infection and response communicable diseases are caused by pathogens that can be viruses bacteria fungi or protests these are single celled parasites they all reproduce in your body and cause damage but viruses can't reproduce by themselves a virus is in fact just a protein casing that surrounds genetic code that it injects into a cell which causes the cell to produce more copies of the virus the cell explodes and the virus goes on to infect more cells creepy isn't it measles is a virus that causes a rat and it can actually be pretty deadly too it's spread by droplets from sneezes or coughs HIV is an STD or STI sexually transmitted disease or infection that compromises your immune system this is also called aids for short it can also be spread by people sharing needles bacteria on the other hand release toxins that damage your body cells like salmonella in undercooked food or gonorrhea another STD that causes a yellow discharge from the genitalia yeah fungi do something similar like athletes foot while protest do all sorts of different things for example malaria is caused by a protest that burrows into red blood cells to multiply then burst out destroying the red blood cell in the process it's spread by mosquitoes so we say mosquitoes are the vector for the disease not only animals though plants are particularly susceptible to fungal infections like rose black spot purple black spots appear on the leaves and then they fall off such infections can be treated with fungicides tobacco mosaic virus affects plants by discoloring leaves due to inhibiting chlorophyll production less photosynthesis occurs and that causes stunted growth our bodies are excellent at protecting us from these pathogens though thank goodness skin is the first barrier to them entering and if they do enter your nose and trachea they can be trapped by mucus acid and enzymes in your digestive system will destroy them too if they still manage to enter the bloodstream though white blood cells are ready to combat them one type of these are called lymphocytes they produce antitoxins to neutralize the PO poisons pathogens produce and also they make antibodies which stick to the antigen on a pathogen and this stops them from being able to infect more cells and it makes them Clump together fago sites are then able to ingest them and Destroy them an antigen on a pathogen will have a specific shape so that means only an antibody that fits it will neutralize it if pathogens are unknown to the immune system lymphocytes will start making all different shapes until one fits miraculously your immune system will then store a copy of this an antibody next to a copy of the antigen so it's ready to stop it from causing an infection next time you're exposed to it you now have immunity a vaccine is a dead or inert version of a pathogen usually a virus that exposes your immune system to the pathogen so it can produce the antibody without it infecting you for example the flu vaccine you're injected with the virus that has been irradiated so the DNA has been damaged inside so we can't do the job incidentally the co jab however was intended to work differently instead you're injected with the DNA technically mRNA needed to trick your cells into synthesizing part of the virus including the antigen it was the first widely used jab that used this mRNA technology antibiotics kill bacteria they don't kill viruses penicillin was the first one there are good bacteria in our bodies so antibiotics are designed to be as specific as possible because you don't want to damage those or your body cells either problem is as bacteria mutate they can become resistant to them so the more you use them the less effective they become drugs used to be extracted from plants and other organisms for example aspirin comes from willow trees penicillin from a mold now synthesizing drugs is one of the biggest industries on the planet they have to be trial to see how effective they are and to check for side effects first we do lab trials on Cell tissue then trials on animals next human trials we give the drug to a group of people but we also give a placebo to a control group without telling them say a pill that's just sugar not the actual drug this is what we call a blind trial because the test subjects don't know what they're taking a double blind trial is when even those analyzing the results from the tests aren't aware of which group is which and that's to eliminate any bias just for triple this is a crazy one monoclonal antibodies they're made from clones of a cell which is able to produce a specific antibody to combat a disease this is achieved by combining lymphocytes from me tumor cells and this makes a hybridoma cell this is then clone to produce a lot of antibodies ready to treat a patient these monoclonal antibodies can also be used for medical diagnosis pathogen detection in a lab or even just identifying molecules in tissue by binding them to a dye so they glow when grouped together because they'll be designed to bind to a specific molecule the downside to these is that the side effects are turning out to be worse than scientists expected so I hope you found that helpful leave a like if you did and pop any questions or comments below I'll see you in the next video