Epidemiology Exam 3

  1. Infectious epidemiology
    Branch of epidemiology that deals with two or more populations at a time, cases are included as risk factors, and the cause of the disease is often known.
  2. Populations in infectious epidemiology
    • Humans
    • Infectious agents
    • Vectors
    • Animals
  3. Why is a case a risk factor?
    Infection in one person can be transmitted to others.
  4. Uses for infectious epidemiology (5)
    • Identify causes of new, emerging infections
    • Study routes of transmission
    • Surveillance of infectious disease
    • Identify new interventions
    • Identify source of outbreaks
  5. Influenza and pneumonia ranking for the leading causes of death in the US.
  6. Infectious/parasitic infections account for what percentage of mortality worldwide.
  7. Respiratory infections account for what percentage of mortality worldwide
  8. Septecemia ranking for leading causes of death in the US.
  9. Infectious disease
    A disease caused by any of the infectious agents
  10. Communicable disease
    Transmission of disease, directly or indirectly, from an infected person
  11. Transmissible disease
    Disease transmission through unnatural routes from an infected person.
  12. Parasitic disease
    An infection caused by a parasite
  13. An organism that lives on or in a host organism and gets it's food from or at the expense of the host.
  14. Three major factors of the epidemiologic triangle.
    • Agent
    • Host
    • Environment
  15. A factor, such as a microorganism, a chemical substance, or a form of radiation- whose presence, excessive presence, or relative absence is essential for the occurrence of disease.
  16. A person or other living animal, including birds and arthropods, that affords subsistence or lodgment to an infectious agent under natural conditions.
  17. The domain in which disease-causing agents exist, survive, or originate.
  18. The ability of an infectious agent to produce an infectous disease in an organism.
  19. Examples of infectious disease agents (6)
    • bacteria
    • rickettsia
    • viruses
    • fungi
    • parasites
    • prions
  20. The capacity of an agent to enter and multiply in a susceptible host and thus establish an infection.
  21. The severity of disease produced, i.e whether the disease has severe clinical manifestations or is fatal in a large number of cases.
  22. Ability of an infectious agent to produce a toxin.
  23. Toxin
    A toxic substance made by a living organism.
  24. Pathogens that cause disease as a result of their presence or activity within the normal, healthy host.
    Primary pathogens
  25. Example of a primary pathogen
  26. Organisms which cause an infectious disease in a host with depressed resistance.
    Opportunistic pathogens
  27. Examples of opportunistic pathogens
    Clostridium difficile
  28. Koch's Postulates
    • The same organism is present in every case of the disease
    • It is isolated or grown in pure culture
    • The disease can be reproduced in animals after infection with pure culture
    • The identical pathogen is reisolated from the experimental animals.
  29. The use of Koch's postulates in infectious epidemiology
    They are one way to prove a disease is infectious.
  30. Host response characteristics
    • Immunity
    • Incubation period
    • subclinical illness
    • generation time
    • carrier status
  31. Resistance to infection by an agent
  32. Active immunity
    Immunity that the host has developed either from natural infection with an agent or from injection of a vaccine containing an antigen.
  33. Active Immunity
    Immunity acquired from natural infection
  34. Artificial Immunity
    Immunity acquired from vaccination with an antigen
  35. Passive immunity
    Immunity acquired from antibodies produced by another person or animal.
  36. Examples of passive immunity (2)
    • Mother to fetus or newborn
    • Injections containing antibodies
  37. The resistance of an entire community to an infectious agent as a result of the immunity of a large proportion of individuals in that community to the agent.
    Herd immunity
  38. Percentage of the community that must be vaccinated before herd immunity comes into effect.
  39. Time interval between invasion by an infectious agent and the appearance of the first signs or symptoms of the disease.
    Incubation period
  40. Incubation period of influenza
    1-3 days
  41. Incubation period of HIV
    10 years
  42. An infection that does not show obvious clinical signs or symptoms. "inapparent infection"
    Subclinical infection
  43. Time interval between lodgment of an infectious agent in a host and the maximal communicability of the host, precedes active symptoms.
    Generation time
  44. A person or animal that harbors a specific infectious agent without discernible clinical disease and serves as a potential source of infection.
