Taeniids- cats and dogs Flashcards
Family Taeniidae
**tapeworms
- Taenia spp= dogs and cats
- Echinococcus spp= dogs
Taeniid and Echinococcus type eggs
-thick radially striated shell
-hooks on hexacanth larva
-very environmentally resistant (need high heat, or very cold eg. -80)
Where do you find Taeniiae spp?
-Small intestine
Adult taenia spp
“ribbon like”
-Scolex head; no mouth
-immature segments, mature segments, gravid segments
-single genital pore
Taeniiae spp DH
dogs and cats
Scolex of Taenia spp
-rostellum with hooks
-4 suckers
**adult tapeworms can be ID’d based on hook morphology and morphometrics. But difficult and usually use genetics
Mature segments of Taenia
-Ovary w/ oocyte
-Testes
-genital pore
-vitelline gland
-uterus
Gravid segments of Taenia spp
“full appearance”
-branched uterus
-single lateral genital pore
**can produce ~2.5 million eggs/day
Taenia spp lifecycle
**indirect life cycle
PPP:6-9weeks
1.Adults in GI tract, eggs released in feces
PP: 2-3mths in IH = time in environment
2. Gravid segments and eggs w/ hexacanth larvae
3. Eaten by IM
4. Develop into metacestode with protoscolex/ices in IM
5. DH eats the IH
Taenia spp in Canada
T. pisiformis- cysticercus metacestode, IH- liver and peritoneum of rabbits and rodents
T. taeniaeformis- strobilocercus metacestode, IH- liver of Rodents
Cysticercus
single protoscolex, fluid filled cyst
Coenurus
many protoscolices attached to wall of a fluid filled cyst
Strobilocercus
miniature adult, no cyst
Cyclophyllid cestode larval stage
Egg can become one of:
-cysticercoid
-cysticercus
-coenurus
-cystic hydatid
-alveolar hydatid
Hydatid
-many protoscolices
Cystic: single fluid filled cyst
Alveolar: multichambered fluid filled cyst
Diagnosis of Taenia spp in dog or cat
-fecal flotation for eggs (not sensitive or specific)
>better to used high specific gravity solution
-coproantigen or coproPCR
-segments or adult cestodes in feces or on necropsy
**do not use perianal tape mount because zoonotic implications
Control of Taenia in DH
Goal: halt environmental contamination.
-risk for any free roaming pet with access to IH, raw meat
-can treat with cestocides
-clean areas
-important to deworm on sheep farms once a yr
**IM: no treatment, often found in meat inspection
Epidemiology of Taeniidae
-prevalent in dogs and cats in western canada; global distribution
-prevalence less affected by age of host
-species-specific host assemblages
-predator-prey indirect life cycles
-eggs immediately infective and very resistant
Echinococcus granulosus/ E. canadensis hosts
DH: wolves, coyotes, dogs
IH: moose, elk, caribou, deer, people
Echinococcus multilocularis hosts
DH: fox, coyotes, wolves, dogs, sometimes cats
IH: rodents, sometimes dogs and people
mm in size
Echinococcus granulosus adults
-scolex
-gravid segment
-genital pore (caudal half of mature segment in granulosis, cranial half in multilocularis)
-1.5cm
Lifecycle of Echinococcus canadensis
PPP: 6 weeks
1.Adults in wolf, coyotes, dog DH
PP:development for 6-12 months in IH
2. Infective eggs released into environment (where humans can ingest causing cystic CE=hydatid cyst in lungs)
3. Ingested by Cervid IH (where they become cystic CE= hydatid cyst of lungs)
4. Cervids preyed upon by DH leading to infection
Cystic hydatid
many protoscolices free in fluid filled cyst
Alveolar hydatid
many protoscolices free in multichambered fluid-filled cysts
Diagnosis of Echinococcus spp in DH
-usually subclinical
-fecal flotation for eggs (low sensitivity)
-CoproPCR- high sensitivity and can be used to ID taenia and echinococcus spp
-adult cestodes in feces or on necropsy
Epidemiology of E. canadensis
-Echinococcus spp found all across Canada, but only E. canadensis
-rare (4/1000 dogs)
-prevalence increases with age
-predator prey indirect life cycles
-eggs immediately infective and very resistant
Echinococcus multilocularis adults
-2-5mm
-genital pore in cranial half of mature or gravid segments
Echinococcus multilocularis distribution
-Endemic in western Canada (maybe not Van isle)
-Present in southern Ontario
**mostly in coyotes (30-70%), foxes (30%), wolves (13%)
Echinococcus multilocularis lifecycles
PPP: 35 days
1.DH: fox, coyote, wolf, dog, sometimes cat. Eggs released in feces
PP: 2-4months in IH
2. IH (voles, lemmings, deer mice,dogs) ingests infective eggs OR humans
**results in alveolar echinococcosis in liver
3. DH ingests IH
Alveolar hydatid
many protoscolices free in multichambered fluid filled cysts
Diagnosis of Alveolar echinococcosis
-common in AB, SK, ON, BC, MB
-medical imaging
-laparotomy
-necropsy
Echinococcus multilocularis in dogs
Dogs can be both DH and IH
-can have adult worms AND alveolar echinococcosis
Diagnosis of canine alveolar echinoccosis
-medical imaging, Ultrasound (liver mass in young dogs)
-serology, histopathology
>difficult because protoscolices are not always present
-immunohistochemistry, PCR
>abdominocentesis fluid, aspirated cyst contents, biopsy, surgical resection
-histology (find protoscolices)
Management of canine alveolar echinococcus
-collect fecal sample for flotation and coproPCR
-treat with adult cestocide or larval cestocide
-surgical debulking/resection if clinically indicated
-advise owner to consult health care provider
-poor prognosis indicators (late detection, significant abdominal effusion, metastases
Control of echinococcus in Dog DH
-Halt environmental contamination with immediately infective, highly resistant eggs
>resistant to chemicals, killed by heat, drying, freezing below -80
-prevent access to IH (freeze or cook)
**high risk dogs
What do you treat echinococcus?
Praziquantel (high efficacy against adults)
*treat every 4-6 weeks, year round
