Bmsc210 Final p5

  1. Epidemiology
    (3 categories of study)
    – The study of the occurrence, distribution, and determinants of health and disease in a population
  2. In developed countries infectious diseases cause ___ deaths than noninfectious diseases
    fewer
  3. Worldwide, infectious disease accounts for __% of all deaths
    30%
  4. Infectious disease hit an all time low around 19__
    1980
  5. Chronic infections:
    • -host and pathogen survive
    • -New pathogens sometimes emerge for which the host has no resistance
  6. Acute infections:
    pathogen eithers kills or is killed not chronic
  7. Epidemiologists trace the spread of disease to identify its ___ and mode of ___
    • origin
    • transmission
  8. A disease is an ___ when it occurs in a large number of people in a population at the same time
    epidemic
  9. A ___ is widespread, usually worldwide
    pandemic
  10. An ___ disease is constantly present in a population, usually at low incidences
    endemic
  11. The ___ of a disease is the number of newcases of the disease in a given period of time
    incidence
  12. The ___ of a disease is the total number of new and existing cases in a population in a given time
    prevalence
  13. arrange diseases according to prevalance
    epidemic
    pandemic
    endemic
    endemic < epidemic < pandemic
  14. subclinical infections
    • -Diseased individuals who show no or mild symptoms
    • -Subclinical individuals are called carriers
  15. Mortality
    is the incidence of death in a population
  16. Morbidity
    -incidence of disease including fatal and nonfatal diseases (all)
  17. Infection:
    the organism invades and colonizes the host
  18. Incubation period:
    the time between infection and onset of symptoms
  19. Acute period:
    the disease is at its height
  20. Decline period:
    disease symptoms are subsiding
  21. Convalescent period:
    patient regains strength and returns to normal
  22. Reservoirs
    • -sites in which infectious agents remain viable and from which infection of individuals can occur
    • –humans, animals and nonliving matter can all serve as reservoirs
    • • For example, soil is a reservoir for Clostridiumtetani, the cause of tetanus
  23. Zoonosis
    • -any disease that primarily infects animals, but is occasionally transmitted to humans
    • – Control of a zoonotic disease in the human population may not eliminate the disease as a potential public health problem
    • – Certain infectious diseases have complex lifecycles involving an obligate transfer from a nonhuman host to humans followed by transfer back to the nonhuman host
  24. Carriers
    • – Pathogen-infected individuals showing no signsof clinical disease, i.e. Typhoid Mary
    • – Potential sources of infections
    • – May be individuals in the incubation period of the disease
    • – Can be identified using diagnostic techniques, including culture and immunoassays
  25. Epidemiologists follow transmission of a disease by correlating:
    (4 types of data)
    • geographic
    • climatic
    • social
    • and demographic data
  26. Direct host-to-host transmission
    – Infected individual transmits a disease directly to a susceptible host without the assistance of an intermediary (e.g., flu, common cold, STDs,ringworm)
  27. Indirect host-to-host transmission
    – Occurs when transmission is facilitated by a living or nonliving agent
  28. vectors
    Living transmission agents
  29. fomites
    Nonliving transmission agents
  30. A common-source epidemic
    (example)
    • usually arises from contamination of water or food
    • • Example: cholera
    • -spike quickly and die off quickly
  31. host-to-host epidemic
    (characteristic)
    (example)
    • the disease shows a slow, progressive rise and a gradual decline
    • • Example: influenza and chicken pox
  32. why is coevolution of a host and its parasite common?
    • Virulence of the parasite in host-to-host transmission diminishes and resistance of the host increases
    • (e.g., myxoma virus introduced to control rabbits in Australia)
    • • A host-to-host pathogen that kills its host before it can infect another host may become extinct
    • -as the grow together virulence and mortality should drop to optimum levels
  33. Herd immunity
    -the resistance of a group to infection due to immunity of a high proportion of the group
  34. How does Herd immunity work?
    • – If a high proportion of individuals are immune to an infection then the whole population will be protected
    • – Immunized people protect nonimmunized people because the pathogen cannot be passed on and the cycle of infectivity is broken
Author
Scottygo
ID
213196
Card Set
Bmsc210 Final p5
Description
Bmsc210 Final p5
Updated