principles of disease and epidemiology – Flashcards
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| pathology |
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| the study of disease |
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| pathogenicity |
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| ability to produce pathological change in disease |
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| pathogenesis |
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| the development of disease |
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| all speciesd interact with some species in some way true or false? |
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| true |
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| symbiosis |
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| defines all interaction of one species with one another |
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| in layperson terms symbiosis is often used to identify |
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| mutualisms, relationship positive for both people |
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| commensalism |
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| one organism benefits the other is neither harmed nor helped, the organism that benefits is called commensal |
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| what is an example of commensalims |
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| skin or surface microbes on plants or animals, the plant or animal releases volitable, soluble, and particulate organic sompounds which are used by commensals |
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| mutualism |
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| both organisms benefit from interaction |
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| example of mutualism |
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| ruminants are animals that have stomach divided into four compartments and chew a cud Rumen, the first of these compartments, is located in the front of the true stomach, the Rumen essentially a fermentation vessel |
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| parasitism |
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| one organism gains ( parasite) and the other is harmed (host), often difficult to distinguish from predation can be used as a forma of biological control |
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| what can be used as a forma of biological control |
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| paracitism |
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| normal microbiota |
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| defined as organism growing on the body surfaces of healthy individuals the permemntly colonize the host |
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| transcient microbiota may be present for |
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| days, moths, or weeks |
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| what protects through competitive exclusion |
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| normal microbiota |
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| how does competitivw microbiota protect and organism |
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| by covering binding sites, so pathogens can not bind, and they compete for nutrients, so nutrients are unavailable for pathogens the also alter conditions ( ph oxygen availability) also produce harmful subastnce |
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| an example of normal microbiota that alters conditions of ph and oxygen availability is |
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| acidophilus lowers ph vagina- inhibits cadida albicans |
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| an example of normaL microbiota that produce harmful toxins are |
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| E.Coli- which produce bacteriocins ) colicin) inhibits growth of bacteria or the same or closely realted species ( salmonell and shigella) |
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| probiotics |
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| the addtion of microbes to the diet in order to provide health benefits beyond the basic nutritional value |
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| proiotics examples are |
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| lactobacillusspp. and bifidobacterium |
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| benefits of probiotics |
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| restores rhe friendly bacteria found in the healthy digestive tract aids in digestion and absorbtion of nutrients promotes proper eleimination of wastes/ helps control diarehea |
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| prebiotics |
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| a " non-digestible" food ingredient that beneficially effects the host by selectively stimulating the growth and/or activity of one or more limited number of bacteria in the colon, and thus imporves the hosts health.` |
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| ologosacacharide polymers are examples of prebiotics and are not processed until when |
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| they hit the large intestine |
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| synbiotic system |
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| combination of prebiotics and probioticsin single supplement, products in which the prebiotic compound selectively favors the growth of the probiotic compound |
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| thus a product containing oligofructose and probiotic bifidobacteria would fulfill what definition |
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| synbiotic system |
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| benefits of probiotics in poultry |
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| PREEMPT- a patient blend of 29 bacteria isolated from chicken cecum sprayed sprayed on day old chicks , preening moves bacteria in establishing a functional microbial community , and limits colonization of the gut by the process of competitive exclusion |
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| what may have an anticancer affect and a pssible modulation of Crohn;s disease |
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| probiotics |
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| one benefit of probiotics is that lactic acid bacteria have been shown to alleviate diarhea and prevent colonization of salmonella enterica during antibiotic thereapy? |
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| True |
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| infection |
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| coloinization of the body by pathogens |
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| disease |
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| impairment of the normal state of an organism or any of its components that hinders the performance of vital function |
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| infectious disease |
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| diseas caused by a microorgasnism |
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| noncommnicable disease |
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| a disease that is not transmitted from one organism to another |
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| communicable disease |
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| a disease that is spread from one host to another |
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| contagious disease |
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| a disease that is easily spread from one host to another |
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| symptoms |
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| a change in the body function the is felt by the patient as a result of disease |
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| syndrome |
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| a specific group of signs and symptoms that acompany a disease |
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| acute stage of disease |
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| symptoms develope rapidly, last a short time |
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| chronic |
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| disease develops slowly likely to continue or reoccur for long periods |
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| subacute |
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| symptoms between acute and chronic |
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| latent |
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| period when agent is inactive, no symptoms, then produces symptoms |
