Pathogens are organisms organisms: living entities-ie animals, plants or microorganisms. that cause disease. They include microorganisms such as bacteria, viruses, fungi and protozoa.ood contaminated with protozoa can cause infections such as amoebic dysentery, of which severe diarrhoea is a symptom. Some protozoa are parasites. These organisms live on, or inside, another organism and cause it harm. Malaria is a disease caused by protozoa that live in the blood.
In most cases, erectile dysfunction is caused by something physical. Common causes include: 1  Heart disease. 2  Clogged blood vessels (atherosclerosis). 3  High cholesterol. 4  High blood pressure. 5  Diabetes.
Erectile Dysfunction Physical and Psychological Causes. While most people think that ED stems from penile dysfunction, it is far from true. There are other numerous physical and psychological causes of erectile dysfunction which is precisely the reason why the problem is complex in nature. A minor physical condition can slow sexual stimulation, resulting in unusual difficulty in maintaining an erection. Gradually, this can even worsen the condition.