A General characteristics B Parts of cestodes C Phenomena in platyhelminthes PDF

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SY 2020-2 ND SEMESTERBS-MLSPARASITOLOGYLE 5 DEAN JULIUS T. CAPILI RMT, MPH, PhD, DPASMAPPHYLUM PLATYHEMINTHESOUTLINE I Phylum platyhelminthes A General characteristics B Parts of cestodes C Phenomena in platyhelminthes II. Cestodes A. Orders of cestodes B. Pesudophyllidean vs Cyclophyllidean III. Di...

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PARASITOLOGY DEAN JULIUS T. CAPILI RMT, MPH, PhD, DPASMAP

SY 2020-2021 2ND SEMESTER BS-MLS

PHYLUM PLATYHEMINTHES OUTLINE Phylum platyhelminthes A General characteristics B Parts of cestodes C Phenomena in platyhelminthes

I

II. Cestodes A. Orders of cestodes B. Pesudophyllidean vs Cyclophyllidean III. Diphyllobothrium latum IV. Taenia spp. A. Taenia saginata B. Taenia solium V. Hymenolepis spp. A. Hymenolepis nana B. Hymenolepis diminuta

PHYLUM PLATYHELMINTHES 

flat worms because they are compressed

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Bilaterally symmetrical o Adult nematodes are also bilaterally symmetrical o Bilaterally symmetrical- when you divide the parasites into two equal halves, right and left margins will be similar in terms of the organ which are present in it and the location of the organs o Difference would be platyhelminthes don’t have body cavities unlike nematodes Compressed/flattened dorsoventrally Lack body cavities Includes: o Class turbellaria (free-living) Not parasitic/pathogenic Ex: Bathrooms of rural communities; Ilad-ilad o Class trematoda (flukes) Has 1 segment – hence it is called fluke Unsegmented o Class cestoda (tapeworms) Very long parasites Would have different segments Segments are described to be proglottids

GENERAL CHARACTERISTICS

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PARTS OF CESTODES  

Plenty of segments Scolex – head of the parasites o Has ventral suckers or will contain acetabulum o 4 ventral suckers o 1 acetabulum Scolex can be armed or unarmed o

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Armed – has rostellum where hooklets are attached Hod-fast organs – allow them to attach to the intestinal mucosa  T. solium, H. nana Unarmed- no rostellum  T. saginata, H. diminuta

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Bothrium –ventral suckers Neck – region for growth o Tends to produce more segments Segments/proglottids o basis of categorizing segments is the maturity of the sex organs o Cestodes/ trematodes are hermaphroditic o Hermaphroditic- both sexes in one segment TYPES OF SEGMENTS: Immature segment – immature organs o Attached nearest to the neck Mature segment – mature organs o Middle of the parasite Gravid segment/ Fertile proglottids – cannot see sex organs but only gravid uterine branches o Towards the end of. The parasite Strobila – complete chain of the segment o – first immature segment until the last gravid segment

PHENOMENA IN PLATYHELMINTHES 

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Protandry – simultaneous maturation of the male and female sex organs, o Male organs mature 2 weeks earlier compared to female organs Hermaphrodicity – each segment having both female and male organs o Nematodes are not hermaphrodite Craspedotry o Ability of parasite to overlap o Diphyllobothrium latum – longest cestodes o platyhelminthes – about 13 meters long  Their segments overlap  Has more than 2000 segments o Long parasites exhibit craspedotry Acraspedot o Echinococcus granulosus – don’t overlap because it has only three segments (one immature, one mature, one gravid)

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PHYLUM PLATYHELMINTHES 

Apolysis – normal detachment of the gravid proglottid(last segment) o Parasites, as they exhibit apolysis – last segment would normally have to detach o Purpose of detachment: for ova dissemination o Some parasites don’t exhibit apolysis  Diphyllobothrium latum- facilitated apolysis  As the adult parasite travel around the body, maiipit sila sa isang part ng katawan then mahihila or maiipit or mapupunit yung segment

CESTODES (TAPE WORMS) Long parasites Living worms are white and yellowish in color, adult is flat and ribbon-like  Body consists of scolex, neck, and proglottids Question: How would you effectively eradicate a cestode in the body or successful recovery? Answer: When the scolex is recovered (coil it out)  

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Species that require vertebrate intermediate host (Taenia spp.) Species that require invertebrate host (D. caninum) Species that may or may not require intermediate host (H. nana)

