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Virology > Viro Lecture 3 + 4 > Flashcards

Viro Lecture 3 + 4 Flashcards

1
Q

Retroviridae (4)

A
  • diploid, + ssRNA, RT for replication
  • Lentivirus group = HIV (non-segmented)
  • oncovirus group = blood cell cancers -> human/adult T cell leukemia (HTLV)
  • outer envelope (from PM of host), w/copies of 1 envelop prot in bilayer + internal capsid (prot w/2 RNAs + RT)
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2
Q

HIV virion (5)

A
  • enveloped conical capsid (type D)
  • 2 + ssRNA copies and 1 RT (RNA dependent DNA pol)
  • integrase (integrating virus DNA w/host)
  • protease (process prots for envelope/capsid)
  • 2 prots for cell attachment = gp41 + gp120 (after infection Abs released against this prot)
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3
Q

Clinical Syndromes of HIV (5)

A
  • AIDS, opportunistic infections, cancers, CNS dysfunction
  • all at T cells of 400/ml
  • initial symptoms = mono/flu, aseptic meningitis/rash, weight lost/wasting/fatigue
  • organ/system specific but all organs can be affected
  • full blow AIDS when CD4 T cells <200/ml
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4
Q

Viral opportunistic infections (3)

A
  • HSV 1+2, VZV (chicken pox, shingles), EBV (eyes), CMV (CNS + retinitis), HHV 8 (kaposi carcinoma) -> all at TH cells < 50ml
  • HPV (warts, anal condylomata)
  • HIV oral ulcers
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5
Q

Bacterial opportunistic infections (3)

A
  • Tb + other mycobacteria
  • TH cells < 400ml
  • other bacteria, normal flora bactera
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6
Q

Fungal/yeast opportunistic infections (3)

A
  • pneumocystis jirovecii pneumonia (LUNGS) -> TH cells < 200ml
  • oral candidiasis w/candida albicans (thrush) -> T cells btwn 250-500 ml
  • cryptocoocus neoformans = cryptococcal meningitis (meningitis + encephalitis in AIDS pts)
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7
Q

Protozoan opportunistic infections (1)

A

toxoplasma gondii = toxoplasmosis

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8
Q

HIV antiviral therapy (7)

A
  • inhibit steps of replication
  • Attachment/entering cell = fusion inhibitors
  • RT inhibitors
  • integration + txn = integrase inhibitors
  • tln (prod viral prots - use monoclonal Abs) + viral protease (cleaving viral prots) = protease inhibitors
  • assembly + budding inhibitors
  • HAART = highly active anti-retroviral therapy
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9
Q

RT inhibitors (6)

A
  • nucleoside analogs = AZT
  • non-nucleoside analogs = delavirdine, nevirapine
  • ddl
  • 3TC = lamivudine - thiacytidine
  • d4T = thymidine
  • ddC = cytidine
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10
Q

Protease Inhibitors (1)

A

Ritonavir w/ idinavir and neflinavir

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11
Q

Togaviridae (5)

A
  • alpha virus group - Western/Eastern/Venezuelan Equine Encephalitis virus
  • Mosquito borne diseases, Wild birds are reservoirs
  • Viremia, CNS infection = Encephalitis (highly linked w/horses -> fatality rates of 30-70%), arthralgia + mild fever
  • Worldwide -> in spring ideal conditions for viral replication, vector pops large
  • Vaccines developed against encephalitic diseases
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12
Q

Rubella (4)

A
  • togaviridae, trans via respiratory droplets, crosses placenta
  • teratogenic = abnormal prenatal development, problems in first trimester of gestation
  • Congenital Rubella Syndrome
  • Attenuated vaccine = single strain, part of MMR
  • have PDA (patent ductus arteriosus) - neonate’s ductus arteriosus doesn’t close after bith
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13
Q

Negative Sense RNA viruses (5)

A
  • enveloped, virion assoc enzymes, replicated in cytoplasm (orthomyxovirus replicated in nuc)
  • linear non-segmented ssRNA
  • Linear ssRNA w/8 segments
  • Linear -> Circular ssRNA w/3 ambisense segments
  • Circular ssRNA w/2 segments
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14
Q

linear non-segmented - ssRNA (3)

A
  • Paramyxovirus (Mumps, Measles, RSV, Parainfluenza)
  • Rhabdovirus (Rabies & VSV)
  • Filovirus (Ebola & Marburg)
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15
Q

Linear - ssRNA w/8 segments (1)

A

all in same virion = Orthomyxovirus (Influenza), replicates in nuc

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16
Q

Linear -> Circular - ssRNA (1)

A

w/3 ambisense segments = Bunyavirus (California encephalitis, Hantavirus & La Cross)

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17
Q

Circular - ssRNA (2)

A
  • w/2 segments: 1 neg sense & 1 ambisense (like neg-sense, but translate genes from positive strand)
  • Arenavirus (Lassa fever & LCMV)
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18
Q

Parainfluenza (2)

A
  • Paramyxoviridae (neg ssRNA, enveloped, helical nucleocaspid)
  • single helical nucleocaspid glycoprot, croup (laryngotracheobronchitis), common cold bronchitis
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19
Q

