Parasites are organisms that live on or inside another organism, called the host, and obtain their food at the host's expense. They depend on the host for survival and often cause harm or disease to the host
. There are three main classes of parasites that affect humans:
- Protozoa: Single-celled organisms, such as those causing malaria and amoebic dysentery.
- Helminths: Multicellular worms like tapeworms and hookworms.
- Ectoparasites: Organisms that live on the surface of the host, such as lice, ticks, and mites
Parasites can be classified based on where they live relative to the host:
- Endoparasites: Live inside the host's body.
- Ectoparasites: Live on the host's surface
Unlike predators, parasites usually do not kill their hosts immediately and often have complex life cycles, sometimes involving multiple hosts. They can cause a range of effects from mild discomfort to severe diseases
. In summary, parasites are specialized organisms that exploit other living organisms for their nutrition and survival, often causing harm in the process
