Final answer:
The big three communicable diseases are tuberculosis, malaria, and HIV/AIDS. They are caused by bacteria or parasites and are transmitted through various means.
Step-by-step explanation:
The three big communicable diseases are tuberculosis, malaria, and HIV/AIDS.
Tuberculosis is caused by the bacterium Mycobacterium tuberculosis and is primarily spread through the air when infected individuals cough or sneeze. It mainly affects the lungs but can also affect other parts of the body.
Malaria is caused by the parasite Plasmodium and is transmitted through the bite of infected mosquitoes. It primarily affects red blood cells and can lead to severe illness and even death if not treated promptly.
HIV/AIDS is caused by the human immunodeficiency virus (HIV). It is primarily transmitted through unprotected sexual intercourse, sharing needles, and from mother to child during childbirth or breastfeeding. HIV weakens the immune system, making individuals more susceptible to opportunistic infections and certain types of cancer.