitis B virus infection with high infectivity?
Hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and hepatitis B core antibody (anti-HBc) IgG
38
What test can be performed in the setting of an inconclusive HIV-1/2 differentiation assay?
HIV-1 nucleic acid test (NAT)
39
What condition in humans is caused by enteroviruses within the picornavirus family?
Aseptic meningitis
40
What RNA virus family does rabies belong to?
Rhabdoviruses
41
Why are the hepatitis B, C, and D viruses unable to spread via the fecal-oral route?
B, C, and D = enveloped viruses which are killed in the gut; A and E = naked viruses are not destroyed in the GI tract (vowels hit your bowels)
42
Infections with which organisms are possible when the CD4+ count is \<200 cells/mm3?
JC virus reactivation, Pneumocystis jirovecii, HIV infection, Histoplasma capsulatum
43
Other than animal bites, how else can rabies virus be transmitted?
Aerosol transmission (eg, bat caves)
44
Name 2 viruses found in the reovirus family.
Rotavirus (fatal diarrhea in kids) and coltivirus (Colorado tick fever)
45
What are the 7 positive-stranded RNA viruses?
I went to a retro (Retrovirus) toga (togavirus) party, where I drank flavored (flavivirus) Corona (coronavirus) and ate hippie (hepevirus) California (calicivirus) pickles (picornavirus)
46
What hepatitis virus is associated with polyarteritis nodosa?
Hepatitis B
47
From what source do enveloped viruses generally obtain their envelopes?
From the plasma membrane as they exit the cell
48
What characteristic liver biopsy findings are seen in hepatitis C?
Lymphoid aggregates with focal macrovesicular steatosis
49
Which lobe of the brain is most commonly affected in herpes encephalitis?
Temporal lobe (implicated virus is herpes simplex virus)
50
What is the RNA structure of the hepatitis D virus (HDV)?
Single-stranded, negative-sense, circular RNA
51
What serologic markers would you expect in a patient immunized against Hepatitis B?
⊕ Anti-HBs (all other hepatitis B markers negative)
52
What is the RNA structure of the orthomyxovirus?
Enveloped, single-stranded, negative-sense, linear (in 8 segments) RNA with a helical capsid
53
How is infection with the Chikungunya virus diagnosed?
Reverse transcription-polymerase chain reaction (RT-PCR) or serology
54
What complications may occur to a fetus exposed to parvovirus B19?
Hydrops fetalis and fetal demise
55
Describe the DNA structure of hepadnavirus, including whether or not it is enveloped.
Partially double-stranded, circular DNA, enveloped
56
How does HIV integrate its genome into the host DNA?
Reverse transcriptase converts HIV viral RNA → double-stranded DNA → integrates into host DNA
57
What 2 groups act as reservoirs for the yellow fever virus?
Monkeys and humans
58
What occurs during the acute phase of infection by human immunodeficiency virus (HIV)?
Widespread dissemination and seeding of the lymphoid organs
59
What rodent-borne bunyavirus causes a hemorrhagic pulmonary syndrome?
Hantavirus
60
What is the function of hemagglutinin antigen on the parainfluenza viral membrane?
Promotes viral entry by binding to sialic acid (hemagglutinin brings virus in)
61
What are the typical symptoms of infection by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)?
Fever, dry cough, shortness of breath fatigue (however often patients are asymptomatic)
62
What is the incubation period before symptom onset in rabies?
Weeks to months
63
What is the viral structure of rotavirus?
Segmented double-stranded RNA virus (reovirus family)
64
Name the 2 major antigens of the influenza virus.
Hemagglutinin and neuraminidase
65
What is the most common cause of measles-associated death in children?
Pneumonia
66
Which 2 picornaviruses commonly cause aseptic meningitis?
Echovirus and coxsackievirus
67
What ⊕ markers would you expect during the acute stage of infection with hepatitis B?
Hepatitis B surface antigen (HBsAg), hepatitis B e antigen (HBeAg), and hepatitis B core antibody (anti-HBc) IgM
68
What presentation might cytomegalovirus infection have in a patient with a CD4+ count \< 100/mm3?
Colitis, Retinitis, Encephalitis, Esophagitis, Pneumonitis (CREEP)
69
What is the name of the disease associated with "slapped cheeks" in children with parvovirus?
Erythema infectiosum or fifth disease
70
In addition to mononucleosis, name 3 diseases caused by Epstein-Barr virus infection.
Lymphomas (eg, Burkitt lymphoma), nasopharyngeal carcinoma (more common in Asian adults), and lymphoproliferative disease in transplant patients
71
What infection in patients with a CD4+ cell count \< 500/mm3 presents with white patches on the lateral side of the tongue that cannot be scraped off?
Oral hairy leukoplakia (due to Epstein-Barr virus)
72
Which RNA virus family causes the often fatal diseases of Ebola and Marburg hemorrhagic fever?
Filoviruses
73
What is considered the normal range of CD4+ cell count?
500–1500 cells/mm3
74
Describe the DNA structure of poxvirus, including whether or not it is enveloped.
Double-stranded, linear DNA, enveloped (largest DNA viruses)
75
Which 3 herpesviruses are transmitted in respiratory secretions?
Herpes simplex virus-1 (HSV-1), Epstein-Barr virus (HHV-4), and varicella-zoster virus (HHV-3)
76
In which type of cells do cytomegalovirus (CMV, HHV-5) establish latency?
Mononuclear cells
77
What is the RNA structure of the hepevirus?
Non-enveloped, single-stranded, positive-sense, linear RNA with an icosahedral capsid
78
What is the RNA structure of the picornavirus?
Non-enveloped, single-stranded, positive-sense, linear RNA with an icosahedral capsid
79
What test is performed for definitive diagnosis of skin and genital findings suggestive of herpes simplex virus?
Viral polymerase chain reaction (PCR) of skin lesions
80
What is the ploidy of the HIV genome?
Diploid RNA (2 molecules of RNA)
81
What are initial symptoms of Ebola?
Abrupt onset of flu-like symptoms, high fever, diarrhea/vomiting, and myalgia
82
Hepatitis C infection confers increased risk for which hematological cancer?
B-cell non-Hodgkin lymphoma (NHL)
83
Which DNA virus is single stranded?
