Resp Viruses Flashcards

Question 1

Q

Resp Tract Broken Down

Answer

A

_Upper Resp: _
Nose (mouth)
Throat
Epiglottis
Larynx
Middle ear & paranasal sinus
Lower resp:
Trachea
Brochi
Bronchioles
Alveoli
Deaths by resp infections #1 among low income populations

Question 2

Q

Defense against infections

Answer

A

Nose: Hair, cilia, turbinates or nasal concha/mucus filter dust & particles = Sneezing
Change in direction: airway from sinuses to pharynx deposits particles @ **back of throat **
Lymphoid tissue:
Adenoid gland: Between nose & throat @ end of soft palate
Tonsils: Both sides of pharynx
Trachea: layer of mucus & ciliated cells=Coughing
Resp secretions: Lysozyme ^{(gram+ bacterial cell walls)}, IgA, lactoferrin, mucus
Alveolar macrophages: Lower resp tract
Normal flora: upper resp tract

Question 3

Q

How Pathogens avoid immune defense

Answer

A

Avoid mucus = NOT being expelled out
Avoid phagocytosis & multiply/divide in phagocytic cell
Major virulence factors(mol secreted by pathogens):
Bacterial adherence-surface structures
Extracellular toxins-Cytoxins
Growth in host tissue-intracellular
Evasion of hose defense:
- Capsules-multiple types
- Production of IgA proteases
TB avoiding immune defense w/granuloma
Multiple strains of strep (94)

Question 4

Q

Syndromes of Upper Resp

Answer

A

Defense = Normal Flora
Common cold
Pharyngitis
Influenza
Diphtheria
Sinusitis & Otitis Media
Rhinocerebral mucrormyosis
- **Effects immunocomprimised **
Epiglottis
Croup/laryngitis

Question 5

Q

Syndromes of Lower Resp

Answer

A

Defense: Macrophages
Whooping cough
Bronchitis/Brochiolitis
Influenza
Pneumonias
Typical
Atypical (walking) develops from bacteria, viruses, fungi not common typical (chlamydo, mycoplasma, legionella)
Community/Nosocomial (hospital)
Occupational-Bacillus anthracis/Chlamydophila psi
Regional
Opportunisitc-Aspergillus spp/pneumocystis Jiro
Pulm TB = Myobacterium TB

Question 6

Q

Etiologic Agents of Resp Infections

Answer

A

Microbal toxins that cause disease-Viruses, bacteria, fungi, Protozoan(unicellular), Helminthes
Viruses more common
Bacterial infection more serious=life threatening diseases
Many of upper resp tract pathogens ALSO cause lower resp tract infections
Influenza can effect BOTH lower/upper
Vocal cords are a marker for upper & lower resp tract
Bacteria:
Staph aureus-major cause of pneumonias
Francisella tularensis-gram(-) lethal cases of pneumonias
Coxiella burnetti-Gram(-) bio weapon

Question 7

Q

Common Cold

Answer

A

Acute viral infection of resp tract w/inflammation in some or ALL airways (nose, paranasal, throat, middle ear, larynx)
Symptoms:
Nasal discharge & obstruction
Sneezing
Sore/scratchy throat
Cough
Chilly sensation w/slight fever
Etiology: Multiple agents 90% viral
Rhinovirus (common)
Coronavirus (SARS-10-15%)
Influenza (25-30%)
Adenovirus (5-10%)
Also less common chlamydia
Human Metapneumoviruses (influenza)
Complications: Sinusitis & otitis media Both Viral/Bacteriral w/asthma
Treat w/1st gen anti-histamines or NSAID

Question 8

Q

Pharyngitis

Answer

A

Divided into Naso, Oro, Laryngo (top-bottom)
More common in children & @ winter time
Symptoms: “Sore throat”
Dysphagia (pain w/swallowing)
Fever & headache
Enlarged lymphnodes(neck)
Occasional runny nose/post nasal drip
- Pus or no pus
Etioloic agents:
Adenovirus
Coxsackie
Epstein Barr ^(mono)
Strep pyogenes
Corynebacterium Diph ^{(mycobacterium)}

