CH. 14 | Principles of Disease and Epidemiology

14 - 1 Define pathology, etiology, infection, and disease

Pathology

• Scientific study of disease

• Structural and functional changes brought by the disease and their effects on the body

  • Pathogen: Disease-causing microorganism
    
    

Etiology

• Study of the cause of a disease
  
  

Infection

• Growth of invasion or colonization of the body by pathogenic microorganisms

  • Infectious disease: Occurs when an infection results in any change from a state of health
    
    

Disease

• An abnormal state in which part or all of the body is incapable of performing its normal functions

Normal microbiota vs. Transient microbiota

Normal microbiota — Permanent residents that don’t cause disease under normal conditions

Transient microbiota — Present for only days, weeks, or months, then disappear

14 - 2 Describe how the human microbiome is acquired

Before Birth (In Utero)

• Microbial populations begin establishing themselves before birth

• The placental microbiome consists of a few bacteria, mainly Enterobacteriaceae and Propionibacterium, which are found in the newborn’s intestine
  
  

During Birth

• Just before childbirth, lactobacilli in the parent’s vagina multiply rapidly and become the predominant organisms colonizing the newborn’s intestine
  
  

After Birth (Early Life)

• More microorganisms are introduced when breathing and feeding begin

• During the first 3 years, the microbiome changes rapidly as E. coli and other bacteria acquired from foods, people, and pets begin to inhabit the large intestine

• Most of the microbiome is established within the first 10 years of their life
  
  

Ongoing Acquisition

• Once established, these microorganisms remain throughout life but may increase or decrease in number in response to environmental changes

• Microbes can only colonize body sites that supply the appropriate nutrients they need

• Physical & Chemical Factors like temperature, pH, oxygen availability, and salinity also shape which microbe colonize where

14 - 3 Compare commensalism, mutualism, and parasitism, and give an example of each

Mutualism

• Type of symbiosis that benefits both organisms

  • Large intestine contains bacteria: E. coli, that synthesize vitamin K and vitamin B

  • Vitamins are then absorbed into the bloodstream and distributed for use by body cells

  • Large intestine provides nutrients used by the bacteria, allowing them to survive

14 - 4 Contrast normal microbiota and transient microbiota with opportunistic microorganisms

14 - 5 List Koch’s postulates

14 - 7 Categorize diseases according to frequency of occurence

14 - 8 Categorize diseases according to severity

14 - 9 Define herd immunity

14 - 10 Identify four predisposing factors for disease

14 - 11 Put the following in proper sequence according to the pattern of disease: period of decline, period of convalescence, period of illness, prodromal period, incubation period

14 - 12 Define reservoir of infection

14 - 13 Contrast human, animal, and nonliving reservoirs, and give one example of each

14 - 14 Explain three methods of disease transmission

14 - 15 Define healthcare-associated infections and explain their importance

14 - 16 Define compromised host

14 - 17 List several methods of disease transmission in hospitals

14 - 18 Explain how healthcare-associated infections can be prevented

14 - 19 List several probable reasons for emerging infectious diseases, and name one example for each reason

14 - 20 Define epidemiology, and describe three types of epidemiologic investigations

14 - 21 Identify the function of the CDC

14 - 22 Define the following terms: morbidity, mortality, and notifiable infectious diseases