Parvovirus (all other DNA viruses are double stranded)
84
The HIV RNA levels peak during which phases of infection?
Acute infection phase and systemic immunodeficiency/AIDS-defining illnesses phase
85
How does central nervous system (CNS) lymphoma differ from a Toxoplasma gondii infection on a brain MRI of a patient who has a CD4+ count \<100/mm3?
A solitary ring-enhancing lesion is usually seen in CNS lymphoma; multiple lesions are usually found in a Toxoplasma gondii infection
86
Name 5 RNA viruses that are picornaviruses?
Poliovirus, Echovirus, Rhinovirus, Coxsackievirus, Hepatitis A virus (PERCH on a "peak" [picornavirus])
87
What kind of infections are HIV ⊕ patients generally at risk for as the CD4+ cell count drops?
Reactivation of past infections (eg, tuberculosis, shingles), non-Hodgkin lymphoma, dissemination of bacterial/fungal infections
88
What disease would be most likely in an unvaccinated young adult with personality changes, dementia, and autonomic dysfunction who had previously contracted rubeola as a child?
Subacute sclerosing panencephalitis (SSPE); occurs years after initial infection
89
In what parts of the world is hepatitis E infection most common?
Asia, Africa, and the Middle East
90
Which viral family includes the hepatitis D virus?
Delta viruses
91
Which human papillomavirus (HPV) serotypes are associated with warts?
Serotypes 1, 2, 6, and 11
92
What viral strains are found in the flu shot?
Viral strains that are most likely to appear during a flu season (reformulated vaccine)
93
What is a patient's HIV status if the nucleic acid test (NAT) is negative following a positive HIV-1/2 Ag/Ab immunoassay?
HIV ⊖ (HIV Ag/Ab immunoassay was likely a false positive)
94
What is the transmission vector of the Chikungunya virus?
Aedes mosquito
95
What CD4+ count is associated with Toxoplasma gondii infection?
\< 100/mm3
96
How is Ebola diagnosed?
Reverse transcription-polymerase chain reaction (RT-PCR) within 48 hours of symptom onset
97
Which types of hepatitis can have a carrier state?
Hepatitis B and C (very common in C)
98
Besides febrile pharyngitis, what other signs or symptoms could adenovirus be responsible for?
Acute hemorrhagic cystitis, pneumonia, conjunctivitis (“pink eye”), gastroenteritis, and myocarditis
99
What are the possible means of transmission for β-pleated prion proteins (PrPsc)?
Transmissible via infected CNS tissue (iatrogenic Creutzfeldt-Jakob disease) or food contaminated by bovine spongiform encephalopathy (BSE; variant Creutzfeldt-Jakob disease)
100
What is the difference between IgM versus IgG hepatitis B core antibodies?
IgM is a marker for acute or recent disease; IgG is a marker for prior exposure or chronic infection
101
What type of infections might be seen with HIV when the CD4+ count is 200-400 cells/mm3?
Skin and mucous membrane infections (generally years post-infection)
102
Which disease caused by a DNA virus has been eradicated through the use of a live-attenuated vaccine?
Smallpox (poxvirus family)
103
What is the genomic structure of the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2)?
Enveloped ⊕ single-stranded RNA with a helical capsid
104
What is the time frame for the development of anti-envelope antibodies (gp120) following initial HIV infection?
Begins after the first month through the acute phase and remains elevated
105
What serological marker is best to detect acute hepatitis A?
IgM hepatitis A virus antibody (anti-HAV IgM)
106
What are 3 possible clinical conditions associated with infection by Dengue virus?
Dengue fever, dengue hemorrhagic fever, or dengue shock syndrome
107
Which well-known RNA virus family has reverse transcriptase?
Retrovirus
108
Name 4 segmented RNA viruses.
Bunyaviruses, Orthomyxoviruses (influenza), Arenaviruses, Reoviruses (BOAR)
109
What part of the nervous system does varicella-zoster virus lie latent?
In the dorsal root or trigeminal ganglia
110
Why are naked nucleic acids of negative-sense RNA viruses (both single- and double-stranded) not infectious?
They require polymerases found in the complete virion to become infectiou
111
What disease process should you consider in a patient with a CD4+ count \<200/mm3, progressive memory loss, and an otherwise negative infectious work-up?
HIV dementia
112
What 5 diseases are caused by paramyxoviruses?
Parainfluenza (croup), measles, mumps, respiratory syncytial virus (RSV), and human metapneumovirus
113
What stage of hepatitis B infection does positive hepatitis B surface antibody (anti-HBs), hepatitis B e antibody (anti-HBe), and hepatitis B core antibody (anti-HBc) IgG indicate?
Recovery stage
114
Name 5 medically significant members of the picornavirus family.
Poliovirus, Echovirus, Rhinovirus, Coxsackievirus, HAV (hepatitis A virus) (PERCH)
115
What is the mechanism of action of palivizumab?
Monoclonal antibody against the surface F protein preventing pneumonia caused by respiratory syncytial virus (RSV)
116
What is the RNA structure of the calicivirus?
Non-enveloped, single-stranded, positive-sense, linear RNA with an icosahedral capsid
117
What are 4 common clinical findings of measles?
Cough, Coryza, Conjunctivitis, and "C"oplik (Koplik) spots (4 C's of Measles)
118
According to the CDC guidelines, all infants should be vaccinated against rotavirus with the exception of which medical conditions?
History of intussusception or severe combined immunodeficiency (SCID)
119
All segmented viruses have what type of viral genome (DNA or RNA)?
RNA
120
Which herpesvirus is the most common cause of mononucleosis?
Epstein-Barr virus (HHV-4)
121
What is the function of the hepatitis B DNA polymerase?
Has both DNA- and RNA-dependent activities Enters nucleus → completes partial double-stranded DNA; also reverse transcribes viral RNA → DNA for progeny genome synthesis
122
Which virus is the most important global cause of infantile gastroenteritis?
Rotavirus (ROTAvirus = "right out the anus")
123
What type of viral genomic structure is necessary for viral genome reassortment?
A segmented genome
124
What are the functions of the influenza viral antigens hemagglutinin and neuraminidase?