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| what are the 3 stages of a disease clssifying the serverity or duration? |
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| acute, chronic, subacute |
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| sporadic disease |
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| occurs occationally in a population ( or in irregular intervals) |
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| outbreak |
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| sudden unexpected occurance of disease usually focal or in a limited segment of population |
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| endemic disease |
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| constantly present in a population |
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| epidemic |
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| aquiring many hosts in a given areas in a short time |
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| pandemic |
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| increase in disease occurance within a large population over a wide region ( usually worldwide) |
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| incidence |
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| fraction of a population that contracts a disease during a specific time |
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| pravalence |
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| fraction of a population having a specific disease at a given time, depends both on incident rate and duration of illness |
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| to determine the disease what steps do you take |
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| 1. causative agent 2. source and or reservior of disease 3. mechanism of transmission 4. host and enviromental factors that facilitate development of disease within a defined population 5. best control measures |
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| inorder to determin what caused the disease what is normally used |
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| koch's posyulates ( or modifications of them) |
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| clinical microbiology lab plays an important role in the |
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| isolation and identification of pathogen |
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| robert Koch |
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| german physician sought the link between bacillus anthracis and the disease anthrax student of henle (formulator for the scientific method) |
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| Koch's postualtes |
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| 1. microbe must be present in every case of the disease, but absent in healthy organisms 2. suspected microbe must be isoloated and grown in the pure culture 3. the same disease must result when the isolated microbe is introduced into the healthy host 4. same microbe must be re-isolated from the newly diseased host |
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| how long has Koch's postulates served scientists for |
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| nearly 100 years |
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| what probelms have arisen from Kochs postulates? |
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| unculturable taxa- cannot survive outside the host - may require micronutrients/habitat we can not currently reproduce some pathogens like streptococcus pyogenes can cause several disease conditions some pathogens cause disease only in humans example HIV |
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| a couple examples pf organism that cannot survive outside their host are |
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| treponema pallidum, mycobacterium leprae rickettsial and viral pathogen |
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| robert Koch |
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| german physician sought the link between Bacillus anthrasis and the disease anthrax also was a student of Henlle and (formulator of the scientific method) |
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| Robert Koch sought the link between what ? |
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| bacillus anthrasis and anthrax |
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| Koch's postulates have served scientists for how many years |
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| 100 |
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| how did we eventually solve the problem for using Kochs postulates? |
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| we used alternative methods for culturing and detecting the pathogen for example: legionellosis(example in text) use of guinea pigs and chick embryos |
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| modern molecular techniques have allowed us to identify agents via.. so that we can incorporate them in animals and fix the problem of Kochs postulate |
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| PCR,DNA arrays ect. by emphasising genes and virulence factors |
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| source |
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| location of which the pathogen is transfered to the host |
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| reservior |
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| site or natural enviromental location in which pathogen is normally found somtimes function as source of pathogen |
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| most of the time hosts are the important animate sourcesof the pathogen |
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| true |
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| what are known as carriers |
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| the infect the infected host |
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| what are the two classes of carriers |
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| 1. casual ( acute or transcient)- harbors pathogen a short time 2. chronic- harbors pathogen for long periods of time ( months years life) |
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| chronic cariersak |
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| harbors pathogen for long periods of time ( months, years, life) |
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| casual carriers |
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| acute or transcient harbors pathogens a short time |
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| what are the types of carriers |
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| 1.active carriers 2.convalescent carrier 3.incubatory carrier 4.healthy carrier |
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| active carrier |
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| has overt clinical case of disease |
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| convalescent carrier |
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| has recoverred from disease but continues to harbor large numbers of pathogens |
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| what kind of carrier would I be of merca |
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| a covalescent carrier |
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| incubatory carrier |
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| habors pathogen but is not yet ill |
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| healthy carrier |
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| harbors pathogens but is not ill |
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| animal reserviors transmission to humans |
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| can be indirect or direct |
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| with animal reseriors numerous diseases are |
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| zoonoses |
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| zoonoses |
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| diseases of animals that can be transmitted to humans by vectors |
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| organisms that spread disease from one host to another by what 4 methods |
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| 1.water 2.air 3.soil 4.food |
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| four main routes that the pathogen is transmitted are? |
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| 1.contact 2.airborne 3.vehicle 4.vector-borne |
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| contact transmission |
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| comming together or touching of source/reservior and host |
