I will sometimes be using technical words in my blog posts.  When I do, I will write them in bold and post a definition/explanation of the word here.  If I miss a word, please point it out for me in the comments below and I’ll add it to the list.

This glossary is a work in progress.  It was originally written as a study guide for undergraduate students in the Introduction to Global Health class at Arizona State University while I was a TA.

2.  Adam Fox. 2003. Glossary Of Epidemiological Terms. The Internet Journal of Pediatrics and Neonatology. Volume 3 Number 1.
3.  Jonathan Swinton. 2002. A Dictionary of (Ecological) Epidemiology.  Available on the web at:

If there is no reference cited, the definition came off of a slide from class or out of my head.

Adaptationist perspective: complex phenotypes, including health-related phenotypes, evolve by natural selection

Amino acids: an amino acid is a molecule that contains both amine and carboxyl functional groups

Amplitude: the magnitude of change in an oscillating variable, visually represented by the vertical distance between the extrema (i.e. maximum and minimum values) of the curve (1)

Antibodies: proteins on the surfaces of B cells and proteins that B cells secrete, also called immunoglobulins

Antigens: a molecule on the surface of the cells or pathogens, or on infected host cells, that stimulate B (and T) cells

Asymptomatic: an individual with an infection that is unapparent throughout its course (2)

Bacilli (plural), Bacillus (singular): rod shaped bacteria

Basic reproduction number, R0: the number of secondary cases generated by a primary infectious case during its period of infectiousness in an entirely susceptible population.

Behavioral ecology: the study of the ecological and evolutionary bases for animal behavior, and how behavior helps an animal adapt to its environment (note: humans are animals!) (1)

Biostatistics: the application of statistics to a wide range of topics in biology (1)

Case mortality: proportion of individuals infected with an active disease who die

“Codes for”: a description of the process by which hereditary information ‘encoded in DNA’ is read and translated into sequences of amino acids; conglomerates of these amino acids form proteins

Concordance: how well host (antibodies) and pathogen (antigens) molecules match each other

Demographic processes: births and deaths.

Directional selection: is when allele frequency continuously shifts in one direction because natural selection favors a single phenotype; directional selection is a mechanism of natural selection (1)

Disease ecology: the study of the interactions between the behaviour and ecology of hosts with the biology of pathogens, and how these interactions lead to different disease patterns in populations

Endemic: the constant presence of disease or an infectious agent within a given geographic area or population (2), used to describe levels of infection which do not exhibit wide fluctuations through time an a particular place (3)

Epidemic: the occurrence of more cases of disease than expected in a given area or population over a particular period of time (2), a rapid increase in the levels of infection (3)

Epidemic growth rate, r: the number of new infections for a given infectious disease arising in the population per unit of time at the beginning of an epidemic.

Epidemiology: the study of the distribution and determinants of health-related states or events in specified populations, and the application of this study to the control of health problems (2)

EpiSimS (Epidemic Simulation System): is an agent-based computer model that simulates the spread of disease in metropolitan areas.

Evolutionary global health: the study of health phenotypes from a human evolutionary ecology perspective, and the translation of findings into policies and programs designed to decrease inequalities in health across populations

Evolutionary medicine: the scientific study of human health integrated with evolutionary theory; the study of health phenotypes from a biological evolutionary perspective

Fertility: the natural capability of giving life, “fertility rate” is the number of children born per couple, person, or population (1)

Food desert: an area where there is little or no access to enough quality food to meet the needs of its residents

Food security/insecurity: refers to the availability of food and one’s access to it, also refers to the quality of food (1)

Genome: all of an organism’s hereditary information encoded in DNA

Genotype:the genetic make-up of an organism

Gini coefficient: a measure of inequality of distribution of income (which is strongly associated with health disparities)

GIS (Geographical Information Systems): a set of computer algorithms that manage numerical information associated with space (maps) and new statistical approaches (spatial-statistics).

Herd immunity: the mechanism by which an infection may be eradicated from a population although some susceptibles remain, because the remainder of the population is immune and thus transmission is reduced (3)

Heritability: strong positive or negative correlation between the mean trait size of the two parents and the size (or other characteristic) of the offspring’s trait

Homogeneous mixing: individuals mix uniformly in the population.

Hypercooperation: the extreme cooperation characteristic of human beings

Immunity: a state in which a host is not susceptible to infection (can be innate (i.e. inherited), acquired after contact with a disease, or artificial from vaccination) (3)

Immunology: the study of the biological mechanisms that hosts and pathogens use to undermine each other’s defense strategy in every way

Immunosuppression: a reduction in the capacity of the immune system (can be caused by infection (i.e. HIV), drug treatment (i.e. cancer chemotherapy), pregnancy, or malnutrition, etc.) (3)

Incubation period: the time that elapses between infection and the appearance of symptoms (NOT the same as the latent period) (3)

Indigenous peoples: an ethnic group that inhabits a geographic region with which they have the earliest historical connection (1)

Infectious: individuals that can transmit the disease to susceptible individuals.

