Human Diseases
The disease causing organisms Bacteria, Viruses and Fungi enter the body through natural openings and wounds/breaks in the skin. Natural openings such as the nose, mouth, urethra, anus and vagina are lined with mucous membranes which are moist providing the perfect environment for microbial growth, and consequently micro-organisms then infect other organs. Wounds and breaks in the skin (which can be caused by a multitude of things including scratches and cuts) enable bacteria to enter and can cause wounds to become septic, alternatively fungi or ringworm could enter and cause their own problems (athlete’s foot being one). Deep wounds can allow pathogens to cause more serious problems, as they can infect muscles and joints. Muscles and joints are normally completely sterile and once infected can quickly succumb to disease. Hair follicles can also be an entry point for pathogens; staphylococci can invade here and cause localised infections. Insect bites are another way a person can be infected in some cases they are a minor irritation but in others they can be very serious, for example the mosquito can inject malarial parasites directly into the bloodstream whilst they are feeding on your blood. A bite from a rabid animal can pass on the disease to the victim through the infected animals’ saliva.
There are a variety of ways that these things can be spread. Water is very effective when spreading diseases a contaminated water supply can spread things such as cholera, typhoid fever and many others, this is particularly the cases when the water is not cleaned and has come into contact with faeces of an infected individual as it will contain pathogens. A clean and sanitary water supply is vital in the fight against these diseases. Food is another way these diseases can spread. As in the natural openings of a human, food is often warm and moist and if not handled in the correct manner pathogens can reproduce at an incredible speed entering each person who eats the food in question. Some bacteria can cause serious food poisoning and can be fatal, for example botulism and clostridium. These bacteria are particularly virulent in foods that are a by-product of animals i.e. eggs meat & milk. Before food is handled the handler must wash their hands and ensure all surfaces and tools are thoroughly cleaned, once food is prepared it needs to be covered (as flies can be carriers of disease) and refrigerated if necessary. Droplet infection such as sneezing, coughing, breathing and talking is another way disease can be transferred from one person to another. If there are any of the disease causing bacteria in the water droplet it can easily be inhaled and cause respiratory infections. Direct contact is the way some diseases make it from one person to another. Sexually transmitted diseases such as AIDS and Gonorrhoea are transferred during direct physical contact. Some fungal diseases can also be transferred in this way although they may only need superficial contact, such as using the same towel or flannel as an infected person.
