infectious diseases Flashcards
classes of infectious agents?
bacteria, virus, fungi, yeast, parasites, prions
organisms capable of living in any tissue?
staph aureus; makes coagulases
organisms capable of releasing products that damage widely?
escherichia coli; produces endotoxins that spread via the blood stream.
organisms that live/ reproduce in very few tissues?
influenza virus, aspergillus spp, clistridium spp.
how does influenza virus cause disease?
binds to sialic acid on respiratory mucosa
how does aspergillus spp. cause disease?
they sporulate when in contact with air
how does clostridium spp cause disease?
in hypoxic conditions
examples of organisms that damage only certain tissues?
clostridium difficile, clostridium botulinum, vibro cholera
how does c.diff cause disease?
releases enterotoxins that damage large intestine mucosa
how does clostridium botulinum cause disease?
releases a toxin ingested with food
how does vibro cholera cause disease?
toxin activates cyclic ATP, causing loss of fluid from intestinal lining
bacteria that damage tissue?
staph aureus; coagulase/ promote blood clotting. strep pyogenes; promote plasminogen activation decreasing clotting and healing. various bacteria; break down ECM framework
what are aggressins?
non-toxic material that enhance survival of the organism
how do viruses damage tissue?
direct cytopathic effects e.g. influenza, hep A. immune reactions e.g. hep B and C. incorporation of viral genes into host genome e.g. oncogene viruses
example of organism causing fungal infections
aspergillus spp
describe different fungal infections?
asthma; airway colonisation. aspergilloma; fungal ball in pre-existing cavity such as sinuses. hepatocellular carcinoma; aflatoxins from A flavus
what organism causes yeast infections?
candida albicans
examples of yeast infections?
local; thrush - caused by poor hygiene, bacterial flora alterations and diabetes. systemic; immunosupressed
examples of parasites?
protozoa, trematodes (flukes), nematodes (roundworms), cestodes (flatorm or tapeworm)
examples of protozoal diseases? (parasitic disease)
amoebiasis, giardiasis, malaria, trichomonas
describe the parasitic disease; amoebiasis
colon colonisation causing amoebic dysentery. amoebic abscesses can occur on the liver
describe the parasitic disease; giardiasis
small intestinal infection causing diarrhoea and weight loss
describe the parasitic disease; malaria;
spread by mosquitoes. colonises red blood cells and can obstruct cerebral capillaries.
describe the parasitic disease; trichomona’s
venereal transmission - a form of STD
describe different types of ‘worms’
roundworms - enterobius vermicularis organisms.
tapeworms - diphyllobothrium latum organism causing vitamin B12 deficiency. echinococcus granulosus; dog tapeworm causing liver cysts
what are prions?
infectious particles with no RNA or DNA
describe sepsis?
an overwhelming response to infection where the body damages its own tissues.
signs and symptoms of sepsis?
temp >38.3C or <36C, HR >90bpm, respiratory rate >20
signs of severe sepsis?
low urine output, change in mental status, low platelet count, difficulty breathing, abnormal heart pump functioning, abdominal pain. septic shock.
causes of sepsis?
pneumonia, abdominal infection, kidney infection, bacteraemia
what can interfere with the body’s defences?
loss or suppression of cough reflex, pulmonary oedema, bronchial obstruction, dead air space
