Giant Roundworm

The giant roundworm (Ascaris lumbricoides) is the largest nematode parasite of the human intestine, with females growing to more than 30 centimeters. It is among the most common human parasites, infecting hundreds of millions of people.

🧬 Field Guide Specimen: Open Giant Roundworm in the CRV Science Field Guide to log the specimen, see its place among the Ecdysozoa lineages in the Cladogram Explorer, and test your recall in the Red List conservation game.

A female can release around 200,000 eggs a day. The thick-shelled eggs remain infective in soil for months or years, and are swallowed from contaminated food, water or hands. Poor sanitation therefore drives transmission.

After hatching in the intestine, larvae burrow through the gut wall, travel via the blood to the lungs, climb the airways, are swallowed, and mature in the small intestine. Lung migration can cause cough and wheezing, and heavy worm loads can block the intestine.

Albendazole and mebendazole are effective, and mass drug administration in schools reduces the burden. Ascaris is one of the soil-transmitted helminths, with hookworms and whipworm.

• Human Whipworm — another soil-transmitted helminth
• Old World Hookworm — a hookworm