Introduction of Cestodes Diphyllobotrium latum Sparganosis Taenia spp. (317221 inter) Asst. Prof. Dr. Atiporn Saeung
Additional Readings น ม ตร มรกต, เกต ร ตน ส ขว จน, บรรณาธ การ.ปรส ตว ทยาทางการแพทย โปรโตซ วและ หนอนพยาธ.พ มพ คร งท 2. เช ยงใหม : คณะแพทยศาสตร มหาว ทยาล ยเช ยงใหม, 2546. น ม ตร มรกต, คม ส คนธสรรพ, บรรณาธ การ. ปรส ตว ทยาทางการแพทย II. หนอนพยาธ. พ มพ คร งท 3. เช ยงใหม : คณะแพทยศาสตร มหาว ทยาล ยเช ยงใหม, 2554. Markell EK, Voge M, John DT. Medical parasitology. 8 th ed. Philadelphia: W.B. Saunder; 1999. Muller R. Worms and Human Disease. 2 nd ed. Wallingford: CABI; 2002. Roberts LS, Janovy J Jr, Nadler S. Gerald D. Schmidt & Larry S. Roberts' Foundations of Parasitology. 9 th ed. New York: McGraw-Hill; 2013. http://www.med.cmu.ac.th/dept/parasite/image.htm
Objectives Be able to explain characters of cestodes Be able to explain life cycle, clinical manifestation, diagnosis, prevention and treatment of diphyllobothriasis, sparganosis, taeniasis and cysticercosis
General morphology of cestodes Ribbon-like, multisegmented, hermaphrodite Scolex (head): situated on the neck - equipped with adhesive organs (grooves or suckers with/without rostellum)
(contained viable embryonated eggs) Neck: germinative portion Strobila: chain of proglottid Immature -> Mature proglottid Mature-> Gravid proglottid -> Eggs
No digestive system (food absorbed through tegument) Reproductive system: - not formed in anteroir ploglottid - well-developed in posterior ploglottid Excretory system : - dorsal, ventral, transverse nephridial canals, finally open at posterior end of last ploglottid Nervous system : - R & L longitudinal nerve cords araise from nerve rings (at scolex) and pass posteriorly along the ploglottid
Scolex Immature Mature Gravid proglottid
Medical important Tapeworm 1. Order Pseudophyllidea - Diphyllobothrium latum - Spirometra spp. 2. Order Cyclophyllidea - Family Taeniidae: Taenia solium, T. saginata, Echinococcus granulosus, E. multicularis - Family Hymenolepiddidae: Hymenolepis nana, H. diminuta - Family Dilepididae: Dipylidium caninum
Scolex Pseudophyllidea spoon-like 2 longitudinal grooves bothria Cyclophyllidea round or square sucker w or w/o rostellum (w/o hookltes)
Pseudophyllidea Cyclophyllidea Genital pore & uterine pore G U G ventral lateral
Pseudophyllidea Cyclophyllidea egg operculum no embryo No operculum embryo (hexacanth onchosphere)
Life cycle Adult worms (in small intestine of Definitive host) Ingestion Larval stages (in intermediate hosts) Eggs (in feces) Tapeworms are heteroxenous, except Hymenolepis nana
[ DH ] ADULT LC of Pseudophyllidea IF PLEROCERCOID [ 2nd IH ] PROCERCOID EGG [Immature] water CORACIDIUM [ 1st IH ] (ciliated oncosphere)
[DH] ADULT EGG mature IF METACESTODES [IH] 4 Types ( ~ spp.) Cysticercus, Cysticercoid, Coenurus, Hydatid Cyst LC of Cyclophyllidea (hexacanth embryo or oncosphere)
Larvae of Pseudophyllidea worms Procercoid - long body with hooks at the knob-liked posterior end Plerocercoid - wrinkled, ribbon-liked - pseudosucker likes bothria - unsegmented strobila - no internal organ
cysticercus Larvae of Cyclophyllidea worms - fluid filled, oval bladder - transparent, thin-walled - inside : scolex cysticercoid - like cysticercus but no fluid - has a tail - inside : scolex
Larvae of Cyclophyllidea worms coenurus - white, semi-transparent bladder - filled with clear, watery fluid - budding of protoscolices from geminative membrane of the cyst
Larvae of Cyclophyllidea worms
Pseudophyllidea Diphyllobothrium latum Spirometra spp.
