Virology Flashcards

Question

herpes diagnosis

Answer 1

1. cell culture - CPE within 2-3 days 2. PCR 3. Tzanck smear: Giemsa stained direct smear of lesional material 4. Histology

Answer 2

1. Infectious mononucleolosis - primary 2. X linked lymphoproliferative disease (Duncan disease) - primary (get B cell lymphoma, mono, aplastic anemia, infections, etc.) 3. Burkitt lymphoma - latent (100% of endemic, 25% of sporadic and immunodeficiency forms) 4. Hodgkin lymphoma - latent 5. PEL - latent (also have HHV-8) 6. Lymphomatoid granulomatosis - latent 7. PTLD - latent 8. Oral hairy leukoplakia - latent 9. Nasopharyngeal carcinoma - latent (100% in Chinese and 75% in US)

Answer 3

**Diagnosis** * evidence of maternal infection during pregnancy * skin lesions on newborn in dermatomal distribution * serologic evidence of infection in the newborn (either IgM or persistent IgG beyond 7 months) * Insulin degrading enzyme is the receptor for VZV **Severity/Incidence** * lowest when maternal infection occurs in the 1st trimester * higher in the 2nd and highest in the third trimester within days of delivery

Answer 4

neonatal VZV pneumonitis, showing multinucleated cells

Answer 5

a, b: CMV placentitis c, d: CMV colitis (Cowdry type A inclusions)

Answer 6

HSV infection

Answer 7

Reactivation of VZV from the geniculate ganglion of the facial nerve: * otalgia * unilateral facial paresis * vertigo * hearing loss * tinnitus * rash

Answer 8

Latency Dorsal root ganglia Acute disease 1. acute gingivostomatitis 2. pharyngitis 3. skin infection (herpetic whitlow) 4. genital herpes (less common) Reactivation 1. herpes labialis 2. herpes encephalitis 3. less likely to cause recurrent genital herpes lesions than HSV2

Answer 9

Latency: Dorsal root ganglia Acute disease: 1. genital herpes 2. herpetic whitlow 3. acute gingivostomatitis Reactivation 1. genital herpes 2. herpes meningitis

Answer 10

Latency: 1. Histiocytes 2. Endothelial cells 3. T cells Acute disease 1. Mono 2. disseminated infection in neonates and immunocompromised Reactivated disease: disseminated infection

Answer 11

Latency: Dorsal root ganglia Acute disease: chicken pox Reactivated disease: shingles

Answer 12

Latency: B cells Diagnosis: * not routinely cultured * serology used (like arboviruses) * similarly rota and rhabdoviruses are not cultured, but are diagnosed with antigen detection Acute disease: 1. infectious mono (primary) 2. X linked lymphoproliferative disease (Duncan disease) (primary) Reactivated disease: 1. Burkitt lymphoma 2. Hodgkin lymphoma 3. PEL 4. lymphomatoid granulomatosis 5. PTLD 6. Oral hairy leukoplakia 7. Nasopharyngeal carcinoma

Answer 13

Latent: T cells Acute disease: roseola (exanthem subitum); childhood febrile seizures Reactivated in immunocompromised hosts (1/2 of BMT and 1/3 solid organ recipients); highly neurotropic (viral encephalitis)

Answer 14

Latency: lymphocytes Acute disease: roseola Reactivated disease in immunocompromised hosts

Answer 15

Latency: B cells and endothelial cells No known acute disease Reactivation disease: 1. Kaposi sarcoma 2. Primary body cavity lymphoma 3. PEL 4. multicentric Castleman disease in HIV+ patients

Answer 16

* asymptomatic or mono * immunocompromised: pneumonia, hepatitis, retinitis, disseminated * neonatal CMV: 1. microcephaly 2. low birth weight 3. intracerebral calcs 4. HSM 5. jaundice 6. chorioretinitis 7. thrombocytopenia 8. petechial rash 9. purpura 10. sensorineural hearing loss

