Lecture 8- Activities of a pathogen 1 and 2

Question 1

colonisation

Answer 1

infection with microbe for a varying period, no host immune response.

Question 2

endogenous infectious disease

Answer 2

arises from colonising pathogen or flora

Question 3

exogenous infectious disease

Answer 3

arises from elsewhere eg. flu

Question 4

primary pathogen

Answer 4

isolation is always pathogenic. there are few examples

Question 5

principle pathogen

Answer 5

isolation is usually pathogenic. cause infection in otherwise well people with intact defenses. usually responsible for disease

Question 6

opportunistic pathogen

Answer 6

cause infection only when defences are down. mostly in younger and older people

Question 7

healthcare associated infection is…

Answer 7

very common complication of healthcare. kills people. is often avoidable. costs Nz 300,000,000 each year.

Question 8

virulence factors

Answer 8

genetic determinants that allow a pathogen to cause disease. adherence, invasion, immune evasion and toxins. requires some breach of defence.

Question 9

pyogenic infection

Answer 9

tissue invasion, multiplication and immune response in a sterile site eg. N.meningitis invades CSF and provokes innate immunity causing meningitis

Question 10

pathogenesis of appendicitis (why do bacteria cause disease and how?)

Answer 10

appendix becomes obstructed and bacteria propagate.inflamed appendix contains a lot of immune cells, bacteria and dead bacteria which causes pain. the inflamed appendix is covered in an momentum and forms a chronic inflammatory appendiceal mass. if the appendix ruptures you will get peritonitis which may lead to sepsis and death

Question 11

adherance

Answer 11

to enable adherance some pathogens are:
viable in the environment
transmitted to their niche
motile
able to use chemotaxis
able to use specific host targets to bind

Question 12

compete with other organisms to cause disease

Answer 12

almost all sites of infection are already colonised by commensal bacteria. need to adapt and compete for space and nutrients

Question 13

compete with the host to replicate and cause disease

Answer 13

in all infectious disease the microbe comes into contact with the host’s immune system. the pathogen must have a strategy to overcome every specific host defense

Question 14

viral structural identification

Answer 14

nucleic acid + or -
capsid
envelope

Question 15

diagnosis of viral illness

Answer 15

clinical
visualisation-seldom useful for submicroscopic entities
viral culture
serology- measure antibodies against viral antigens in serum
detection of viral NA

Question 16

management of viral infections

Answer 16

preventions-immunisations, avoidance
symptomatic management
immune therapy
specific anti viral drugs