Which among the following causes Autoinfection?
Autoinfection refers to the ability of ceain parasites, paicularly helminth to establish life cycle within the host, eliminating the need for an intermediate stage and secondary host. Strongyloides has a cycle of autoinfection. Here the rhabditiform larvae mature into the infective third stage larvae during their passage down the gut. These filariform larvae cause reinfection by piercing the perianal and perineal skin during defecation. The larvae wander in the dermis of the perianal region for some time, causing a radiating perianal creeping eruption, a form of cutaneous larva migrans. They ultimately enter the lymphatics or venules and are carried to the right hea and the lungs to complete the life cycle as above. This ability to cause autoinfection explains the persistence of the infection in patients for long periods, even 30-40 years after leaving the endemic areas. Some of the organisms where autoinfection occurs are Strongyloides stercoralis, Enterobius vermicularis, Taenia solium, and Hymenolepis nana. Ref: Textbook of Medical Parasitology, 5th Ed, Page 161
Ascaris lumbricoides
Strongyloides
Giardia
Gnathostoma