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| there are three types of contact transmission which are |
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| direct contact- ( person to person); the physical interaction between source/reservior ( infected host) and suseptable host 2. indirect contact- involves an intermediate ( usually inanimate object) 3. droplet spread- large particles (>5mm)that travel < 1 meter |
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| with contact transmission droplet spread conditions are if.. |
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| the particles (are greater than 5mm and travel less than meter) |
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| airborne transmission |
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| pathogens suspend in air that are less than 5mm and can travel farther than 1 meter |
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| airborne pathogens are called |
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| droplet nuclei |
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| can airborne pathogens remain airborne for a long time? ( hours or days) |
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| yes |
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| what kind of pathogen transmission can travel long distances? |
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| airborn transmission |
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| airborne transmission usually propells from respiratory tract or source organisms by |
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| coughing .. sneezing, or vocalizing, as well as dust particles which are important in transmission |
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| vehicle transmissions are |
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| inanimate materials or objects involved in pathogen transmission |
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| common vehicle transmission is what |
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| single vehicle pathogen spreads to multiple hosts |
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| what are four types of vehicles |
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| water food soil air |
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| what type of transmission are fomites? |
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| vehicle transmission, they are surgical instruments, bedding, eating utensils, |
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| note* fomites can be considered what? |
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| indirect contact transmission |
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| vector-borne transmission.. 2 types are? |
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| external ( mechanical transmission- passive carriage of pathogen on body or vector no growth of pathogen during transmission OR internal transmission- carried within vector |
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| with vectotr internal transmission |
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| pathogen undergoes change within vector |
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| with vector internal transmission what is it called when pathogen does not undergo changes within vector? |
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| harborage transmission |
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| there are two main factors of why the host was suseptable to the pathogen |
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| defense mechanism of host and the pathogenicity of pathogen |
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| the pathogen left the host in two ways |
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| active escape passive escape |
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| active escape |
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| movement of pathogen to portal of exitq |
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| what is a parasitic helminths examples of |
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| active escape of a pathogen |
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| passive escape |
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| excretion in feces, urine, droplets, saliva, or desquamated |
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| what mode of escape is most frequently used |
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| passice escape |
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| when controlling epidemics you have to consider 3 things |
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| available resources and time constraints adverse effects of potential control measures human activitites that might influence the spread of infection |
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| control measures reflect comprimise |
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| true |
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| identify components of the disease cycle that are primarily responsible for particular epidemic...then |
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| find the weakest link and focus control measures there |
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| there are three methods for controlling epidemics |
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| 1. reduce or eliminate source or resevior of infection 2. break connection between source and suseptable individual( general sansatation measures) 3. reduce number of suspectable individuals ( raise the number of herd immunity) |
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| reducing or eliminate source or reservior infection includes 4 things |
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| 1. quarantine or isoldation of cases and carriers 2. destruction of animal reservior 3.treatment of sewage to decrease water conaminant 4. therapy that reduces or emilinates infectiviy of cases |
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| break connection between source and suseptable individual includes |
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| chlorination of water supplies pasterization of milk supervision and inspection of food and food handlers destruction of insect vectors with pesticides |
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| reduce number of suseptable individuals includes what |
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| passive and active immunization |
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| active immunization purpose is to |
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| to protect the individual from the pathogen and the population from the epidemic. |
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| passive immunization purpose is to |
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| to give temporary immunity following exposure to a pathogen or when a disease threatens to take a epidemic form. |
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| active immunizations are |
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| protection from suseptable humans and animals from communicable disease by administration of vaccine ( preparation of infecting agent) |
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| passive immunization is |
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| already aquiring passive immunity |
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| how is passive immunization accomplished |
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| by injecting humans or animals with preformed antibodies |
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| vaccines are useful for diseases that are? |
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| acute |
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| how do vaccines and immunization actually work |
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| mimics the pathogen and stimulates an immune response similar to actual infection |
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| vaccines are useful for diseases that are |
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| acute |
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| what do vaccines do |
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| they mimic the pathogen and stimulates an immune responce similar to the actual infection examples small pox, polio, hepatitis A, B, measles |
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| successful vaccines have not developed for numerous deadly and diliberating disease yet because they are |
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| chronic diseases the pathogen is able to evade or subvert the immune system AIDS, herpes, hepatits C, malaria |
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| 4 types of vaccines are |