Answer 17

Immunosuppressed patients IBD exacerbation

Answer 18

1. serology - positive IgM or 4x rise in IgG 2. pp65 antigenemia on DFA of peripheral blood leukocytes 3. PCR on any tissue 4. histology 5. culture - up to 2 weeks for CPE

Answer 19

* Primary infection occurs at pharyngeal or genital mucosa sites by infecting B cells via the C3d receptor (CD21) * CD8+ T cells proliferate and are responsible for the peripheral blood atypical lymphocytosis * LFTs often elevated * EBV genome persists in episomal form

Answer 20

X linked immunoproliferative disease * fulminant primary EBV infection that is often fatal * males * mechanism of death: hepatic necrosis, hemophagocytosis, agammaglobulinemia, B cell lymphoma * defect in the SH2D1A gene * uncontrolled activation of T/NK cells following EBV infection

Answer 21

Heterophile antibodies: * positive in acute disease * monospot test detects antibody with affinity for beef RBC that is uninhibited by adsorption with guinea pig kidney antigen (the differential absorption test) * **monospot** is specific but insensitive (less positives in young children) **IgM anti VCA** * positive in acute infection (1-2 months) **IgG anti EA** * positive in acute, convalescent and remote infection **IgG anti VCAgG** * positive in early acute through remote stages **Anti EBNA** * positive in acute through remote **order of appearance:** **IgM-VCA, heterophile and IgG VCA, EA, EBNA**

Answer 22

* EBER ISH: RNA produced by EBV detected (HL RS cells) * ISH with BamHIW sequence of EBV DNA * IHC for LMP1 The above two perform almost as well as EBER

Answer 23

* Molecular methods (FISH or PCR) * IHC (LANA1 expression in a speckled nuclear pattern) * Serology (IFA, ELISA, or Western blot)

Answer 24

**Clinical Features** * respiratory infections caused by serotypes 1-14 and 21 * Types 11 and 21 are associated with hemorrhagic cystitis * Types 40 and 41 are seen in childhood gastroenteritis **Diagnosis** * Serology * Direct antigen detection * PCR * Culture: CPE in 1-7 days (grapelike clusters) * Histology (basophilic nuclear inclusions)

Answer 25

* P antigen is the target (associated with Donath-Landersteiner ab, PCH, neutralized pigeon egg and hydatid cyst fluid) * Erythema infectiosum (slapped cheek disease; fifth disease) * Aplastic anemia * primary maternal infection during gestation can lead to hydrops fetalis * infection in persons with chronic hemolytic anemia (e.g., sickle cell) * smudgy nuclear inclusions in bone marrow biopsies * IHC, FISH, or PCR * don't culture this because it requires nucleated RBCs

Answer 26

respiratory virus that is detectable only by PCR

Answer 27

* papovaviridae * acquired in childhood * latent in epithelia of UG tract and lymphocytes * Reactivated in immunosuppressed: * JC virus * PML in oligodendroglia - demyelinating * AIDS patients * smudgy nuclear inclusions * BK virus * hemorrhagic cystitis and/or polyomavirus nephropathy * usually in transplant patients * smudgy nuclear inclusions in urothelial cells: decoy cells

Answer 28

* papovaviridae * associated with **Merkel cell carcinoma** and **CLL** * clonally **integrated and mutated MCPyV DNA** in 80% of MCC * mutated in 15% of normal skin but not integrated

Answer 29

* papovaviridae * episomal in benign lesions and integrated into host DNA in malignant lesions * viral E6 and E7 genes are needed for oncogenesis

