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78 Cards in this Set
- Front
- Back
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Epidemiology
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Frequency and distribution of a disease in a defined population
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Morbidity
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Means illness, or degree of illness
Expressed: #cases/100,000 persons/year |
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Morbidity Rate
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Number of people ill with the disease within the total population over a given time
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Mortality
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Death; number of people who have died from a disease
Expressed: # deaths/100,000 persons/year |
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Mortality Rate
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Number of people dying of a disease within the total population over a given time
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Prevalence
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The number of existing cases in a given time
(total # of cases/total population) x 100 Expressed: % |
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Incidence
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The number of new cases in a given time
(# cases/100,000 persons/year) |
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Endemic
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Present continually within the population of a geographic area; generally the number of cases and severity remain low
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Epidemic
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A rapid or sudden increase in occurrence of the disease within a population
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Outbreak
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A localized epidemic; small scale
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Pandemic
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A global epidemic; large scale
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Sporadic
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Occurs in random, unpredictable manner involving isolated cases (ex: food poisoning)
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Point Source
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The infectious agent came from a single source; all victims exposed to single source (ex: restaurant employee didn't wash hands --> customers getting sick)
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Common Source
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A single source of infection that occurs over a period of time (ex: infected water source)
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Propagated Epidemic
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Infectious communicable agent is spread person-to-person (ex: coughing on hand--> shaking hands with someone)
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Reservoir of Infection
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Site where an organism persists and maintains its ability to establish new infections (soil, water)
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Carrier
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Individuals who are infected by an organism but have no signs/symptoms (ex: Typhoid Mary)
Chronic or intermittent |
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Zoonosis
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A disease that's naturally transmitted from animals to humans (ex: rabies)
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Vector
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An living organism (insect) that transmits (carry) a disease to a person
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Passive Transport
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Pathogen is carried on the feet or other body part of the vector (ex: fly lands on diseased feces --> lands on food -->person eats food and gets sick)
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Active Transport
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Pathogen must complete part of its life cycle in the vector before the vector can transmit the infected form of the pathogen
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Portals of entry and exit
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Sites in the body at which the pathogen enters the host
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Direct Transmission
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Close personal contact with someone who has the disease, or their infected bodily fluids
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Indirect Transmission
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Contact with fomites (inanimate object that carries a pathogen; ex: doorknob, dishes)
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Vehicle
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A natural, non-living material that can transmit infectious agents (water, soil, air, food)
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Infectious Dose
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The number of organisms needed to cause disease
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Target Tissue
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The preferred niche or site for infection by a parasite (ex: herpes --> genitals)
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Isolation
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A patient who has an infectious disease is prevented from having contact with the general public
Involves treatment precautions |
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Quarantine
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Applies to healthy people who were exposed to an infectious disease
Just limits movements, no treatment |
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Nosocomial Infection
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An infection acquired in the hospital or other medical facility (ex: Legionnaire's)
Vectors: staff, visitors, fomites |
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Universal Precaution
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Precautions taken to reduce the risk of infection in health care settings, especially to health care workers, or relating to blood-borne pathogens
Apply to all patients (assumed they're all infected) Precautions relate to exposure to body fluids |
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Symbiosis
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Two organisms living together
Mutualism Commensalism Parasitism |
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Mutualism
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Relationship is beneficial to both organisms (ex: bees and flowers)
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Commensalism
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Relationship is beneficial to one organism, the other is neither harmed nor benefitted (ex: shark and remora)
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Pathogen
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A parasite capable of causing disease in a host
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Parasitism
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Relationship is beneficial to parasite and harmful to host (ex: any infectious disease)
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Contamination
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Microbe is present and possibly multiplying at a mucosal surface
No effect on host Has ability to invade if it wants (ex: on the nose) |
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Opportunistic Pathogen
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Pathogen that causes disease in certain hosts under certain conditions; needs predisposing factors (ex: shingles)
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Secondary Infection
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Occurs as a consequence of another infection
Infection that immediately follows a primary infection (ex: person with a common cold getting an ear infection because of weakened immunity) |
