MI 1.4

Case-control study

Study where a group of individuals with the disease, referred to as cases, are compared to individuals without the disease, referred to as controls.

Cohort study

Study where a group of exposed individuals (individuals who have been exposed to the potential risk factor) and a group of non-exposed individuals are compared.

Epidemic

Affecting an atypically large number of individuals within a population, community, or region at the same time.

Epidemiology

A branch of medical science that deals with the incidence, distribution, and control of disease in a population.

Herd immunity

Resistance of a group to an attack by a disease to which a large proportion of the members of the group are immune.

Inoculation

Introduction of a pathogen or antigen into a living organism to stimulate the production of antibodies.

Plasmid

Small ring of DNA that carries accessory genes separate from those of the bacterial chromosome.

Recombinant DNA

DNA molecule made in vitro with segments from different sources.

Vaccination

Procedure that presents the immune system with a harmless variant of a pathogen, thereby stimulating the immune system to mount a long-term defense against the pathogen.

Vaccine

Harmless variant of a pathogen that stimulates a host's immune system to mount defenses against the pathogen.

Edward Jenner

Known for developing the first vaccination by inoculating cowpox virus to protect patients from smallpox.

APCs

Antigen presenting cells that break the vaccine antigen apart and 'wear' it to alert T helper cells.

T helper cells

T cells that are stimulated by antigen to provide signals that promote immune responses.

Naive B cells

B cells that have not been exposed to an antigen, can turn into plasma B cells or memory B cells.

Plasma B cells

Cells that produce antibodies.

T cells

Cells that send cytokines to the immune system so the body can produce what it needs.

Cytokines

Chemical messengers produced by T cells.

Cell-mediated response

The response of T cells to antigens.

Memory B cell/T helper cell/Killer T cell

Cells that 'remember' immune responses.

Subcutaneous

Administration route under the skin.

Intramuscular

Administration route within the muscle.

Intradermal

Administration route within the skin.

R_0 (R sub 0)

Number of people 1 person can infect with the disease.

Threshold

Percentage of the population that must be vaccinated to achieve herd immunity.

Inactivated vaccines

Killed with heat, chemicals, or radiation; harmless but still recognizable; requires larger doses and more boosters.

Live attenuated vaccines

Longer lasting, requires fewer boosters, elicits strong immune response, may mutate, not for the immunocompromised.

Toxoid vaccines

Purified/inactivated toxin produced by bacteria.

Conjugate/subunit vaccines

Part of pathogen (protein, gene, piece of capsule) that may require a 'carrier' virus/cell to make protein copies.

mRNA vaccines

mRNA wrapped in lipid sphere that codes for protein of virus.

Purifier

Separates the pathogen from other materials.

Live vaccine example

Smallpox.

Attenuated vaccine example

Measles.

Killed vaccine example

Polio.

Toxoid vaccine example

Tetanus.

Subunit vaccine example

Hepatitis B.

Naked DNA vaccine example

HIV.

Restriction endonucleases

Molecular scissors; enzyme that cuts DNA when it recognizes a specific base sequence.

Ligase

Molecular glue; enzyme that connects ends of DNA molecules together.

Sticky ends

Single stranded ends of DNA left after cutting with enzymes.

John Snow

Known as the father of epidemiology; investigated the source of the cholera outbreak to prove contaminated water was the source.

Gene

Section of DNA that codes for a particular characteristic.

Alleles

Different forms of a gene that codes for a particular trait.

Genotype

Combination of parent's alleles.

Phenotype

Physical characteristics.

Probability formula

of desired outcomes / # of total possible outcomes.

Food-specific attack rate formula

of people who ate a certain food and became ill / total # of people who ate that food.

Active immunity

Antigen activates the immune system to produce immune substances; includes natural immunity and vaccine-induced/artificial immunity.

Natural immunity

Acquired from infection with the actual disease through exposure to the disease organisms.

Vaccine-induced/artificial immunity

Acquired through the introduction of a killed or weakened form of the disease organisms through vaccination.

Passive immunity

Individual receives antibodies that were produced actively in the body of another person.