Cestodes

Question 1

Describe the general characteristics of Cestodes (Tapeworms).

Answer 1

-flat body
-no alimentary canal
-nutrients absorbed thru tegument
-scolex = head
-stroblia (body) w proglottids (individual repro unit)
-hermaphroditic
-indirect (1 or 2 IH)

Question 2

Describe the neck & strobila of cestodes.

Answer 2

Neck:
-germinative region & produces segments asexually
Strobila:
-immature proglottids
-mature proglottids
-gravid proglottids

Question 2

Describe the general characteristics of cestodes.

Answer 2

-adults = sm intestine
-adults = non pathogenic to definitive host (unless alot = obstruction)
-infection site of larvae (metacestodes) = diff w species
-diff types of larval stages (may be pathogenic)
-some are zoonotic

Question 2

Describe the IH of Cyclophyllidea. (picture)

Answer 2

Question 2

Compare Order Cyclophyllidea & Order Pseudophyllidea.

Answer 2

Order Cyclophyllidea
-advanced
-1 IH
-scolex, suckers, (+/-) hooks
-eggs = oncosphere w hooks
Order Pseudophyllidea
-2 IH
-scolex & bothria
-egg = oncosphere w cilia

Question 2

Describe the life cycle of cestodes. (picture)

Answer 2

Question 3

Describe the IH of Pseudophyllidea.

Answer 3

Fish & crustaceans
-dibothriocephalus latus
-spirometra spp

Question 4

Describe Dipylidium caninum.

Answer 4

‘flea tapeworms, cucumber tapeworm’ *double pore
-FH = dogs, cats, humans
-zoonotic
-IH = (arthropods) flea, louse
>larval stage (cysticercoid) in IH
-adults in sm intestine
-fresh segment in feces, around anal region, & bedding = cucumber seed
>dry = grain of rice
-fecal float (egg packet, or individual eggs)
-excessive grooming
-adhesive/scotch tape for egg packets
-treat FH w cestocide (praziquantel)
-control IH with insecticide (host + environment)
-PPP = 21 days

Question 5

Describe the life cycle of Dipylidium caninum. (picture)

Answer 5

Question 6

Describe Choanotaenia spp & Raillietina spp.

Answer 6

-domestic/wild fowl
-sm intestine
-IH = arthropods (ants, beetles, flies)
>cysticercoid
-IH eat feces of FH that has eggs -> develop into cysticercoid -> IH eaten by FH -> develop into adults in sm intestine
*Choanotaenia spp non pathogenic
*Raillientina spp = reduced growth, emaciation, weakness, decreased egg production
>heavy infection ‘nodular tapeworm disease’ = intestinal granulomas
-eggs dont float well & not diagnostic = necropsy!
-prevent IH in poultry houses

Question 7

Describe Anoplocephala perfoliata & Anoplocephala magna.

Answer 7

equine cestodes
1. A. perfoliata (common)
-4 cm
-rounded scolex, lappet
-ileocecal valve (partial occlusion)
>intussusception
>colic
*heavy infections = ulcerations, ill health
2. A. magna
-80 cm
-no lappets
-sm intestine
-less pathogenic
BOTH:
-fecal float, sediment, antigen ELISA
-irregular shape (triangular)
-embryo surrounded by pyriform apparatus
-PPP: 1-2mo
-treat w/ praziquantel
-no seasonality

Question 8

Describe Anoplocephala perfoliata & Anoplocephala magna life cycle.

Answer 8

-gravid proglottids pass in feces -> ingested by oribatid mites -> develop into cysticercoids -> IH eaten by FH

Question 9

Describe Moniezia spp.

Answer 9

‘Milk tapeworm’
-double pored
-FH = sheep, goat, cattle, other ruminants
-IH = oribatid mites
>infective cysticercoid metacestode
-PPP 1-2mo
-adults 2m
-unarmed (no hooks), scolex w 4 suckers
-segments broader, around anal, in feces = fecal float
-eggs triangle
-non pathogenic
>heavy infection = unthriftiness, GI issue in lamb/goat
-albendazole, praziquantel, niclosamide = weaning treatment

Question 10

Describe Moniezia expansa VS Moniezia benedeni.

Answer 10

Moniezia expansa = sheep, goats, triangle egg (small)
Moniezia benedeni = cattle, cube egg (larger)

Question 11

Describe Taenia spp.