Question 9

Q

Sinusitis & otits media

Answer

A

Occurs after viral infections
Sinusitis: Inflammation & obstruction of sinuses due to pus_(may follow tootch extraction due to normal flora)_
Fever-headache
Thick colored post nasal discharge
Halitosis
Otitis media: Inflammation & obstruction of middle ear due to pus behind tympanic(NOT present in viral)-sharp pain w/hearing loss, vomiting (anorexia)
Pathogens:
Strep pneumoniae ^{(normal flora)}
Haemophilus influenzae ^{(normal flora)}
Moraxaella catarrhalis ^{(common)}
- gram(-) aerobic
Pseudomonas aeruginosa ^{(common)}
- Immunocomprimised

Question 10

Q

Croup: Laryngotracheobronchitis

Answer

A

Area between pharynx/trachea contains vocal cords w/mucous membrane
Symptoms: Resp obstruction swelling
Follows upper resp infection
Breathing diff, hoarseness w/Seal’s bark cough, Inspiratory stridor (high pitched-vibrating)
Gets worse laying down
High risk in 3 months-5 years
Exam: Restrictions on breathing, PROLONGED inspiration/expiration, wheezing
Sucking in of skin on inhalation-increased use of chest wall muscles
X-ray-Steeple sign ^{(narrowing of upper trachea)}
Etiology: Parainfluenza virus (80%), RSV, measles, adeno, influenza

Question 11

Q

Bronchitis/Bronchiolitis

Answer

A

Inflammation of bronchial tubes-occurs after upper resp
Symptoms:
Fever, cough, & sputum production
Sore throat
Runny or stuffy nose
Headache
Muscle aches & extreme fatigue
Etiology: Virus & bacteria
RSV (syncytial-COMMON)
Parainfluenza/Influenza
Mycoplasma pneumon
Chlamydophilia (community)

Question 12

Q

Pneumonias Classification

Answer

A

Infection of alveoli or walls
Could involve interstital ^{(between alveoli)}
Classification:
Location-Community or nosocomial
Oset-typical (acute), atypical (gradual), Chronic
Site affected- lobular, multilobular, broncho, interstitial
Regional- found only certain areas
Occupational-zoonotic ^{(cross species)}
Aspiration-Normal flora from Upper

Question 13

Q

Symptoms of Pneumonia

Answer

A

Typical: rapid onset, high fever/chills, dyspnea, productive cough (blood), wheezes/cracks
- X-ray: Dense consolidation
Atypical: moderate onset, low fever/chills, sudden attack cough w/moderate sputum
- X-ray: Vague-patchy consolidation
Chronic: Gradual onset, night sweats, low grade fever, weight loss w/productive cough

Question 14

Q

RNA virus Rhino (Non-enveloped-Picornav fam)

Answer

A

ss(+) RNA & 100 types known
Replication in cytoplasm ^{RNA-dep/RNA poly}
Reservior: Humans/Chimpanzees
Transmission: Worldwide, seasonal(summer-fall), Direct contact, resistant to drying/Detergents
Pathogensis: receptor on host ICAM-1
Low infectious dose/Nose, eye, mouth
Infected cells make-histamine/bradykinin
Replicates @ 33C better for upper resp
Acid labile-Killed in stomach
Diagnosis: Rarely done
Viral isolation-swabs saliva, nasal, pharyngeal
Serology-confirm virus as infection & assessment of immune status
Treatment: Hand washing w/NO vaccine due to so many serotypes

Question 15

Q

RNA virus Corona (enveloped-Coronavir fam)

Answer

A

Spikes on surface due to large glycoprotein=Looks like *corona/crown *
(+) ssRNA virus replicated in cytoplasm w/RNA dependent RNA poly
optimum temp 33-35C=Upper resp
S protein for attachment coating itself resemmbling Fc-gamma receptors on immunoglobulins
Reservior-Corona(Human)
SARS-Cov(bats, cats, raccoon)
MERS-NCOV(middle east bats, camels)-Immunocomprimised
Transmission-Airborne droplets nasal or Oral-fecal (winter-spring)
SARS-COV: kills alveolar cells w/diarrhea
High fever, sore throat, ATYPICAL pneumonia, dyspnea
RT-PCR w/ELISA Ab=Diagnosis
Treat: Interferon-Ribavirin

Question 16

Q

DNA virus (non-enveloped) Adenovirus life cycle

Answer

A

Icosahedral shape w/hexon capsid proteins
Peplomers: Pentons @ apices w/protuding fibers=attachment (HE)
- Purified fibers toxic to human cells
Reservoir: Humans w/asymptomatic shedding
Receptors on host cells:
CAR-Coxsackie: Glycoproteins in Ig super family ^{(CAR used by Coxsackie virus too)}
CD46 (membrane co-factor protein)
MHC class 1
Integrin (internalization)
Sialic acid (RBC & Upper resp)
Endocytosis-Repication in nucleus
Early protein synthesis FOLLOWED by replication THEN late protein synthesis