Hemagglutinin binds sialic acid to promote viral entry (hemagglutinin lets virus in); neuraminidase promotes progeny virion release (neuraminidaways sends virus away)
125
What are the 4 stages of untreated HIV infection?
Flu-like (acute); Feeling fine (latency); Falling count; Final crisis (Four stages)
126
Name the 4 families of RNA viruses that have no envelope.
Reoviruses, picornaviruses, hepeviruses, and caliciviruses
127
What are the characteristics of the vaccine against dengue virus?
Live, recombinant vaccine that uses yellow fever virus genes into which dengue virus envelope and premembrane proteins are inserted
128
Chronic hepatitis B is associated with what hematologic abnormality?
Aplastic anemia
129
What is the source of the hepatitis B e antigen (HBeAg) found in the serum of a patient infected with hepatitis B?
Secretion by infected hepatocytes into the circulation; it is not part of the mature HBV virion
130
What 3 organs are affected by Kaposi sarcoma?
Skin, gastrointestinal tract, and lungs
131
What is expected on a biopsy of bacillary angiomatosis in a patient who is HIV ⊕?
Neutrophilic inflammation caused by Bartonella spp
132
How do the Epstein-Barr virus (HHV-4) and strep throat differ in the location of cervical lymphadenopathy?
HHV-4 is more strongly associated with posterior cervical lymphadenopathy; strep throat involves anterior cervical lymphadenopathy
133
Which herpes simplex virus is more likely to cause viral meningitis?
Herpes simplex virus-2 (HSV-2)
134
Why are contact sports avoided in patients with mononucleosis?
Risk of splenic rupture
135
What 2 vaccines can be used for poliovirus infections?
Salk = inactivated polio vaccine (IPV); Sabin = oral polio vaccine (OPV)
136
To what viral family does hepatitis B virus belong?
Hepadnaviridae
137
All DNA virus are linear with the exception of which DNA virus families?
Papillomaviruses, polyomaviruses, and hepadnaviruses (circular genomes)
138
What is the prognosis for most patients who do not receive treatment for HIV infection?
Most eventually die due to complications of HIV infection
139
What is the RNA structure of the arenavirus?
Enveloped, single-stranded, positive- and negative-sense, circular (in 2 segments) RNA with a helical capsid
140
What are the most common endocrine manifestations of hepatitis C?
↑ risk of diabetes mellitus and autoimmune hypothyroidism
141
At what levels of CD4+ cell count do infections with Mycobacterium avium-intracellulare and M avium complex most commonly occur in immunocompromised patients?
CD4+ cell count \< 50/mm3
142
How does the monospot test work, and what is it used to detect?
Detects heterophile antibodies via agglutination of sheep or horse red blood cells as a method to detect Epstein-Barr virus
143
What population is vulnerable to infection by paramyxoviruses?
Children and infants
144
What are the characteristics of the Reovirus family?
Naked, multisegmented, double-stranded RNA viruses with double icosahedral capsids
145
What is the viral receptor for rabies?
Nicotinic acetylcholine receptor (AChR)
146
What are possible central nervous system sequelae of measles?
Subacute sclerosing panencephalitis (SSPE) and encephalitis
147
What rare sequela of measles can arise in the lungs, particularly in the immunosuppressed?
Giant cell pneumonia
148
Which DNA virus contains the reverse transcriptase enzyme in order to replicate its genome?
Hepadnavirus (eg, hepatitis B)
149
What is the most common complication of shingles?
Post-herpetic neuralgia
150
What infection is associated with a CD4+ \< 200/mm3 and fever, fatigue, weight loss, cough, nausea, vomiting, dyspnea, and diarrhea?
Histoplasma capsulatum infection
151
What are the possible presentations in a patient with herpes simplex virus-1?
Cold sores, herpetic whitlow, keratoconjunctivitis, erythema multiforme, esophagitis, temporal encephalitis, and gingivostomatitis
152
What is the typical presentation of rubella (German measles) infection?
Fever, postauricular and other lymphadenopathy, arthralgia, and maculopapular rash
153
Coltivirus is the causative agent for which illness?
Coltivirus causes Colorado tick fever
154
Purified nucleic acids from which 2 double-stranded DNA viruses are not considered infectious?
Poxvirus and hepatitis B virus (HBV)
155
What is the RNA structure of the paramyxovirus?
Enveloped, single-stranded, negative-sense, linear (nonsegmented) RNA with a helical capsid
156
What antigen is associated with the core of hepatitis B virus?
HBcAg
157
What infection presents with nonenhancing areas of demyelination on MRI in a patient with a CD4+ cell count \< 200/mm3?
Progressive multifocal leukoencephalopathy (due to JC virus reactivation)
158
In contrast to the other picornaviruses, what type of infection does rhinovirus not cause, and why?
Gastrointestinal tract infections; it is acid labile and destroyed by stomach acid
159
Which RNA virus causes croup?
Parainfluenza
160
What common diseases are possible in the population with HIV/AIDS when the CD4+ count is \<500 cells/mm3?
Oral thrush (Candida albicans), oral leukoplakia (Epstein-Barr virus), Kaposi sarcoma (Human herpesvirus-8), squamous cell carcinoma (Human papillomavirus )
161
Which hepatitis types can be transmitted by blood?
Hepatitis B, C, and D
162
Name 4 medically important paramyxoviruses.
Parainfluenza virus (croup), Respiratory syncytial virus (RSV, infantile bronchiolitis), Mumps, and Measles (PaRaMyxovirus)
163
Epstein-Barr virus is associated with what medical complications in patients with a CD4+ count \< 100/mm3?
B-cell lymphoma (eg., non-Hodgkin lymphoma, CNS lymphoma)
164
Palivizumab is used to prevent respiratory syncytial virus (RSV) in what age group?
Premature infants (palivizumab for paramyxovirus prophylaxis in preemies)
165
What disease presents with esophagitis and linear ulcerations on esophagogastroduodenoscopy (EGD) in a patient with a CD4+ count \<100/mm3?
Cytomegalovirus esophagitis
166
How does transmission for herpes simplex virus (HSV) 1 and 2 differ?
