MMG301 1nd Edition Lecture 32Outline of Last Lecture I. Human microbe interactionsOutline of Current Lecture II. EpidemiologyIII. Public healthCurrent Lecture-Prevalence: number of cases (new + existing) in a population at a given time-A “snapshot” of the total number of cases within a population-Often reported as a percentage of population having the disease-Incidence: number of new cases in a population over a given time period-Outbreak: sudden increase in cases above normal low levels-endemic: disease occurs at normal levels, no coherent pattern-epidemic: larger incidence of disease, larger populations and regions are infected-pandemic: covers many continents on the earth are involved-Basic Reproductive Number R0: number of infections that one infected individual causes; example a person sneezes, how many people catch their cold?-generation time: the time that it takes to get from the initial infected individual to the next infected individual-Common source epidemics: all the individuals who get sick get the pathogen from the same source; example from food or water-Host-to-host epidemics: the pathogen spreads from individual to another individual, takes time for the pathogen to incubate in each individual-Index case: the first case of an epidemic; aka “patient zero”These notes represent a detailed interpretation of the professor’s lecture. GradeBuddy is best used as a supplement to your own notes, not as a substitute.-Example of Seasonal Cycles: Disease prevalence increases seasonally when insect vectors emerge-vector: live agent that transmits disease-Incidence of California encephalitis follows the prevalence of the mosquito vector with peaks in summer months-Infection: initial exposure and entry-Incubation: time between infection and onset of symptoms; can be days or years-Acute stage: fever and other symptoms at their worst-Decline: symptoms subside, reduced fever-human à human … epidemic-animal à animal … epizootic-Reasons why emerging diseases are becoming more common:-Ecological changes/economic development – agriculture, dams, deforestation-Human demographics – population growth, migration; wars; I.V. drug use-Increased international travel-Technology and industry – centralized processing of food supplies, overuse of antibiotics-Microbial adaptation – ability to undergo genetic changes and acquire genes-Shortcomings of public health measures – cutbacks in mosquito abatement and pollution
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