Exam 3 Micro Study Guide

Chapter 14: Disease / Epidemiology

Microbiota (the host)
Transient Microbiota may be present for days, weeks, or months
Normal Microbiota (normal flora) permanently colonize the host becoming resident Microbiota
Symbiosis is the relationship between normal Microbiota and the host

Symbiosis
Commensalism: One organism is benefited
Mutualism: both organisms benefit
Parasitism: one organism is benefited at the expense of the other
Some normal Microbiota are opportunistic pathogens
E. coli  bladder infection (opportunistic pathogen)

Microbial Antagonism
Competition between the microbes
Normal Microbiota protect the host by:
Occupying niches that pathogens may occupy
Producing acids
Producing bacteriocins
Probiotics are live microbes applied to or ingested into the body, intended to have a beneficial effect

Infectious Disease
Transmissible/ contagious  tetanus or clostridium tetani (rusty nails), puncture wound needed
To grow it must multiply
**It is a growth in the body that causes a deviation from the normal symptoms**
*Classifying Infectious Diseases*
Symptom: is a change in body function that is felt as a result of disease
Sign: is a change in a body that can be measured or observed
Syndrome: is a specific group of signs and symptoms that accompany disease
Communicable Disease: is a disease that is spread from one host to another
Contagious Disease: is a disease that is easily spread from one host to another
Noncommunicable Disease: is a disease that is not transmitted from one host to another

First Line of Defense
1st line of defense
Structural defenses  skin, mucous membranes
Mechanical defenses  movement (tears), mucociliary system, flushing (urine flow)
Biochemical defenses  dryness, acidity, lysozyme, or bile
Skin
Size is 2m2
Secretions  sweat
Apocrine at puberty, hypocrine for cooling
Limiting Factors  dryness or a pH of 3.5-5.5
Adaptations of microorganisms
Adhesions  adhere to cells and bind sugars
Mucous Membrane  400m2 (mostly in intestines)

Anatomical Location of Bacteria
Staphylococci and corynebacteria (diphtheria) can be found residing in the skin but are also found in nasal membranes and in the Urogenital tract in the anterior urethra.

Public Health Terms
Incidence: (new#/year) fraction of a population that contracts a disease during a set time
Prevalence: fraction of a population having a disease at a given time
Sporadic Disease: a disease that occurs occasionally in a population
Endemic Disease: a disease that is constantly present in a population
Epidemic Disease: acquired by many hosts (relative) in a given area in a short time sometimes only 2 cases can cause an epidemic.
Pandemic Disease: is a worldwide epidemic
Herd Immunity: is the immunity in most of a population

Severity or Duration of a Disease (approx. 3 months)
Acute Disease: symptoms usually develop rapidly
Chronic Disease: disease develops slowly
Subacute Disease: symptoms develop between acute and chronic
Latent Disease: Disease with a period of no symptoms when the patient is inactive

Host Involvement
Local Infection: Pathogens are limited to a small area of the body
Systematic Infection: Infection throughout the body (small pox)
Focal Infection: Systemic infection that begins as a local infection
Bacteremia: Bacteria in the blood
Septicemia: Growth of bacteria in the blood
Toxemia: Toxins in the blood
Viremia: Viruses in the blood
Primary Infection: acute infection that causes the initial signs/illnesses
Secondary Infection: Opportunistic infection after a primary infection
Subclinical Disease: No noticeable signs/symptoms (inapparent infection)

Stages of Disease
Incubation Period: no signs are shown
Prodromal Period: mild signs begin to show
Period of Illness: most severe signs and symptoms are now expressed
Period of Decline: some signs and symptoms are still visible but depleting
Period of