HSV-1 is spread in respiratory secretions and saliva; HSV-2 is spread by sexual contact and perinatally
167
What viral infections are associated with intranuclear eosinophilic Cowdry A inclusions?
Herpes simplex virus-1 (HSV-1), herpes simplex virus-2 (HSV-2), varicella-zoster virus (VZV)
168
What is a pseudovirion?
The genetic material of one virus coated by the surface proteins of a different virus
169
Which picornavirus causes the "common cold?"
Rhinovirus
170
What is the test of choice for cryptosporidium infection in patients with chronic, watery diarrhea and a CD4+ count \<200/mm3?
An acid-fast stain of the stool sample to show acid-fast oocysts
171
What is the RNA structure of the filovirus?
Enveloped, single-stranded, negative sense, linear with a helical capsid
172
Where does HIV replicate during the clinical latency phase?
Lymph nodes
173
What are the physical findings of Kaposi sarcoma associated with human herpesvirus-8 infection with CD4+ cell count \< 500/mm3?
Invading perivascular spindle cells that form vascular tumors visible on histology
174
Describe the DNA structure of papillomavirus, including whether or not it is enveloped.
Double-stranded, circular DNA, non-enveloped
175
Name the 2 RNA viruses that have reverse transcriptase.
Human immunodeficiency virus (HIV) → AIDS and human T-lymphotropic virus (HTLV) → T-cell leukemia
176
Which hepatitis virus is most likely to progress to cirrhosis or carcinoma?
Hepatitis C; most likely to progress to Cirrhosis or Carcinoma
177
To what common sterilization procedure are prion diseases known to be resistant
Standard autoclaving
178
What DNA virus in adults can cause pure red blood cell aplasia and rheumatoid arthritis-like symptoms?
Parvovirus B19
179
Of the 2 viruses that can cause roseola, which is a less common cause of the disease?
Human herpesvirus-7 (HHV-7) is a less common cause than human herpesvirus-6 (HHV-6)
180
How is infection by dengue virus diagnosed?
Polymerase chain reaction (PCR) or serology
181
Congenital rubella presents with what classic triad of clinical findings?
Sensorineural deafness, cataracts, and patent ductus arteriosus
182
In which part of the nervous system does the herpes simplex virus-1 lie dormant after initial infection?
Trigeminal ganglia
183
Coinfection by what virus can occur with the dengue virus?
Chikungunya virus (same mosquito vector)
184
What type of capsid shape do most negative-sense RNA viruses have and with what exception?
Helical; delta viruses have an unspecified capsid symmetry
185
What DNA virus is associated with "milkmaid blisters"?
Cowpox (Poxvirus)
186
Which virus in the reovirus family causes fatal diarrhea in children?
Rotavirus
187
All DNA viruses have double-stranded DNA genomes with what exception?
Parvoviridae = single-stranded DNA (ssDNA; parvovirus is "part-of-a-virus")
188
What is the RNA structure of the coronavirus?
Enveloped, single-stranded, positive-sense, linear RNA with a helical capsid
189
What sequelae can rarely occur after infection with the rubeola virus in an immunocompromised patient?
Giant cell pneumonia
190
A young child presents with a flesh-colored papule with central umbilication. What is the causative agent?
Molluscum contagiosum (poxvirus)
191
What is the prognosis for hepatitis B in adults and neonates?
Adults = mostly a full resolution; neonates = a worse prognosis
192
In which part of the nervous system does the herpes simplex virus-2 lie latent?
Sacral ganglia
193
What is the mechanism through which parvovirus results in fetal and maternal presentation (eg, hydrops fetalis, rheumatoid arthritis-like symptoms in adults)?
Red blood cell destruction due to selective infection of red blood cell precursors and endothelial cells
194
Which herpesvirus is the most common cause of sporadic encephalitis?
Herpes simplex virus-1
195
Name 6 medically significant conditions caused by flaviviruses.
Hepatitis C, Yellow fever, St. Louis encephalitis, Zika virus infection, West Nile disease (meningoencephalitis, flaccid paralysis), and Dengue
196
Describe the structure of orthomyxoviruses.
Enveloped, negative-sense, single-stranded RNA viruses with a segmented genome
197
Which test determines appropriate antiretroviral therapy in HIV ⊕ patients?
HIV genotype testing
198
What is the most appropriate treatment for patients infected by Zika virus?
Supportive care (no definitive treatment)
199
How can hepatitis E be acquired?
Via the fecal-oral route, especially from waterborne sources
200
How many RNA segments does each segmented RNA virus family have?
Bunyaviruses: 3 Orthomyxoviruses: 8 Arenaviruses: 2 Reoviruses: 10-12 "BOARding flight 382 in 10-12 minutes"
201
What is the most common mosquito-borne viral disease in the world?
Dengue virus
202
What 2 sensory changes may occur with infection by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)?
Anosmia (loss of smell) and dysgeusia (altered taste)
203
What are the differences in duration of illness of Hepatitis D virus (HDV) in relation to Hepatitis B viral (HBV) infection?
A superinfection (HDV after HBV) is shorter while coinfection is longer
204
Which is the only positive-sense RNA viral family with a helical capsid?
Coronaviruses
205
Which serologic marker indicates prior infection (or vaccination) with Hepatitis A and protects against reinfection?
IgG anti-hepatitis A virus antibody (anti-HAV IgG)
206
Given the high mortality rate, what steps should be taken to prevent transmission of the Ebola virus?
Vaccinations, barrier practices for health care workers, and strict isolation of infected individuals
207
What hepatitis virus can initially present like serum sickness (fever, arthralgias, and rash)?
Hepatitis B
208
What human papillomavirus (HPV) serotypes are most commonly associated with cervical cancer?
Serotypes 16 and 18
209
All DNA viruses replicate in the nucleus with the exception of which virus?
Poxvirus (carries its own DNA-dependent RNA polymerase, does not require nuclear enzymes)
210
What viruses are part of the Togavirus family?
Toga CREW - Chikungunya virus, Rubella, Eastern and Western equine encephalitis
211
What infection in patients with a CD4+ count \< 200 cells/mm3 presents with cough, fever, and dyspnea with bilateral ground-glass opacities on chest X-ray?
Pneumocystis pneumonia (Pneumocystis jirovecii)
212
Which nonenveloped RNA virus causes the common cold?
