ID Exam 2 Viral respiratory infections Flashcards by Cameron Niswander

Respiratory viruses

Common URTI/LRTI

Target and infect epithelial cells
URTI: rhinovirus unique
Either URTI/LRTI: parainfluenza, RSV, flu, adeno

How well did you know this?

Not at all

Perfectly

Common causes of:
Bronchiolitis
Common cold
PNA
Croup

Bronchiolitis: RSV
Common cold: rhinovirus, coronavirus
PNA: flu, RSV, adeno
Croup: parainfluenza

How well did you know this?

Not at all

Perfectly

Viral infections of respiratory tract: characteristics
Symptoms result of?
Temp preference

Fomites/aersol transmission
Targets epithelial cells
Cytokine release = symptoms
Rhino prefers 33˚ -> URI, compared to warmer lower
Attenuated vaccines also prefer 33˚

How well did you know this?

Not at all

Perfectly

Patterns of replication
Infect and exit?
Persistent infection?
Systemic?

Just surface epi and exit: para/orthomyxovirus
Persistent epi: EBV, adeno, papillo
Systemic replication: MMR, HHV types

How well did you know this?

Not at all

Perfectly

RNA - characteristics

Must bring own DNA polymerase
All replicate in cytoplasm (except orthomyxo)
All single stranded (except rio)

How well did you know this?

Not at all

Perfectly

Orthomyxovirus: characteristics

Genetics/mutations

Enveloped
Replicates in nucleus (NOT cytoplasm)
Segmented genome (8) -> BOAR
Flu A: shift and drift - pandemics (multi-animal)
Flu B: just drift - epi/endemics (only human)
Flu C: only human, not worried about
A/B/C differentiated by nuclear protein and M protein

How well did you know this?

Not at all

Perfectly

Antigenic drift vs. shift

Drift: point mutation, epidemics (seasonal flu)
Shift: segments are shared (reassortment), pandemics

How well did you know this?

Not at all

Perfectly

Orthomyxovirus: pathophys and complications

Hemagglutinin (H1, H2, H3) - binds sailic acid
M2 protein - creates pH for replication
Neuraminidase - cleaves sailic acid to release
Complications: bacterial superinfection (PNA) by S. aur, S. pne, H. flu

How well did you know this?

Not at all

Perfectly

Orthomyxovirus: treatment and vaccine

Tx: -mantadine: target M2 (Flu A only) lots of resistance
Tx: -tamivir: prevent NA cleavage (give early)
Killed vaccine and live attenuated (nasal)

How well did you know this?

Not at all

Perfectly

Paramyxovirus:

-RNA, enveloped
MMR vaccine
PaRaMMyxo:
Parainfluenza - croup
RSV - bronchiolitis in babies; Rx - ribavirin
Measles (rubeola)
Mumps

How well did you know this?

Not at all

Perfectly

Measles: S/Sx

CCCC:
Cough
Coryza (runny nose)
Conjunctivitis
Koplic spots (small, blue/white spots on red, buccal mucosa)
Fever
Maculopapule rash after koplic (face and down), confluence rash - not important for transmission

How well did you know this?

Not at all

Perfectly

Measles complications

Giant cell PNA

Subacute sclerosing panencephalitis (SSPE)

How well did you know this?

Not at all

Perfectly

Measles characteristics

HA but no NA
Fusion protein: multinucleated giant cells
Warthin-Finkeldey giant cells (fused lymphocytes)

How well did you know this?

Not at all

Perfectly

Measles treatment and vaccines

Vitamin A can help
MMR vaccine (CI in pregnancy and immunosuppressed)

How well did you know this?

Not at all

Perfectly

Mumps: characteristics, virulence

Replicates in parotid glands
Humans are only reservoir
Worse infection with older age
Later can present as unilat/bilat orchitis
Meningitis
Virulence: HA and NA, fusion protein

How well did you know this?

Not at all

Perfectly

RSV: characteristics, virulence, treatment

Attached to G protein to infect epithelium
Most common cause of PNA and bronchiolitis in infants
Virulence: fusion protein
Tx: ribivirin used in adults (not kids or pregnant)
Tx: prevent in high risk (premies) infants w/ palivizumab

How well did you know this?

Not at all

Perfectly

Parainfluenza virus: S/Sx, virulence factors, CXR

Croup, stridor (laryngotracheobronchitis)
Virulence factors: HA, NA, and fusion protein
CXR: steeple sign
2-6 days incubation
Children aged .5-2
4 types (PIV4=rare, but can cause URI in adults)

How well did you know this?

Not at all

Perfectly

Segmented viruses

Bunyaviruses
Orthomyxoviruses
Arenaviruses
Reoviruses

How well did you know this?

Not at all

Perfectly

Influenza spread and symptomology

Can spread in absence of symptoms
Replicated in ciliated epi of URT
Self-limited, 3-7 days
Bacterial superinfection most common cause of death
(except 1918 pandemic)

How well did you know this?

