Micro Chap 14

Epidemiology
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Terms in this set (68)
Epidemiology
Branch of medical science concerned with the incidence, distribution, and control of diseases that affect large numbers of people.
Pathology
the scientific study of disease
Etiology
study of the cause of disease
Pathogenesis
the manner in which a disease develops
Infection
Contamination or invasion of body tissue by pathogenic organisms
Disease
An abnormal state in which the body is not functioning normally
microbial antagonism
competition between microbes
opportunistic pathogens
cause disease when the host's defenses are compromised or when they grow in part of the body that is not natural to them
Probiotics
live microbes applied to or ingested into the body, intended to exert a beneficial effect
Syndrome
A group of symptoms typical of a particular disease or condition
Contagious diseasea disease that is easily spread from one host to anotherSporadic Diseasedisease that occurs occasionally in a populationherd immunityThe resistance of a group to an attack by a disease to which a large proportion of the members of the group are immunelatent diseasecausative agent is inactive for a time but then activates and produces symptomsSepsistoxic inflammatory condition arising from the spread of microbes, especially bacteria or their toxins, from a focus of infectionSepticemiainfection in the bloodSubclinical diseaseno noticeable signs or symptoms (inapparent infection)zoonosesDiseases transmitted from animals to humansFomitesobjects contaminated with infectious material that contains the pathogensDroplet Transmissiontransmission via airborne droplets less than 1 meterVehicle transmissionspread of pathogens via air, drinking water, and food, as well as bodily fluids being handled outside the body--greater than 1 metertransient microbiotainhabit temporarilyNormal microbiotapermanently colonize the host and do not cause disease under normal conditionsCommensalismA relationship between two organisms in which one organism benefits and the other is unaffectedmutualismA relationship between two species in which both species benefitparasitismA relationship between two organisms of different species where one benefits and the other is harmedSymptomsubjective evidence of a disease, such as pain or a headacheSignobjective evidence of disease such as a fevercommunicable diseaseA disease that can be spread from one person or species to another. ex: genital herpesnon-communicable diseasea disease not capable of being spread from one person to another. ex: tetanusIncidenceThe number or rate of new cases of a particular condition during a specific time.PrevalenceThe number or proportion of cases of a particular disease or condition present in a population at a given time.Endemicconfined to a particular country or area--constantly present. ex: common coldEpidemicA widespread outbreak of an infectious disease. occurs between many hosts in short period. ex: infuenzapandemicDisease that occurs over a wide geographic area and affects a very high proportion of the population. worldwide. ex: sars-cov-2Acute diseasesymptoms develop rapidly but the disease lasts only a short time. ex: influenzaChronic diseasea disease that develops gradually and continues over a long period of time. ex: tuberculosisSubacute Diseasedevelops in host over intermediate rate and period. ex: sclerosing panencephalitisLocal infectionmicrobes are limited to a small area of the body. ex: boilssystemic infectionmicrobes are spread throughout the body via blood or lymph. ex: (measles)focal infectionmicrobes from a limited area begin to spread to other parts of the body. ex: dental cariesBacteremiabacteria in the bloodtoxemiatoxins in the bloodviremiaviruses in the bloodPrimary infectionacute infection that causes the initial illness. ex: common coldSecondary infectionresulting from an opportunistic microbe and an initial illness. ex: pneumoniadirect transmissionTransmission of blood or body fluids through touching (including shaking hands), kissing, coughing, sneezing, and talking.indirect transmissionTransmission of blood or body fluids through contact with an intermediate contaminated object such as a razor, extractor, nipper, or an environmental surface.CarrierOrganism (usually refers to humans) that harbors pathogens and transmits them to others.vectorAn arthropod that carries disease-causing organisms from one host to another.Healthcare-associated infection (HAI)an infection acquired within a healthcare setting during the delivery of medical careEmerging infectious diseases (EIDs)a new or changing disease that is increasing or has the potential to increase in incidence in the near futureMechanical transmissionthe passive transport of the pathogens on the insects feet or other body partsbiological transmissionpathogen reproduces in the vector; transmitted via bites or fecesMorbidityRefers to ill health in an individual and the levels of ill health in a population or group.mortalitydeath ratemorbidity rate`number of people affected in relation to the total population in a given time periodmortality ratenumber of deaths from a disease in relation to the population in a given timeCenters for Disease Control and Prevention (CDC)The primary federal agency that conducts and supports public health activities in the United States. The CDC is part of the US Department of Health and Human Services.John Snow (1813-1858)•A physician and the anesthesiologist of Queen Victoria of England •Conducted a descriptive study during a cholera outbreak in 1848 •Mapped locations of deaths and plotted data on the course of the epidemic •Hypothesized that the source of the disease was a public water well, the Broad Street Pump, for which he removed the handle •Conducted an analytic study during a larger cholera outbreak in 1854 •Compared deaths among residents that were supplied water by two separate companies, Lambeth Water Company and Southwark and Vauxhall Company (S&V) •Found mortality rates 8-9 times greater among those with water from S&V and finally proved his hypothesis that cholera can be transmitted in water5 stages of disease1. incubation period--no signs or symptoms 2. prodromal period--mild signs or symptoms 3. period of illness--most contagious 4. period of decline--can be re-infected 5. period of convalescence--least contagiousreservoirs of infection1. human--STIs, carriers 2. animals--zoonoses ex: rabies 3. nonliving--soil, water ex: tetanusContact transmissiondirect, droplet, congenital, indirect via fomitevehicle transmissiontransmission by an inanimate reservoir (food, water, air), blood and drugsnosocomial infectionhospital acquired infection --microorganism in hospital environment --chain of transmission --compromised hostContributing factors to EIDs-genetic recombination -evolution of new strains -widespread use of antibiotics and pesticides -changes in weather patterns -modern transportation -insect vectors -ecological disaster, war, and expanding human settlement -animal control measures -public health failure -bioterrorismIgnaz Semmelweis (1818-1865)hand washingFlorence Nightingale (1820-1910)spread of typhus and how to decrease typhus