  45. 4 types of carriers
    • Incubatory
    • Active
    • Convalescent
    • Health/Passive
  46. Carrier that has been exposed to and harbors a pathogen, are in the beginning stages of disease showing very few symptoms, and can transmit the disease.
  47. Carrier that has been exposed to and harbor a disease causing organism.
  48. Individuals who harbor a pathogen and are still infectious while in recovery
  49. Individuals who have been exposed to and harbor a pathogen but have not had any symptoms of disease
  50. A parasitic nucleic acid, can contain RNA or DNA genome, can be enveloped or nonenveloped, has no cell.
  51. Prokaryotic organism with either gram positive or gram negative cell wall and can be aerobes, anaeorobes, or both.
  52. A eukaryotic organism, can be yeast or mold.
  53. Unicellular, eukaryotic organisms with complex life cycles.
  54. Infectious protein particles that are viral in form and are composed completely of protein with no nucleic acid present.
  55. Large organisms (animals) with complex life cycles.
  56. The first case of a disease to come to the attention of authorities.
    Index case
  57. Case
    Person who has been diagnosed as having a disease, disorder, injury, or condition.
  58. First case of the disease in the population
  59. Those persons who become infected and ill from contact with the primary case
  60. Persons infected by a secondary case
  61. A person who has been exposed but does not have any symptoms yet.
    Suspect/Subclinical case
  62. Endemic
    Refers to an infectious disease agent that is habitually present in an environment.
  63. Hyperendemic
    Increase in endemic disease within a given area or group
  64. Health-related state or event in a defined population above the expected over a given time period
  65. Epidemic affecting a large number of people, many countries, continents, or regions.
  66. Highly prevalent and commonly acquired early in life in most all of the children of a given population
  67. A place where infectious agents normally live and muiltiply
  68. Two types of Human Reserviors
    • Symptomatic
    • Asymptomatic
  69. Diseases associated with symptomatic human reservoirs
    • Polio
    • Flu
    • Chickenpox
  70. Diseases associated with asymptomatic human reservoirs
    • STDs
    • Hepatitis
    • Herpes
  71. Three types of reservoirs
    • Human
    • Animal
    • Environmental
  72. Diseases with animal reservoirs
    • Rabies
    • Ebola
    • West Nile Virus
  73. Two main environmental reservoirs
    • Soil
    • Water
  74. Diseases with water reservoirs
    Gastrointestinal diseases
  75. Organisms associated with soil as a reservoir
    Clostridium botulinum
  76. Direct and esssentially immediate transfer of infectious agents to a receptive portal of entry though which a human or animal infection may take place.
    Direct Transmission
  77. Transmission involving an intermediary source of infection such as a vehicle, droplet nuclei, or vectors.
    Indirect transmission
  78. Site where an infectous agent enters the body.
    Portal of Entry
  79. Site where the infectious agent leaves an infected persons body.
    Portal of Exit
  80. Vehicle-borne infections
    Result from contact with contaminated vehicles.
  81. Vehicles
    Contaminated nonmoving objects.
  82. Vehicle examples
    • Food
    • Fomites
    • Impure water
  83. Fomite
    An inanimate object that carries an infectious disease
  84. Typhoid Fever: Cause and transmisson
    • S. typhi
    • Foodborne
    • fecal-oral route
  85. Salmonella enteritis: Cause and Transmission
    • S. enteritidis
    • Foodborne
    • Fecal-oral
  86. Hepatitis C: Cause and Transmission
    • Hepatitis C virus (HCV)
    • Vehicle borne- contaminated needles or blood products
  87. Cholera: Cause and transmission
    • Cause: Vibrio cholerae
    • Water borne
    • Fecal-oral
  88. Cryptosporidium parvum: Cause and transmission
    • Parasite
    • Water borne
    • fecal-oral
  89. Mad Cow Disease (CJD): Cause and transmission
    • prion
    • foodborne zoonotic disease
  90. Botulism: cause and transmission
    • Clostridium botulinum
    • Food borne
  91. Campylobacter: Cause and transmission
    • Bacteria
    • Foodborne
    • fecal-oral
  92. Shigellosis: Cause and transmission
    • Shigella
    • food borne
    • fecal-oral
  93. Three Types of Anthrax
    • Cutaneous
    • Inhalation
    • Gastrointestinal
  94. Fatality percentage of the three types of anthrax
    • Cutaneous- 20%
    • Inhalation- 95-100%
    • GI- 25-100%
  95. Most common form of anthrax
  96. Second most common form of anthrax.
  97. Airborne infections
    Spread of droplet nuclei present in the air.