Rhinovirus (rhino has a runny nose)
213
What patient population has a high mortality rate if infected with hepatitis E virus?
Pregnant women (HEV: Enteric, Expectant mothers, Epidemic)
214
What are the typical symptoms of acute laryngotracheobronchitis?
"Seal-like" barking cough and inspiratory stridor (croup from parainfluenza viral infection)
215
Name the 6 negative-stranded viral families.
Arenaviruses, Bunyaviruses, Paramyxoviruses, Orthomyxoviruses, Filoviruses, Rhabdoviruses (Always Bring Polymerase Or Fail Replication)
216
Which 2 diseases are caused by arenaviruses?
Lymphocytic choriomeningitis virus (LCMV) and Lassa fever encephalitis (spread by rodents)
217
How does cytomegalovirus infection present on fundoscopy?
Cotton-wool spots
218
What infectious entity causes high fever, black-colored vomitus, jaundice, hemorrhage, and backache?
Yellow fever virus
219
What is the mechanism behind phenotypic mixing?
Two viruses coinfect a cell → virus A becomes coated with virus B proteins → progeny have type A genome and coat
220
What is the test of choice for herpes simplex virus (HSV) encephalitis?
HSV polymerase chain reaction (PCR) of the cerebrospinal fluid
221
Name 8 naked (nonenveloped) viruses.
Calicivirus, Picornavirus, Reovirus, Parvovirus, Adenovirus, Papillomavirus, Polyomavirus, and Hepevirus (give CPR and a PAPP smear to a naked hippie)
222
Describe how genetic/antigenic shift occurs.
1 cell is infected by 2 different segmented viruses → RNA segment reassortment → dramatically different virus → major global outbreaks
223
Which RNA virus family does Ebola hemorrhagic fever belong to?
Filoviruses
224
What is the purpose of the RNA-dependent RNA polymerase that ⊖ strand RNA viruses carry?
Transcribes ⊖ strand → ⊕ in the host cell in order to replicate
225
Which antibody is protective against hepatitis B infection acquired after recovery from an infection or vaccination?
Hepatitis B surface antibody (anti-HBs)
226
What malignancy is associated with human papillomavirus infection in the population with HIV/AIDS?
Squamous cell carcinoma of the anus, cervix, and oropharynx
227
What 3 fatal bacterial superinfections most commonly occur with influenza virus infection?
Staphylococcus aureus, Streptococcus pneumoniae, and Haemophilus influenzae
228
What are the clinical manifestations of congenital Zika syndrome?
Microcephaly, ocular anomalies, motor abnormalities (eg, spasticity, seizures)
229
Viruses A and B infect a cell. Virus A mutates and becomes nonfunctional while virus B expresses a protein that serves both A and B. What is this mechanism called?
Complementation
230
Coronaviruses are the causative agents of what 4 diseases?
Common cold, Middle East respiratory syndrome (MERS), severe acute respiratory syndrome (SARS), and COVID-19
231
Which animal bites are most likely to result in rabies infection in the United States?
Bat, raccoon, and skunk bites \> dog bites
232
Parvovirus B19 uses what receptor to attach to red blood cells?
P antigen on red blood cells (Parvovirus)
233
For infection with Hepatitis D virus (HDV) and Hepatitis B virus (HBV), what incubation state has the worse prognosis?
Superinfection (HDV after HBV)
234
What is the test of choice for the diagnosis of Zika virus?
Reverse transcription polymerase chain reaction (RT-PCR) or serology
235
What is the definition of viral genetic recombination?
Gene exchange between 2 chromosomes via crossing over within regions of homologous base sequences
236
What are the criteria for the diagnosis of acquired immunodeficiency syndrome (AIDS)?
CD4+ count ≤200 cells/mm3 or HIV ⊕ with an AIDS-defining illness
237
How do you evaluate response to antiretroviral therapy for HIV?
Test the amount of viral RNA in plasma
238
What 3 hematologic manifestations can occur in hepatitis C infection?
Essential mixed cryoglobulinemia, idiopathic thrombocytopenic purpura (ITP), and autoimmune hemolytic anemia (AIHA)
239
What mediates the granular eosinophilic "ground glass” appearance found on a liver biopsy specimen of hepatitis B?
Due to accumulation of surface antigen in infected hepatocytes and cytotoxic T-cell-mediated damage
240
Which organ transplant does the BK virus commonly target?
Kidneys (BK virus = Bad Kidney virus)
241
What CD4+ count is associated with oral thrush from a Candida albicans infection in patients with HIV?
\<500 cells/mm3
242
What is the most common diagnostic test used to determine infection by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)?
Reverse transcriptase-polymerase chain reaction (RT-PCR); antigen and antibody tests are also available
243
What is the RNA structure of the togavirus?
Enveloped, single-stranded, positive-sense, linear RNA with an icosahedral capsid
244
What are 6 significant risk factors for severe illness or death secondary to infection by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)?
Age, obesity, diabetes, hypertension, chronic kidney disease (CKD), and severe cardiopulmonary illness
245
What double-stranded, linear DNA virus can cause conjunctivitis, myocarditis, and febrile pharyngitis?
Adenovirus
246
What is the treatment of choice for Ebola?
Supportive care (no definitive treatment)
247
To which virus family does rhinovirus belong?
Picornavirus
248
What is seen on biopsy of tissues infected with cytomegalovirus?
Cells with intranuclear inclusion bodies (owl's eye appearance)
249
What is the primary pattern of transmission for the severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)?
Respiratory droplets and aerosols
250
Describe the DNA structure of parvovirus, including whether or not it is enveloped.
Single-stranded, linear DNA, non-enveloped (smallest DNA virus)
251
What signs and symptoms are characteristic of all hepatitis viruses?
Fever, jaundice, and ↑ alanine aminotransferase (ALT) and aspartate aminotransferase (AST)
252
What infection in patients with a CD4+ count \<100 cells/mm3 presents with pleuritic chest pain, and hemoptysis?
Aspergillus fumigatus
253
What prion disease causes typically sporadic, rapidly progressive dementia?
Creutzfeldt-Jakob disease
254
From what cells does Kaposi sarcoma arise?
