Lesson 1 - Cestodes Flashcards
Cestodes
Intermediate host: Pigs. Transmitted by ingestion or larvae from undercooked pork or eggs in food and water contaminated by human feces
Taenia solium
Scolex has four suckers and circle of hooks arranged around a rostellum
Taenia solium
Adult tapeworm in intestines causes taeniasis, Cystericercus in brain causing cysticercosis
Taenia solium
Diagnosed by Gravid Proglottids in stool (Larvae) or by Biopsy, CT scan (Eggs)
Taenia solium
Treatment of choice: Praziquantel
Taenia solium / Taenia saginita / Diphyllobothrium latum
Scolex has four suckers but no hooklets (no rostellum). Gravid proglottids has 15-25 uterine branches. Larvae (cysticerci) infective stage.
Taenia saginata
Transmitted by ingestion of larvae (cysticerci) in undercooked beef. Adult tapeworm in intestine causes taeniasis.
Taenia saginata
Symptoms include: Abdominal pain, weight loss, Pruritus ani, intestinal obstruction
Taenia saginata
Difference between T. solium and T. saginata
T. saginata does not cause cysticercosis in humans.
T. solium has 5-10 uterines, while T. saginata hsa 15-25 uterine branches.
Longest of the tapeworms. Scolex has two elongated sucking grooves for attachment, no hooks. First Intermediate Host: Copepods, Second IH: Fish.
Diphyllobothrium latum
Transmitted by ingestion of plerocercoid larvae in undercooked fish.
Diphyllobothrium latum
Adult tapeworm in intestines can cause diphyllobothriasis.
Diphyllobothrium latum
Vitamin B12 deficiency in D. latum caused by preferential uptake of the vitamin by the worm
Megaloblastic anemia
Unembryonated operculated eggs in stool
Diphyllobothrium latum
Composed of a scolex and only three proglottids - one of the smallest tapeworms. Scolex has circle of hooks and four suckers.
Echinococcus granulosus
Intermediate host are Sheep. Humans are accidental IH. Eggs ingested in food contaminated with dog feces (dogs are definitive host)
Echinococcus granulosus
Larva causes unilocular hydatid cyst disease, especially in liver and lung.
Echinococcus granulosus
Liver Cyst > hepatic dysfunction.
Pulmonary Cyst > erode into a bronchus > bloody sputum
Cerebral cysts > headache and focal neurological signs.
Rupture of cysts > anaphylactic shock
Echinococcus granulosus
Treatment of Choice: Albendazole or surgical removal of cysts
Echinococcus granulosus
Definitive Hosts: FOXES. IH: Rodents.
Transmitted by accidental ingestion of food contaminated with fox feces.
Larvae form multiloculated cysts (honeycomb vesicles).
Treatment: ALBENDAZOLE or surgical cyst removal
Echinococcus multilocularis
Dwarf tapeworm (smallest cestode). Most frequently found tapeworm in developed countries.
Ingestion of cysticercoid larvae from infected RICE or FLOUR BEATLE.
Eggs are directly infectious for humans and can pass in the stool or reinfect the small intestine (autoinfection).
PRAZIQUANTEL treatment of choice.
Hymenolepsis nana
Rat tapeworm.
Transmitted by ingestion of Rat Flea cysticercoid larvae. Accidental parasite.
Hymenolepsis diminuta
Most common tapeworm of dogs and cats. Transmission is by ingestion of dog or cat fleas carrying cysticerci.
Diagnosis is by identification of “barrel-shaped” proglottids in stool.
NICLOSAMIDE drug of choice.
Dipylidium caninum