Question 17

Q

DNA virus (non-enveloped) Adenovirus Pathogenesis

Answer

A

Lytic: Permissive cells=host cell death
Target cell-muco-epithelial cells in resp tract ^{(upper & lower)}, GI, Urinary
Latent: non-permissive cells=recurrence in immuno comprimised pts
Target cell-Infections in lymphoid cells ^{(tonsils, adenoid, peyer’s patches)}
Transforming infection: Cancer @ the site on incoculation ^{(hamsters only)}
Transmission: Close contact, aerosol, fecal-oral
Resists dryness, deteregents, mild Cl- (survive up to 90 days in pools)
High Risk: Children, crowded areas, SWIMMING clubs

Question 18

Q

DNA virus (non-enveloped) Adenovirus Clinical

Answer

A

Pharyngitis=1,2,3,5,7:
Common cold symptoms
Fever, Sore throat, Inflammed Pharynx
Pharyngoconjunctival fever=3,7:
Assoc w/pools
Conjunctivitis, fever, vocal cord inflamm
Acute resp disease=4,7,21:
Military recruits
3rd week of training
Fever, malaise, sore throat
Sudden drop in O2 in blood
Vaccine available (made of 4&7) oral & replicate in GI bypas resp
Pneumonia=1,2,3,7:
Mostly children and severe
GI^(diarrhea)=40,41
Diagnosis: Immunoassay fluorescent Ab or ELISA or PCR

Question 19

Q

RNA virus Coxsackie (Non-eveloped Picornaviri)

Answer

A

(+)ssRNA w/2 types A & B
Reservoir: Humans
Transmission: P to P, fecal-oral, Airborne
- ^{Ex. Diaper changing stations}
High risk: infants & young children in Summer/Fall seasons
Treatment: COXA self-limiting (4-7days)
No vaccines
Prevention: Proper hygiene, boiling utensils
Herpangina: Vesicular pharyngitis
Sudden fever, headache, Sore throat, Dysphagia
Ulceration/Rash in pharynx, tonsils, mouth
Hand-foot-mouth: mild fever, vesicular lesion-hand, foot, mouth, tongue
Caused by type COXA16

Question 20

Q

DNA virus Herpes (enveloped) General

Answer

A

Large w/linear dsDNA
Lytic, persistant or latent transforming infections
Vesciles seen in HSV1/2
HSV 1=Cold sores-latent in trigenminal
Grouped on what cell types they infect
Alpha herpes(infect epi cells):
Simplex (HSV-1 & 2)-Upper resp
Zoster-varicella (HHV 3)
Gamma herpes(infect vareity cells):
Epstein-Barr (HHV4)
Kaposi sarcoma (HHV8)
Beta herpes(infect lymphoid cells):
Cytomegalovirus (HHV5)-Upper resp

Question 21

Q

DNA virus Herpes (enveloped) Epstein Barr

Answer

A

ds linear DNA-Enveloped HHV4
Asymptomatic shedding w/saliva w/lifelong infection
Transmission-P to P saliva
High risk-Young adults not infected ^{(mono)}
Infections in infants (when maternal Ab stops) or early childhood life long immunity
Cell infected = Epithelial (oro/Naso) & B-lymph
Virual gp350 attaches to comp C3b receptor-CR2(CD-21)->Gp42->MHC2
Permissive(productive): replicates/lysis of infected cells contain-
Early Ag, Viral capsid Ag, Membrane Ag
Non-permissive(latent):B cell mitogen ^{(uncontrolled prolif)} EBV DNA in nucleus, NOT integrated w/chromosome
Epstein barr nuclear Ag & Latent membrane protein = Immortal growth

Question 22

Q

DNA virus Herpes (enveloped) Epstein Barr Clinical

Answer

A

Acute: Infectious Mono=Heterophile Ab (+) sheep blood agar ^{(paul-bunnel test)}
Fever, Sore throat, Lymphadenopathy, Splenomegaly & FATIGUE 1-4 weeks
Chronic: Recurrent-Fatigue, low grade fever, sore throat
Ampicillin^{(beta-lactam)}rash seen in pts under treatment
Additional diseases associated:
Leukemia/Lymphoma-T-cell def or Immunosuppresed
Burkitt’s-Tumor of Bcell, Jaw/face, Africa-malaria belt
Nasopharyngeal carcinoma-Cancer of epi, Asia, genetic
Oral Hairy leukopenia-AIDS pt, Wart like growth, multiplies in epi cells

