Cestodes Flashcards
Describe the general characteristics of Cestodes (Tapeworms).
-flat body
-no alimentary canal
-nutrients absorbed thru tegument
-scolex = head
-stroblia (body) w proglottids (individual repro unit)
-hermaphroditic
-indirect (1 or 2 IH)
Describe the neck & strobila of cestodes.
Neck:
-germinative region & produces segments asexually
Strobila:
-immature proglottids
-mature proglottids
-gravid proglottids
Describe the general characteristics of cestodes.
-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
Describe the IH of Cyclophyllidea. (picture)
Compare Order Cyclophyllidea & Order Pseudophyllidea.
Order Cyclophyllidea
-advanced
-1 IH
-scolex, suckers, (+/-) hooks
-eggs = oncosphere w hooks
Order Pseudophyllidea
-2 IH
-scolex & bothria
-egg = oncosphere w cilia
Describe the life cycle of cestodes. (picture)
Describe the IH of Pseudophyllidea.
Fish & crustaceans
-dibothriocephalus latus
-spirometra spp
Describe Dipylidium caninum.
‘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
Describe the life cycle of Dipylidium caninum. (picture)
Describe Choanotaenia spp & Raillietina spp.
-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
Describe Anoplocephala perfoliata & Anoplocephala magna.
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
Describe Anoplocephala perfoliata & Anoplocephala magna life cycle.
-gravid proglottids pass in feces -> ingested by oribatid mites -> develop into cysticercoids -> IH eaten by FH
Describe Moniezia spp.
‘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
Describe Moniezia expansa VS Moniezia benedeni.
Moniezia expansa = sheep, goats, triangle egg (small)
Moniezia benedeni = cattle, cube egg (larger)
Describe Taenia spp.
-eggs similar (stay in environment)
>striated shell
>sm than toxocara egg
-larval stage = cysticercus
*EXCEPT T. taeniaeformis = strobilocercus
-adults in sm intestine
-non pathogenic
Describe Taenia pisiformis.
-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
Describe Taenia taeniaeformis.
-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
Describe Taenia hydatigena.
-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
Describe Taenia saginata.
‘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
Describe Taenia solium hosts.
‘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
Describe taenia solium life cycle.
Describe Taenia solium clinical signs.
-Pigs = no CS
-humans
>taeniosis - intestinal discomfort (proglottid aesthetics)
>neurocysticercosis - seizure, headache, hydrocephalus, blindness, dementia, death
Describe taenia solium diagnosis & treatment/prevention.
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
Describe echinococcus granulosus general characteristics.
-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
Describe echinococcus granulosus life cycle.
Describe echinococcus granulosus pathogenesis & diagnosis.
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
Describe treatment/prevention in echinococcus granulosus.
-praziquantel every 6wk
-dont feed dogs uncooked organs
-hygiene
-sylvatic cycle
Describe echinococcus canadiensis.
-FH = dogs, wild canids (wolf, coyote)
-IH = wild cervical (elk, deer, caribou, moose), humans (ZOONOTIC)
*similar to E. Granulosus!
Describe the general characteristics + treatment of echinococcus multiocularis.
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
Summary of Echinococcus tapeworms!
Describe mesocestoides spp.
-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
Definitions!
- Coracidium = ciliated larvae in water
- Procercoid = 1st parasitic larvae infecting copepods
- Plerocercoid = 2nd parasitic larvae (spargana) infecting fish
Describe dibothriocephalus latus general characteristics.
‘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
Describe dibothriocephalus latus clinical signs, diagnosis & treatment.
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
Describe the general characteristics of Spirometra spp.
‘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
Describe human sparganosis.
-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
Describe the clinical signs, diagnosis & treatment for Spirometra spp.
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
