Exam 4.4

• Normal microbiota

  Bacteria that permanently colonize the host

  *Protect the host

  *Produce vitamins + bacteriocins
• Transient microbiota

  Microbes that may be present for relatively short periods of time
• Mutualism

  Both organisms benefit
• Commensalism

  One organism benefits, and the other is unaffected
• Parasitism

  One organism benefits at the expense of the other organism (ex. pathogens)
• Pathology

  Study of disease
• Etiology

  Study of cause of something
• Pathogenesis

  Development of disease
• Infection

  Colonization of the body by pathogens
• Disease

  Abnormal states in the body in which the body is functioning properly
• What are Koch's Postulates?

  *Still used to demonstrate that a microbe causes an infectious disease

  *Some cause several diseases

  *Some cause disease only in certain animals
• Why are there loopholes in Koch's Postulates?

  *Not all infectious microbes grow in a lab

  *Not always a need to grow the pathogen to diagnose a disease

  *Some diseases can be caused by multiple pathogens

  *Some pathogens can causes multiple diseases

  *Some pathogens only attack humans (HIV)
• Symptom

  Change in a body function that is felt or noticed by a patient as a result of a disease
• Sign

  Change in a body that can be measured or observed as a result of a disease (fever, swelling, lesion)
• Syndrome

  Specific group of signs and symptoms that accompany a disease
• Communicable diseases

  Disease that can be spread from host to host
• Contagious diseases

  Disease that is easily spread host to host
• Noncommunicable disease

  Disease that is not spread from host to host
• Incidence

  Fraction of a population that contracts a disease during a specific timeframe
• Prevalence

  Fraction of a population that has a disease at a specific time
• Sporadic disease

  Disease that occurs occasionally in a population
• Endemic disease

  Disease that is constantly present
• Epidemic

  Disease acquired by many people in a given area in a relatively short period of time
• Pandemic

  Worldwide epidemic
• Acute disease

  Symptoms develop rapidly
• Chronic disease

  Disease develops slowly
• Subacute disease

  Symptoms between acute chronic
• Latent disease

  Disease with a period of no symptoms when the causative agent is inactive
• Subclinical disease

  No noticeable signs or symptoms (inapparent infection)
• Sepsis

  Toxic inflammatory condition arising from the spread of microbes from a focus of infection
• Bacteremia

  Bacteria in the blood
• Septicemia


  Growth of bacteria in the blood
• Toxemia

  Toxins in the blood
• Viremia

  Viruses in the blood
• What factors could make you predisposed to disease?

  *Chemotherapy

  *Pre-existing diseases

  *Inherited traits

  *Climate + weather

  *Fatigue

  *Age

  *Lifestyle
• What are the stages of disease?

  *Incubation (after infection, before signs/symptoms)

  *Prodromal (short duration, early signs/symptoms)

  *Illness (most severe)

  *Decline (signs/symptoms reduce, secondary infections)

  *Convalescence (recovery)
• Reservoir

  *Continual source of infection

  *Nonliving reservoirs (soil, H2O), human reservoirs (HIV, STDs), animal reservoirs (rabies, lyme disease)
• Transmission of disease

  *Direct contact: requires close association between infected and susceptible host

  *Indirect contact: spread by fomites (non-living object)

  *Droplet: airborne droplets
• Vehicle transmission

  Inanimate reservoir (food, water, air, blood)
• Vectors

  Arthropods (ticks, fleas, mosquitos)

  *Mechanical transmission: arthropod carries pathogen on feet

  *Biological transmission: pathogen reproduces in vector