How many types in human disease?

Diseases can be of two types

Infectious Diseases

Diseases that spread from one person to another are called communicable diseases. They are usually caused by microorganisms called pathogens (fungi, rickettsia, bacteria, viruses, protozoans, worms). When an infected person discharges bodily fluids, pathogens may exit the host and infected a new person (sneezing, coughing etc). Examples include Cholera, chickenpox, malaria etc.

Non-infectious Diseases

These diseases are caused by pathogens, but other factors such as age, nutritional deficiency, gender of an individual, and lifestyle also influence the disease. Examples include hypertension, diabetes, and cancer. They do not spread to others and they restrain within a person who has contracted them. Alzheimers, asthma, cataract and heart diseases are other non-infectious diseases.