  98. Whooping cough: cause and transmission
    • pertussis
    • direct contact
    • airborne (sneezing and coughing)
  99. Chicken pox: cause and transmission
    • Varicella-zoster virus
    • Direct contact
    • airborne (sneezing and coughing)
  100. Inhalation anthrax: Cause and transmission
    • Bacillus anthracis
    • airborne
  101. Hantavirus: Cause and transmission
    • Virus
    • Airborne
  102. Cutaneous anthrax: cause and transmission
    • Bacillus anthracis
    • direct contact (zoonotic)
  103. Vector-borne infections
    Diseases transmitted by an animate, living insect or animal.
  104. Vectors
    An arthropod, especially fleas and ticks.
  105. Mechanical transmission
    Arthropod carries the pathogen on its feet
  106. Biological transmission
    Pathogen reproduces in vector
  107. Lyme disease: cause and transmission
    • Borrelia burgdorferi
    • Vector borne (tick bite)
  108. Malaria: cause and transmission
    • Plasmodium
    • vector borne ( mosquito bite)
  109. Rabies: cause and transmission
    • rabies virus
    • vector borne (animal bite)
  110. Sexually transmitted diseases
    • Gonorrhea
    • HIV
    • Chlamydia
  111. Gonorrhea: cause and transmission
    • N. gonnorrheae
    • Direct contact (sexual)
    • Mother to fetus causes opthalmia neonatum
  112. Chlamydia: cause and transmission
    • Chlamydia trachomatis
    • Direct contact
    • Mother to newborn causes pneumonia and conjunctivitis
  113. HIV/AIDS: cause and transmission
    • HIV virus
    • Vehicle- infected blood products or needles
    • Direct contact- sexual contact
  114. Four stages of HIV
    • Primary/Stage 1
    • Asymptomatic/ Stage 2
    • Symptomatic/ Stage 3
    • HIV to AIDS/ Stage 4
  115. Stage of HIVwith short flu like illness.
    stage 1/ primary
  116. Stage of HIV that lasts an average of 10 years, patient is free of symptoms, very low HIV levels in blood, detectable antibodies in blood.
    Stage 2/ Asymptomatic
  117. Stage of HIV where symptoms are mild and there is an emergence of opportunistic infection
    Stage 3/ symptomatic
  118. Stage of HIV where the immune system weeakens and illnesses become more severe
    Stage 4/ HIV to AIDS
  119. Opportunistic infections with AIDS
    • TB
    • Kaposi sarcoma
    • herpes
    • Pneumocysis carinii
    • Candida
  120. Vaccine preventable diseases, their causes and modes of transmission
    • Diptheria- bacterial- direct contact
    • Tetanus- clostridiuim tetani- vehicle borne
    • Pertussis (Whooping cough)- pertussis- direct contact/airborne
    • Hepatitis A and B- A- HAV, fecal-oral/foodborne
    • B- HBV, vehicleborne
    • Chicken Pox- varicella-zoster virus- direct contact
    • Polio- poliovirus- foodborne
  121. Zoonisis
    An infection or infectious agent transmissible under natural conditions from vertebrate animals to humans.
  122. Zoonotic infections
    • Rabies
    • Hantavirus
    • Anthrax
  123. Emerging infections
    An infectious disease that has newly appeared or that has been known for some time but is rapidly increasing in incidence or geographic range.
  124. E. coli O157:H7 (emerging infection)
    • Virulent E. coli strain
    • Produces Shiga toxin
  125. Types of Vaccines
    • Live
    • Killed
    • Toxoid
  126. Bioterrorism attack
    The deliberate release of viruses, bacteria, or other germs used to cause illness or death in people, animals, or plants.
  127. Food borne hepatitis
    A and E
  128. Blood borne hepatitis
    B, C, D
Card Set
Epidemiology Exam 3
infectious disease