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Disease
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Microbe is present and multiplying with clear adverse effects on the host (shows signs and symptoms)
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Infection
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Multiplication of the microbe in the host, but not substantial effect on the host
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Local Infection
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Limited to a single area of the body (ex: bladder infection)
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Pathogenicity
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The ability to cause disease
Depends on: host defenses, amount of pathogens that enter the host |
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Virulence
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The intensity of disease caused by a pathogen (high, low or avirulent)
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Frank/Primary Pathogen
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Pathogen that when present, is always associated with disease (ex: anthrax, AIDS)
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Nonpathogenic
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Not associated with disease; 99% of bacteria
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Normal Flora
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The population of organisms that resides in or on the body
Found on body openings (mouth, skin, eye, etc) |
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Transient Flora
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Present temporarily or only under certain conditions (ex: organisms on hands after going to the bathroom and not washing hands)
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Microbial Antagonism
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Normal flora competes with and excludes pathogens; fills the niche so pathogens can't enter
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Systemic Infection
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Infection where pathogen spreads through the body; often through blood or lymph
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Immunostimulation
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Provides routine priming or stimulation for the immune system
Helps body prepare defenses |
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Virulence Factors
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Structural or physiological traits that enable a microbe to cause disease in a host (ex: pili-->adhesion to cells; capsules-->increased survival; degree of invasiveness; enzymes-->invade or protect; toxins)
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Competent
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The bacteria has the right surface proteins to take in the DNA and the right enzymes to incorporate it into its DNA (in transformation)
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Signs
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Can be observed or measured by examining the patient (ex: temperature, swelling, elevated bp)
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Symptoms
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Can only be felt by the patient (ex: pain, aches, nausea, headache)
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Chronic Severity
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Disease develops slowly, possibly less severe; longer duration (ex: HPV, hepatitis, lyme, HIV)
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Latent Disease
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Disease with periods of inactivity before signs/symptoms appear and/or reappear long after infection (ex: herpes)
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Subclinical Infection
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Fails to produce the full range of signs/symptoms because of too few organisms or a vigorous host response (ex: UTI bacteria, chlamydia, HIV, gum disease)
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Primary Infection
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Infection that occurs in an otherwise healthy host
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Resident Flora
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Always present on the body; well adapted to persist at the site
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DNA Replication
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When the DNA is copied to make more DNA
DNA --> DNA |
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Transcription
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DNA is used as a template by RNA polymerase for mRNA synthesis
DNA --> mRNA |
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Acute Severity
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Disease that develops rapidly, and wanes quickly; short duration (ex: food poisoning, flu)
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Translation
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mRNA is used as a template for protein synthesis
mRNA --> protein |
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RNA Polymerase
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Enzyme that reads a sequence of DNA and creates mRNA sequence
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Codon
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A sequence of 3 mRNA bases that code for a particular amino acid (ex: AUG --> start codon)
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Spontaneous Mutation
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Mutation that occurs by chance, in a natural course of events, with no known cause
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Phenotype
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The physical characteristics displayed by an organism
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Mutation
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A permanent change in the nucleotide sequence of DNA
Can be passed on or inherited |
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Induced Mutation
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A mutation caused by a physical or chemical agent that effects DNA
Increase the mutation rate above the spontaneous mutation rate |
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Genotype
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The genetic information contained in the DNA; the base sequence
In a mutation, the genotype will always be changed |
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Mutagen
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A physical or chemical agent that effects DNA and increases the mutation rate above the spontaneous mutation rate
Also known as carcinogens if they lead to uncontrolled cell growth |
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Base Analogs
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A molecule with a similar structure to nitrogenous bases in DNA that get incorporated into DNA and cause an error in base pairing and during replication, can cause a point mutation
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Transduction
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A horizontal transfer of DNA from one bacteria to another by a bacteriophage (a virus)
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Obligate Intracellular Parasite
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A virus/organism that can live or multiply only inside a living host cell, uses host's replication, transcription, and translation enzymes to replicate their viral genome
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Bacteriophage
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A virus that infects a bacterium
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Conjugation
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The transfer of DNA from host to recipient by means of a conjugation pilus and direct contact
Conjugation bridge is formed to transfer info |
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Thymine Dimers
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When two thymines are bonded together in a DNA strand
Impairs DNA replication; transcription stops at this point Creates a kink in DNA backbone, prevents base-pairing |
