Resp Viruses & Atypical Resp Pathogens Flashcards
Surface infection
Local spread
Short incubation
Common cold, oral candiditis
Systemic infections
Spreads from mucosal site of entry to somewhere else in body.
Long incubation
May return to surface for final shedding stage
MMR
Common cold
URT
Rhinovirus
Transmitted as aerosol
how does virus affect cells
sticks to receptor on ciliated epithelium
virus absorbed into cell and replicates
causes cell death
IS kicks in and removes cells causing more damage (snot)
Repair
Pharyngitis and tonsillitis
Rhinoviruses, adenoviruses
Common implication of colds
Group A step - enlarged LN, redtonsiles , sore throat, fever
Virus that causes mumps
Paramyocovirus
Air-borne saliva
Laryngitis and tracheitis
Parainfluenza viruses, adenovirus, influenze
Burning pain in larynx and trachea, loss of voice
Croup couch in kids w narrowed airways.
Bronchitis and bronchiolitis
Influenza, corona, adeno
Usually in kids as narrow airways, smokers also more susceptible.
Mainly secondary when airways narrow
RSC causes 75% of bronchiolitis
Resp Syncytial Virus (RSV)
Aero and hand transmission
Creates large fused cells (snotty) which blocks airways
Increased resp rate, cough
Treat severe cases w anti-virals (-mab drugs (monoclonal antibody))
Influenza
Droplet spread
Affects all of resp system plus can be systemic
Caused by Orthomyxoviridae - RNA virus
Common in cold months-more time indoors
Sudden onset fever (faster onset than cold)
V bad flu symptoms
Influenza structure
RNA w 8 segments
2 surface glycoproteins - HA (h-antigen) binds to sialic acid receptoes and NA (n-antigen) involved in release of virus from host cell
How does influenza virus get into cell?
HA binds to cell
Endocytosis
HA fuses viral envelope and endosome membrane to create pathway for viral RNA and polymerases to be delivered into the cell
Replication within cell
Antigenic drift
Mutations in surface proteins of influenza viruses that accumulate over time.
Source of yearly epidemics.
Combatted w yearly flu virus
What is antigenic shift, what does it cause?
Big chunks of viral DNA moving from one virus to another.
Causes more cases of flu and virus is majorly differently than those seen by body before.
Pandemic caused
Only influenza A
Influenza A
Source of yearly epidemics
Reservoirs in animals
How does antigentic shift happen
simultaneous infection of 2 influenza viruses at the same time - one human/animal + one human virus.
Covid-19
RNA virus
Spike protein - trimet=3 proteins
Binds to ACE2 receptors through body therefore symptoms where most ACE2 receptors are
Pneumonia
Swelling of lung tissue
Only affected by org <5mm - larger cannot enter alveoli
Secondary to preceding damage e.g. CF, influenza
Immunocomp
Bacterial or viral
Shaddow on lung xray
Aytp pneumonia
Walking pneumonia - not hospitalised
Chest pain, SOB, cough
Mycoplasma pneumoniae
Chlamydophilia
Legionella pneumophilia
Mycoplasma pneumoniae
Walking pneumonia
V small w small genome
No peptidoglycan (cholesterol instead) - penicillin resistant
Young adults and students
Chlamydophilia pneumoniae
Small, obligate gram -ve intracellular pathogen
No peptidogly (penicillin resistant)
Flu
Detect w ELSA or microimmunofluorecence
Legionnaires disease
Legionella pneumophilia - motile aeorobic gram -ve rod
Cough, chest pain + CONFUSION (neurological comps)
No human transmission - hot tubs, shows, spa
Common in hosps, hotels, high rise blocks (water systems)
Lives within amoebas symbiotically
Invades phagosomes and lung cells - hides from IS and replicates
Urinary antigen test
