Epidemiology Terms

welcome to this video on epidemiology terms we'll go through a few of the main terms associated with epidemiology let's start out with that just a reminder of a little bit of history John Snow lived in the 1800's in London and he is considered the father of Epidemiology he's famous for tracking down the cause of a cholera outbreak he's also famous for working on anesthesia and delivering one of Queen Victoria's babies but the father of Epidemiology part comes in because he tracked down the water pump that was starting a cholera outbreak okay so let's go ahead and go through some terms I want to start out with epidemiology terms that have to do with the onset of a disease so if something is acute that means it had a fast onset it can sometimes also mean it has a fast resolution but not necessarily so for example someone could get an acute illness that causes their joints to hurt just overnight or we could compare that with if they had a chronic disease and that comes on over time and lasts for a long time so that would be chronic I think I can just put this here so the disease lasts for a long time and you often build slowly or develop slowly this is not always the case though so for example my dog got an autoimmune meningitis and they don't always know what causes that obviously there's something wrong with his immune system that made that happen but most dogs so it came on it was acute and then some dogs get better pretty quickly from it and other dogs have to maybe be on steroids long term and then their condition is considered chronic so how quickly it comes on as well as the potential for how long it's going to last is whether someone will call it acute or chronic and like a lot of terms on this page there's some subjectivity there okay then the third term I want to know about for timing is latent and this and actually I'm going to throw this on here and I didn't originally recurrent or a relapse I'd like to put these terms on here too so this could be it comes and goes maybe it has different triggers latent means that someone could have the infection but not showing symptoms so like if they got chickenpox and then the infection was kind of hiding and then later on they got shingles from that latent infection and then recurrent or relapse so we've got a few different terms here and all of these come under the category of timing okay and then I'm going to do one other thing to make this make more sense let's put a line down here like this and then box this in and then when you're looking at this later it'll be like okay here are some terms that tell me about the timing of disease so the terms were acute chronic latent and I would say relapse would be the other one okay so now the next one is like a real-estate term location location location we'll do these ones in green so in this situation what's happening is we're going to give the terms depending on where they are occurring in the body so let's say that this person had a big pimple on their skin this is a perfect example of a local infection it's it's contained in one place uh-uh sorry that was really not the way I meant to put that local contained in one place or one spot this could be all different kinds of infections as long as they're confined to that one spot but if they move and spread throughout the body then they can be systemic full-body infection and usually that would also mean you have a full-body immune response so that would be where something like septic shock could be a problem so the inflammation that occurs locally could be helpful but if it's in systemic it could actually cause too much inflammation in the body could go into shock on the other hand systemic doesn't always mean something so scary if you have the flu you have a systemic infection it means that your whole body is affected but most people recover just fine from that okay so now oh and maybe I should say circulating in the bloodstream either the infection or the inflammation at that point okay so next up we will talk about if an infection moves from one location to another we call that a focal infection so let's imagine that this person here has what's called gingivitis or periodontal disease okay so these are meant to show what have started out as a local but the bacterial infection in the mouth chronic okay so there's another word chronic overtime then was able to get into the bloodstream and travel to the heart and specifically it will often then the bacteria will literally grow and stick to the heart valves and along the way the bacteria might take up residence the blood vessel walls so they're found in atheroma so in in atherosclerosis there's bacteria that are often living in the clot so we didn't used to know this but it's becoming more well known that this is happening so a focal infection is what we call this it's it moved to another place it could move so that local infection could start out local and then it could move systemically or it could start out local and then just move to another spot and then it's called focal so there's a third term then focal as it moves to another spot and the classic example is gum disease gum disease bacteria and a lot of times it's things like streptococcus mitis or other strips in the mouth so gum disease bacteria go in the blood and then they go stick to heart valves where they're called vegetative growth or the blood vessel walls where they contribute to atherosclerosis so that's the classic example there okay so now let's go and look at some terms that have to do with the symbiotic relationships oh and we should let's block this off so this was our location location location this get your green highlighter doo doo doo doo doo doo you hear the birds singing outside my window spring is here we're all loving it it's supposed to be warm today I'm happy about that okay maybe I'll actually clean my house this weekend I don't know maybe okay so here we go - symbiosis so a lot of times people assume symbiosis means that something is a good thing and it can be but it also can be bad because term just means that two organisms living together so living together is what it littered well so bio means life and then sim means together so it can be good it can be bad the common one for good is mutualism and that one is a type of symbiosis in which both organisms benefit and so the example I would give you we can