Cestodes Flashcards
What is T saginata associated with?
Undercooked beef
What are some characteristics of T Saginata?
More than 15 lateral branches 10 meters in length No hooks Lives in Upper Jejunum Ingested eggs become oncospheres which travel to muscle Larvae, not eggs cause disease Life expectancy 2 to 3 years
What are some characteristics of T. Solium?
Less than 12 lateral branches
Eggs are infectious
What disease is caused by T Solium?
Cysticercosis
What does Cysticercosis usually effect?
Most commonly the CNS, but the skin, muscle and eyes can also be affected.
What are CNS manifestations of Cysticercosis?
Parenchymal and extraparenchymal lesions of terminal vessel inflammation release cytokines which can cause both mass effect and seizures
What are the 4 stages of Neurocysticercosis?
- Viable Cyst with invaginated scolex- 3mos
- Initial Inflammation with Colloidal Granular and thick wall 3 to 5 years
- Degenerating 1 month
- Calcified Parasite with intense gliosis 2 mos to 1 year
How is Neurocysticercosis diagnosed?
CT or MRI. Western Blot. Serum better than CSF
How is Neurocysticercosis treated?
Treat for seizures especially in stage 4
Prednisone 1mg/kg /day for 14 days, begin 2 days prior to Albendazole
Albendazole for 14 days if a cystic and enhancing lesion
Albendazole for 28 days if extraparenchymal
Do not treat calcified lesions
Surgical intervention I f compression of Ventricles or eyes occur
What causes Echinococcal disesase?
The larval stage of the worm
What are the types of Echinococcal disease?
Granulosus(Cystic Hydatid) and Multilocularis
( Alveolar Hydatid)- look for hooks
What are the 2 types of echinococcal infection?
Sylvatic-Dogs or WIld Animals
Pastoral- WIld or domestic Dogs
How is the disease spread?
Humans ingest eggs.
What occurs after the eggs are ingested?
The eggs give rise to a cyst. The cyst wall is laminated with the inner layer being germinal. This gives rise to larvae. The slow growing cyst acts like a cancer.
How is the disease diagnosed?
The Hydatid antigen Skin test and the serology which cross reacts with cysticercosis.
What is the treatment for this disease?
Puncture Aspirate Inject with 95% Ethanol/HypertonicSaline/Formaldehyde+ Albendazole, Steroids and Antihistamines Reaspirate
What are the two classes of cestodes?
Pseudophyllidea-2 longitudinal sucking grooves
Cyclophyllidea- Circularsuckers
Cysticercosis and Echinococcus are not caused by adult cestodes. What are they caused by?
Larvae
How do cestodes nourish themselves?
Nutrient absorption through the skin.
What cestode does not have an intermediate host?
H. Nana
What is the sexual orientation of cestodes?
They are hermaphrodites.
What are some facts about Diphyllobothrium Latum?
15 meters long
Proglottids are wider than long ergo Broad Tapeworm
Found in Salmon, Pike, Perch, Turbot, Gefillte Fish, Sushi, Sashimi, Ceviche.
What is the life cycle of D. Latum?
The tape worm attaches to the Jejunum. Proglottids give rise to eggs which are passed by humans.The eggs give rise to Coracidia which then enter fish. these give rise to Larvae which are ingested by humans. The larva matures into a tapeworm.
What are the sx of D. Latum infection?
Cramping, weight loss, B12 deficiency, sx related to biliary tree or colon.
How is D. Latum diagnosed?
Stool exam. eggs are opercular and have an abopercular knob and have no embryo inside.Tapeworm proglottids when injected with india ink look like Chinese Characters or rosettes.
What other eggs are operculated and what are their sizes?
Clonorchis Sinensis- 30um- Fluke
D. Latum-60um- tapeworm
Paragonimus Westermani-90um Fluke
Fasciola Hepatica- 120um Fluke
How is D. Latum prevented?
Freezing to -180 degrees for 24hrs or -10 degrees C for 72 hrs.
What is the appearance of the proglottids of Dipyllidium Caninum?
They look like grains of rice or cucumber seeds. They can be mistaken for mucous strands. Look for hooklets in eggs.
Where does D. Caninum reside?
The Small Intestine.
How is the infection transmitted?
Fleas containing larvae bite dogs/humans. The larvae mature and become tapeworms.
What are some characteristics of H. Nana infection?
Most common cestode to infect humans
Passes from human to human
Humans ingest eggs or larvae
Beetles can be an intermediate
What is the treatment for cestodes?
Praziquantel for adult worms
Albendazole for Larval forms