Answer 11

-eggs similar (stay in environment)
>striated shell
>sm than toxocara egg
-larval stage = cysticercus
*EXCEPT T. taeniaeformis = strobilocercus
-adults in sm intestine
-non pathogenic

Question 12

Describe Taenia pisiformis.

Answer 12

-FH = dog, fox, coyote
>sm intestine
-IH = rabbit, squirrel
>cysticercus in liver & messentry
-PPP 56 d (2mo)
-scolex w nonretractable armed rostellum & 4 suckers
-strobila 2m - rectangular segment w single genital pore
>client worry of segments around anal
-not zoonotic
-non pathogenic (may be nutrient competition in malnourished host)
-praziquantel & epsiprantel

Question 13

Describe Taenia taeniaeformis.

Answer 13

-FH = cat, lynx
>sm intestine
-IH = rodents
>strobilocercus in liver
>raised pale tan foci on liver surface
-PPP 34-80d
-not zoonotic
-scolex w non retractable armed rostellum & 4 suckers
-strobila 2m - rectangular segment w single genital pore
>client worry of segments around anal
-non pathogenic (may be nutrient competition in malnourished host)
-praziquantel & epsiprantel

Question 14

Describe Taenia hydatigena.

Answer 14

-FH = canids
>sm intestine
-IH = ruminants incl pig
>cysticercus in liver, abdominal/peritoneal cavity
-no clinical signs/pathology in IH or FH
-economic losses due to meat inspection

Question 15

Describe Taenia saginata.

Answer 15

‘Beef tapeworm’
-FH = humans (ZOONOTIC)
>sm intestine
>discomfort of passing segments
-IH = bovine
>cysticercus in striated/cardiac muscle
>no clinical signs except in heavy infections w cysticerci in heart
-8m long
-unarmed scolex w 4 suckers (no hooks)
-taeniid egg
-diagnosis via serology (antigen/antibody) for low infection
-economic losses due to meat inspection
-praziquantel, niclosamide
-public health education (cook/freeze meat!)
-sewage treatment/vaccine = hygiene on pasture to prevent contamination

Question 16

Describe Taenia solium hosts.

Answer 16

‘Pork tapeworm’
has hooks
-DH = humans ‘taeniosis’ in intestine
>zoonotic, DEH (larval stage)
>cysticercus under skin/CNS/eye/SQ tissue
>neurocysticercosis
-IH = pigs (tongue/muscle), humans

Question 17

Describe taenia solium life cycle.

Answer 17

Question 18

Describe Taenia solium clinical signs.

Answer 18

-Pigs = no CS
-humans
>taeniosis - intestinal discomfort (proglottid aesthetics)
>neurocysticercosis - seizure, headache, hydrocephalus, blindness, dementia, death

Question 19

Describe taenia solium diagnosis & treatment/prevention.

Answer 19

Diagnosis:
-serology/PCR in humans/pigs
-lingual exam in pigs
-CT, MRI for human cysts in brain
-biopsy of nodules in humans
-fecal exam in humans
Treatment:
-oxfendazole in pigs
-praziquantel/albendazole in humans
Prevention:
-pig husbandry
-meat inspection
-hygiene & sanitation
-health education

Question 20

Describe echinococcus granulosus general characteristics.

Answer 20

-FH = dogs, canids (fox, dingo)
-IH = herbivores (SHEEP), omnivores & humans (ZOONOTIC - DEH)
-small
-few proglottids
-larval = hydatid in liver, lungs, bones, brains of IH
-adults in sm intestine
-taeniid egg in feces
dog-sheep cycle most IMP

Question 21

Describe echinococcus granulosus life cycle.

Answer 21

Question 22

Describe echinococcus granulosus pathogenesis & diagnosis.

Answer 22

Path: -adults = non path in dog -hydatids = non path in livestock -hydatids = pathogenic to humans >organ damage-pressure atrophy >anaphylactic shock Diagnosis: -eggs of Taenia spp & Echinococcus spp (indistinguishable) -purgation or coproantigen testing -meat inspection of IH -ultrasound/image of humans -serology

Question 23

Describe treatment/prevention in echinococcus granulosus.

