RT4 Flashcards
viral agents of infectious bronchitis and bronchiolitis
AIR - adenovirus, influenza virus, respiratory syncitial virus
bacterial agents of infectious bronchitis and bronchiolitis
bordatella pertussis, mycoplasma pneumonia, chlamydophilia pneumonia
clinical syndrome of bordatella pertussis
whooping cough (chronic bronchitis)
population susceptible to bordatella pertussis
unvaccinated children
reservoir of bordatella pertussis
adults (part of their normal flora) – who can pass it to children
what are bordatella toxins
TCT = tracheal cytotoxin PT = pertussis toxin ACT = adenylate cyclase toxin DNT = dermonecrotic toxin LOS = lipooligosaccharide Filamentous haemagglutinin (FhA)
pathogenesis of bordatella pertussis
transmission –> adhesion –> growth and toxin release –> local and systemic pathology –> bacterial clearance (if the patient survives)
stages of whooping cough
incubation –> catarrhal (symptoms of common cold) –> paroxysmal (coughing vomiting) –> convalescence
all this happens in a matter of days
sample used for bordatella pertussis and what type of sampling to avoid?
- get a nasopharyngeal swab then do PCR
- avoid cotton swab because they contain lipids and bordatella pertussis is easily killed by lipids/inhibits its growth
how to prevent bordatella pertussis
DaPT – acellular Pertussis
what happens over time with bordatella pertussis vaccine
immunity decreases over time – vaccine does not last a lifetime so must give boosters
what culture is used for bordatella pertussis
charcoal blood agar (bordet-gangou) with cephalosporin
clinical syndrome of HPIV (human parainfluenza virus) (paramyxovirinae)
laryngotracheobronchitis, bronchitis
physical feature of HPIV
-ssRNA, hemagglutinin and neuraminidase on surface, F spike (fusion protein), enveloped
pathogenesis of HPIV
important proteins/enzymes are HA, NA, F-protein, V protein
-V protein is also a fusion protein which is needed for evasion of host immune response; also will alter cell cycle, prevent apoptosis, inhibit synthesis of interferon and dsRNA signaling
what is Croup
aka laryngotracheobronchitis commonly caused by respiratory viruses (HPIV, pneumovirus, RSV)
symptoms of Croup
-Happens mostly in young children and infants -Swelling and narrowing of the airway
-Distinctive cough, sounds like the barking of a seal.
-Can rarely be fatal, especially if case is mishandled
what infection tends to be worse if vaccinated against using heat-killed vaccine
RSV infection (Respiratory Syncitial Virus)
what leads to clinical outcome of RSV infection
tropism of respiratory epithelium, anatomy of airways, immunologic response
how is epidemic flu transmitted
from man to man (even though it is zoonotic)
how is influenza transmitted
inhalation of respiratory droplets
adult symptoms of flu
- Rapid onset after short incubation of 1 to 4 days
- Sudden malaise and headache lasting a few hours
- Abrupt rise of fever, chills, severe muscle aches. Loss of appetite, non-productive cough. This can last from 3 to 8 days
- Recovery is complete in 7 to 10 days
- Patient is contagious from before symptoms appear (end of day 1) for the next 7 days
- Risk of secondary infection highest in time from 6 to 12 days after infection
children’s symptoms of flu
-symptoms in adult flu plus the following:
-Higher fever
-G.I symptoms: (Vomiting, Abdominal pain)
-Ear ache (Otitis Media)
-Muscle pain and sometimes swelling
-Croup often but not always
-Febrile Convulsions (Children under 3: Rare)
describe the symptoms in a common cold: fever, headache, general malaise, nasal discharge, sore throat, vomiting/diarrhea
rare fever and headache, slight general malaise, abundant nasal discharge, common sore throat, rare vomiting/diarrhea
describe the symptoms in a flu: fever, headache, general malaise, nasal discharge, sore throat, vomiting/diarrhea
common fever and headache, severe general malaise, less common nasal discharge, less common sore throat, common vomiting/diarrhea
complications of flu
Primary Viral Pneumonias
Secondary Bacterial Pneumonias
Muscle inflammation – Cardiac involvement
Rare Neurological syndromes
which types of influenza are hemagglutinin and neuraminidase present
all except for type C
which influenza type is most important
type A because it infects both humans and animals and can cause epidemics and pandemics
while type B and C are only in humans
type B can cause only epidemics
type C cannot do either
two surface glycoprotein on influenza and their function
hemagglutinin - helps virus get into the host cell by adhering to the respiratory tissues
neuraminidase - helps virus get out of the host cell
M2 protein is on A only (ion channel)
all three are where antigenic variation can occur
animals that are reservoir for influenza type A
ducks and pigs
how many H types and N types are found in ducks
all 15Hs and 9Ns
can immunity for H1 give immunity for H2
no, one has to develop immunity for each type separately
which human hemagglutinin types have not been associated with a human disease
H6 through H15 with the exception of H7N9
it is possible that H4 may not exist
how many segments of RNA are needed for influenza
A and B must have 8 segments
C must have 7 segments
all segments must all be different
features of hemagglutinin
- rod shaped
- it’s 25% of the viral protein
- major antigen - neutralizing Ab directed at it
- highly variable
- 4 subtypes - H1-3, H5
- requires cleavage by cellular proteases to be active
- changes in structure of protein that alters it length so that it can grab on to the target host cell
features and function of neuraminidase
- sialidase enzyme (removes terminal sialic acid from glycoproteins and glycolipids)
- enables release of newly budding viruses from host
- helps virus move through the mucin layer
- two subtypes N1 and N2???
- no stimulation of neutralizing antibodies
