Microbial Interactions with Humans Flashcards
How many microbial species can be found in a human mouth?
700
Who is generally believed to be the first person to have observed microbes?
Antoni van Leeuwenhoek
Approximately how many microbial cells does the human GI tract contain?
10 to 100 trillion
What bacteria cause stomach ulcers?
Helicobacter
Define Pathogen
Microbial parasite
Define Pathogenicity
The ability of a parasite to inflict damage on the host
Define Virulence
Measure of pathogenicity
Define Opportunistic Pathogen
Causes disease only in the absence of normal host resistance
Define Infection
A situation in which a microorganism is established and growing in a host
Define Disease
Damage or injury to the host that impairs host function
Where do infections usually begin?
At sites in the animals mucus membrane
Define Attenuation
The decrease or loss of virulence
Define Toxicity
Organism that causes disease by means of a toxin that inhibits host cell function or kills host cells.
Toxins can be heat stable
What is the name of the bacteria that causes food poisoning from starchy foods
Bacillus cereus
(Produces a toxin)
Define Invasiveness
Ability of a pathogen to grow in host tissue at densities that inhibit host function
(Causes damage without producing a toxin)
Define Epidemic
A disease that occurs in a large number of people in a population at the same time
Define Pandemic
A disease that is widespread, usually worldwide
Define Endemic
A disease that is constantly present in a population, usually at low incidences
Define Incidence
The number of NEW cases of the disease in a given period
Define Prevalence
The TOTAL number of new and existing disease cases in a population at a given time
Define Mortality
The amount of deaths
Define Morbidity
The amount of disease
Define Herd Immunity
The resistance of a group to infection
