Principles of Disease and Epidemiology

Chapter 14 – Principles of Malady and Epidemiology Pathology Corruption and Malady 1. Pathology is the or-laws con-over of malady – unquiet delay fruitr (etiology) and mode in which malady expands (pathogenesis) - Too unquiet delay structural and administrative diversifys brought environing by malady and laexperience goods on the collectiveness 2. Corruption – irruption or subsidence of the collectiveness by pathogenic microorganisms 3. Malady – when corruption fruits in diversify in aver of bloom Regular Microbiota – 1. Free of microbes in utero, at nativity fruit lactobacilli in interior from mothers vaginal canal, E. oli fascinated through prop and inhabits interior thru individualality 2. Ten seasons past bacterial cells than ethnical cells in the collectiveness 3. Regular flora – regular microbiota 4. Transient microbiota – exhibit for a season but terminate 5. Distribution of regular flora contingent on visible and chemical factors, ramparts of the multitude and effortdeficient factors Relationship unformed Regular Flora and Multitude 1. Microbial animosity – aka competitive disruption – regular microbiota power to shield the multitude from overgrowth of injurious microorganisms 2. Regular microbiota and multitude feed in symbiosis – one is contingent on the other 3. The three types of symbiosis – commensalism (one organism uses, other simple), mutualism (twain use) and parasitism (one harmed and one uses) 4. Probiotics – feed microbial cultivations applied to or ingested that are purposed to exact a advantageous movables Opportunistic Microorganisms 1. E. coli – regularly innocuous but in other talents of the collectiveness – fruitr UTI, pulmonary corruptions, meningitis or abscesses. 2. AIDS – arbitrates immune order – extensions irritability to opportunistic corruption e. g. Pneumocystis pneumonia The Etiology of Infectious Malady – Koch’s Grounds – 1. Koch orderly that microorganisms fruitr detail malady 2. Absolute microorganisms from maladyd voluptuous, grew in guiltdeficient cultivation and attested, injected bloomy voluptuous, malady imitated and identical 3. Experimental requirements – identical pathogen must be exhibit in full instance of malady, pathogen must be absolute from maladyd multitude and aged in guiltdeficient cultivation, pathogen must fruitr malady when inoculated into bloomy voluptuous, pathogen must be absolute from inoculated voluptuous and shown to be primary organism Exceptions to Koch’s grounds – 1. Unique cultivation environments – mitigated to demonstrate etiologies of those that cannot be aged on simulated media e. g. banees, syphilis, leprosy 2. Some malady such as tetanus entertain dogmatical signs and symptoms 3. Some malady may be fruitrd by a calculate of microbes e. g. pneumonia and nephritis 4. Some pathogens fruitr sundry maladys e. g. S. pyogenes 5. Certain pathogens merely fruitr malady in ethnicals e. g. HIV Classifying Infectious maladys – 1. Full malady remodels collectiveness structures and functions in feature ways ad are implied by sundry kinds of evidences 2. Symptoms – diversifys in collectiveness functions 3. Signs – concrete diversifys the physician can remark or value e. g. lesions, turgescence, flush and paralysis 4. Syndrome – a detail assemblage of signs or symptoms that accompany a malady 5. Communicable malady – any malady that opens from one multitude to another e. g. herpes, chickenpox, measles, typhoid flush and TB 6. Contagious maladys – Open easily from multitude to multitude e. g. chickenpox 7. Noncommunicable Malady – fruitrd by microorganisms that anticipate collectiveness and merely rarely fruit malady or feed after a suitablenessout the collectiveness and fruit malady when introduced e. . tetanus Occurrence of Malady – 1. Stroke – the calculate of nation in a population who expand a malady during a feature duration of season 2. Custom – calculate of nation in a population who expand a malady at a detail season, unmindful of when it pristine appeared – old and new 3. Sporadic malady – betides merely rarely e. g. typhoid flush 4. Endemic malady – forever exhibit in a population – e. g. contemptible frigid 5. Epidemic malady – Many nation in a consecrated area expand malady n near season e. g. AIDS, STD’s 6. Pandemic – Epidemic malady that betides worldwide e. g. avian flu Severity or Duration of Malady – 1. Quick malady – expands speedily but merely lasts a near season e. g. influenza 2. Chronic Malady – expands past reluctantly and collectiveness’s reactions may be deficient bitter but continues or recurs for hanker durations of season e. g. Mono, TB & HepB 3. Subquick – Intermediate unformed Quick and Chronic e. g. Sclerosing panencephalitis 4. Undeveloped Malady – prolific vicegerent sediment slothful for some season but than becomes erratic to fruit symptoms e. . shingles 5. Herd Privilege – Privilege to malady in most of population Extent of Multitude Involvement – 1. Topical corruption – microorganisms poor to proportionately fine area e. g. boils 2. Systemic corruption – Open throughout the collectiveness by race or lymph e. g. measles 3. Focal corruption – topical corruption enters race or lymph and open to other detail collectiveness talents where they are onesided – originate f/ teeth, tonsils, sinus 4. Sepsis - toxic aggravating situation arising from open of microbes from a convergence of corruption 5. Septicemia – race poisoning orderic corruption arising from teeming of pathogens in race 6. Bacteremia – nearness of bacteria in race, Toxemia – nearness of toxins in race and viremia – nearness of bane in race 7. Primary corruption – quick corruption that fruitrs primal indisposition 8. Induced corruption – fruitrd by an opportunistic pathogen succeeding primary weakens ramparts 9. Subclinical (inapparent) corruption is one that does not fruitr any sublime indisposition e. g. Polio & HepA can be carried but never expanded Patterns of Malady . Sequence – must be reservoir of corruption as a spring pathogen communicated to tender multitude by contiguity or vectors transmission followed by irruption (enters multitude, multiplies) injures multitude through pathogenesis 2. Despite these goods, betideance of malady generally depends on opposition Predisposing factors – makes collectiveness past tender and may remodel race of malady 1. Gender – Females past UTI, Men past meningitis 2. Genetic setting – sickle cell over malaria 3. Climate and sphere – respiratory malady extension in evening 4. Others – alimentation, age environment, individualalitystyle, habitat, indisposition, chemo, emotions. Development of Malady – 1. Incubation Duration – season unformed primal corruption and pristine calm signs and symptoms, season depends on bitterness, calculate of microorganisms, and opposition 2. Prodromal duration – characterized by likelihood of the pristine calm signs and symptoms 3. Duration of indisposition – malady at its crisis and all signs and symptoms likely, PT dies during this duration if not conquer 4. Duration of Decsuccession – signs and symptoms subside- tender to induced corruption 5. Period of convalescence – collectiveness avail to its pre-unpolite aver and bloom is restored The Open of Corruption Reservoirs of Corruption – 1. Reservoir of Corruption – A enduring spring of corruption- may be ethnical voluptuous or nonliving 2. Ethnical reservoirs – Many nation entertain pathogens and cast them – Carriers are living reservoirs and entertain the malady delay or delayout signs or symptoms – Can convey malady during undeveloped phases such as incubation or convalescent – avow leading role in open of AIDS, typhoid flush, diphtheria, hep, gonorrhea, and streptococcal corruptions 3. Animal Reservoirs – Disorderly or private – Zoonosis are maladys that betide in disorderly but can be communicated to ethnicals e. g. Rabies, Lyme malady – Can betide through contiguity of voluptuous, its lavish, decrease or contamination. 4. Nonliving Reservoirs – Soil and Introduce – Soil e. g. Ringworm, Botulism and Tetanus, Introduce e. g. – usually contamination akin, cholera , typhoid flush Transmission of Malady 1. Contiguity – open od an vicegerent of malady by plain contiguity, inplain contiguity or droplet transmission a. Plain Contiguity – moving kissing, commerce, - Any rest visible contiguity e. . STDs, AIDS, frigid, influenza, staph, Hep A, measles etc. b. Inplain Contiguity – betides when vicegerent of malady is communicated from reservoir to multitude by media of nonliving sight – Fomite is a sight concerned in open of corruption e. g. tissues, bedding, syringes etc. c. Droplet Transmission – microbes are open in droplet nuclei that journey near space – Sneezing, coughing, talking – not considered airborne e. g. flu, pneumonia and pertussis 2. Vehicle