Infectious period: the time an individual remains infectious before he/she recovers or succumbs to the disease.

Kin selection: strategies that favor the reproductive success of an organism’s relatives even at the cost of their own survival or reproduction (1)

Latent period: the time from infection to when the individual is infectious to others (NOT the same as the incubation period) (3)

Life history: in biology, the life history of an organism is the reproductive cycle of animals and plants which involves the coevolution of traits such as number of offspring, length of life, age-specific survivorship probability, overlap between generations, and age at first reproduction

Longevity: life expectancy, the average length of life of individuals in a population (3)

“Modern Synthesis”: the union of ideas from several biological specialties which forms a sound account of evolution, specifically the combination of Mendelian genetics with Darwin’s theory of evolution by natural selection (1)

Morbidity: illness.

Morphology: refers to the outward appearance (shape, structure, color, pattern) of an organism and its component parts.  Emphasis is on structure (morphology), rather than function (physiology) (1).

Mortality: death.

Mycobacterium: a genus of bacteria which includes species known tocause serious diseases in mammals, including tuberculosis and leprosy (1)

Natural selection: the process by which heritable traits become more common in successive generations of a population because organisms carrying those traits are more likely to survive and reproduce than others in that population’s environment (1)

Oscillation: the repetitive variation (usually in time) of a measure about a central value between two or more different states (1)

Outbreak: synonymous with epidemic; sometimes used to describe a localized as opposed to a generalized epidemic (2)

Pandemic: an epidemic occurring over a very wide area (several countries or continents) and usually affecting a large proportion of the population (2)

Parasitism: a symbiotic relationship where the parasitic organism benefits from a prolonged, close association with a host organism at the expense of the host’s fitness (1)

Pathogen: same as a parasite (3)

Pharmaceutical: a drug treatment, medication (1)

Phenotype: is any observable characteristic of an organism, such as its morphology, development, biochemical or physiological properties, or behavior.  Phenotypes result from the expression of an organism’s genes (genotype) as well as the influence of environmental factors and possible interactions between the two (1).

Philanthropic organization: donates money, goods, services, time, and/or effort to support a socially beneficial cause with no financial or material reward for the donor (1)

Physiology: the study of the mechanical, physical, and biochemical functions of living organisms (1).

Prophylaxis: drug treatment to prevent a future occurrence of disease (3)

Proteins: conglomerates of amino acids; important for the structure and function of organisms

Proximity: distance

Reaction norms: describes the pattern of phenotypic expression of a single genotype across a range of environments (1).

Reciprocal altruism: where one organism provides a benefit to another (unrelated) organism without expecting immediate compensation, the benefactor only expects the favor to be returned sometime in the future (1)

Recovered: individuals that have recovered from an infectious disease.

Reproduction number: measures the transmissibility in a partially immune population.

Rickets: softening of bones in childhood, leading to skeletal deformities and frequent fractures

Sanitized/Sanitation: the hygienic means of preventing human contact from the hazards of wastes (physical, microbiological, or chemical agents of disease) to promote health (1)

Sociobiology: attempts to explain social behavior in all species by considering the evolutionary advantages the behaviors may have (1)

STD: sexually transmitted disease

Stigmatization: a negative social label that leads to discrimination or social exclusion of persons; can be based on physical characteristics (physical deformities, leprosy, obesity), personal traits (addiction, unemployment, sexual preferences), or tribal affiliation (nationality, religion, race)

Strain: a genetic variant or subtype of a microorganism (1)

Susceptible: individuals that can be infected by an infectious agent if they are exposed to it.

Transmission: the process by which a pathogen passes from a source of infection to a new host; two major types are horizontal and vertical transmission; the majority of transmission processes operate horizontally

Transmission rate: measures how many new infections each infectious individual generates per unit of time.

Unsanitized: unhygienic; see “sanitized/sanitation”

Vaccination coverage: the fraction of the population that is vaccinated against an infectious disease.

Vaccination efficacy: the fraction of the vaccinated population that is able to reach protective antibody levels.

Vaccination threshold: the minimum fraction of the population that would need to be effectively vaccinated in order to control an infectious disease.

Vaccine: an immunity booster to a specific infectious disease (e.g. measles, rubella, polio).

Variant traits: for example: if we examined eye color as a trait, the variants would be: brown, blue, green, hazel, etc.

Vector: a carrier that transmits disease from one organism to another

Virgin soil epidemic: describes a situation where a population that is immunologically naive comes into contact with an infectious disease for the first time, the population has no history of contact with that disease and are largely defenseless against it

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