Endothelial cells
255
How are HIV envelope proteins acquired?
Acquired via budding from the host cell plasma membrane
256
What are the viral receptors for HIV?
CD4, CXCR4, and CCR5
257
What is the route of transmission for the yellow fever virus?
Aedes mosquitos
258
Which hepatitis viruses do not have carrier states?
Hepatitis A and E
259
What are potential complications of infection by severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)?
Respiratory failure, hypercoagulability, shock, organ failure, death
260
Describe the DNA structure of herpesviruses, including whether or not they are enveloped.
Double-stranded, linear DNA, enveloped
261
How are human herpesviruses-6 and -7 transmitted?
Saliva
262
What are 3 severe complications of Ebola?
Disseminated intravascular coagulation (DIC), diffuse hemorrhage, and shock (high mortality rate)
263
How is the reovirus genome unique among RNA viruses?
It has double-stranded RNA; all other RNA viruses are single stranded
264
Describe the lymph node biopsy findings of a patient with measles.
Warthin-Finkeldey giant cells (fused lymphocytes) present in a background of paracortical hyperplasia
265
All RNA viruses have single-stranded RNA genomes except which viral family?
Reoviridae = double-stranded RNA ("repeatovirus", reovirus)
266
How does severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2) gain entry into host cells?
Attachment of viral spike protein to angiotensin-converting enzyme 2 (ACE2) receptor on cell membranes
267
What are 3 general mechanisms for Zika virus transmission?
Aedes mosquito bites (most common); sexual and vertical transmission can also occur
268
What intervention can reduce morbidity and mortality in children infected with the rubeola virus?
Vitamin A (especially in malnourished children)
269
Once picornavirus RNA has entered the cell, what is the process by which functional viral proteins are generated?
The RNA is translated into a single polypeptide then cleaved by virus-encoded proteases into functional viral proteins
270
What is a distinguishing characteristic of the hepatitis D virus as an infectious agent?
Hepatitis D is a "defective" virus because it requires co-infection with hepatitis B virus to replicate
271
What causes pandemics versus epidemics?
Genetic/antigenic shift causes pandemics; genetic/antigenic drift causes epidemics (sudden shift is more deadly than gradual drift)
272
Describe the DNA structure of polyomavirus, including whether or not it is enveloped.
Double-stranded, circular DNA, non-enveloped
273
Which RNA virus family does the influenza virus belong to?
Orthomyxoviruses
274
What viral infection is associated with aplastic crises in sickle cell disease?
Parvovirus B19
275
What would you see on the liver biopsy of a patient infected with hepatitis A?
Hepatocyte swelling, monocyte infiltration, and Councilman bodies
276
Rhinovirus has how many serotypes?
\>100 serologic types of rhinovirus
277
Describe the DNA structure of adenovirus, including whether or not it is enveloped.
Double-stranded, linear DNA, non-enveloped
278
The Chikungunya virus is a member of what viral family
Alphavirus member of the togavirus family
279
What are symptoms of mumps?
Parotitis, Orchitis, aseptic Meningitis, Pancreatitis (mumps makes your parotid glands and testes as big as POM-Poms)
280
What is the definition of moderately immunocompromised in HIV?
CD4+ count: 200-400 cells/mm3
281
What might a liver biopsy reveal in a patient diagnosed with yellow fever?
Councilman bodies (eosinophilic apoptotic globules)
282
As an exception to most other enveloped viruses, from what cellular structure in their hosts do the herpesviruses acquire their envelopes?
Nuclear membrane
283
What virus family causes respiratory tract infections (including bronchiolitis and pnuemonia) in infants?
Paramyxoviruses
284
What is the RNA structure of the deltavirus?
Enveloped, single-stranded, negative-sense, circular RNA with an uncertain capsid symmetry
285
How do intramuscular and intranasal flu vaccines differ?
Injection contains killed virus (more common); nasal spray has a live attenuated virus (temperature sensitive, replicates in the nose)
286
Cranial nerve V1 involvement of varicella-zoster virus results in what disease?
Herpes zoster ophthalmicus
287
What 3 DNA viruses have circular genomes?
Hepadnavirus (circular, incomplete), papillomavirus (circular, supercoiled), and polyomavirus (circular, supercoiled)
288
How might a patient infected with hepatitis A virus typically present?
Acute and self-limiting in adults; Asymptomatic in children
289
Which DNA virus is not icosahedral in shape?
Poxvirus (complex)
290
What are the tests of choice for cryptococcal meningitis infection?
Capsular antigen ⊕ or India ink stain to reveal encapsulated yeast
291
What is the function of the 2 envelope proteins on the surface of HIV?
Gp120 helps HIV adhere to CD4+ T cells; gp41 facilitates HIV fusion/entry
292
What is the mechanism by which rabies virus causes infection?
Binds to acetylcholine receptors on nerve axons, then migrates to the CNS in a retrograde fashion via dynein motor proteins
293
How is hepatitis B acquired?
Parenteral (Blood), sexual (Baby-making), perinatal (Birthing)
294
What class of viruses does the virus causing rubella (German Measles) belong to?
Togavirus
295
Which populations are at particularly high risk for rotavirus in the US?
Infants and young children, especially in day care centers and kindergartens during the winter
296
What are the clincal findings of opportunistic infection by Bartonella spp in a patient with a CD4+ count \< 100/mm3?
Multiple red to purple papules or nodules
297
Describe the viral structure of all herpesviruses.
Enveloped, double-stranded, and linear DNA viruses
298
What are the capsid differences between retroviruses human T-cell leukemia virus (HTLV) and human immunodeficiency virus (HIV)?
HTLV = icosahedral; HIV = complex and conical
299
What RNA virus family contains the hepatitis E virus?
Hepevirus
300
What virus family does Ebola belong to?
Filovirus
301
Describe the cutaneous findings of Kaposi sarcoma.
Dark, violaceous plaques/nodules resembling vascular proliferation caused by human herpesvirus-8
302
What 3 virus families have circular RNA structures?
Arenaviruses, bunyaviruses, and delta viruses
303
What is the test of choice for determining maternal HIV transmission to a newborn child?
HIV viral load in the newborn
304
In what central nervous system tissue are Negri bodies commonly found in rabies infection?
