The parasites are organisms that derive the nourishment and protection from other living organisms known as hosts. They may be transmitted from animals
to humans, from humans to humans, or from humans to animals. Several parasites have emerged as significant causes of foodborne diseases. The Parasites
live and reproduce within the tissues and organs of infected human and animal hosts, and are often excreted in feces. These parasites are transmitted from
one host to another by different ways. They may be transmitted from host to host through consumption of contaminated food and drinking water, or by
putting things into human mouth that has touched with the stool of an infected person or animal. The parasites are of different types and range in size from
tiny, single-celled, microscopic parasites are protozoa to larger, multi-cellular worms are helminthes that may be seen without a microscope. The size ranges
from one to two µm or micrometers to two meters or more long.