Question 23

Q

DNA virus Herpes (enveloped) Epstein Barr Diagnosis

Answer

A

Incubation time 2 months or more
Hematologic:
Atypical T lympho (Downey cells)
T cells are larger w/vacuolated cytoplasm & basophilc inclusions
Serology:
Heterophile Ab: non specific IgM Ab-Bind to paul-Bunnel Ag on horse, sheep RBC
- Monospot test(horse)-quick
EBV specific Ab test: IgM active infection against viral capsid Ag or Early Ag
- IgG & AntiEBNA for chronic
Treatment: Self-limiting or Steroids for controlling swelling

Question 24

Q

RNA virus (enveloped) Paramyxoviridae

Answer

A

(-) sense ssRNA & non-segemented
Cytoplasmic replication
Buds from plasma membrane
3 genera cause Resp tract infections
Paramyxovirus: Parainfluenza/Mumps
2 spikes:
F peplomer spike=fusion results in multinucleated cells (synctia)
Posses spike=Hema & Neuraminidase
Pneumovirus: Resp syncytial & Metapneumo
Morbillivirus: Measles

Question 25

Q

RNA virus (enveloped) Parainfluenza Clinical

Answer

A

Transmission: inhalation of large droplet
High risk: Children 6mos-12yrs, short term immunity after disease
Pathogenesis: Inside epi cells-form giant cell & lysis
Adhesion mediated by Hemagglutnin-binds to sialic acid
Neuraminidase clips sialic acid for virus release
Clinical: Croup & Laryngotraceobronchitis
Mild cold-like upper resp infection
Can extend to larynx, trachea, & bronchial tree = CROUP or bronchiolitis & pneumonia
Croup=cough is sharp like seal’s bark due to subglottal swelling=High pitch
X-ray steeple sign

Question 26

Q

RNA virus (enveloped) Parainfluenza diagnosis

Answer

A

Best specimens are nasopharyngeal secretions
Ag detection: Immunofluorescence
Serology: Hemagglutination inhibition test, ELISA
Treatment:
Hospitalization-Treat symptomatically & monitor airway continuosly
Cold or warm mist (humidirfier)-Croup tent
O2-may have intubated due to narrowing of trachea
IM dexamethasone (corticosteroid) & inhaled epinephrine (pediatric)
NO vaccine & re-infections common

Question 27

Q

RNA virus (enveloped) RSV General

Answer

A

(-) ssRNA w/surface spikes only F protein (NO HG or Neuraminidases)
F protein: fusion multinucleated (syncytia)
Reservior: Humans everyone infected by age 3
Subtype B: asymptomatic affect majority of population
Subtype A: More severe & dominant in most outbreaks
Transmission: Inhalation of large droplets-Peaks in winter
High Risk: Premies-more severe w/lower resp=Brochiolitis
Common cause of acute FATAL resp tract infections
Adults: Mild symptoms, common-cold like. Very few infections are life threatening

Question 28

Q

RNA virus (enveloped) RSV Pathogenesis

Answer

A

Cause of fatal acute resp tract infection in infants
Infects epi cell & make giant cells & kills cells
Immuno mediated (CD-8) cell injury-necrosis/sloughing of bronchiolar epi
Formation of plugs-Mucus, fibrin, necrotic material obstructs airway=Bronchiolits
More dangerous in infants due to smaller peripheral airways than adults
Symptoms: Mild Upper resp infection progress to cough->wheeze->dyspnea
Increased resp rate=Tachypnea
Rales, fever->turns into Lower resp=Pneumonia
RSV sign: intercostal/substernal retraction
Long-term=Asthma & pulm deficits

Question 29

Q

RNA virus (enveloped) RSV Diagnosis

Answer

A

Ag detection assays (immuno)-
Cytophatic effect=Multinucleated cells w/basophilic cytoplasmic inclusion bodies
Treatment:
Symptomatic-Bronchodialators (metaproterenol/Albuterol) helps relieve chest congestion & wheezing
Severe cases=O2 therapy, Aerolized Ribavirin (analogue of guanosine)
Passive immunization: Hyperimmune globulin against RSV (Respigam)
Prevention: Infection for re-infection
Immuno-prophaylaxis-Children under 2 who have chronic lung disease
Monoclonal Ab against F-protein(palivizumab)