Respiratory Syncytial Virus (RSV) (3)

A
  • Paramyxoviridae (neg ssRNA, enveloped, helical nucleocaspid)
  • major cause of bronchiolitis and pneumonia in babies
  • Tx: Ribavirin(GMP analog) inhibits nucleoside synth + mRNA capping, inc detrimental mutations in large #
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20
Q

Measles (5)

A
  • Paramyxoviridae (neg ssRNA, enveloped, helical nucleocaspid)
  • fusion prot, photophobia, 3 Cs: Cough, Coryza (stuffy nose) and Conjunctivitis
  • Koplik spots (grains of salt) on oral mucosa -> maculopapular rash behind ears down = giant cell pneumonia
  • Rare but serious complication - subacute sclerosing panencephalitis (chronic CNS degenerative disease)
  • Live vaccine: single strain = MMR
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21
Q

Mumps (2)

A
  • Paramyxoviridae (neg ssRNA, enveloped, helical nucleocaspid)
  • fusion prot, parotiditis (inflammation of parotid gland near ear), pancreatitis, orchitis (males, sterility), meningoencephalitis -> live vaccine = MMR
22
Q

Rhabidoviridae (5)

A
  • Rabies from dogs, raccoons, fox, bats - bullet shaped, asymptomatic, prodrome (flu symptoms, anorexia)
  • Neurological symptoms (hydrophobia, dementia -> virus along nerve fibers), coma + death
  • Tx: if symptoms evident -> too late, no treatment
  • Must treat immediately after bite (post-exposure prophylaxis) w/HRIG or w/killed virus vaccine
  • Prevention = vaccination to high risk groups/animals, pre-exposure prophylaxis, kill rabid animals
23
Q

Filoviridae (3)

A
  • filamentous, enveloped, neg RNA -> Severe hemorrhagic fever, often fatal
  • Ebola, Marburg
  • Ebola trans via direct contact or body fluids
24
Q

Bunyaviridae (4)

A
  • segmented neg ssRNA - enveloped helical capsid
  • California encephalitis + LaCrosse encephalitis (mosquito borne, <15 years have severe case)
  • Hantavirus (rodent feces - mouse shit) pulmonary syndrome - cough, myalgia, dyspnea, tachycardia, pulmonary edema and effusion + hypotension (50% mortality)
  • High in UT, AZ, NM, CO
25
Q

Orthomyxoviridae (3)

A
  • neg ssRNA, enveloped, 8 segments
  • Influenzavirus type A = Infect people + animals
  • Influenzavirus type B & type C = Infect people, Type C viruses = mild upper respiratory disease
26
Q

Influenza A + B (4)

A
  • Enveloped
  • Hemagglutinin (HA) = Entry of virus into cells, binds sialic acid (N-acetylneuraminic acid) on host cell surface
  • Neuraminidase (NA) = invasive enzyme, cleaves term sialic acid, help access epi cells by liquefying mucus in resp tract
  • NA inhibitors block function of NA = Anti-flu drug target
27
Q

Antigenic Drift (2)

A
  • random mutations in viral genes seen by immune sys - can change viral Ags, help evade immune sys
  • Flu A + B antigenic drift responsible for epidemics (H1N2 -> H2N2) -> why people need flu vaccine every year
28
Q

Antigenic shift (4)

A
  • abrupt major change in viral antigenicity from gene recomb
  • Influenza A antigenic shift assoc w/pandemics (1918 pandemic) -> H3N2 + H5N1 = H5N2
  • 2 diff strains of segmented RNA virus infect same cell
  • Avian (highly pathogenic) + Human flu strain infect same cell = Major new genetic combs made via gene shuffling = New highly pathogenic human flu strain
29
Q

Influenza Pathenogenesis (4)

A
  • resp droplets -> mucous mem lining resp tract, infects ciliated columnar epi cells
  • HA binds to sialic acid receptors = virus phagocytosis
  • M2 prot = ion channel in virus envelope, endosome pH drops to 5.5 due to nucleocapsid release into cytoplasm
  • Virus interferes w/respiratory tract “clearing” mechanisms
30
Q

Influenza disease (4)

A
  • Abrupt fever, Headache, Myalgia, Sore throat, Non-productive cough
  • Resp symptoms predominate - Pharyngitis, laryngitis, and tracheobronchitis -> infection confined to resp tract
  • Cough + malaise 2 weeks after other symptoms disappeared
  • Influenza complications = Primary viral pneumonia + Secondary bacterial pneumonia
31
Q

Amantadine + Rimantadine (4)

A
  • specific against flu type A = block M2 ion channel
  • Given as prophylaxis to prevent infection, recommended for high risk people (e.g. immunosuppressed pts)
  • Given therapeutically to reduce severity (ideal in first 48 hours)
  • Teratogenic -> Cause fetus malformation (don’t use in preggo women)
32
Q

Neuraminadase inhibitors (4)

