Pathogens are organisms that cause disease. They include microorganisms such as bacteria, viruses, fungi and protozoa.
Parasites are organisms that live on or in a host organism.
Malaria is a disease caused by a protozoan, a type of single-celled organism. The malaria parasite is spread from person to person by mosquitoes. These insects feed on blood and the malaria parasite is passed on when the mosquito takes a meal. Organisms that spread disease, rather than causing it themselves, are called vectors. The mosquito is the vector for malaria. The parasite itself can be killed by giving infected people drugs such as Lariam.
A cancer happens when cells begin to divide out of control. They form tumours that can sometimes be felt as an unusual lump in the body.
Benign tumours grow slowly and are usually harmless – warts are benign tumours. malignant tumours often grow more quickly and may spread throughout the body.
The body protects…