<prompt> Which of the following infestation is associated with autoinfection?Ascaris lumbricoidesStrongyloidesGiardiaGnathostoma  <response>: Auto Infective life cycle is present in Strongyloides stercoralis. In this cycle, the rhabditiform larvas passage through the colon to the outside world is delayed by constipation or other factors. This allows it to transform into an infective filariform larva while still within the body of its host. This larva may then invade the internal mucosa internal autoinfection or perianal skin external autoinfection without an intervening soil phase. Strongyloidiasis is diagnosed by the presence of the larvae in the stool. When it is absent in the stool, it can be isolated from duodenal or jejunal aspirates. Enzyme-linked immunosorbent assays for antibodies to excretory-secretory or somatic antigens are now available in reference laboratories. Ref: Ray C.G., Ryan K.J. 2010. Chapter 53. Intestinal Nematodes. In C.G. Ray, K.J. Ryan Eds, Sherris Medical Microbiology, 5e. 