Introduction to Infectious Diseases Flashcards
direct and indirect transmission of infectious diseases
1) direct contact with an affected individual or discharges: airborne, droplet, bloodborne 2) indirect means: vector (animal), famine (inanimate object– virus can live on a doorknob)
T/F Infectious diseases make up majority of death in children in the world
true. 64% are due to infectious diseases like malaria, measles, meningitis, pertussis, AIDS, pneumonia
most common hospital acquired infections
UTI, pneumonia, and surgical infections. Theres also a breeding ground for antibiotic resistance
superbug
highly drug resistant organisms that are created through constant mutation because of our overuse of antibiotics
clinical syndrome
the sun of signs of any morbid state, a typical constellation of symptoms, physical findings and diagnostic tests which characterize a primary disease process - a “pattern” of signs and symptoms May be as a result of a number of different underlying primary disease processes (infectious and non-infectious)
a clinical syndrome may be systemic or ___
focal: involve a specific organ like hepatitis systemic: many organ systems like influenza like illness
infectious causes of hepatitis
viruses (A, B, C) Bacteria (salmonella) Fungi and yeast (Candida) Parasites (malaria)
non infectious causes of hepatitis
medications and toxins (acetaminophen, alcohol), autoimmune (lupus) inherited conditions (WD, hemochromatosis) cryptogenic (can’t figure out the cause)
contiguous vs hematogenous spread
contiguous: local infection due to breach in natural barriers hematogenous “seeded” from a systemic infection
tropism
only certain cells and tissue support the growth of a particular pathogen
colonization vs infection
infection: when body site is sterile colonization: when body site isn’t sterile ex/ infection in mouth
how does a fever come to be?
- microorganism releases exogenous pyrogens 2. leukocytes rally but produce endogenous pyrogens 3. hypothalamus releases PGE2 to increase set point. 4. PGEs cause vasoconstriction, shivering, behavioural changes, and increased metabolism which results in fever.
example of endogenous and exogenous pyrogens
endogenous: cytokines: ex/ interleukein I, G or TNF alpha can act on the hypothalamus to produce fever via the release of PGE2. exogenous: bacterial endotoxins. they interact with macrophages to activate the cell mediated immune system.
cause of rigors during infection
they’re shaking chills. a violent attack of uncontrolled shivering/shaking associated with chills and fever. caused by the effect of PGE2 on peripheral nerves to induce a reflexive shivering phenomena– tense muscles produce heat.
4 cardinal signs of local infection
- warmth 2. erythema 3. edema 4. pain. 5. BONUS: psu. due to dead neutrophils.
pathogens that induce pus formation
pyogenic. ex/ streptoccocus pyogenes (strep throat) causes tonsils to become ulcerated.
possible infection?
malaria
if a person is IgG positive and IgA negative they are likely:
vaccinated or were previosuly infected, but are well now
how does Staph aureus permeate into the soft issue/extracellular invasion?
via hyaluronidase (proteases and enzymes allow organism to move deeper into soft tissue)
how does listeria infect host?
through intracellular invasion: they survive phagocytosis
how does strep pneumo end up causing meningitis?
via dissermination: they pass the innate immune system and get into lymphatics/blood stream and then onto end organ targest.
examples of enterotoxin
ehec via shigella toxin
how does staph auereus cause toxic shock syndrome?
via exotoxin release of superantigens: causes non-specific stimulation of T cells –> uncontrolled cytokine release.
example of an endotoxin
LPS on a cell wall of a gram negative bacteria. can trigger inflammatory response and sepsis but it is inherent to the bacteria– they do not produce it as a toxin.
type 1 hypersensitivity reaction (autoimmune response)
anaphylaxis/rash due to IgE response.
type II hypersensitivity reponse (immune mediated damage)
apoptosis via cytotoxicity. (ex/ cell necrosis due to Hep B)
bacteria-caused Type III immune complexes (autoimmune response to infection)
fever and inflammation: post-streptococcal glomerulonephritis
bacteria-caused type IV hypersensitivity immune response (autoimmune response to infection)
delayed type. T cell mediated, causes granulomas or endemic fungii.
H. pylori transformation
recall: transformation is the ability for some organisms to favor the development of cancer.
Hpylori is linked to gastric adenocarcinoma
How does HIB overtly outsmart the immune system?
Via T cell infeciton– they destroy CD4_ cells.
name examples of infections that use capsules to covertly evade the immune system
streptococcus pneumo or pyogenes
haemophilus influenzar
neisseria meningitidis
cryptococcus neoformans
Yes, Some Killer Baceria Have Nice Capsules (yersinia, strep, klebsiella, bacillus, haemophilus, neisseria, cryptococcus neoformans)
examples of bacteria that use biofilm production as a method of avoiding the immune system
coagulase negative staphylococci.
example of virus that uses antigenic variation to evade the immune system
influenzae. H1N1;H3N2 etc.
example of infection that uses mimicry to evade the immune system
shistosoma haemotobium (liver fluke)– coats itself with host antigens to evade the immune repsonse.
