C1 & 2 Flashcards
Name the 5 routes of infection
- Person to person
- vector
- fomite
- Orally: food
- contaminated water
name 3 types of person to person transmission & examples
A. direct contact e.g. chicken pox/
B. contaminated body fluids e.g. Herpes simplex-2: increased chance HIV (females)
C. Vertical transmission e.g. Toxoplasma gondi (cat)
Define viral infection
vector bone diseases are infected are infection transmitted by the bite of infected arthtopod species e.g. mosquitoes, ticks, triatomine bugs, sandflies, blackfiles
Name examples of vector transmission
- sandfly born disease: Leishmaniasis
(protazoan parasite) - tick born encephalitis: flaviviridae: acts on receptors & reservoirs
- Lyme Borreliosis: bacteria spirochete Borrelia burgorferi (lxodes genus)
name a fever which can be caused by a tick
CCHF: crimean-congo pnemorrhagia fever
RNA virus of Bunyaviridae family
- transmitted: Hyalomma spp ticks from domestic animals (zoonosis)
Name examples of fomite infection
non living objects. Bedding, toys, towels, flu on surfaces, athletes foot
which immune components protect at each entry site?
- Soluble mediators: anti-infectives e.g. desfensins, complement
- tissue resident cells: eg. epithelial cells, alveolar macrophages
- recruited cells: innate: neutrophils, NK. Specific: B/T
- antibodies: different classes = diff functions
C2.
Soluble blood components
complement, antimicrobial protein: lactoferrin/ bactericidal, permeability. a-defensins & B-defensins are cationic peptides: disrupt membranes
often present in an inactive form -> activated when immune response is taking place
describe carbohydrate outer membrane
carbohydrate chain interlocked by short peptide strands
describe function of lysosome
breaks down carbohydrate chains & damages structural integrity of bacterial outer membrane
(bacterial burst under own internal pressure)
explain process defensins
Electrostatic attraction & transmembrane electric fields bring defensin into lipid bilayer
defensin peptides form a pore
Cathelicidins
stored in granules & inactive precursors: released when cleaved by neutrophil elastase
LL37 - only CAMP gene in humans
where is LL37 expressed
circulating neutrophils & myeloid BM cells, epithelial cells of the skin, GI, epididymis & lungs
Function of CD3 T cells
co receptor helps to activate both cytotoxic CD8+ & CD4+
what does a product mean
small product EXCEPT C2 (C2a=BIG): anaphylatoxins
may initiate localised inflammatory response by binding to receptors
what does product b mean
BIG product - bind near activation sites
what do all 3 pathways of complement generate
generate C3 convertase which cleaves C3, leaving C3b bound to the microbial surface & releasing C3a
C3a & C5a recruit what cells to site of infection
phagocyte cells, also promote inflammation
MAC leads to
disrupts cell membrane & causes cell lysis
- recruits cells to site of infection (to kill infected cells)
- reduces damage
define alternative pathway
C3 undergoes spontaneous hydrolysis to C3(H20) to initiate eventual desposition of C3 convertase on microbial surfaces
