Ascaris lumbricoides
Ascaris lumbricoides, the giant roundworm, are the largest nematode that is a parasite to humans. They grow up to 30 cm in length. They live in the small intestine of humans.
These worms reproduce inside the small intestine and the eggs pass out in the stool. After two weeks the eggs become infectious. You can be infected from the soil in which they reside. The eggs can remain dormant in the soil for up to ten years and only hatch once ingested.
Once ingested, the eggs hatch in the duodenum(upper part of the large intestine). They then penetrate the mucous membrane and enter the circulatory and lymphatic systems and move through the liver towards the heart and lungs. They then migrate up to the trachea where they are coughed up to the mouth, they are swallowed again and return to the small intestine. This whole time the larva molts and achieves sexual maturity after 8-12 weeks.
These worms reproduce inside the small intestine and the eggs pass out in the stool. After two weeks the eggs become infectious. You can be infected from the soil in which they reside. The eggs can remain dormant in the soil for up to ten years and only hatch once ingested.
Once ingested, the eggs hatch in the duodenum(upper part of the large intestine). They then penetrate the mucous membrane and enter the circulatory and lymphatic systems and move through the liver towards the heart and lungs. They then migrate up to the trachea where they are coughed up to the mouth, they are swallowed again and return to the small intestine. This whole time the larva molts and achieves sexual maturity after 8-12 weeks.
Male worms find females by tracing their pheremones. They have no visual capability. The male uses his papilae, spicules, and curved tail to hold the female during mating. The male has two testes. he transfers his sperm into the vagina of the female during mating. Zygotes are formed and the female lays the eggs. Females lay up to 234,000 eggs per day.