Diphyllobothrium latum Common name: 10 meters long broad or fish tapeworm The longest human tapeworm Disease: Diphyllobothriasis Habitat: small intestine of man and fish-eating mammals
Distribution - Northern hemisphere (Europe, USA, Asia) - Uganda, Chile - High prevalence: Finland, Sweden, Lithuania - In Asia: Japan, Taiwan, Philippines - No report in Thailand - Transmitted by Salmon, burbot, trout, and pike fish
Morphology Scolex: - elongated 1x3 mm. (spoon-like) - 2 shallow, longitudinal grooves (bothria)
Morphology Proglottids: - width > length - genital pore at center - coiled uterus is rosette in appearance
Morphology Egg: - Oval or ellipsoidal - Size: 65 x 45 µm. - yellow-brown color - an operculum (lid) - a small knob
Life cycle Complex life cycle DH: Fish-eating mammals (Dogs, cats, bears, etc.) 1 st IH: Copepods 2 nd IH: Small freshwater fish Paratenic host: Large predator fish (pike, perch, trout) Prepatent period ~ 5-6 wks
Procercoid in copepod Plerocercoid in fish
Clinical features Asymptomatic, long-lasting infection Abdominal discomfort, diarrhea, vomiting, weight loss and weakness Vitamin B12 deficiency -> pernicious anemia Massive infection -> intestinal obstruction
Diagnosis, treatment and prevention Eggs or proglottids in stool Praziquantel, niclosamide Cooked fish Freeze -18 0 C, 1-2 days
Spirometra spp. Plerocercoid of Spirometra spp., so called sparganum Sparganosis: larval tapeworm infection of man DH : dogs and cats (adults) 1 st IH : copepods (procercoid) 2 nd IH : frogs, snakes (plerocercoid)
Epidemiology Found in most parts of the world Most human cases in China, Korea, Japan, Taiwan and Southeast Asia
Morphology Mature ploglottid Egg Similar as D. latum exception: coiled uterus (spring-like) Similar as D. latum
Sparganum (Plerocercoid) wrinkled, ribbon-like, ivory larva with 60-100 x 0.5-0.6 cm in size pseudosegmented, no internal organ movement: contraction and elongation found in human tissue (AH)
DH 2 nd IH AH 1 st IH
Plerocercoid in snake
Transmission to human 3 major routes: 1. Drinking untreated water (copepods infected with procercoid ) 2. Consuming uncooked meat (snake, frog, etc. infected with plerocercoid 3. poultices as folklore medicine (placing frog/snake flesh on wounds/eyes common in Asian cultures)
Sparganosis
Clinical manifestations Mostly infect to subcutaneous tissues, visceral organs, eyes, lung, brain (seizures, paresthesia) Asymptomatic in early migratory stage At final site: edematous, painful inflammation around tissue (nodule 1-2 cm. in diameter)
Diagnosis CT scan or MRI (to localize the lesions) Surgical removing (definitive diagnosis) Serodiagnosis: ELISA (cerebral sparganosis)
Treatment Surgical removal of sparganum larvae Praziquantel 120-150 mg/kg, over 2 days
Sparganosis of the breast Nodular fibrofatty tissue and sparganum
Ocular sparganosis sparganum
Common name Taenia solium: Pork tapeworm Taenia saginata: Beef tapeworm
Geographical distribution Worldwide distribution T. solium is rare in muslim countries In Thailand, both species exist, but T. saginata prevalence is much higher than that of T. solium
Morphology Size: Rostellum: Tape-liked with 7-14 mm x 1.5-12 m with /without
Morphology (cont.) Taenia solium Taenia saginata Scolex Rostellum/hooklets No rostellum
Morphology (cont.) Taenia solium Taenia saginata mature proglottid - Ovary gravid proglottid * - lateral uterine branches trilobed 7-12 branches bilobed 18-32 branches *
Gravid proglottid Taenia solium Taenia saginata
Taenia egg * can not be differrentiated - Spherical shape - Walnut-brown in color - Egg shell: thick and radially striated embryophore - Contains hexacanth oncosphere inside
IF DH IH
Larval stage = Cysticercus - Thin- walled, transparent - round or oval white bladder - Diameter 5-8 mm. - Liquid inside Cysticercus bovis* Cysticercus cellulosae* => Taenia saginata => Taenia solium
Larval Stage = Cysticercus Cysticercus cellulosae Cysticercus bovis in pork in Beef
Diseases & Symptoms Taeniasis caused by adult worm - Taeniasis saginata /solium - no specific symptoms (abdominal discomfort, hunger pain, headache, etc.) - heavy infection (bowel obstruction, appendicitis, cholecystitis) Cysticercosis* caused by larva stage (cysticercus) - more severe symptoms - Caused by T. solium
Cysticercosis Having cysticerci of T. solium in internal organs (brain, muscle, eyes, etc.) Neurocysticercosis : the most severe form headache epilepsy nausea vomiting
Cerebral cysticercosis CROSS SECTION
Causes of Cysticercosis 1. Eating of food contaminated with T. solium eggs 2. Autoinfection within patients themselves - Internal autoinfection regurgitation of gravid proglottids of T. solium up to the stomach - External autoinfection fecal-oral infection with T. solium eggs
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Diagnosis for taeniasis Stool examination Egg (species can t be identified) Gravid Segment - uterine branches Scolex - Rostellum, Hooks Mature Segment - Reproductive organs: no. of ovary lobes
Diagnosis for cysticercosis Brain imaging (to detect calcified cysticerci) - X-ray - CT - MRI (magnetic resonance imaging) Biopsy Serological diagnosis - confirmation test: electroimmunotransfer blot (EITB)
CT scan MRI
X-ray
Treatment Taeniasis - Praziquantel (T. solium), niclosamide (T. saginata) - Single dose of 5-10 mg/kg Cysticercosis: varies depending on type of disease - Albendazole + steroid - Praziquantel - Surgery for cysticerci
Prevention Taeniasis - Consuming cooked meat - freezing meat at -5 C, 5 days Cysticercosis - good hygiene - public health education