Scientists Say: Ectoparasite | Science News for Students

Scientists Say: Ectoparasite

This is parasite that lives on — not in — another organism
Mar 12, 2018 — 6:30 am EST
head louse
This is a human head louse. It’s a type of parasite that can live on a person’s scalp.
Giles San Martin/Wikimedia Commons (CC BY-SA 2.0)

Ectoparasite (noun, “ECK-to-PAIR-a-site”)

Like a terrible houseguest, a parasite relies on another organism — one it lives on or in — for its nutrients and gives nothing in return. The parasite benefits, while the host usually suffers in some way. Many parasites, such as tapeworms, live inside the host’s body. But ectoparasites are found outside the host. (“Ecto-“ is from the Greek language, and means “outside.”) Examples include a dog’s fleas and the head lice that spread from kid to kid in the classroom.

In a sentence

Lice and fleas that lived on people were ectoparasites that helped spread the infamous Black Death through Europe.

Check out the full list of Scientists Say here

Power Words

(for more about Power Words, click here)

Black Death     A European outbreak of bubonic plague in the Middle Ages that claimed the lives of up to 200 million people throughout a period of about four years. By the time it was over in 1351, between a quarter and half of all European residents had died.

ectoparasite     A parasite such as a flea or louse, which lives outside of its host.  

host      (in biology and medicine) The organism (or environment) in which some other thing resides. Humans may be a temporary host for food-poisoning germs or other infective agents.

organism     Any living thing, from elephants and plants to bacteria and other types of single-celled life.

parasite     An organism that gets benefits from another species, called a host, but doesn’t provide that host any benefits. Classic examples of parasites include ticks, fleas and tapeworms.