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Diagnosis  Example: 1 segment Check for:  Genital pore o For pseudophyllidean: found at the center of the segment  Diphyllobothrium latum -only pseudophyllidean parasite  If genital pore is located in the sides of a segment: o Any of the cylophyllideans  If genital pores are alternating – 1st segment left 2 nd segment right and so on tapos nasa middle ng height o Taenia spp. o Kapag eichinococcus nasa top pero alternating parin  If genital pore is in 1 side of the parasite – lahat nasa left or lahat nasa right (unilateral pattern) o Hymenolepis spp. (H. nana/ H. diminuta)  Genital pores on both sides – present in left and right o Dipylidium caninum

DIFFERENCE BETWEEN PSEUDOPHYLLIDEA AND CYCLOPHYLLIDEA

ORDERS OF CESTODES 

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Order Pseudophyllidea (False tapeworms) o False tapeworm because of the absence of uterine pore  Example: Diphyllobothrium latum Order Cyclophyllidea (True tapeworms) o It has uterine pore

Difference

Scolex:  Pseudophyllidean – 1 midventral and 1 mid-dorsal sucking groove (acetabulum) o Shape: elongated, almond, spoon-shaped  T. solium (armed parasite)  Cyclophyllidean – 4 muscular cup-like suckers (bothrium)  T. saginata (unarmed parasite)  Neck – region for growth  Segments/proglottids o Strobila – complete set of proglottids o Pseudophyllidean – broader than long (width is longer than its height) o Cyclophyllidean – longer than broad (length is longer than its width)  Lateral uterine branches – indicator of gravid proglottid o Proglottid that will have to exhibit apolysis *count the lateral uterine branches for species identification Number of uteline branches:  7-13 – Taenia solium or Hymenolepis nana  14 and above- Taenia saginata and Hymenolepis diminuta  Count the main branch  After you identify if 7-13 or 14 and above, malalaman mo from 4 choices to 2 so hanap ka na ng ova o Look for the ova of the parasite in the stool sample

AMAN, MALUPENG, MELAD, VENTURINA

Compression technique – get 1 slide o Rule: choose 1 side of the parasite where you believe there are more of uterine branches – either top or bottom

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Pseudophyllidean

Cyclophyllidean

Scolex

Spoon-shaped w/ slit-like sucking grooves (bothria) and no hooklets

Quadrate with 4 cuplike suckers (rostellum) with or without hooklets

Strobila

Anapolytic (no sheeding of segments)

Apolytic (shedding of segments)

Ova

Oval, operculated, immature/ unembryonated

Spherical, nonoperculated, mature/ embryonated (jexacanth

Larval stages

Coracidium— procercoid-plerocercoid

Cysticeroid (Dipyllidium & Hymenolepis) Cysticercus (Taenia) Hydatid (Echinococcus)

Operculum- part of the ova that normally opens to liberate the plerocercoid (laman ng ova) Opposite of operculum the thick structure is the abopercular knob Rim – where the operculum attaches to ova Middle part is the body of the ova 2

PHYLUM PLATYHELMINTHES   

Immature ova- contains granules Mature ova- lacks granules Hexacanth embryo – have 6 hooklets

Question: How many adults will emanate from a coracidium? (D. latum) Answer: One since it’s a solid type larva Question: How many parasites will emanate from a cystic type of a larva Answer: it depends From cysticercus to cysticercoid – Answer: 1  Taenia and hyminelopis spp From hydatid cyst – 4 From conyorous – more than 30

DIPHYLLOBOTHRIUM LATUM 

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PSEUDOPHYLLIDEAN Life cycle (Diphyllobothrium latum)  Ova (immature and unembryonated when laid) in water develops coracidium (embryo with ciliated epithelium) – looks like sea urchin  Coracidium is Ingested by 1st intermediate host (Sparganum/ copepod/ small shrimp- stage is procercoid – solid type of a larva)  Procercoid in the flesh of the sparganum is ingested by 2nd IH – broad fish hence the common name for D. latum is broad fish tapeworm–  stage matures into plerocercoid(elongated and still solid state of a larva)  When plerocercoid is ingested by man (DH) – it will turn into an adult parasite –(adult is hermaphroditic so it can fertilize itself)

