The majority of parasites do not use the oxygen available within the host, but employ systems other than oxidative phosphorylation for ATP synthesis. In addition, all parasites have a life cycle. In many cases, the parasite employs aerobic metabolism during their free-living stage outside the host.

Do parasites breathe oxygen?

“When parasites are outside the body, which they are for a part of their lifecycle, they breathe oxygen just like we do,” says Andrew Fraser, a senior author and a professor of molecular genetics in the Donnelly Centre for Cellular and Biomolecular Research at U of T's Faculty of Medicine.

Can worms survive without oxygen?

Air contains more oxygen than water does, and remember, earthworms need oxygen. Without it, the earthworm would suffocate! ... These researchers say earthworms can survive underwater for a little while, but come to the surface after the rain because it is easier to move on a wet surface.