A pathogenic or an infectious disease is caused by an external infectious agent or pathogen such as viruses, bacteria, parasites and fungi. These pathogens are found in water, soil and air and a human body can be infected from drinking, eating or touching something infected with germs.Examples of a bacterial pathogenic disease are pneumonia and gonorrhea, while viral pathogenic diseases include influenza and measles.
An example of a parasitic pathogenic disease is malaria, while an example of a fungal pathogenic disease is candidiasis.Deficiency diseasesA deficiency disease is caused by a deficiency of vital nutrients in the diet, especially a mineral or vitamin. The disease could be as a result of an insufficient intake of nutrients, their digestion, their absorption or their utilization within the body.A nutritional disease is normally connected to chronic malnutrition. Examples of deficiency diseases are scurvy and rickets. Acute poisoning can also result from excessive intake of certain nutrients.
Hereditary diseases Hereditary diseases or genetic disorders are caused by an abnormality in a person’s genome or genetic material. It is a disease that is passed down through several generations within the same family and is transmitted from a parent to their child. An example of a hereditary disease is cystic fibrosis. Hereditary diseases are more frequent in males.
Physiological diseasesA physiological disease is when the normal working of a person’s body is being affected because the organs are malfunctioning or the structures of the cells have changed over time, causing illness.Examples of physiological diseases would be diabetes and Chrohn’s Disease. Physiology encompasses the cellular, organ and tissue functions within the human body. When there is an abnormality in the normal physiology of the body then something within the body will fail to function as normal.