Tapeworms – Microbiology – Flashcards
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Unlock answers| What are the two orders of tapeworms? |
True:Cyclophyllidea False: Pseudophyllidea |
| Cestoidea |
| Tapeworms! |
| Where are adult cestodes found? |
| SMALL INTESTINE!!! |
| Is the cestode life cycle direct or indirect? |
Indirect! Intermediate hosts can be vertebrates or invertebrates |
| Another name for tapeworm larva |
| Metacestode |
| How is the definitive host infected with a cestode infection? |
| By ingesting the intermediate host containing the metacestode |
| Each Metacestode stage contains at least one of these that develops into the tapeworm. |
| Scolex (or scolices) |
| Which metacestode has a single scolex in a liquid filled bladder? |
Cysticercus Ex Taenia |
| Which have a cysticercoid? |
| Dipylidium |
| What's an example of a species with a strobilocercus? |
| Taenia |
| Which metacestode contains more that one scolex but not thousands |
Coenurus Ex Multiceps spp |
| Which metacestode has a fluid filled bubble with thaounsads of scolices? |
Hydatid cyst Ex. Echinococcus granulosus |
| Scolex |
| Head |
| Strobila |
| body |
| Which tapeworms have a scolex? |
| True tapeworms (order Cyclophyllidea) |
| What does the final scolex consist of? |
4 radially dispersed muscular suckers Rostellum (can be armed w/ hooks or unarmed) |
| What do Pseudophyllidea have in place of the suckers? |
| Bothria- longitudinal grooves |
| Repeating segments of a tapeworm |
| Proglottids |
| Each proglottid contains which reproductive systems |
| Male and Female |
| Aside from reproductive organs, what else do the proglottids contain? |
| Excretory structures and nerve cords |
| How does the tapeworm absorb nutrients? |
| Through the integument |
| How do true tapeworms produce eggs? |
Do not lay or deposit!! Gravid segments break off from tapeworm and exit host in feces |
| The gravid segment of true tapeworms can break apart where? |
| Lower intestinal tract or in the environment |
| What is within a mature Cestode egg? |
First stage larva called a hexacanth embryo *plus two membranes |
| How long until the hexacanth embryo is infective for the intermediate host? |
| Immediately!!! |
| Describe a pseudophyllidea egg |
| Operculated (has a cap on the end) |
| What does a pseudophyllidea egg contain? |
| Ciliated larva called a coracidium |
| How does pseudophyllidea lay its eggs? |
| Through a uterine pore |
| Dipylidium caninum |
| Double pored tapeworm |
| What speices is Dipylidium caninum found in? |
| Dog, cat, fox. Most common tapeworm found in dogs and cats |
| Why is Dipylidium caninum called the double pore tapeworm? |
| It has two vaginal pores. |
| What order does Dipylidium caninum belong to? |
| Cyclophyllidea |
| How large does Dipylidium caninum get? |
| Up to 50 cm |
| Describe the proglottids of Dipylidium caninum |
Genital pores open laterally on either side Eggs are in egg packets Mature and gravid proglottids have a cucumber seed appearance |
| Describe Dipylidium caninum rostellum |
| Retractable with hooks |
| What are Dipylidium caninum egg packets eaten by? |
Flea larvae Rarely biting lice |
| What does the hexacanth embryo develop into in Dipylidium caninum |
| Develops into a cysticercoid in the flea as flea develops from larva-pupa-adult |
| How does a definitve host become infected in Dipylidium caninum |
When it eats an infected flea Adults develop in small intestine |
| What is the PPP of Dipylidium caninum |
| 2-3 weeks |
| Pathology of Dipylidium caninum |
Usually minimal, possible emaciation blockage in heavy infections is possible |
| Clinical signs of Dipylidium caninum |
Emaciation in severe infections Abdominal discomfort, convulsion, nervous disorder (rare) "scooting" but probably unrelated |
| Diagnosis of Dipylidium caninum |
Gravid segments around anus or in hair coat Fresh look like cucumber seeds, Dry look like rice grains Egg packets in fecal exam (vary from 150-200 um) |