Answer 23

-praziquantel every 6wk -dont feed dogs uncooked organs -hygiene -sylvatic cycle

Question 24

Describe echinococcus canadiensis.

Answer 24

-FH = dogs, wild canids (wolf, coyote) -IH = wild cervical (elk, deer, caribou, moose), humans (ZOONOTIC) *similar to E. Granulosus!

Question 25

Describe the general characteristics + treatment of echinococcus multiocularis.

Answer 25

Humans = ‘hepatic alveolar echinococcosis’ Canids = ‘echinococcosis’ -cats can be affected but poor hosts -northern hemisphere -FH = wild canids (foxes) & domestic dogs >taeniid eggs in feces -IH = rodents, lagomorphs, dogs, humans *zoonotic* >larvae = alveolar hydatid in liver of IH & metastases of other organs -adults = <6mm in sm intestine TREATMENT -adults = praziquantel (baits for wild canids) -larval infection in humans/dogs = long term Anthelmintics or surgery

Question 26

Summary of Echinococcus tapeworms!

Answer 26

Question 27

Describe mesocestoides spp.

Answer 27

-cyclophyllidea but share some characteristics w pseudophyllidea (ex. Requires 2 IH) -FH = dogs, cats, humans *zoonotic* -IH = 1) arthropod 2) reptile, amphibians, birds, rodents, cats, dogs -larvae = tetrathyridia >in body cavities, organs, asexual repro, ingested in meat/organs by FH -adults = sm intestine >sucker but no hooks >400 proglottids (motile) w parauterine organ w egg -PPP: 2-3wk

Question 28

Definitions!

Answer 28

1. Coracidium = ciliated larvae in water 2. Procercoid = 1st parasitic larvae infecting copepods 3. Plerocercoid = 2nd parasitic larvae (spargana) infecting fish

Question 29

Describe dibothriocephalus latus general characteristics.

Answer 29

‘Fish/broad tapeworm’ *pseudophyllidea* -FH = fish eating mammals (dogs, cats, bears), humans *zoonotic* -IH = 1) copepod infected w procercoid 2) freshwater fish infected w plerocercoid -bothria = elongated muscular grooves that provide attachment by pinching host tissue -12m -square shaped proglottids (3000+) that release 1 mil eggs/day in water -adults in sm intestine -larvae in muscles/viscera of fish (plerocercoid) -PPP: 5-6wk

Question 30

Describe dibothriocephalus latus clinical signs, diagnosis & treatment.

Answer 30

CLINICAL SIGN -non symptomatic = dogs -abdominal discomfort, weight loss, vomiting, diarrhea = humans >macrocytic anemia bc of uptake of VitB12 from intestine >intestinal obstruction or gall bladder disease DIAGNOSIS -operculated eggs/proglottids in poo -sedimentation TREATMENT -cestocidals (praziquantel, niclosamide) for adults -avoid raw, undercooked meat & feeding them to domestic animals -dont let humans or animals poo in freshwater

Question 31

Describe the general characteristics of Spirometra spp.

Answer 31

‘Zipperworm, wildlife tapeworm’ (Sparganosis in humans) -FH = dogs, cats, lynx, bobcat, raccoon -IH = 1) crustacean 2) fish, reptile, amphibian, bird, rodents, humans *zoonotic* (can also be PH) -2 m -small scolex w bothria -repro organs at center of proglottids (shed in groups) -PPP: 2-4wk -adults in sm intestine -larva in 2 IH

Question 32

Describe human sparganosis.

Answer 32

-not infected w adult -2nd IH DEH if ingest copepods -PH if ingest plerocercoid (spargana) in 2nd IH (fish, reptile, amphibian) or from frog/water snake meat as poultices -spargana migrate thru bod >SQ tissue, breast, eye, urinary tract, pleural cavity, lungs, abdominal viscera, CNS

Question 33

Describe the clinical signs, diagnosis & treatment for Spirometra spp.

Answer 33

CLINICAL SIGNS -dogs = adults cause enteritis w intermittent diarrhea >proliferative sparganosis (poor prog in dog) -human sparganosis DIAGNOSIS -egg in feces (sedimentation) -diff egg from trematodes TREATMENT -treat FH w cestocide (praziquantel, niclosamide) -surgical removal in humans -avoid contaminated water -dont feed IH to domestic animals -avoid poultices