Answer 30

* Epidermodysplasia verruciformis - AR * first decade * lesions may undergo malignant transformation to SCC * similar syndrome in organ transplant patients * Recurrent respiratory papillomatosis (RRP) * 6 and 11 * 2 types: * juvenile onset acquired through birth canal * adult form sexually transmitted * true vocal cords * 2-4 yo usually (can also present in adults) * Anogenital HPV * benign: 6 and 11 * Bowenoid: 16 and 18 * SCC: 16 and 18 * Verrucous carcinoma (aka giant condyloma of Buschke and Lowenstein): 6 and 11 * Head and neck SCC - * HPV positive gives good px especially in oropharynx * stain with p16 IHC

Answer 31

1. 1, 2 2. 2, 1, 4 (HPV 7 in fish and meat handlers) 3. 3, 10 4. 13, 32 5. 2, 3, 10, 5, 8 6. 16, 18, 31, 33, 35 7. 18, 16, 45

Answer 32

1. variola * smallpox * bioterrorism 2. vaccinia * derived from variola used in small pox vaccine 3. molluscum contagiosum

Answer 33

1. variola 2. Hemorrhagic fever viruses 3. B anthracis 4. yersinia pestis 5. C botulinum 6. F tularensis

Answer 34

1. Encephalitis viruses 2. Brucella 3. Burkholderia mallei (glanders) 4. C psittaci 5. Burkholderia pseudomallei (meliodosis) 6. Coxiella burnetii 7. C perfringens 8. Foodborne bacteria ( E coli, shigella, salmonella) 9. waterborne bacteria (Vibrio, cryptosporidium, rickettsia prowazeckii (typhus), staph aureus enterotoxin B)

Answer 35

1. Influenza 2. Nipah 3. Hantavirus 4. Rabies 5. Yellow fever 6. Drug resistant TB 7. Rickettsia conorii

Answer 36

* RNA picornavirus family * fecal oral * acute disease only: children * Relapse can occur within 5 months * Dx: IgM anti HAV * IgG persists for life

Answer 37

* DNA virus; intact particle = Dane particle * Viral markers begin to emerge between 2-10 weeks after exposure * HBsAg - indicates active disease (acute infection or chronic carrier state) * HBeAg - chronic carriage with active viral replication * anti HBc - present in anyone who has been infected (IgM and IgG present in resolved HBV) * anti HBe - found when HBeAg becomes negative; does not imply resolved infection or immunity; indicates chronic carrier without active viral replication * HBsAb - resistance to infection (immunized or successfully cleared infection)

Answer 38

HBV DNA, HBs antigen, HBe antigen, IgM c antibody, anti-HBe, anti-HBs (anti-HBc and anti-HBs occur with symptom onset) (majority of patients clear infection heralded by anti HBs and anti HBe)

Answer 39

* Definition: HBsAg \> 6months; if this occurs without symptoms then the person is a "chronic carrier" * Chronicity occurs in * 5% of healthy adults * 10% of IC * 90% of neonates infected transplacentally * Chronic HBs antigenemia can be associated wtih PAN

Answer 40

* tendency toward fulminant hepatitis with liver failure * mutations in the C or pre C region of the HBV genome impairing e synthesis

Answer 41

1. making initial diagnosis of HBV 2. Replicative vs nonreplicative chronic HBV: (\> 10⁵ copies DNA/ ml) are replicative) 3. response to therapy: undetectable HBV DNA is considered a virologic response

Answer 42

(Flavivirus family) * most common cause of transfusion associated viral hepatitis * 60% of those infected develop chronic HCV * 15% with chronic disease become cirrhotic * 5% of those with cirrhosis develop HCC * Extraheptic manifestations * mixed cryoglobulinemia * glomerulonephritis * aplastic anemia * Diagnosis * EIA * RNA - positive earlier than other methods; \<3 months) * RIBA - recombinant immunoblot assay; positive in cleared infections * Sustained virologic response: undetectable RNA for 24 weeks after treatment ends

Answer 43

Molecular or serologic assays * US: most common is genotype 1 * Genotype 1 divided into 1a and 1b (mostly 1a) * 1a more likely to develop resistance to treatment