Not at all

Perfectly

Dx of flu

RT-PCR

Clinical dx: fever, HA, myalgia, season

How well did you know this?

Not at all

Perfectly

Tx of flu

Study These Flashcards

NA inhibitors: zanamivir, oseltamivir, peramivir (A and B)
Must give within 48 hours of onset to decrease duration
Maybe prevent bacterial superinfections
M2 inhibitors: amantidine, rimantadine (A)

Sub types of parainfluenza

Study These Flashcards

PIV-1: outbreaks of croup in Fall
PIV-2: Fall outbreaks leading to bronchitis/PNA
PIV-3: Peak=spring/summer, but can be all year
PIV-4: rare, but can cause URI in adults

RSV diagnosis and complications

Study These Flashcards

Rapid nasal swab tests

Most common cause of PNA in kids under 2

Measles in pregnancy

Study These Flashcards

Infection in unvaccinated, pregnant women:
Premature labor
Spontaneous abortion
Low BW infants

Mumps: s/sx

``` glands as big as POM-Pom's Parotitis Orchitis aseptic Meningitis Pancreatitis Sterility (post-pubertal) ```

Sensitivity

TRUE positive rate

Specificity

Disease absent patients | TN/(TN+FP)

Assays in diagnostic viruology can detect:

Virus nucleic acid Viral antigens Virus Virus-specific antibody

HIV diagnostic and confirmatory testing (in order)

1. ELISA (HIV-ab) | 2. Western blot (HIV-ab)

Viral cultures

``` Abx added Looks for cellular changes = cytopathic effect (CPE) CPE = rounding up, fusion, lysis CPE is evidence of infectious virus Not all viruses result in CPE ```

Hemadsorption test vs. Hemadsorption inhibition test vs. Hemagglutination inhibition test

Infected cells result in RBC binding and aggregation Inhibition test: add antibody specific for virus, block of RBC binding indicates which antibody binded Agg inhib: Serological test with virus, inhibition of agglutination indicates presence of viral antibody in serum

Rapid influenza diagnostics

Rapid antigen tests (range of sensitivity) Direct fluorescent antibody assay (required technical experience) RT-PCR (technical experience and expensive equipment) *Still need to do culture to determine future vaccine and potential viral resistance*

Togavirus group

Arborvirus (Wester/Eastern/Ven equine encephalitis) Rubella Enveloped, +RNA

Rubella

Postauricular and occipital lymphadenopathy Fine, confluent rash that starts face and moves down Long polyprotein cleaved by proteases MMR vaccine (HIV >200)

Rubella s/sx

Mild, self limiting febrile rash in infants BUT infected pregnant mother: TORCHES Infects within first 3 months -> infects placenta

Acute vs convalescense serum

Acute: during infection Convalescent: 4 weeks after recovery Rise in ab (ex. IgM) from acute to con = was active infection

Zika virus s/sx and diagnosis for active/recent infection

Eye pain, myalgia, conjunctivitis, fever, rash Travel to Mexico, Guatamala, Belize IgM and RT-PCR NO aminocentesis (s/s not known, progression not known)

Zika virus fetal s/sx

Neuronal cell death | Decrease in head circumference

Flaviviruses

+RNA, enveloped Dengue fever (type II, break bone) -> thrombocytopenia, hemorrhagic, renal failure, sepsis (mosquitos) Yellow fever: jaundice, bloody both ends, back pain, live attenuated virus West nile: encephalitis, meingitis, seizure Hep C

Capture ELISA

Start with known anti-human antibody instead of known virus antigen Add virus antigen later

DFA testing

Base of cells Add patient serum (and potentially virus) Virus infects cells, expresses surface proteins 1˚ to bind surface 2˚ to bind ab and have flouro

Human Metapneumovirus

Causes URI and LRI Usually mild and self-limited RT-PCR, grows very slowly in culture Treatment is supportive

Adenovirus

dsDNA, Most are asx, long latent periods Reactivations are problem in AIDS patients Can be shed for long periods of time

Adenovirus: diseases

Conjunctivits Acute hemorrahgic cystitis GI Myocarditis

Adenovirus: vaccines and treatment

Vaccines: Live vaccine, military recruits only Treatment: self limiting, supportive care

Rhinoviruses

A picornavirus, naked +RNA Yuuuuge amount of serotypes, no vaccine Replicate best at 33˚ (URI, colder) C can replicate at 37˚

Coronaviruses

Enveloped with glycoprotein spikes (crown) Unstable in environment (vs. rhino) Respiratory and enteric (neonates) disease Replication in respiratory epithelium 1/3 cause of common cold Can be systemic (like mumps)

Coronaviruses and more severe illness

SARS and MERS

Spillover vs. genetic change

Reservoir population with high pathogen comes in contact with novel host population So far, none have included fast human to human transmission

Patterns of replication and examples: Acute Persistent Systemic

Acute - confined to respiratory epi: paramyxovirus Persistent - EBV, adeno, papilloma Systemic - mumps, measles

ID Exam 2 Viral respiratory infections Flashcards

(50 cards)