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Broad tapeworm or fish tapeworm or broad fish tapeworm o Broad because segment is broader than long o Fish because the 2nd IH is fish  Examples of broad fish – Imelda, dalag, hito, bangus, tilapia Largest tapeworm of man – extend 10.5 to 13 m long – more than 2,000 segments Adult parasite resembles spirometra Only Pseudophyllidean parasite Scolex is spatulate/ spoon shaped/ almond shaped with sucking organ referred as bothrium Uterus with characteristic rosette (flower shaped) formation o 1st IH are copepods (sparganum)- small shrip o 2nd IH are freshwater fish Disease caused – tapeworm anemia, vit b12 deficiency, megaloblastic anemia Megaloblastic anemia-RBCs are macrocytic (bigger than normal size) and hyperchromic (darker than normal color) o Folic acid deficiency- not a disease associated to D. latum o runs secondary because of vit b12 deficiency Stool exam will not show segments, eggs resemble that of Paragonimus westermani D. latum is non apolytic- there is no normal detachment of gravid Sedimentation procedures are done, never flotation techniques

CYCLOPHYLLIDEANS GENUS TAENIA AND GENUS HYMINELOPIS        

bladder like larva/cystic Ova is expelled by person who harbors the parasite Doesn’t require water Ova turns to be a hexacanth embryo/ onchosphere (contains 6 hooklets inside) If oncosphere is ingested by the 1 st IH it will turn into a cysticercus If cysticercus is ingested by 2nd IH – it will turn into cysticercoid And when ingested by the man it will become an adult parasite 2 parasites: Genus taenia (saginata at solium) and Genus Hyminelopis(nana and diminuta)

ECHINOCOCCUS GRANULO SUS       

Ova turns to be a hexacanth embryo/ onchosphere (contains 6 hooklets inside) Ingested by the IH it becomes a hydatid cyst it will turn to hydatid sand Once ingested by DH (man) turns as hydatid adult Other parasite: (Railientina garrisoni) Ova turns to be a hexacanth embryo/ onchosphere (contains 6 hooklelts inside) Turns into coenurus after ingested by 1st IH Ingested by DH (man) turns into adult

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Diphyllobothrium latum eggs  

Have granules inside that are immature when laid The granules mimic the operculum , that’s why it looks like an Ascaris egg

TAENIA SPECIES Points of difference Common Name Intermediate Host Scolex

Taenia saginata Beef tapeworm Cattle

Length No. proglottids

25 meters 1000-2000

of

None, no rostellar hooks

Taenia solium Pork tapeworm Pig With rostellum, armed with 2 rows of large and small hooklets 7 meters Less than 1000

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PHYLUM PLATYHELMINTHES Gravid proglottids

Egg (Hexacanth)

Larva Infective stage Pathogenesis

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15-20 lateral branches (dichotomous or tree-like) Spherical, striated, inside is an embryo with 6 hooklets Cysticercus bovis Cysticercus bovis Taeniasis saginata (obstruction)

7-13 lateral branches (dendritic/fingerlike) Spherical, striated, inside is an embryo with 6 hooklets

TAENIA SOLIUM     

Cysticercus cellulosae Cysticercus cellulosae/ egg Taeniasis solium (Cystecercosis)

Parasites are irritated with bouts alcohol, they would have to get out of the human body Taenia spp are too long – 10 m long Dapat mabilis ang pag hugot Habang cinocoil out pwedeng ma cut sila (when coughing) Dapat marecover mo ang scolex dahil pag hindi, tutubo nang tutubo ang parasite Condition when performing the coiling out of cestodes should be humid (warm may vapor, so magpakulo ka ng tubig) Habang kinocoil out para mag open yung anus

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Armed scolex -1 huge crown and 1 small crown Finger-like lateral branches More serious and solium na may IS ng cysticercus cellulosae – pwede mag migrate Can invade hollow organs of the body Ova will appear the same with radial striation, “sunlike” ova o Only difference is size o Saginata is bigger by 5 um than solium If you are going to see an ova appearing like that of Taenia and not sure if what specie, report it as positive for Taenia ova Praziquantel – gold standard treatment of platyhelminthes Not over the counter product Only distributed by DOH Larva of solium and saginata will emanate from hexacanth embryo/ oncosphere Will become cysticercus then cysticercoid Taeniasis- ova of Taenia is seen in stool Cysticercosis- encysted larva (cysticercoid) in hollow organs of the body Cysticerrcus cellulosae- more serious complication o Larva can migrate and would have to infect other organs

