platyhelminths : cestodes
DESCRIPTION
Platyhelminths : Cestodes. Pseudophyllidea Diphyllobothrium latum (pernicious anemia). Cyclophyllidea Taenia solium (pork tapeworm) Taenia saginata (beef tapeworm) Echinococcus granulosus (cystic, CE) Echinococcus multilocularis (alveolar, AE). A rare and emerging disease. - PowerPoint PPT PresentationTRANSCRIPT
![Page 1: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/1.jpg)
Platyhelminths : Cestodes
• Pseudophyllidea• Diphyllobothrium latum (pernicious anemia)
• Cyclophyllidea• Taenia solium (pork tapeworm)• Taenia saginata (beef tapeworm)• Echinococcus granulosus (cystic, CE)• Echinococcus multilocularis (alveolar, AE)
![Page 2: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/2.jpg)
![Page 3: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/3.jpg)
A rare and emerging disease
![Page 4: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/4.jpg)
Macroparasite example 2 : Taenia solium :
Disease Neurocysticercosis
Cestode. Unique zoonosis. Under-reported disease.
Diagnostic difficulties. Lack of epidemiological data.
![Page 5: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/5.jpg)
Biology of Taenia solium
• Unique zoonosis : Human only known definitive host, pig intermediate host
• Humans carry both adult worms in the intestine & larval cysticercosis in the muscle & other tissues
• Infection with adult worm in humans dangerous to host & other contacts
• Under-reported disease
![Page 6: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/6.jpg)
Symptomatology and pathology 1
• Primarily due to pressure effects of a space-occupying cyst or lesion in an organ or tissue
• CNS involvement : Neurocysticercosis (NCC) : pathology relates to number, size, type (cellulose or racemose), condition & site of cysticerci in the brain
• Active versus inactive NCC
![Page 7: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/7.jpg)
![Page 8: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/8.jpg)
Symptomatology and Pathology 2
• Active NCC : arachnoiditis (spinal fluid pleocytosis, increased CSF protein, positive CSF serologic test)
• Small number of patients : obstructive hydrocephalus, cranial nerve involvement, intercranial hypertension, arterial thrombosis & stroke
• Epilepsy, dementia, meningitis
Intraocular cysts : visual impairment
![Page 9: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/9.jpg)
Location of parasites in 2188 cases of cysticercosis
• CNS 82%• Eye 17%• Subcutaneous tissue 7%
• Muscle 5%• Other organs 6%• Generalized 1%
Flisser & Craig, 2005
![Page 10: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/10.jpg)
Diagnosis 1
Adult worms
• Stool analysis : uterine branch structure or scolex morphology after treatment
• Molecular differentiation of adult worms
• Capture ELISA for coproantigen detection
![Page 11: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/11.jpg)
![Page 12: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/12.jpg)
Diagnosis 2Cysticercosis
• Imaging methods (CT scan useful for brain & calcified cysts ; MRI not but excellent for detecting active cysts in soft tissue)
• Serology (ELISA versus Immunoblot)
![Page 13: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/13.jpg)
Epidemiology :
cysticercosis
• Retrospective case finding• fixed time period, annual incidence rate per 100,000 population
• Active screening• Mass radiological imaging surveys
• Immunodiagnostic surveys
• Autopsy surveys
![Page 14: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/14.jpg)
Cysticercosis in communities
• Endemic focus: Rural Latin America• Major risk factor: current or past case of intestinal Taenia in the household
• Non-endemic community: New York City• Significant number of human cysticercosis cases in an Orthodox Jewish community
![Page 15: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/15.jpg)
Treatment : cysticercosis
• Until recently symptomatic patients : anticonvulsants, corticosteroids, surgery
• Chemotherapy • CT useful for monitoring• Active parenchymal brain cysts and subarachnoid (racemose) cysts : albendazole
• Albendazole also effective against ocular cysticercosis
• Alternative drug : praziquantel less effective
![Page 16: Platyhelminths : Cestodes](https://reader036.vdocuments.us/reader036/viewer/2022062309/56813942550346895da0dcd2/html5/thumbnails/16.jpg)
Control : Taenia solium
• Freezing and appropriate cooking of pork
• Identification and treatment of Taenia carriers (mass treatment ?)
• Improved health education, prevention of vegetables irrigated with contaminated water
• Confinement of pigs• Porcine vaccine