Infection 1 Flashcards
(32 cards)
Factors that affect the beginning of an infection?
The pathogen, its virulence factors and the host
Basic beginning of an infection?
Exposure of the host to a disease causing pathogen
What is the main way of pathogen transmission?
Directly from one host to another
Difference between direct and indirect horizontal transmission?
Direct–> direct contact
Indirect–> transmitted by inanimate objects, food etc
What is a fomite?
An inanimate object that may harbour a pathogen that can then be taken up by another host
What is vertical transmission?
Passing a disease to your offspring (done by insects)
What is a vector transmission?
Organism passing the disease from host to host e.g. malaria with mosquitos
What is a reservoir ?
A host for a pathogen
How was the origin of the cholera outbreak in london in 1854 discovered?
John Snow plotted the cases on a map and found they clustered around a water pump
What must a pathogen do once it has entered a host?
Reach a site of colonization
How does a pathogen remain in a site of colonisation?
Attachment mechanisms
Why is there mucus on epithelial surfaces?
To prevent pathogens making contact
What characteristics of mucus sites prevent pathogen attachment?
Fluid flow, microflora and secrete antimicrobial peptides
What is the mucociliary escalator?
Cilia on surface of cells in respiratory tract epithelium are constantly moving
What are examples of structures that bacteria have developed to stick to host tissues?
Pili/fimbriae, and adhesins
What are pili?
Hair-like protein appendages that extend out from the bacterial cell surface
Most common pilli produced by bacteria?
Type 1 and type 4
How are pili formed?
Repeating subunits assembled on cell surface
What can happen to the tip proteins on a pilli?
They can be changed to recognize diff host cell receptors
What can type IV pilli do?
Retract to bring bacteria into closer contact w/ host cells
Which motility can pilli be used for?
Twitching
WHat happens as a result of the interaction between pili and host cells being v specific?
The pilli that are being used can determine which body site, and even which host is infected
WHat is one, human oriented way, what E.coli can be characterised?
The types of disease, and where in the body the disease is caused from
What does enteropathogenic E. coli (EPEC) cause?
Small bowel diarrhoea