Question 30

Q

RNA virus (enveloped) Metapneumovirus

Answer

A

ss(-) RNA from family paramyxoviridae
Recently recognized pathogen
Could cause 15% of children’s colds
Can cause:
Bronchitis (mucous membranes)
Bronchiolitis (small bronchioles)
Pneumonia
Very common-children by age 5 are seropositive

Question 31

Q

RNA virus (enveloped) Influenza-General

Answer

A

ss(-)RNA & 8 Segmented RNA
Replicates in nucleus^{(instead of cytoplasm)}
Has RNAdep-RNApoly
Matrix proteins important in uncoating:
HA (hemagglutinin)
Initiate by binding to sialic acid on epi cells
Agglutinates clumping-RBC
NA (neuraminidase)
Cuts sialic acid to release virus/dissolves mucus
Vaccines target these proteins (no binding=no infection)
3 types based on variation of matrix proteins & nucleocaspid proteins (viral penetration into host nucleus)

Question 32

Q

RNA virus (enveloped) Influenza-Life Cycle

Answer

A

HA sticks to sialic acid on host cell-Virus enters by fusion into endosome (storage b4 nucleus)
Matrix proteins=uncoating
Nucleocapsid to host cell nucleus, viral polymerases require methylated cap of RNA ^{(Cap-mRNA-Poly A)} of host cell. Cap region of RNA for binding to ribosomes.
(+) RNA made from each segment=viral polymerase on each segment(-)sense RNA for viral progeny made=^{viral Shedding}
+mRNA proteins in cytoplasm.
Early proteins (polymerases and NP) for transcription and replication go to nucleus and mix w/–ssRNA.
HA and NA , M proteins transported to host cell membrane.

Question 33

Q

RNA virus (enveloped) Influenza-Types

Answer

A

Type A ONLY one w/sub-types based on variation on HA/NA Ag
- 16 HA sub = H1-H16
- 9 NA sub = N1-N9
Found in many species_-Native host is duck_
Type A assoc w/Pandemic ^{(Spanish Flu)}
Reassortment Antigenic shift:
Abrupt change when 2 strains infect one cell=RNAs mix giving rise to NEW strain
ONLY A
Type B ONLY humans
Point mutation/Antigenic shift:
Type A&B-Yearly epidemics occur
RNA segments are altered affect major Ag sites for glycoproteins
RNA virus prone to more mutations than DNA
Peplomers mutation=Cross species infect

Question 34

Q

RNA virus (enveloped) Influenza-Clinical

Answer

A

Incubation 1-4 days
Fever, headache, sore throat, muscle pain, DRY cough
Recovery 7-10 days
Severity in young & elderly ALSO pts w/chronic cardio-pulm diseases
Pneumonia caused by Influenza
Pneumonia caused by secondary bacterial infection-MOST COMMON (Staph aureus, Staph pneumoniae, H. Influenzae)
Reye’s syndrome-Acute encephalomyelitis^{(inflammation of CNS)}in children-assoc w/aspirin use
CNS issues-Seizures, weakness in periphery, hallucinations

Question 35

Q

RNA virus (enveloped) Influenza-Diagnosis

Answer

A

Nasal/throat swabs, sputum
Detection=Ag/genome DFA, ELIZA, RT-PCR specific ID for types or subtypes
Fast results-used in screening during epidemics
Viral isolation & ID-Cell/egg culture:
Hemagglutination or Hemabsroption assay NOT specific
Serology: measure Ab lvl (titer)-Acute hemagglutination inhibition assay, Comp fixation
Treatment: neuraminidase inhibitors stop viral release given 48 hrs of onset
- Oseltamivir(tamiflu)-oral
- Zanamivir(Relenza)-inhaled
Stop uncoating-block martix proteins_^{ONLY A}_
Amantadine or Rimantadine

Question 36

Q

RNA virus (enveloped) Influenza-Vaccine

Answer

A

Flu shot-Inactivated vaccine (killed virus)
Composed of H1N1, H3N2 + type B
Nasal spray vaccine:
Live attenuated=Reconstructed from mutant strain & virulent strain (weak)=Reassortment
Mutant strains does NOT grow well above 25C=Cold adapted mutant
Will grow in upper BUT not Lower resp making it less virulent

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Resp Viruses Flashcards

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