T. saginata- beef tapeworm bec IH are cows/cattles Question: Which Taenia parasites are recovered from monkeys, roosters, rabbits? Answer: T. saginata T. solium- specific for pigs

TAENIA SAGINATA     

Unarmed scolex 14 - >35 lateral branches Tree-like lateral branches Do not migrate in other parts of the body Will only bring about obstruction in large or small intestines

Taenia saginata ovum

Taenia saginata 

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has 4 muscular cup-like suckers (2 anterior and 2 posterior) that functions for the attachment of the parasite Cyclophyllidea unarmed because it does not have hooklets

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bigger than solium by 5um

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Taenia solium or Sun-like ova with radial striations at the side

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PHYLUM PLATYHELMINTHES

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Scolex of Taenia solium crowned and armed parasite

Taenia solium because of alternating genital pore pattern and armed strobella 1. Immature Proglottid 2. Mature Proglottid – where the cestode structure is appreciated because of genital pores 3. Gravid Proglottid – no more sex organs, but rather the lateral branches 

Taenia solium (crowned with 2 rows of large and small hooklets)

Cyclophyllidean Cestodes’ bodies become bigger as they get farther from the neck DETERMINANT OF CYCLOPHYLLIDEAN:  

armed or unarmed, but always crowned with 4 muscular suckers segments are longer than broad

HYMENOLEPIS SPP Taenia  

Cyclophyllidean parasites are longer than broad Pseudophyllidean are broader than long) Common name Egg

Segment of Taenia saginata 

16 or more branches Scolex

Infective stage

Intermediate Host

Segment of Taenia solium  

7-14 branches Seen inside are gravid uterine branches that indicate that the segments are gravid proglottids o Uterine branches indicate a fertile proglottid o Lateral branches: helps in specie identification AMAN, MALUPENG, MELAD, VENTURINA

Hyemenolepis nana Dwarf tapeworm Eggs contain an oncosphere enclosed in an inner membrane with two polar thickenings, from each of which arise 4-8 polar filaments With rostellum armed with a ring of 20-30 spines Eggs (direct life cycle) Cysticeroid (indirect life cycle) Does not require an intermediate host to complete its life cycle, however, insects may act as an intermediate

Hyemenolepis diminuta Rat tapeworm Eggs contain an oncosphere in an inner membrane with two polar thickenings but without filaments (sunny-side up eggs) With unarmed rostellum

Cysticeroid larva

Insects

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PHYLUM PLATYHELMINTHES

Definitive host

host in some occasions Man

Rats Rats)

(Norway.

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Common name of cestodes are taken from their intermediate host

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Intermediate Host: rat flea Has bigger ova then H. nana Definitive Host – Rats Unarmed scolex 800-1000 segments Sunnyside up ova – H. diminuta and A. lumbricoides ova 3 layers ova o Outer layer – more heterogenous o Middle layer – intralaminar layer/space o Clear/laminar space

HYMENOLEPIS DIMINUTA

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Hymenolepis scolex

Cysticercoid

Hymenolepis diminuta eggs 

Has hooklets inside

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Does not have intermediate host most of the time o Flour beetles as well as cockroaches as intermediate host can be I.H Dwarf tapeworm because the ova and adult parasite is shorter than H. diminuta Inside ova is more granulated consistency compared to the outer layer Has 2 polar filaments Has 2 layers o More heterogenous inner layer o Homogenous outer layer Definitive Host - Man Length – 600 – 800 segments Armed with 1 crown

HYEMENOLEPIS NANA

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Cysticercoid that has the black neck-like feature at the left of the first image because this stage brings about the adult form

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Copulatory organ – cirrus o For nematodes – spicule Solenocytes – flame cells beating in unison important as excretory system of flatworms o Beats like cilia o Pass excretory material to the next segment o Solenosome – the system

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REFERENCES Notes from the discussion by Dean Julius T. Capili, RMT, MPH, PhD, DPASMAP

Hymenolepis nana egg 

with hooklets inside and homogenous sides

AMAN, MALUPENG, MELAD, VENTURINA

Cagayan State University PowerPoint presentation

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PHYLUM PLATYHELMINTHES

AMAN, MALUPENG, MELAD, VENTURINA

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