Cerebellum (Purkinje cells) and/or hippocampus
305
What herpesvirus can cause shingles, encephalitis, and pneumonia?
Varicella-zoster virus (HHV-3)
306
What CD4+ count is associated with esophagitis from a Candida albicans infection in patients with HIV/AIDS?
\<100 cells/mm3
307
What disease does respiratory syncytial virus (RSV) cause in babies?
Bronchiolitis
308
In which viral family do viruses have single-stranded, circular RNA that is both positive sense and negative sense (ambisense)?
Arenaviruses
309
Which HIV proteins are encoded from the gag gene and located in the matrix and capsid?
p17 (matrix) and p24 (capsid)
310
What are the 6 common symptoms of dengue fever?
Fever, headache, rash, myalgia, arthralgia, neutropenia
311
What gene mutation can cause immunity to HIV?
Homozygous CCR5 mutation
312
Describe how genetic/antigenic drift occurs.
Random mutations in hemagglutinin (HA) or neuraminidase (NA) genes cause frequent minor changes → major global outbreaks
313
Name the 7 DNA viruses.
Hepadnavirus, Herpesvirus, Adenovirus, Poxvirus, Parvovirus, Papillomavirus, and Polyomavirus (HHAPPPPy viruses)
314
What prion disease is notable in tribal populations practicing human cannibalism?
Kuru
315
A patient with mononucleosis is wrongly prescribed an antibiotic and develops a rash. What antibiotic is it?
Amoxicillin (occurs when presumed streptococcal pharyngitis is treated in a patient with mononucleosis)
316
The Centers for Disease Control (CDC) no longer recommends what confirmatory testing for HIV?
Western blot
317
What is the RNA structure of the retrovirus?
Enveloped, single-stranded, positive-sense, linear (2 copies) RNA with either an icosahedral capsid or a complex, conical capsid
318
What is the treatment for flu caused by influenza viruses?
Supportive +/– neuraminidase inhibitors (oseltamivir, zanamivir, etc.)
319
What is the difference in likely transmissibility between testing positive for hepatitis B e antigen (HBeAg) compared to hepatitis B e antibody (anti-HBe)?`
HBeAg indicates active viral replication (high transmissibility and poorer prognosis); anti-HBe indicates low transmissibility
320
How can cytomegalovirus be transmitted?
Via sexual contact, transfusion, urine, saliva, organ transplants, and congenitally
321
Why is HIV-1/2 Ag/Ab testing not recommended in babies with suspected HIV?
Results are confounded due to maternally transferred HIV antibodies
322
Under what conditions are outbreaks of Zika virus more common?
Tropical and subtropical climates
323
What is the RNA structure of the bunyavirus?
Enveloped, single-stranded, negative-sense, circular (in 3 segments) RNA with a helical capsid
324
What dermatological conditions can be seen in patients with hepatitis C?
Sporadic porphyria cutanea tarda and lichen planus
325
What are the symptoms of systemic infection by the Chikungunya virus?
Inflammatory polyarthritis (can become chronic), high fever, maculopapular rash, headache, and lymphadenopathy; hemorrhagic fever is uncommon compared to dengue fever
326
What condition is caused by West Nile virus?
Meningoencephalitis
327
What vascular pathology can occur with hepatitis C?
Leukocytoclastic vasculitis
328
Name 2 coreceptors HIV can use to enter immune cells and associated stages of infection.
CCR5 (on macrophages for early infection) and CXCR4 (on T cells for late infection)
329
Name 5 medically significant conditions caused by coxsackieviruses.
Aseptic meningitis, pericarditis, myocarditis, herpangina (mouth blisters and fever), and hand, foot, and mouth disease
330
What is the role of the surface F (fusion) protein that is common to all paramyxoviruses?
Causes respiratory epithelial cells to fuse and become multinucleated cells
331
What are 4 primary ways by which Ebola virus is transmitted?
Direct contact with bodily fluids, fomites (including corpses), infected bats/primates, and nosocomial infection (high incidence)
332
What does the window period found during infection with Hepatitis B refer to?
The period where serum hepatitis B surface antibody (HBsAg) drops to undetectable levels, while serum anti-HBs begin to form (5-6 months post-infection)
333
What 5 clinical manifestations does β-pleated prion protein (PrPsc) accumulation cause?
Spongiform encephalopathy, dementia, ataxia, startle myoclonus, and death
334
Which calicivirus commonly causes viral gastroenteritis?
Norovirus
335
During which phase of HIV infection does the CD4+ cell count drop most sharply?
Acute phase (first 1-2 months)
336
What does a heterozygous CCR5 gene mutation indicate for the disease course in a patient with HIV?
Slower disease course
337
Name the family of each of the hepatitis viruses (Hepatitis A, B, C, D, and E).
HAV - RNA picornavirus; HBV - DNA hepadnavirus; HCV - RNA flavivirus; HDV - RNA deltavirus; HEV - RNA hepevirus
338
What is the disease condition also named "mad cow disease"?
Bovine spongiform encephalopathy (BSE)
339
What is the vector of transmission for the Dengue virus?
Aedes mosquito
340
What 3 treatment modalities are available to treat hospitalized patients infected with severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2)?
Remdesivir (nucleoside analog), convalescent plasma, and dexamethasone (treats cytokine release syndrome)
341
In phenotypic mixing, what determines the tropism (infectivity) of a progeny virus?
The protein coat of the hybrid virus
342
What does a positive test for hepatitis B surface antigen (HBsAg) indicate?
Active hepatitis B infection
343
What should be done for postexposure prophylaxis in rabies?
Clean the wound and administer killed rabies vaccine and rabies immune globulin (passive-active immunity)
344
What is the purpose of the HIV-1/2 differentiation immunoassay following a positive HIV-1/2 Ag/Ab immunoassay?
Determines whether it is HIV-1 or HIV-2 infection
345
What findings would you expect on neuroimaging in a patient with HIV dementia with CD4+ cell count \<200/mm3?
Cerebral atrophy
346
Which DNA viruses have the smallest and largest structures?
Parvovirus is the smallest; poxvirus is the largest
347
Two segmented viruses undergo reassortment and produce a new, highly virulent strain. What is this mechanism called?