| Treatment and control of Dipylidium caninum |
Praziquantel (Droncit) Epsiprantel (Cestex) ; Treat fleas!!! |
| Is Dipylidium caninum zoonotic? |
| Children have rarely become infected by ingesting fleas |
| What is the definitive host of members of the family Taeniidae? |
| Dogs and cats |
| What eggs do members of Taeniidae produce? |
| Taenia-type eggs |
| What are the two species we study in the family taeniidae? |
Taenia Echinococcus |
| What are the metacestodes seen in Taenia spp? |
| Cysticercus, Strobilocercus, Coenurus |
| What are the metacestodes seen in Echinococcus spp? |
| Hydatid cyst |
Taenia Pisiformis Definitive Host: Metacestode: Intermediate host: Location in IH: |
D: Dog M: Cysticercus IH: Rabbit L: Peritoneal cavity |
Taenia hydatigena Definitive Host: Metacestode: Intermediate host: Location in IH: |
Definitive Host: Dog ; Metacestode: Cysticercus ; Intermediate host: Cattle, sheep, deer ; Location in IH: Peritoneal cavity ; |
Taenia ovis Definitive Host: ; Metacestode: ; Intermediate host: ; Location in IH: ; |
Definitive Host: Dog ; Metacestode: Cysticercus ; Intermediate host: Sheep ; Location in IH: Muscle ; |
Taenia taeniaformis Definitive Host: ; Metacestode: ; Intermediate host: ; Location in IH: ; |
Definitive Host: Cat ; Metacestode: Strobilocercus ; Intermediate host: Rodents ; Location in IH: Liver ; |
Taenia serialis Definitive Host: ; Metacestode: ; Intermediate host: ; Location in IH: ; |
Definitive Host: Dog ; Metacestode: Coenurus ; Intermediate host: Rabbit ; Location in IH: CT ; |
Taenia multiceps Definitive Host: ; Metacestode: ; Intermediate host: ; Location in IH: ; |
Definitive Host: Dog ; Metacestode: Coenurus ; Intermediate host: Sheep ; Location in IH: Brain ; |
Echinococcus granulosus Definitive Host: ; Metacestode: ; Intermediate host: ; Location in IH: ; |
Definitive Host: Dog, cat, fox ; Metacestode: Unilocular hydatid cyst ; Intermediate host: Sheep, humans ; Location in IH: Lung, liver ; |
Echinococcus multilocularis Definitive Host: ; Metacestode: ; Intermediate host: ; Location in IH: ; |
Definitive Host: Dog, cat, fox ; Metacestode: Alveolar hydatid cyst ; Intermediate host: Mice, voles, humans ; Location in IH: Lung, liver, other organs ; |
| How many genital pores are seen in taenids? |
| Just one single marginal genital pore |
| How are eggs released in taenids? |
| Gravid segments break off and hexacanth embryos inside eggs are immediately infective for IH |
Length of taenids? Description of head? Size of eggs? |
Few centimeters to several meters Scolex with armed rostellum Eggs brownish and about 40 um |
| Metacestode with one invaginated scolex and a bladder |
| Cysticercus |
| Metacestode that is a cysticercus that has begun to elongate and segment while in the IH |
| Strobilocerucs (Taenia taeniaformis) |
| A metacestode with a single bladder with many scolices |
| Coenurus |
| A metacestode consisting of a fluid filled cyst containing hundreds to thousands of scolices surrounded by a thickened membrane |
| Hydatid cyst (Echinococcus spp) |
| Life cycle of Taeniids |
Gravid segment passed in feces, break open in intestine or passed intact Egg ingested by IH, hexacanth embryo liberated in SI Migrates through mucosa to the bloodstream, carried to various organs Develops in 2-3 months into a specific metacestode Definitive host is infected by ingesting the metacestode Metacestode released during digestion and matures in SI ; |
| PPP of Taeniids |
| 2-3 months |
| Pathology of Taeniids |
| typically no problems unless heavy infections |
| Pathology of the larval stages of taeniids |
Can cause severe disease typically causes physiological or nurological damage to IH |
| Clinical signs of Taeniids |
No definite signs with adults Heavy infection may cause obstruction ; |
| Diagnosis of Taenias |
Segments in feces Eggs may be seen if proglottids disintegrate in gut Fecal flotation History of predation |
