A disease is an abnormal, often medical, condition that affects the body, and it is usually associated with specific symptoms. It could be caused by internal factors, like the immune system being unable to fight an infection, or external factors, like a contagious virus.
Any condition that causes pain or problems to an individual can be called a disease, including injuries, disabilities and infections, and there are four main types of disease:
If we want to avoid ending up here we have to understand how diseases work. Image by Geo Swan for Wikimedia
Pathogenic – caused by disease-causing agents, like viruses and bacteria
Deficiency – caused by a lack of a particular nutrient in a person’s diet
Hereditary – caused by are caused by genetic abnormalities
Physiological – caused by problems within the body
Along with common diseases such as cancer, heart disease and malaria, there are many unusual diseases with all sorts of different symptoms.
- Pica is the urge to eat non-food substances like paper or clay, and it’s thought to be linked with mineral deficiency, but scientists don’t really know of its cause or a cure.
- Vampire disease makes skin blister in the sun
- The genetic disorder progeria causes individuals to age rapidly.