Med Micro - Review Questions 2 Flashcards
Give some major classes of virulence factors
Adhesins (capsule, fimbrae), enzymes (invasins, extracellular (nutrients)), motility (flagella), immune system avoidance (biofilm, intracellular, evade phagocytosis), siderophores (get iron)
Antiphagocytic factors
stop phagocyte killing. Inhibit pH drop in phagosome, destruction of phagosome before pH drop, phagocyte killing (kill before internalized), capsule (slip, cloaking).
Bacterial surface function
Covers surface; Protect against antibodies; Escape parts of innate immunity; in Gram -, LPS outside of S layer
Stages of infectious disease
Incubation; Prodromal: mild symptoms - not always present!; Illness: signs and symptoms at peak; Decline; Convalescence: repair.
What is happening during each stage of infectious disease
Incubation: phagocytosis, adaptive immunity starting up (takes 2-3 weeks); Decline: immune system is winning, or drugs are helping
How long does convalescence last?
Depends on how much energy is needed to repair damage from the disease
During which stages are we infectious?
During all of them!
What is incubation period dependent on?
Infectious dose, site of infection, general health of host, nature of pathogen (some are fast, some slow), virulence factors
What are the major pathways for exit of pathogens from the host?
Most of them are the same as the entry. Has to do with microenvironment, need similar binding
What is the most common route of exit?
Respiratory tract and GI tract (fecal-oral route)
Do all pathogens exit?
No; pathogens that lack a mode of entry that enter via parenteral route would not have a mode exit
What is a dead end host?
Does not pass it on to someone else
What are reservoirs of infection and why are they important?
Where pathogens hang out waiting to infect (water towers, humans); door handles are not a reservoir, cannot survive for long
What are the major reservoirs of infection?
Soil and water; animals; humans.
What is the main method of disease transmission? (double check this with Steve*)
Contact: direct (kissing, cough < 1m) and indirect (cough > 1m)*; vector; vehicle: dust, water, cough on a table then someone else touches it
How do we classify infection disease?
Body system affected; taxonomy (bacteria, virus, fungus); longevity and severity (chronic or acute); spread to host; effects of populations
Define epidemiology
Study of where and when diseases occur and how they are transmitted within populations. Important when Koch’s postulates aren’t possible and to consider traveling etc.
What is incidence and prevalence and why is the incidence of infections disease important (what info can it give us)?
Incidence = number of new cases in an area; prevalence is total number of cases.
Endemic; sporadic; epidemic; pandemic
General to an area; spike in one area; spike then spread at national level; international
How does healthmap work?
Healthmap: Collect reports every hour to track diseases around the globe, publish reports and warnings, share info to promote awareness
How does biodiaspora depend on healthmap?
Takes data from healthmap, then adds in other factors to provide thorough analysis of an outbreak
What is the goal of biodiaspora?
To prevent the spread of disease, provide awareness, evaluate potential for spread
Three approaches to epidimiology
Descriptive: tabulation of data; analytical: probable cause, transmission, prevention; experimental: test hypothesis
How do the approaches to epidemiology address Koch’s postulates?
Very important when you cannot use them
Nosocomial disease
Infections disease caught from a health care environment
3 types of nosocomial disease?
Iatrogenic: from a surgery; endogenous: you have the pathogen but something in environment causes it to cause disease; exogenous: disease caught in hospital
What factors are involved in a health care environment that lead to an increase in infectious disease?
Immunocompromised; pathogens that we aren’t exposed to normally; proper hygiene of the staff
How does biodiaspora work ?
Integrate infectious disease threats and evaluate risks of spread; data from healthmap; understand the local environment/context of disease: temp, alt, transport; healthcare situation and spending; track number of travellers from regions