Antigenic shift (associated with reassortment)
348
How does the rash seen in roseola infantum spread anatomically?
Starts on the trunk and then spreads to extremities
349
In viral genetics, what is the definition of reassortment?
The exchange of genetic material among viruses with segmented genomes (eg, the influenza virus)
350
If the receptor CD21 is blocked, what virus will have difficulty infecting the cells?
Epstein-Barr virus (EBV)
351
How can cytomegalovirus present in immunocompetent patients compared to immunocompromised patients?
Immunocompetent = mononucleosis; immunocompromised = retinitis, esophagitis, and infection (eg, pneumonia in transplant patients)
352
What is the mode of transmission for hepatitis C virus?
Primarily blood (eg, intravenous drug use or blood transfusions)
353
What are the viral receptors for CMV?
Integrins (heparan sulfate)
354
Describe the shape of the rabies virus
Bullet-shaped
355
At what CD4+ count are acquired immunodeficiency syndrome- (AIDS) defining illnesses expected to emerge in HIV?
\<200 cells/mm3
356
What is the function of the env gene of HIV?
Encodes gp160 precursor that is cleaved into gp120 and gp41
357
What findings might be seen on fundoscopic exam in a patient with vision loss due to cytomegalovirus retinitis?
Hemorrhage and cotton-wool exudates (associated with AIDS)
358
Hemorrhage and cotton-wool exudates (associated with AIDS)
Normal prion protein (PrPc) converts predominantly α-helical protein → β-pleated form (PrPsc); resist proteases and facilitate further conversion of PrPc → PrPsc
359
To which class of viruses does yellow fever virus belong?
Flavivirus; also an arbovirus
360
Name 3 enveloped DNA viruses.
Herpesvirus, Hepadnavirus, Poxvirus (enveloped DNA viruses Have Helpful Protection
361
Name the proteins for which each of these HIV genes code: env, gag, pol.
env: gp120 and gp41; gag: p24 and p17; pol: Reverse transcriptase, Integrase, Protease (RIP “Pol” [Paul])
362
What does the HIV-1/2 Ag/Ab immunoassay detect?
Viral p24 capsid protein antigen and IgG antibodies to HIV-1/2
363
What is the Tzanck test?
An outdated diagnostic test that uses a smear of an open skin vesicle to detect multinucleated giant cells associated with herpes simplex virus (HSV) infections
364
What biopsy findings are associated with a Histoplasma capsulatam infection in patients with CD4+ cell count \< 100/mm3?
Macrophages containing oval yeast cells
365
What rare CNS sequelae of measles infection occurs a few days following the development of the classic rash?
Encephalitis (1:1000 cases)
366
366
Describe the type of virus shown in the image.
Bacteriophage
367
What disease condition is most likely in a child who presents with epigastric pain and enlarged parotid glands seen in the picture (image)?
Mumps (causing parotitis and pancreatitis)
368
What is depicted from the Tzanck test shown (image)?
Multinucleated giant cells
369
Describe the type of virus shown in the image based on 1) the presence of envelope and 2) capsid type.
Naked virus with an icosahedral capsid
370
What is the name of the cytoplasmic inclusions found in Purkinje cells of the cerebellum and hippocampus in rabies (image)?
Negri bodies
371
Explain the finding in the blood smear shown (image) from a patient with mononucleosis due to infection by Epstein-Barr virus.
Atypical lymphocytes (reactive cytotoxic T cells)
372
Describe the type of virus shown in the image based on 1) the presence of envelope and 2) capsid type.
Enveloped virus with an icosahedral capsid
373
What is the most likely diagnosis for a child presenting with a maculopapular rash and the oropharyngeal exam findings shown (image)?
Measles (rubeola); the oropharynx exam shows Koplik spots (bright red spots with blue-white centers on buccal mucosa)
374
A college student reports malaise, fevers, sore throat, and abdominal pain. An abdominal CT scan is shown (image). What is the most likely diagnosis?
Mononucleosis due to Epstein-Barr virus infection (image demonstrates associated hepatosplenomegaly)
375
This itchy rash is seen on a 4-year-old boy in daycare (image). What is the most likely infectious agent?
Varicella-zoster virus (chickenpox)
376
This virus was isolated from aerosols taken from a bat cave (image). What virus is it?
Rabies virus (classic bullet-shaped virion)
377
Diagnosis of the cutaneous plaques shown (image)?
Kaposi sarcoma (vascular proliferations); seen in HIV/AIDS and transplant patients
378
Each winter, a woman presents with the bothersome lip lesion shown (image). Most likely diagnosis?
Herpes labialis (cold sores) caused by the herpes simplex virus-1 (HSV-1)
379
Diagnosis of the unilateral rash shown in the image?
Shingles due to reactivation of latent varicella-zoster virus
380
What is the name of the ocular findings (image) found with human simplex virus-1 infection?
Keratoconjunctivitis
381
Which 2 viruses cause high fever in children \<2 years old for several days that can cause seizures, followed by the diffuse rash shown (image)?
Human herpesviruses-6 and -7; roseola infantum or exanthem subitum (Roseola: fever first, Rosy [rash] later)
382
What is the cause of disease for a patient presenting with the sign shown on this plain film (image)?
Croup ("steeple sign" from narrowing of upper trachea and subglottis during parainfluenza viral infection)
383
A newborn infant with microcephaly had brain imaging revealing findings shown (image). What is the likely diagnosis?
Congenital Zika syndrome (ventriculomegaly, subcortical calcifications)
384
What is the most likely cause for the development of a maculopapular rash that starts at the head and spreads caudally on a young child as shown (image)?
Rubeola virus (Measles)
385
A febrile child has a fine, maculopapular rash that started on his face and spread to his trunk and extremities (image). What is the most likely cause?
Rubella virus (rubella or German measles)
386
Which virus has the classic histological findings of "owl eyes," as seen in the image?
Cytomegalovirus (HHV-5)
387
What virus is the cause of the disease in the image (location: genitals)?
Herpes simplex virus-2
388
This virus was isolated from a health care worker volunteering in Sub-Saharan Africa (image). With which virus is the patient infected?
Ebola virus
