Taenia solium and Cysticercosis

Cysticercosis is an infection of larval stages in humans and pigs, while taeniasis is an intestinal infection with the adult tapeworm.

Humans are usually exposed to eggs by ingestion of food/water contaminated with feces containing these eggs or proglottids.

Oncospheres hatch in the intestine, invade the intestinal wall, enter the bloodstream, and migrate to multiple tissues and organs where they mature into cysticerci over 60-70 days.

<p>Some cysts of Taenia solium migrate to the central nervous system, causing neurocysticercosis.</p> Signup and view all the answers

<p>Humans can acquire intestinal infections after eating undercooked pork containing cysticerci.</p> Signup and view all the answers

<p>Cysts evaginate and attach to the small intestine by their scolices.</p> Signup and view all the answers

<p>Small intestine</p> Signup and view all the answers

<p>They evaginate, attach to the intestinal mucosa, and develop into adult stages</p> Signup and view all the answers

<p>Hepatic and pulmonary signs/symptoms</p> Signup and view all the answers

<p>Fever, urticaria, eosinophilia, and potentially anaphylactic shock</p> Signup and view all the answers

<p>They act as the definitive host</p> Signup and view all the answers

<p>Oncospheres</p> Signup and view all the answers

<p>Avoid handling and caressing infected dogs, and ingestion of water and vegetables polluted by infected dog feces.</p> Signup and view all the answers

<p>The terminal proglottids are characterized by the presence of an egg-filled uterus with a few short branches in the middle one-third of the segment, usually described by the central rosette.</p> Signup and view all the answers

<p>The first intermediate host is a suitable crustacean, and the second intermediate host is usually a small fish.</p> Signup and view all the answers

<p>The infectious stage for the definitive host is the plerocercoid larvae (spargana).</p> Signup and view all the answers

<p>The characteristic rosette-shaped structure found in Dyphillobothrium latum is the uterus centrally filled with eggs.</p> Signup and view all the answers

<p>Adult Dyphillobothrium latum worms can grow more than 10 m in length, with more than 3,000 proglottids.</p> Signup and view all the answers

<p>Arthropods serve as intermediate hosts for Hymenolepis nana, allowing the development of cysticercoids which can infect humans or rodents upon ingestion.</p> Signup and view all the answers

<p>The eggs of Hymenolepis nana are immediately infective when passed with the stool as they contain oncospheres (hexacanth larvae) that can penetrate the intestinal villus upon ingestion.</p> Signup and view all the answers

<p>The cysticercoids, upon rupture of the villus, return to the intestinal lumen, evaginate their scoleces, attach to the intestinal mucosa, and develop into adults that reside in the ileal portion of the small intestine producing gravid proglottids.</p> Signup and view all the answers

<p>Hymenolepis nana var. fraterna infects rodents and uses arthropods as intermediate hosts, while Hymenolepis nana infects humans and rodents but uses arthropods as intermediate hosts for its cysticercoid development.</p> Signup and view all the answers

<p>Upon ingestion of the eggs either in contaminated food or water, or from hands contaminated with feces, the oncospheres contained in the eggs are released in the host.</p> Signup and view all the answers

<p>Eggs of Hymenolepis nana are passed in the stool when released from proglottids through its genital atrium or when proglottids disintegrate in the small intestine.</p> Signup and view all the answers

<p>Larger predator species serve as paratenic hosts by consuming smaller intermediate hosts, allowing the plerocercoid to migrate to their musculature. Humans acquire the parasite by consuming undercooked fish from these larger predator species.</p> Signup and view all the answers

<p>Adult diphyllobothriids attach to the intestinal mucosa using two bilateral groves called bothria located on their scolex.</p> Signup and view all the answers

<p>Most infections are asymptomatic, but gastrointestinal symptoms may occur in some patients. Rarely, massive infections can cause intestinal obstruction, and aberrant migration of proglottids can lead to cholecystitis or cholangitis.</p> Signup and view all the answers

<p>Prevention can be achieved by avoiding the consumption of raw or undercooked fish, such as sushimi, and by not tasting fish while cooking.</p> Signup and view all the answers

<p>Definitive host specificity among medically important diphyllobothriids is low. In addition to humans, other carnivorous, fish-eating mammals and a few birds can also serve as definitive hosts.</p> Signup and view all the answers

<p>Adult worms of Hymenolepis nana measure 1-3 cm in length and reside in the small intestine of their definitive host. Immature eggs are discharged from the proglottids and passed in the feces, appearing in the feces 5 to 6 weeks after infection. The intermediate host is typically an insect, such as a beetle or flea.</p> Signup and view all the answers