Communicable diseases

Health is the state of physical and mental well-being.

Communicable (infectious) diseases are caused by pathogens (bacteria and viruses) that can be spread.   Non-communicable diseases can't be spread (heart disease, arthritus etc.)   Both are major causes of ill health, other factors can make us ill:

1. Diet, if don't eat enough or the right nutrients can suffer from anemia, rickets and starvation

2. Stress, a certain level of stress can cause heart disease, cancers and mental health problems

3. Life situations, part of the world you live in, gender, financial status, ethnic group, levels of free health crae provided in your area, how many children you have and the local sewage and rubbish disposal.

Microorganisms that cause disease are called pathogens, pathogens can be bacteria, viruses, protists or fungi and they all infect animals and plants.   Bacteria and viruses cause the majority of infectious diseases.   Viruses are ven smaller than bacteria and usually have regular shapes, viruses cause diseases in very type of living organism.   Once bacteria or a virus enters the body then they will start to reproduce at a rapid rate.

Bacteria divide at a rapid rate by spiltting in two (binary fission) and may produce toxins (poison) that affect your body and make you feel ill, sometimes directly damage the cells.   Viruses take over the cells in the body, they live and reproduce inside the cells and starts damaging and destroying them.

common symptoms: high temperatures, headache and rashes.   This is the way your body responds to the cell damage and toxins produced by the pathogens.

Pathogens can spread through the air (droplet infection.)   Sneezing and coughing leaves droplets of bacteria and virus in the air, if inhaled can spread into the other person.  Direct contact: Pathogens such as HIV/AIDS are spread through direct sexual contact.   Cuts, scratches and needle punctures give access to the blood.   By water: fungal spores carried in water.   Eating raw , undercooked or contaminated food, or drinking water containing sewagecan spread diseases (diarrhoeal, cholera and salmonellosis.)   the Pathogens enter the body through the digestive system.

There are many ways to prevent the spread of communicable diseases between people, animals and plants.    Hygiene, isolating infected individuals, destroying or controlling vectors and vaccinations.

Hygiene: hand washing, especially after using the toilet, before cooking, or after animal ontact or contact with someone ill.   The use of disinfectantson kitchen work surfaces and toilets etc.   Keeping the raw meat away from other foods (to avoid contamination.)   Couging and sneezing in a tissue or hands (then washing them.)   

Isolating infectious people: especially a serious disease (ebola or cholera etc)   if they are kept isolated the risk of infecting others is very little.

Destroying or controlling vectors: some are passed on this way, mosquitoes carry a range of diseases (such as malaria and dengue fever.)   Flies can carry over over 100 diseases, rats are also vectors of disease.   By controlling the number of vectors, the spread of diseases can be reduced.

Vaccinations: doctors introduce a small unharmful amount of a specific pathogen into the body, as a result, if your body is then attacked by that pathogen you will have the antibodies in your blood stream to fight it off.   however this doesnt work in plants as they don't have an immune system.

1. The vaccine enters the body (contains an unharmful small dose of a specific pathogen,) this then triggers the immune system to respond.

2. WBC (White blood cells) produce antibodies to attack the microbe, (these anti-bodies are to suit this specific pathogen.)

3. The microbe has been made harmless by the lymphocytes in a process called lymphocytosis (meaning it can't reproduce) so it is then quickly engulfed by the Phagocytes in a process called Phagocytosis.

4. The body now has the defences against the microbe.

5. These defences are called anti-bodies and are now in the bloodstream (stored in special white blood cells called memory cells.)

6. If that microbe then attacks the body, the memory cells produce the antibodies again to attack and destroy the microbes as quickly as possible.