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| whole organism vaccines purified molecule vaccines recombinant vector vaccines DNA vaccines |
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| whole-organism vaccines can be |
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| can be inactivated ( killed) or attenuated ( live but avirulent) |
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| inactivated whole organism vaccines are vaccines that |
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| oftern require booster shots because they do not normally stimulate cell-mediated immunity or IgA production |
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| attenuated whole organism vaccines |
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| are less stable and may revert to virulent form |
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| purified macromolecule vaccines use what |
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| macromolecules derived from the pathogen to create an immune responce |
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| three types of macromolecule vaccines are |
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| capsular polysacharides surface antigens ( hepatitis B) toxiods - inactivated exotoxins ( diptheria, tentanus) |
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| what is the process of a recombinant vector vaccine |
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| gene from pathogen isolated and inserted into nonvirulent virus or bacterium microbe vectro replicated within host and expresses pathogens gene pathogens antigen causes a humoral and cell-mediated responce |
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| what is the process of a DNA vaccines |
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| plasmid containing genes for pathogen's antigens is injected into host plasmid is taken up by muscle cell plasmid borne genes are expressed pathogen's anitgen cause a humoral and cell mediated response |
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| what are 8 contributing factors to reemerging disease |
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| genetic recombination evolution of new strains inappropriate use of antibiotics and pesticides modern transportation public health failure animal control measures ecological disaster, war, and expanding human settlement changes in weather pattern |
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| an example of genetic recombination would be |
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| avain influenza virus (H5N1) and E.coli |
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| an example of evolution of strains would be |
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| V. Cholerae |
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| and example of an inapprpriate use of antibiotics and pesticides would be |
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| antibiotic resistant strains |
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| an example of the effects of changing weather pattern would be the |
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| Hantavirus |
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| an example of the effects of modern technology would be |
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| the west nile virus |
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| an example of the effects of ecological diaster, war, and expanding huamn settlement would be |
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| coccidioidomycosis |
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| an example of animal control measures would be |
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| lyme disease |
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| an example of public health failure would be |
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| diptheria |
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| what infections are acquired as a result of hospital stay |
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| nosocomial infections |
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| what percent of hospital patients are affected by nosocomial infections |
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| 5-15% |
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| what are nosocomial infections usually caused by |
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| bacteria that are members of the noraml microbiota |
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| an infection can exist in the absence of a disease |
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| true |
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| are microbes absolutly essential to animal life? |
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| no |
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| microbial antagonismb or competitive exclusion |
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| involves competition among microbes |
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| when the normal balance between normal microbiota and pathogens is disrupted what happens? |
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| disease results |
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| the relationship between the normal microbiota and the host is called |
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| symbiosis |
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| one example of a communsalism relationship is |
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| the normal microbia of the human skin, one organism benefits and the other is uneffected these organisms live on the secretion or slougb off cells, and bring no aparent benefit or harm to the host |
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| an example of mutalism would by |
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| E.coli in the large instestine which feeds off the nutrients provided by the body and releases vitamin B and K |
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| opportunistic pathogens |
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| they do not normally cause disease but can if taken out of their normal habitat |
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| adrenoviruses cause what kind of disease |
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| respiratory |
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| are all diseases caused by microorganisms |
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| no |
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| what are two agents that cause disease that are only found in humans |
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| HIV and AIDS virus |
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| what are subject changes like symptoms |
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| they are noot apparent to the observer they are only felt by the patient |
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| are are objective changes |
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| changes that are seen by the observer such as signs |
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| chicken pox and measles are examples of a ---- disease |
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| contagious |
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| what examples of a disease is tetanus |
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| a noncommunicable disease |
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| the inicidence os a disease is the amount of population affected by the disease at a particular time period and is an indicator of the spread of disease |
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| true |
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| pravalence |
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| is the number of people in the population who have developed the disease at a specific time regardless of when it first appeared, both old and new cases |
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| what does pravelence indicate |
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| how seriously and how long disease affects population |
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| what does incidence indicate |
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| the spead of disease |
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| frequency of occurance is another way for us to classify diseases |
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| true |
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| sporadic disease |
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| occurs occationally |
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| endemic disease |
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| constintly present in the population |
