epidemiology
science that evaluates occurrence, determinants, distribution, and control of health and disease in a defined human population
-John Snow was the first
sporadic disease
occurs occasionally and at irregular intervals
endemic disease
maintains a relatively steady low-level frequency at a moderately regular interval
hyperendemic disease
gradually increase in occurrence frequency above endemic level but not to epidemic level
outbreak
-sudden, unexpected occurrence of disease
-usually focal or in a limited segment of population
epidemic
-sudden increase in frequency above expected number
-index case - first case
pandemic
increase in disease occurrence within large population over wide region (usually worldwide)
remote sensing
gathering of digital images of Earth's surface from satellites and transforming data into maps
geographic information system
data management system that organizes and displays digital map data from RS
morbidity rate
-an incidence rate
-number of new cases in specific time period per unit of population
prevalence rate
-total number of individuals infected at any one time
-depends both on incidence rate and duration of illness
mortality rate
number of deaths from a disease per number of cases of the disease
infectious disease
disease resulting from an infection by microbial agents
communicable disease
can be transmitted from one host to another
common source epidemic
single common contaminated source - food
propagated epidemic
one infected individual into a susceptible group, infection propagated to others
herd immunity
level of resistance of population to infection and microbe spread because of immunity of large percentage of the population
systematic epidemiology
focuses on ecological and social factors that influence development and spread of emerging and reemerging diseases
endogenous pathogen
brought into hospital by patient or acquired when patient is colonized after admission
exogenous pathogen
microbiota other than the patient's
autogenous infection
caused by an agent derived from microbiota of patient despite whether it became part of patient's microbiota following admission
vaccine
-preparation of microbial antigens used to induce protective immunity
-may consist of killed, living, and weakened microbes or inactivated bacterial toxins
immunization
result obtained when vaccine stimulated immunity
adjuvants
-are mixed with antigens in vaccines to enhance the rate and degree of immunization
-can be any nontoxic material that prolongs antigen interaction with immune cells and stimulated the immune response to the antigen
acellular (subunit) vaccines
use of purified molecules from microbes avoids some of the risks of whole-cell vaccines
recombinant-vector vaccines
-pathogen genes that encode major antigens inserted into nonvirulent viruses or bacteria which serve as vectors and express the inserted gene
-released gene products can elicit cellular and humoral immunity
DNA vaccines
-DNA directly introduced into host cell via air pressure or gene gun
-DNA taken into nucleus and pathogen's DNA fragment is expressed
bioterrorism
intentional or threatened use of viruses, bacteria, fungi, or toxins from living organisms to produce death or disease in humans, animals, and plants