A
  • inhibit NA of both influenza A + B
  • dec rate of infection by preventing further infection of cells = Less severe disease, Shorter duration of symptoms
  • Analogs of sialic acid (SA) bind NA, block its active site => SA remain uncleaved
  • on viral cell envelopes HA binds cells SA = aggregation of virus on cell surface, less virus particles released into circulation
33
Q

Tamilfu (2)

A
  • Tamiflu (Oseltamivir) = NA inhibitor, tx & prevention

- Given orally to treat uncomplicated infection in the first 48 hours of symptoms (patient over 1 year)

34
Q

Zanamivir (2)

A
  • Zanamivir (Relenza) = NA inhibitor, tx & prophylaxis

- Given by inhalation to treat infection in the first 48 hours of symptoms (patient over 5 years)

35
Q

dsRNA viruses (3)

A
  • Reoviridae = linear dsRNA, segmented, Icosahedral, double shelled, unenveloped, Virion has assoc polymerase
  • Reoviruses = URT infections
  • Rotaviruses = GI tract infection, major cause of infant mortality in developing countries (600,000 under 5 yearly) -> Prolonged diarrhea
36
Q

Prions (3)

A
  • transmissible particles w/o nucleic acid, only modified prot (PrPsc) -> no recombinant infection material
  • No characterization of infectious particle, specific activity of purified agent extremely low
  • Infection w/o protease resistant PrPsc found
37
Q

Kuru (2)

A
  • prion disease

- Subacute spongiform encephalopathy (SSE), Fore Tribe, New Guinea, Cannibalism, Human

38
Q

Creutzfeldt-Jakob (2)

A
  • prion disease

- SSE, Genetic predisposition, Ingestion of infected cow brains, Human

39
Q

Fatal familial insomnia (FII) (2)

A
  • prion disease

- human, infects part of brain -> spongiform = can’t sleep -> ppl die from this

40
Q

Bovine spongiform encephalitis (BSE) (3)

A
  • prion disease
  • in cattle = mad cow disease
  • in Humans = no motor control, dementia, paralysis wasting, death, non-inflammatory lesions: vacuoles + amyloid prot deposits + astrogliosis
41
Q

Scrapie (2)

A
  • prion disease

- SSE, scraping wool off on fences, sheep

42
Q

Lentiviruses (5)

A
  • HIV part of lentiviruses (lentiviruses in monkeys = simian virus = SIV)
  • HIV descendant of SIV (certain SIV like HIV-1 and -2)
  • HIV-2 like SIV in sooty mangabey (SIVsm) = green monkey (west Africa)
  • SIVcpz (chimps) used to be closest to HIV-1 (more virulent strain)
  • Zoonosis - humans contracted HIV by eating infected chimps
43
Q

HIV in america (5)

A
  • Can now see HIV presence + subtype in blood samples -> get deeper look into origin + evolution of HIV in humans
  • To find source of AIDS, look for origin of HIV
  • AIDS deaths/diagnoses dec, but HIV infection inc
  • Inc in younger ppl, low socioeconomic status, IVDU, women
  • Condoms don’t protect against Hep A, Hep B much easier to get than HIV - but vaccines for A and B
44
Q

HIV transmission (3)

A
  • Injected body fluid - blood, semen, vaginal secretions + breast milk
  • Entry into body - mucous membrane (anal, oral, vaginal sex), blood-blood (needle, broken skin), perinatal (in utero, during birth, breast feeding)
  • no transmission by contact
45
Q

Oral Sex Transmission (4)

A
  • not often assoc, only 5-10% of cases
  • Receptive partner (person w/mouth to genital contact) at greatest risk
  • Jizz in mouth, poor oral hygiene, brushing/flossing prior to sex assoc w/transmission
  • Protective factor of enzymes in saliva
46
Q

Perinatal transmission (3)

A
  • dec from antiretroviral therapy in pregnancy (24% down to 8% vertical transmission w/AZT)
  • Nevirapine also successful
  • Women w/higher viral loads more likely to transmit than women w/low viral loads
47
Q

Factors affecting transmission (2)

A
  • STD co-infection = more likely to become infected, transmit infection
  • Viral load = stage of infection, treatments
48
Q

Primary Infection (3)

A
  • 2-6 weeks average, 75-90% have symptoms
  • Only way to know for sure = HIV Ab test -> waiting time = time to develop Abs
  • Disease progression = infection -> primary infection/Ab development -> asymptomatic period -> AIDS (opportunistic infections, CD < 200)
49
Q

Congenital Rubella Syndrome (6)

A

= rash at birth, low birth weight, small head size, heart abnormalities, visual problems + bulging fontanel

50
Q

HIV Testing (7)

A

PCR, ELISA, Western Blot, Oral fluids test, ORASURE, rapid test, urine test

51
Q

Antiretroviral treatment (5)

A

triple drug cocktail (attack virus in replication
prophylaxis/tx of opportunistic infections
vaccines
immune therapy
alternative tx

52
Q

Post-exposure prophylaxis in HIV

A
  • tx w/antiretroviral drugs after HIV exposure
  • starts within 72 hrs, continue for month
  • PEP showed 80% dec in HIV infections for occupational exposure
  • concern for drug + sex exposure

Virology (1 decks)

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