| Treatment for taenia type tapeworms |
Fenbendazole Praziquantel Epsiprantel |
| Control of taenia type tapeworms |
Regular anthelmintic treatment Destroy cysticerci from slaughtered animals, keep pets away from carcasses Cook meat! |
| Are taenia type tapeworms zoonotic? |
Yes! Hydatid disease and Alveolar hydatid disease Caused by Echinococcus granulosus Echinococcus multilocularis (very small tapeworms) |
| Hydatid disease |
Multilocular cysts contain hundreds to thousands of scolices develop in liver, lungs and other organs of the IH Multilocular cysts are highly invasive in tissues of the IH, may mimick malignant metastatic tumors Humans can be the IH and get the cysts in liver and lungs, brain and other organs |
| Hosts of Mesocestoides |
| Dogs, coyotes, raccoons, foxes, cats |
| Geographic distribution of Mesocestoides |
| Widely distributed but uncommon |
Morphology of Mesocestoides Scolex: |
| 4 suckers but no hooks |
Mesocestoides pouch of uterus where eggs are stored What does this organ contain? |
Paruterine organ Hexacanth embryos |
| Size of eggs of Mesocestoides |
23 x 18 um Thin shelled and hyaline in appearance |
| What is unique about the life cycle of Mesocestoides |
| Two IH are required |
| IH 1 of Mesocestoides |
| Oribatid mite or dung beetle |
| IH 2 of Mesocestoides |
| Amphibians, reptiles, birds, mammals |
| What does the metacestode of Mesocestoides look like in the 2nd IH? |
| Tetrathyridium found in serous cavities |
| Description of tetrathyridia |
Flattened with invaginated scolex with four suckers asexual multiplication infective for DH |
| How long after the 2nd IH is ingested does the tapeworm mature? |
| Within two weeks |
| Pathology of Mesocestoides |
INtestinal infections usually non-pathogenic Tetrathyridial infections in dogs and cats can cause peritonitis |
| Clinical signs from adult Mesocestoides |
Usually none anorexia Loose, mucoid stools w/ tapeworm segments |
| Clinical signs of Tetrathyridia in Mesocestoides |
Anorexia and weight loss depression fever emesis and diarrhea abdominal distension |
| Diagnosis of Mesocestoides |
Usually observe motile segments in stools or from around perineum demonstration of tetrathyridia in abominal effusion recover eggs in fecal (rarely ascites; distended fluid filled abdomen |
| Treatment and Control of Mesocestoides |
Praziquantel Fenbendazole |
| Diphyllobothrium latum |
| Broad fish tapeworm |
| Hosts of Diphyllobothrium latum |
| Dog, fox, humans |
| Geographic Distribution of Diphyllobothrium latum |
| Great lakes, central canada and alaska |
| Order for Diphyllobothrium latum |
| Pseudophyllidea |
| IH of Diphyllobothrium latum |
| Aquatic invertebrates and vertebrates |
| How are eggs passed in Diphyllobothrium latum |
| Uterine pore |
| Morphology of Diphyllobothrium latum |
Large (several meters 10+) Scolex elongated with two bothria (no suckers or hooks) |
| Eggs of Diphyllobothrium latum |
| Operculate, 65 x 40 uM |
| Life cycle of Diphyllobothrium latum |
Operculate eggs escape intestine and it reaches water a ciliated larva (coracidium) will hatch Swimming Coracidium ingested by aquatic crustacean develops into a procercoid w/in body of copepod in 2-3 weeks |
| First IH of Diphyllobothrium latum |
| Copepod (aquatic crustacean) |
| Life cycle of Diphyllobothrium latum after 1IH |
Crustacean eaten by a fish and a plerocercoid develops in the fish musculature Definitive host eats raw or badly cooked fish |
| PPP of Diphyllobothrium latum |
| 2-6 weeks |
| Pathology of Diphyllobothrium latum |
| Adult worm not very pathogenic in dogs |
| Clinical signs of Diphyllobothrium latum |
| Usually none |
| Diagnosis of Diphyllobothrium latum |
Fecal sedimation ID operculated egg (don't confuse with Trematode egg!) Egg's don't float well 65x40 uM |
| Treatment of Diphyllobothrium latum |
Praziquantel (droncit) Cook fish! |
| Is Diphyllobothrium latum zoonotic? |
| Yup. Anemia, diarrhea, constipation |
