Heaphy 8 Pathogenesis Flashcards
(48 cards)
Pathology:
study of disease (pathos = suffering).
progress of disease,
deviation from, or interruption of normal structure/function of any body part.
SEVERITY:
Mild, severe, localised, systemic.
syphilis:
mild & localized progressing to severe systemic
Symptoms: lesion goes, months=> rash, yrs => dementia arthritis major organ failure => fatal.
HPV:
warts, cancer, oval cancer, cervical cancer => 80% of population risk increase with partners
80-90% cleared by immune system some chronically infected, some severe pathology (cancers) over period of yrs.
Medical microbiology:
“pathology of infectious diseases, caused by micro-organisms, capable of being transmitted e.g person-to-person, animal-to-animal”.
Dynamic interaction:
between disease-causing organisms and their victims - host-pathogen/parasite interaction. – genetics, resistance
Pathogens:
- micro-organisms that cause disease (viruses, bacteria, fungi including yeasts and amoebae)
• Most microorganisms are not harmful (even helpful)
Parasites:
larger pathogens e.g. Plasmodium. (malaria)
Pathogenicity:
mechanisms employed to bring about disease
Virulence:
ability to cause disease, relative,
- measles virus is more virulent than cold virus, because it is more deadly/dangerous.
Opportunistic Pathogens
do not normally cause disease - may live in host as commensals, may cause disease when body compromised
E. coli:
Opportunistic
harmlessly in GI tract, but may contaminate urinary tract (poor hygiene?
• Especially babies and females), infect urethra & bladder (cystitis) => (pyelonephritis) inflammation of kidneys. (can occlude kidneys)
Pseudomonas aeruginosa :
Opportunistic
burns patients lose defensive barrier of skin destroyed, can invade.
• environmental bacteria
Pneumocystis carinii (protozoan) :
Opportunistic
infects lungs of immunocompromised patients=> pneumonia,
• From animal faeces
• Killed most people with HIV/AIDS which is zooninoses:
Staphylococcus aureus :
Opportunistic
problem in immunosuppressed transplant patients
• and weak patients in hospital
in blood stream
associated w/ spots/boils, fatal to elderly with pneumonia => septicaemia
Name opportunistic pathogens
x4
E. coli
Pseudomonas aeruginosa
Pneumocystis carinii (protozoan)
Staphylococcus aureus
Obligate pathogens
evolved virulence factors that cause disease in otherwise healthy hosts as part of the normal life cycle.
Obligate pathogens
x 5
Vibrio cholerae POLIO Salmonella typhi, typhoid fever Mycobacterium tuberculosis HIV causes AIDS
Vibrio cholerae
Obligate
makes powerful toxin to induce massive fluid loss into intestine
- large investment in sanitation & water systems reduces/eradicates . prone in places without this
- makes protein that stops gut working properly => nutrients normally absorbed.
- Switch fluid pump from gut to body to body to gut => 10L of cholera particles into environment. => infection cycle.
- Use rehydration therapy or fatal.
POLIO
Obligate
water born virus, GI infection => dierhera
Salmonella typhi, typhoid fever:
Obligate
invades gut wall, enters blood and lymph systems, systemic spread
-water sanitation = prevention
Mycobacterium tuberculosis:
Obligate
causes TB, induces tubercles that result in necrosis of lung tissue and possible systemic spread via blood-stream. Can infect other organs
-irritaion of lugs => cough => spread
HIV causes AIDS:
Obligate infects class of immune cells (CD4+ lymphocytes), reduces immunological defence => fatal
virulence factors:
toxin production, the ability to invade, cytotoxicity (kills cells).