Answer 44

RNA virus fecal oral chronic infection is rare 15-35 yo more virulent in pregnant women with 30% mortality

Answer 45

RNA virus in Flaviviridae family parenteral transmission chronic infection common not shown to cause clinical hepatitis

Answer 46

1. EBV 2. CMV 3. HSV 4. VZV 5. yellow fever

Answer 47

* influenza A more common than B and more serious * cold weather outbreaks * antigenic changes * Drift (minor): point mutations in H and N genes; produces annual outbreaks and epidemics * Shift (major): genetic reassortment betwen strains (q10-20 years pandemics) * morbidity * pneumonia * secondary bacterial pneumonia * Reye syndrome * myositis * myocarditis * Guillain-Barre syndrome

Answer 48

* H - binds sialic acid containing receptors on respiratory mucosa and becomes expressed on infected cells (basis for hemadsorption test) * Neuraminidase (N)

Answer 49

influenza A and B parainfluenza mumps

Answer 50

* specimens: throat and nasopharyngeal swabs, BAL * Culture gold standard (being replaced by PCR) confirms dx by * CPE * hemadsorption * IF * EIA * Rapid antigen tests (e.g., DFA) is 50-80% sensitive, but very specific * Nucleic acid detection (NAT) - detects RNA by PCR * very S and S * allows for determination of subtype and strain * Serology - most common is hemagglutination inhibition; allows for determination of subtype and strain

Answer 51

1. cell cultures (detection by hemabsorption/hemagglutination) 2. antigen detection (IF) 3. PCR

Answer 52

* descending rash starting on head * otitis media \> pneumonia, myocarditis * atypical measles: * teenage patients who have gotten only 1 vaccine * SSPE - incubates for 7 years

Answer 53

* parotitis +/- meningoencephalitis, orchitis, myocarditis, or pancreatitis * DX: culture, NAT, serology

Answer 54

* most common cause of lower RTI (pneumonia and respiratory bronchiolitis) in infants and toddlers * outbreaks have 100% attack rate * immunity is short-lived and recurrence throughout childhood is the rule, but infections become less severe * DX: DFA, EIA, culture, PCR

Answer 55

1. poliovirus - destruction of spinal ventral horn motor neurons 2. coxsackie A - herpangina, hand foot mouth disease (diagnose by seeing flaccid paralysis in suckling mice) 3. coxsackie B - epidemic pleurodynia (the grippe), myocarditis, and pericarditis 4. Enterovirus - most common cause of viral meningitis

Answer 56

(picornavirus) - common cold - culture requires incubation at 32 degrees, but PCR preferred

Answer 57

1. hantavirus - aerosolized rodent excreta, pulmonary syndrome 2. bunyavirus - e.g., California encephalitis 3. nairovirus - e.g., Crimean Congo hemorrhagic fever 4. phlebovirus - rift valley fever virus

Answer 58

1. rubella 2. alphavirus (equine encephalitis) 3. flavivirus (HCV, dengue, yellow, St. Louis encephalitis, WNV)

Answer 59

* person to person * febrile illness with rash * Fetal infections: * first trimester: most serious (sensorineural deafness, cataracts, glaucoma, microphthalmia, PDA, IUGR, microcephaly) * should test IgG titer in women before pregnancy * booster vaccination recommended in nonimmune women of childbearing age

Answer 60

1. HCV 2. dengue fever (breakbone fever) and yellow fever - transmitted by Aedes mosquitos and cause fever, chills, backache, jaundice, hemorrhage 3. yellow fever is viscerotropic for heart, kidney, GIT, liver (latter has midzonal necrosis, councilman bodies, microvesicular steatosis, no inflammation) 4. St louis encephalitis 5. WNV - bird - mosquito (culex) - bird cycle with humans as incidental host

