so we are going to be talking about chapter 10 which is all about infectious diseases so when we are talking about uh infectious disease we have to break down the word disease first by the way and we have to know what does the word disease means uh disease is just basically the disorder of the body or mind which means to say certain parts of um your body or mind are not functioning optimally for example if you were to have lung disease your lung is not able to function at a perfect state or if you have a mental disease or mental disorder there are certain things uh wrong with the brain chemistry uh which may manifest in certain disorders such as depression such as uh schizophrenia or such other examples of diseases may include things like coronary heart disease cancer and like I just mentioned earlier depression so when you use the word infectious disease however uh infectious disease can also mean transmissible diseases or it can also mean communicable diseases and infectious transmissible or communicable diseases basically means that you will have a person who is infectious and when the person is infecti inside their body they contain something called pathogens pathogens are just basically organisms that can cause diseases in our body we will talk about a few pathogens later but what happens is the pathogens from this infectious person will go out of their body and enter another person so the pathogen has spread from one person to another and when the second person receives the pathogen they get the disease this is what is meant by infectious disease because it's a disease that can spread from one person to another due to pathogens not all diseases are infectious by the way like for example if the person has coronary heart disease um you know it can't spread to another person you you can't just cough uh a heart attack to another person right uh but like in the case of uh covid covid-19 that is an infectious disease because it's caused by a pathogen called the Corona virus but weirdly enough uh even though Co happened recently it is not part of our syab us okay don't worry about that so the question over here is how do diseases actually spread um so to answer the question about how diseases spread there is no one clear answer because different pathogens will spread in different ways which we will see in the later videos because the way chera spreads the way malaria spreads the way HIV spreads and the way tuberculosis spreads are very different from each other so each pathogen has a specific way of jumping from one person to another but an interesting thing is before the invention of microscopes to be able to visualize the existence of this pathogens people generally had an idea of something called the miasma Theory now the myma theory you do not need to memorize for the exam but I just want to talk about it a little bit the miasma theory was actually uh sort of spoken about before we knew that microorganisms existed people back then uh understood that when you had dead organisms of foul liquids such as urine or dirty laks or ponds and even feal matter or feces in the area they said that this particular things could actually pollute and poison the air and when they poison the air it creates this kind of uh you know toxic and known as the miasma and because of that miasma it was able to spread from one person to another where they said that there was death in the air uh of course we know now that the miasma theory is not uh what actually happens we now know that pathogens are the reason why people fall sick but the myma theory laid the foundation of how diseases spread from one place to another so we we still use this practice today where if there are dead organisms of F liquid or feces around the area it is always best to avoid those kind of areas because diseases are quite rampant over there so in the future videos we are going to be looking at four specific uh infectious disease we have to talk about what is the causative pathogen which means to say what's the name of the pathogen that actually causes that particular infectious disease we also have to know how does the disease spread from one person to another what are some of the symptoms symptoms are just basically the way your body presents the disease for example if you have covid-19 your body's symptoms will usually be things like fever sore throat coughing uh breathing difficulties if you had um heart attack the symptom would be like you know chest pain and also difficulty of breathing as well and dizziness these are symptoms and symptoms help doctors diagnose or detect what kind of disease is in your body so it is also important to know some of the symptoms of the diseases that we are going to be studying and the next very important thing is if the person has the disease how do we treat the disease in their body and more importantly when we talking about infectious disease is how do we prevent the disease from spreading in the larger population last but not least we also have to talk about something very something very important where we know how to treat the disease we know how to prevent the disease but why can't we totally eradicate this particular disease why is it still existing in our general population so these are the six aspects that you will have to know when we are studying cholera tuberculosis HIV and malaria