respiratory viruses Flashcards
fomites
inaminated object contaminated with secretions containing viruse
influenza incubation and contagion
incubation is 1-3 days and a person is contagious from 1 day to 7 days after the onset of symptoms
influenza description
negative sense single stranded RNA with 8 segments
important influenza proteins (3)
- RNA pol- genome replication and transcription
- HA- binds cell receptor and fuses envelope with the cell membrane
- NA- helps release virions from cells surface after budding ** antiviral target
antigenic drift
epidemic
antigenic shift
pandemic
small antigenic changes in the virus
antigenic drift
large antigenic changes in the virus
antigenic shift
Type A influenza
both epidemics and pandemic
***migratory acquatic birds are the reservoir
A/california/7/2009 (H1N1)
type/location of the outbreak/strain/year of the outbreak (subtype)
how does the antigenic drift occurs?
viral RNA pol is error-prone- makes mistakes and does not correct them
how does antigenic shift occurs?
exchange (reassortment) of genome segments between avian and mammalian viruses - only in type A
different cell receptors between human and bird flu?
Human HA binds to alpha-2,6-sialic acid while bird flu HA binds to alpha-2,3- sialic acid
what about the HA targets of pid?
have both sialic acid receptors
concern for the reassortment of bird and human flu
results in a highly contagious and virulent strain
why are influenza vaccines are manufactured and administered every year?
antigenic drift
antiviral do what?
block neuraminidase to block virion release
respiratory syncytial virus
paramyxovirus family, -ssRNA enveloped
RSV disease lead to what in children
laryngotracheobronchitis- croup or barking cough
RSV in infants
bronchiolitis
RSV prevention: ________ with palivizumab in high risk infants
passive immunization
common cold viruses first 2 causes
- rhinoviruses
2. coronavirus
adenoviruses
dsDNA non enveloped that is lead to acute pneumonia
*** military recruits
