Parasites Parasitism The good host Commentary

Francesco Redi parasitology

Parasites

• Francesco Redi described
• about 180 parasites,
• animals that live
• in living animals.
• They don’t appear
• out of thin air,
• but lay eggs
• in the nostrils of deer,
• or find a freshwater snail
• from which they emerge as larva
• and then we eat
• raw watercress.

Parasitism

• Ectoparasites live on the outside;
• endoparasites live on the inside.
• Intracellular endoparasites
• live in the body’s cells.
• Intercellular endoparasites live
• in body spaces, such as the veins or gut.
• Epiparasites feed on other parasites.
• Kleptoparasites steal things from their hosts,
• their food, their homes, their efforts.
• Any parasite is a living creature,
• and invites comparisons.

The good host

• Protozoa and worms
• inhabit our bodies.
• Ticks, lice, and scabies
• cling to us for life.
• We make good hosts
• if we don’t try too hard
• to get rid of them.
• We don’t tend to
• feel sorry for them,
• but they go back
• as far as we do.
• Together we have picked
• a path from the forest.