Transmission – transmission of malady by a moderation, such as introduce prop or air and garbages race IV and collectiveness fluids d. Waterborne – tainted introduce, cholera leptospirosis e. Foodborne – raptureed through undercooked, illnessd kept or unsanitary prop such as tapeworm f. Airborne – droplet nuclei in clay that journeys past than 1 meter – measles bane and TB bacteria as polite as some spores can be carried in clay and fruitr malady coccidiodomyosis 3. Vectors – voluptuouss that convey malady from one multitude to another – g. Effortdeficient Transmission – disclaiming rapture on insects feet or collectiveness part-among-unformed – houseflies forward from feces to prop h. Biological transmission – erratic way and past obscure – arthropod gladness defiled individual pathogens refruit in vector extension fruitrs past possibility of cast. If arthropod vomits or defecates season gnawing multitude, can forward from gut. Often parasites, too embraces – Lyme malady, rack, Malaria etc. Nosocomial (Hospital Acquired) Epidemic 1. A nosocomial corruption is any corruption that is extraneous during the race of arrive in a hospital, nursing settlement or other bloomcare pliancy 2. Environing 5 – 15% of all hospitalized resigneds gain reach this 3. Result from consortment of weakened multitude, fastening of transmission in hospital and availpower of microorganisms in hospital. Microorganisms in the Hospital 1. Often regular flora are a quantity when introduced to collectiveness in catheters and surgical procedures 2. Major quantitys embrace coagulase disclaiming staph, S. aureus, E. coli, Enterococcus, P. aeruginosa, Enterobacter, K. pnuemoniae, Candida albicans 3. Most numerous are opportunistic gram disclaiming, garbage impenetrable Compromised Multitude 1. Opposition mixed by malady, therapy and burns. 2. Two principals – Broken skin/Mucous membranes and suppressed privilege . Broken skin and mucous membranes – disentitle pristine succession of rampart 4. Invasive devices too fruitr quantitys 5. Adverse goods to B and T Cells arbitrate multitude Fastening of Transmission – 1. Plain transmission from staff limb to resigned and unformed resigneds 2. Fomites such as catheters, syringes and respiratory devices Repress of Nosocomial Epidemic – 1. Aseptic techniques can anticipate – Hand washing most leading 2. Hospital corruption repress staff limbs are lawful for overseeing equitable cleaning, storage and handling of equipment and anticipation Emerging Infectious Diseases . EID’s are new or changing, increasing recently and showing forthcoming extension. 2. Calculate of factors give to emergence including new strains which may fruit from genetic reconsortment (E. coli), a new serovar fruiting from diversifys or extrication (Vibrio cholerea) , use of antibiotics and pesticide to fruitr opposition, diversifys in sphere patterns (Hantavirus), existent raptureation (West Nile), Ecological diversifys from unless disasters fabric or wars, voluptuous repress values (butcher deer predators, past deer, past Lyme malady and failures in notorious bloom values. . CDC priorities (1) Detect summon and instructor pathogens and malady (2) Expand basic and applied scrutiny on ecological and environmental factors microbial diversifys and multitude interaction (3) Enhance notorious counsel (4) Demonstrate plans to instructor and repress worldwide Epidemiology 1. The understanding of epidemiology is the con-over of transmission stroke and quantity of malady 2. Modern epidemiology began in mid-1800s delay the works of Snow, Semmelweis and Nightingale 3. Descriptive Epidemiology – axioms environing defiled nation is placid and analyzed – embraces info environing individual fix and duration 4. Analytical epidemiology – analyzes malady to determine likely fruitr – (instance repress system) a assemblage of defiled nation is compared delay an undefiled assemblage or (Cohort Method) nation in contiguity delay an vicegerent vs. hose not in contiguity delay the identical vicegerent 5. Experimental Epidemiology – repressled experiments contrived to experience fancy are performed e. g. fixbo con-overing 6. Instance recitaling furnishs axioms on stroke and custom to topical, aver and social bloom officials 7. The CDC is the deep spring of epidemiologic counsel in the US 8. The CDC publishes the Morbidity and Mortality weekly recital to furnish info on stroke and deaths.