The Life Cycle of Oesophagostomum

Fast Facts
+ Eggs are passed into the feces and hatch into L1.
+ L1 develop into infective L3 in the environment in 6-7 days.
+ L3 are ingested and end up in the small intestine.
+Larvae exsheath in the S.I. and penetrate the wall, forming nodules.

Possible Life Cycle of Oesophagostomum in Humans

Life Cycle Uncertainty in Humans
Although the life cycle for Oesophagostomiasis has been characterized for animals, the route of transmission and infectivity are unknown for humans. It is hypothesized that, because this disease is a zoonosis, the parasite's life cycle is similar to the life cycle seen in animals like sheep, goats, and cows (see below). One distinct difference in the parasitic life cycle during human infection is that the eggs are usually not transmitted out of the body along with the feces. This is because the parasite is unable to complete its life cycle of penetrating the intestinal wall and the nodules in which it has become encapsulated. Therefore it is hypothesized that transmission between humans is low and that the majority of the infections are a result of soil contamination by livestock. This explanation fails to explain the localization of the disease though. It is important to note that the parasite's inability to complete its life cycle is actually one of the causes of disease. center>

Confirmed Life Cycle of Oesophagostomum in Livestock

Borrowed from Colin Johnstone's lecture on The Strongyloidea

Life Cycle
Clinical Manifestations
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