Answer 61

* enters axon terminus of nerve cells at neuromuscular junction * transported via retrograde fast axonal transport to CNS * damages CNS and travels to periphery along autonomic and sensory neurons where it enters salivary gland, hair follicles * Negri bodies in Purkinje cells of cerebellum and hippocampus and Babes (microglial) nodules

Answer 62

1. lassa fever virus 2. machupo virus 3. lymphocytic choriomeningitis (LCM) virus Only LCM is in the US virus particles contain host cell ribosomes, giving them a granular appearance parasite of rodents that shed virus in their urine and feces - hamsters and house mice are hosts to LCM virus

Answer 63

* Japan, Caribbean, southern Africa, Brazil * Transmission: parenteral (IV drugs, transfusion, sexual) and transplacental * Infects CD4 T cells * Dx similar to HIV: screening ELISA, confirmatory western blot or PCR * Acute infections usually asymptomatic * After incubation may have late sequelae: * Tropical spastic paraperesis (HTLV1 associated myelopathy) * women: men = 3:1 * short incubation * demyelinating lesions within upper thoracic and lower cervical cord * Adult T cell leukemia/lymphoma * incubates 20-30 years * 5% risk in people infected before age 20 * HSM, jaundice, weight loss * hypercalcemia * skin rash * increased IL-2 receptor * very thirsty

Answer 64

1. 13-64 yo, 2. new dx of TB, and 3. seeking treatment for STD

Answer 65

1. IVDU and sexual partners of IVDU 2. sex workers 3. MSM 4. heterosexual people who themselves or whose sex partners have had \>1 sex partner since their most recent HIV test

Answer 66

1. patients with signs or symptoms of HIV 2. when acute phase of infection is considered both HIV RNA test and HIV antibody test are offered 3. patients with an opportunistic illness charactersistic of AIDs written consent not required (but verbal consent is)

Answer 67

* CDC recommends screening all women prior to conception or early in pregnancy * CDC urges repeat testing in 3rd trimester for all pregnant women for following groups: * women in states with elevated incidence of HIV/AIDS if ages 15-45 * women treated in facilities that identify at least 1 HIV infected pregnant woman per 1,000 women * women who are known to be at risk for HIV * women who have signs or symptoms of acute HIV * women who present in labor with unknown HIV status or deliver before status is known should undergo opt-out screening with a rapid HIV test (newborn should get rapid testing so that treatment can be started within 12 hours)

Answer 68

1. ELISA - test for anti HIV1/2 antibodies to recombinant antigens and peptides is principle screening method * detectable within 6-8 weeks of infection * p24 protein directly detectable by 2-3 weeks 2. Western blot is used for confirmatory testing 3. Detection of proviral DNA can confirm diagnosis - highly S and S (but low by HIV standards); cDNA integrated into host cell genome

Answer 69

* sample with known HIV proteins undergoes gel electrophoresis * gel is transferred onto nitrocellulose paper to which patient serum is added, then stained * Positive HIV1: presence of any 2 of the following bands: * p24 * gp41 * gp120/160 * If no bands are present: negative * Indeterminate: if one or more bands present but not in combination that meets criteria for positivity; repeat test within 6 months * If repeated test within 6 months has another indeterminate test with no risk factors, then considered negative, otherwise do nucleic acid test

Answer 70

* undergoes diurnal variation * age dependent * counts monitored every 6 months * used in making treatment decisions

Answer 71

* correlation with 10 year outcome better than CD4 count, but inferior to 6 month outcome * expressed in log units * change of 0.5 log is considered significant * increase may occur transiently after immunization * primary variable used to determine response to HAART * 100% sensitivity, but false positives do occur

Answer 72

PCR testing for HIV proviral DNA, but HIV RNA may be equally good

Answer 73

**Screening**: _4th generation_ assay detects IgM and IgG antibodies to HIV1/2 & p24 protein **Confirmation and differentiation**: _2nd generation discriminatory test_ differentates HIV-1 from HIV-2 (Bio-Rad Multispot immunoassay)

Answer 74

Negri body