Edition Robert W. Bauman
What are the sites of the human body with the normal microbiota? - ANSWER:
colonize skin and mucous membranes of the human body (upper respiratory tract,
intestinal tract-colon, urogenital tracts-terminal portion of urethra/vagina), without
normally causing disease
What is meant by symbiotic relationships between human host and normal
microbiota? - ANSWER: indicates the relationship between microbes and human
host → In mutualism, both organisms benefit
What is meant by opportunistic pathogens of the normal microbiota? - ANSWER:
Changes in the normal microbiota can lead to opportunistic infections caused by
members of the normal microbiota
What is meant by competitive exclusion of pathogens by the normal microbiota? -
ANSWER: Using nutrients/take up space
Producing toxic products that inhibit other microbes (bacteriocins)/decreasing the
pH (acids in the vagina)
Why is dysbiosis of the normal microbiota critical to human health? - ANSWER:
linked to various human diseases, such as anxiety, depression, hypertension,
cardiovascular diseases, obesity, diabetes, inflammatory bowel disease, and cancer.
What is the definition of an infectious disease? - ANSWER: Infectious disease is an
infection that results in disease, which can be communicable/contagious or non-
communicable
What is the difference between a primary pathogen and an opportunistic pathogen?
- ANSWER: opportunistic (or facultative) pathogens require an injured host to cause
infection, primary pathogens do not
Reservoirs - ANSWER: Zoonoses: People with active disease (signs/symptoms of a
disease) can transmit it.
Carriers: Certain infected people can remain both asymptomatic and infective for
years, some eventually will develop the disease, others do not
Carriers Reservoirs - ANSWER: Gonorrhea
Typhoid fever
Syphilis
AIDS
, Hepatitis B
Nonliving reservoirs include - ANSWER: Soil (Clostridium botulinum and C. tetani)
Water (Water contaminated by human-animal feces/urine: Vibrio cholerae and
Schistosoma)
Foods
Portal of exit (how do pathogens exit the human host?) - ANSWER: Many portal of
exit are also portal of entry, though pathogens often leave the infected host via
bodily secretions and excretions
Routes of transmission - ANSWER: Airborne transmission
- Transmission of pathogens via aerosols - droplets/small particles suspended in the
air
- (Distance >1m)
- Aerosols from sneezing and coughing , air conditioning systems, mopping, flaming
inoculating loops
Fecal-oral route of transmission
- is a major source of disease in the world and it can involve both water and
foodborne pathogens
Water
- can function as a reservoir/vehicle
- Spread of gastrointestinal diseases (giardiasis, cholera)
Contamination of foods with feces/pathogens
- Food inadequately processed, undercooked, poorly refrigerated
Contact Transmission - ANSWER: direct and indirect
Direct contact - ANSWER: Involves:
- Person-to-person contact
- Sexual intercourse
- Transfer across the placenta
- Animal-to-person contact - zoonosis (rabies/ring worm)
Indirect contact - ANSWER: Spread by fomites (non-living objects)
Medical equipment, needles (HIV virus)
Portal of entry - ANSWER: Skin
- A barrier to pathogens if it remains intact
- Abrasions, cuts, bites, scrapes, stab wounds/surgical sites allow for entry of
pathogens