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| epedimic disease |
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| many people in a given area in a short time |
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| pandemic |
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| epidemic world wide many people short time world wide |
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| we classify infectious disease based on the occurance, the severity or duration |
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| true |
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| is influenza an example of an acute disease |
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| yes |
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| is shingles a good example of a latent virus |
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| yes |
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| herd immunity |
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| many immune people are present in the enviroment |
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| local infection |
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| invadinf organisms are limited to a small area of the body |
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| systemic generaliozed infection |
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| microorganisms and their products are spread throughout the body by the blood or lymph |
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| focal infection |
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| when microbes of local infections eneter the blood stream or lymphatic vessels and spread to other specific parts of the body where they are confined |
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| sepsis |
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| toxic inflamatory condition arising from the spread of microbes |
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| septimia |
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| blood poisoning presence of bacteria or other toxins in the bloodstream |
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| viremia |
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| refers to viruses in the blood |
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| subclinical infection |
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| one that does not cause any noticable illness, some people can carry the virus and not show any illness |
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| for an infectious disease to occur there must be a reservior? |
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| true |
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| a definite sequence of events usually occurs during infection and disease |
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| true |
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| predisposing factor |
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| makes the body more suseptable to disease |
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| incubation period |
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| the interval between the intial infection and the first appearence of any signs or symptoms |
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| prodromal period |
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| relatively short and follows the incubation period. The normal mild symptoms of disease such as general aches |
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| period of illness |
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| period when the disease is most severe, if the immune system does not overcome the pathogen the patient dies during this period |
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| period of decline |
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| the signs and symptoms subside, fever decreases |
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| period of convalescence |
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| the person regains strength |
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| neutralism |
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| (0,0)Neutralism describes the relationship between two species which interact but do not affect each other. |
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| amensalism |
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| (-,0) It is specifically a population interaction in which one organism is harmed, while the other is neither affected nor benefited |
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| competition |
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| (-,-)Competition is a mutually detrimental interaction between individuals,Competition can be defined as an interaction between organisms or species, in which the fitness of one is lowered by the presence of another |
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| predation |
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| (+,-)one organism benefits and one does not |
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| mutalism |
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| (+,+) |
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| predation |
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| (-,+) |
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| commensulism |
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| (+,0) |
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| coooperation |
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| 0,+ there is no benefit for the actions the animal is giving out but it benefits some other organism in some way. like me mowing the lawn for mom |
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| about ---zoonoses are known |
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| 150 |
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| contact transmission is the spread of disease by what 3 things |
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| direct contact indirect contact or droplet trasnmission |
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| what is the general term used for a nonliving object in indirect contact? |
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| fomite |
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| what is money , toys, hankercheif, napkins.. ect all examples of |
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| fomites |
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| one sneeze can produce how many droplets |
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| 20000 |
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| what are the most important group of disease vectors? |
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| arthropods- animals that carry vectors to more than one host |
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| mechanical transmission of a vector |
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| passive transport of the pathogen on the insects feet or other body parts ( flys land on food) |
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| biological transmission |
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| is an active process and is more complex. the arythropod bites an infected person pr animal an ingests some of the infected blood. the pathogens repoduce inside the vector. ans the increase of transmission has increased |
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| a nosocomial infection does not show any evidence of being present during admission to the hospital it is a result of the hospital stay |
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| true |
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| lister and semmelwies decrease the number of nosocomial infections tramedesly |
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| true |
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| noscomial infections represent the eighth leadin cause of death in the united states |
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| true |
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| all three factors together cause noscomial infections |
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| true. microorganisms in the hospital enviroment, the weakened host, the chain of transmission in the hosiptal |
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| the hospital is consered a major reservior |
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| true |
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| comprimised hose |
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| one whose resistant to infection is impaired by disease, therapy or burns |
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| what is the order of the main cause of noscomial infections |
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| urinary tract, surgical, and lower resperatory |
