Test 4: Cestodes (Tapeworms) Flashcards
What Cestode has unembryonated, operuclated eggs?
Diphyllobothrium latum
what areas are Taenia Solium to be more prevalent?
- Poorer communities
- Close contact w/pigs
- Eat undercooked Pork
Describe the Scolex of Taenia Saginata?
- Four, Muscular cup-shaped suckers
- No Crown of hooklets on rostellum
Used to determine species, How many uterine branches are found in Taenia Solium and Taenia Saginata?
Taenia Solium: 7-13
Taenia Saginata: 12-30
What is the length vs width relationship for a Taenia Proglottids? (Generalize, no numbers)
Longer than they are wide
What may be useful in detecting early invasive stages when the eggs & proglottids are not yet apparent in the stool?
Antibody Detection
What is the pointed end of the scolex that has point of attachments (suckers, hooklets, etc…) called? Cestodes Characteristic
Rostellum
Cestodes have what type of reproduction system?
Hermaphroditic (Monoecious)
How do Cestodes obtain their nutrition?
Through Body Walls
-Lack Digestive System
What are the segments that form the body of Cestodes (AKA Tapeworms) called?
Proglottids
A chain of proglottids is called?
Strobila
What is the portion of a Cestodes in which differ in number and placement of suckers and presence or absence of hooklets?
Scolex (head)
Describe the Life Cycle of the cestodes, Taenia Saginata and Taenia Solium?
1) Eggs or gravid proglottids passed to environment
2) Cattle- T. Saginata
Pigs- T. Solium, ingest contaminated vegetation
3) Oncosphers hatch, penetrate intestinal wall, circulate to musculature
4)Oncosphere develops in cysticerci in pig/cow muscle
5) Humans- ingest undercooked infected meat
6) T. Saginata or T. Solium, scolex attaches to intestine
7) adults in small intestine pass gravida proglottids in stool to environment
How many eggs are contained in the gravid proglottids of T. Saginata and T. Solium?
T. Saginata: 100,000 per
T. Solium: 50,000 per
What is the geographic Distribution of Taenia asiatica?
Asia (Mostly Republic of Korea, China, Taiwan, Indonesia, Thailand)
What causes Cysticercosis?
Infection with larval stages of T. Solium
How are humans infected with T. solium that will cause Cysticercosis?
1) Autoinfection: ingest eggs either by fecal contamination or proglottids carried into stomach by reverse peristalsis
2) Ingest food contaminated with feces that contains eggs
The Eggs of Taenia spp. are indistinguishable from what?
Cestodes of genus Echinococcus (tapeworms of dogs/other canid hosts)
How can species determination be accomplished for Cestodes?
Microscopic identification of Gravid proglottids or scolex
The microscopic identification of eggs and proglottids in feces is diagnostic for taenisasis, but this is not possible until when?
Development of adult tapeworms (first 3 months following infection)
Describe the Scolex of Taenia Solium?
Crown of hooklets
Four, muscular cup-shaped suckers
Give the Characteristics of Helminths.
- Multicellular organisms
- elongated and bilaterally symmetric
- Larger > protozoa
- Tegument: protective covering or cuticle
- Attachment: hooks, suckers, teeth, or plates
- Primitive nervous and excretory systems
- Alimentary canal (some)
- No circulatory system
Most Cestode eggs characteristics are what?
Nonoperculated and contain hexacanth embryo
What is the six-hooked larval form released when the Cestodes eggs hatch called?
Oncosphere
What is the clinical presentation of Taenia Saginata taeniasis?
- Mild abd symptoms
- Passage (active/passive) of proglottids
- Appendicitis or cholangitis (occasionally)
What is the clinical presentation of Taenia solium taeniasis?
- Less frequently symptomatic than T. Saginata taeniasis
- Passage (passive) of proglottids (main)
- Risk of development of Cysticercosis (MOST IMPORTANT FEATURE)
What is the drug of choice for treatment of active taeniasis and what drug is an alternative treatment?
Praziquantel
Alt.: Niclosamide
When must Praziquantel be used with caution and why?
Pt w/ Cysticercosis.
-Praziquantel is cysticidal and may cause inflammation around dying cysts, may lead to seizures or other symptoms
What are the post treatment procedures for Taenia?
- Stool collection for 3 days, species id
- Stool re-examined for Taenia eggs at 1 and 3 months
What is the intermediate hosts of the Taenia solium parasite?
Pigs
Describe the Scolex of Diphyllobothrium latum?
- Lance-shaped
- Two Leaf-shaped suckers
- Bothria-lateral grooves, serve as organs of attachment
Describe the Scolex of Echinococcus?
- Four Sucking Discs
- Double Row of hooklets
What is the general characteristics of the Strobila of the Echinococcus spp.?
Three Proglottids
- One Immature
- One Mature
- One Gravid
What is the larval form in humans, slow-growing, tumor-like, and space occupying structure w/membrane (unilocular) called? Echinococcus Characteristic
Hydatid Cyst
What are the structures on the wall of the membrane of the hydatid cyst called? Echinococcus Characteristic
Brood Capsules
What is a protoscolices? Echinococcus Characteristic
Tapeworm heads that develop in brood capsules
Describe the Scolex of Hymenolepis nana?
- Four Muscular suckers
- Crown of hooklets
Echinococcus characteristic in which this forms within the original mother cysts?
Daughter Cyst
What is formed when the daughter cysts and brood capsules disintegrate and liberate the protoscolices? Echinococcus Characteristic
Hydatid sand
Describe the Scolex of Hymenolepis diminuta?
- Four Muscular suckers
- No hooklets
Symptoms of Cysticercosis are caused by what?
Development of Cysticerci in various sites
What is of the greatest concern in the formation of Cysticercosis?
Neurocysticercosis (Cerebral Cysticercosis)
What symptoms/manifestations may occurs from formation of Neurocysticercosis?
- Seizures
- Mental Disturbances
- Focal neurologic deficits
- Sign of space-occupying intracerebral lesions
- Sudden Death
What may cause ocular, cardiac, or spinal lesions w/ associated symptoms?
Extra cerebral Cysticercosis
Laboratory Diagnosis: Demonstration of T. Solium eggs and proglottids in the feces, what is the diagnosis?
Taeniasis
Not Cysticercosis
Laboratory Diagnosis: How is definitive diagnosis of Cysticercosis made?
Demonstration of Cysticercus in tissue
In a person found to have eggs or proglottids in their feces what laboratory evaluation should occur?
Serologically tests (concern for autoinfection, resulting in Cysticercosis)
Diagnosis of Cysticercosis by demonstration of cysticerci in the tissue is accomplished how?
- X-rays: Appearance of calcified cysticerci in soft-tissue
- CT: CNS lesions detected
- Surgical removal of subcutaneous nodules
- Cysts in the eye
This is the immunodiagnostic test of choice for confirming clinical and radiologic presumptive diagnosis of Neurocysticercosis?
CDC’s immunoblot assay w/purified T. Solium antigens (Cysticercosis immunoblot) (Ab detection)