maybe make some okra see is like purple for gram positive lactobacillus in your gut using a purple highlighter if you can see that or maybe staph epi on your skin so these would be normal normal flora or probiotic flora I'm using purple here so your normal flora that are good and and they if you are going to give this a theme it would be you scratch my back I scratch yours so they're both giving something to the other we are giving the bacteria a place to live and food to eat and they often are regulating our metabolism our mood our immune system it's just amazing the things that are being becoming understood about the importance of our normal flora okay then something that's not so pretty would be pear oh and this is the scratching of my my back then parasitism though this is still considered a symbiotic relationship but it's when only or I'm gonna I'm going to change the definition just a little bit normally they say it's only one organism benefits and the other doesn't but what about this what about if one organism benefits a lot more because if you think about a tapeworm so this would be classic example would be parasitic worms like a tapeworm they get to live inside of us and get nutrients from that but they actually give our immune system some calming signals and they help to potentially this is an area of research to calm our own immune system down and reduce the risk of autoimmune disease or allergies of course a lot of times we just notice the bad things here and that if they get out of control there can lead to malnourished and actually weaken the host to the point where then they get other what we call secondary infections so there it's always a little more complicated to never just as black and white as maybe the terms that we would like it to be okay so this one will box in an orange this is your relationship category so we've done timing the location and then relationships okay next set of terms I want to do have to do with how far has the infection spread so if you the ficers like the infection started here and in a population and then how far did it get that Center would be what we would call ground zero patient or patient zero sometimes they call it patient patient zero I think is the name oops I think I should have saved patient zero like in an Ebola Ebola outbreak they might try to figure that out and you can put see Orange Oh yellow let's use yellow okay so this would be just at the beginning of the infection and then if an infection is locally found normally in a population we say it's endemic so like this graph over here would say so let's say the flu there's always a little bit of it going on in a population endemic it's low levels in population and then compare that with epidemic let's use a different color for that how about blue look at now how it spiked up from its normal endemic population and now all of a sudden we have a lot more people getting it so maybe put some blue arrows out like this and put that in blue so an epidemic is a sudden increase or it could maybe it's not always sudden it could also be a dramatic increase so like they often talk about obesity being an epidemic and it has didn't come on overnight but it certainly has had a dramatic increase and then if you go all the way and you know crossing country lines crossing potentially like oceans things like that then something could be called a pandemic and that's when it is either worldwide or has spread across country lines or oceans so it's a little subjective okay so let's go ahead and box this one in okay and then how easy is it to catch something can I get home can I catch that so if it is able to be passed at all it's called communicable it can be communicated to another person if it is very easily spread to another person then we describe it as contagious or even sometimes you'll see people say highly contagious so if it is spreadable at all we call it communicable and if it's very easily spread then we say that it's contagious or easily or highly contagious and then some diseases are described as non communicable a good example of that would be if you know someone that has rheumatoid arthritis or lupus basically any autoimmune disease those would be considered non communicable wait what did I do Oh yellow what's that way miss one in yellow okay and then the last terms are what you would see if you're looking like at the Centers for Disease Control to study something so our country has a government agency called the Centers for Disease Control they're the ones that put out all the vaccine information and stuff like that so that's called the CDC and every week they publish a paper called I think morbidity and mortality so morbidity is whoever is sick and mortality so this would be morbidity so if like they might say obesity is a great cause of morbidity in the country meaning if someone's obese then they might end up getting diabetes diabetes or other illnesses if they died from a disease then we say mortality what color have I not used red Oh pink I might use a pink on this one so let's use pink for mortality and morbidity so if they're sick its morbidity if they've died its mortality and then there are some terms as the disease catches on so this person let's say they've caught the plague they would be reported by our government as incidents this would be the number of new cases and then when they're keeping track of at any given time how many people actually have the illness that is the prevalence so all the new people that got sick that week plus the number of people that are still sick so total number of sick people from that disease so which number will virtually always be greater will be prevalence and incidence is just like now we've added this many new cases this week and then mortality or and they would keep track of how many people died from a disease in a given week as well okay thanks for your attention see you in the next video at least I'm assuming you I did attention I'm sure you did

Channel: susannaheinze

Views: 7,944

Rating: 4.7519379 out of 5

Keywords: epidemiology, epidemiology terms, latent, acute, chronic, systemic infection, morbidity, mortality, CDC, centers for disease control, incidence, prevalence, local infection, focal infection, relapse, mutualism, symbiosis, parasitism, endemic, epidemic, pandemic

Id: _iEOhy4qgyU

Length: 18min 9sec (1089 seconds)

Published: Sun May 12 2019