Cats and dogs cestodes and trematodes

Question 1

Epidemiology/ecology of Taeniids

Answer 1

Adults found in both canids and felids. Larval stages found in a variety of hosts
Global distribution
Predator-prey based indirect life cycle
Carnivore definitive hosts
Herbivore intermediate hosts
Eggs immediately infective and resistant in the environment (months)
Prevalence in DH tends to increase with age

Question 2

Characteristics of Taenia spp

Answer 2

Have a rostellum with hooks and suckers on the side
One genetialia per mature segment - hermaphrodite

Question 3

Life cycle of Taenia spp

Answer 3

Eggs in feces
Egg contains a single hecanth larvea
IH with metacestode with protoscolex eater
takes 2-3 months to develop in IH
PPP 6-9 weeks

Question 4

Common Taenia spp. tapeworms in Canada

Answer 4

Taenia hydatigena
T.pisiformis*
T.ovis
T.krabbei
T. serialis
T. taeniaeformis*

Question 5

Common Taenid species in canids

Answer 5

Taenia hydatigena
T.pisiformis*
T.ovis
T.krabbei
T. serialis

Question 6

Diagnosis and clinical signs of taenia spp. In the DH (dog or cat)

Answer 6

Almost always subclinical
Fecal flotation for eggs
Not sensitive (20-30%)(using high specific gravity solution >1.3, or sedimentation)
Not specific- morphological identical to echinococcus
Coproantigen or coporoPCR
Segments or adults cestode in feces or on necropsy (fairly easy to determine genus- usually sent to a specialized lab to determine species)

Question 7

Control and treatment of Taenia in DH

Answer 7

Animals at risk are any free-roaming pet with access to IH (hunt,scavenge), potentially raw meat diets
Goal: halt environmental contamination with immediately infective, resistant eggs
Several pesticides labelled for dogs and cats that will kill adult tapeworms
Control: prevent access to IH, cook or freeze offal and meat before feeding to dogs
There are no pharmaceutical control measures for intermediate hosts
Remember these will cycle wherever wild hosts are present
Taenia spp. From dogs and cats are not zoonotic

Question 8

Echinococcus granulosus/E. Canadensis DH and IH

Answer 8

DH: wolves, coyotes, dogs
IH: sheep, moose, elk, caribou, deer (people)

Question 9

Echinococcus multilocularis DH and IH

Answer 9

DH: fox, coyotes, wolves, dogs (cats)
IH: rodents (dogs, people)

Question 10

Epidemiology/ecology of E.canadensis

Answer 10

All across canada except NL (so far)
E.canadensis is only species present in canada
11% of dogs in eastern SK reserve community
70% of wolves, 30% of coyotes
Prevalence tends to increase with age
Predator-prey indirect life cycles
Carnivore DH
Herbivore IH
Eggs immediately infective and very resistant

Question 11

Life cycle of Echinococcus canadensis

Answer 11

Infective egg in feces of DH
Eaten by IH cystic hydatid
Devlops for 6-12 months in IH
IH eaten by DH
PPP~6 weeks

Question 12

IH of Echinococcus canadensis

Answer 12

Moose>caribou>elk>deer
Cervid IH

Question 13

Diagnosis and clinical signs of Echinococcus spp, in DH (dog)

Answer 13

Almost invariably subclinical
Fecal flotation for eggs (low sensitivity, 17-27%)
CoproPCR (higher sensitivity, >80%) and can distinguish among Taneia and 2 Echinococcus spp.
Adult cestodes in feces or on necropsy?

Question 14

Life cycle of Echinococcus canadensis with humans

Answer 14

Humans can eat the infective eggs

Question 15

Echinococcus multilocularis distribution

Answer 15

All of western Canada now considered endemic (maybe not Vancouver island)
Also in southern Ontario
Prevalence
30-70% in coyotes
30% of foxes
13% of wolves

Question 16

Echinococcus multilocularis life cycle

Answer 16

Infective eggs in feces
Alveolar echinococcosis develops in IH
Develops in 2-4 months in IH
DH eats IH
PPP 35 days

Question 17

Echinococcus spp.:larval stages

Answer 17

Cystic hydatid- many protoscolices free in single chambered fluid-filled cyst
Alveolar hydatid- many protoscolices free in multi chambered fluid filled cysts

Question 18

Diagnosis of canine Alveolar echinococcosis (AE)

Answer 18

Suspicion: medical imaging, liver mass in young dog
Ddx neoplasia, granuloma, other causes of cyst
Suggestive: serology, histopathology
Protoscolices only present in about ⅓ of dogs
Periodic acid-Schiff (PAS) stain to detect membrane
Calcareous corpuscles
Potential for misdiagnosis with other larval cestodes
Definitive: immunohistochemistry, PCR
Abdominocentesis fluid
Aspirated cyst contents
Biopsy, surgical resection

Question 19

Risk factors for AE

Answer 19

There have been at least 35 cases in dogs across most of Canada since 2009, 6+ in SK, 15+ in AB
Contact with wildlife, esp coyotes and foxes
Habitat overlap
70% of coyotes in a study
European strain E.multi
Use of off leash areas
Copropahgic dog

Question 20

Management of canine AE

Answer 20

Collect fecal sample for flotation and/or fecal PCR
Treat with adult cestocide (initially)
I.e. praziquantel at 5 mg/kg daily for 2 days
Treat with larval cestocide (long term/life long)
I.e. albendazole (larval cestocide) at 10 mg/kg daily
Surgical debulking/resection if clinically indicated
Advise owner to consult health care provider
Poor prognosis indicators: lare detection, significant abdominal effusion, metastases

Question 21

Control of Echinococcus in DH (dog)

Answer 21

Goal: halt environmental contamination with immediately infective, highly resistant eggs
Resistant to most chemicals
Killed by heat, drying, and freezing below -80*C
Control: prevent access to IH (freeze or cook off)
Why treat? Primarily public health considerations
With what? Praziquantel- high efficacy against adults
Who and where? High risk dogs in endemic regions
Free-roaming, hunting, scavenging, raw meat

Question 22

When to treat Echinococcus in DH

Answer 22

High risk: prophylactically, year round, q 4-6 weeks
Known positive (eggs may shed for 3 days post tx)
Advise owner to consult health care provider

Question 23

Cysticercoid means

Answer 23

single protoscolex, no cyst, in an arthropod

Question 24

Cyclophyllid cestodes larval stages

Answer 24

Cysticercoid- single protoscolex, no cyst, in an arthropod
Cysticercus- single protoscolex, fluid filled cyst
Coenurus- many (10s) protoscolices attached to wall of fluid flipped cyst
Strobilocercus- single miniature adult, no cyst
Cystic hydatid- many (1000s) protoscolices free in fluid filled cyst
Alveolar hydatid- many (100s) protoscolices free in multi chambered fluid filled cysts

Question 25

Cystic hydatid is

Answer 25

many (1000s) protoscolices free in fluid filled cyst

Question 26

Alveolar hydatid is

Answer 26

many (100s) protoscolices free in multi chambered fluid filled cysts

Question 27

Epidemiology/ecology of Dipylidium

Answer 27

IH is fleas
Present wherever you have fleas
More common on the coasts and further south
35% of shelter cats in Oklahoma: proglottids were detected in 19% of these; all negative on fecal float
Global distribution
Indirect life cycles
Dog or cat definitive host (DH)(rarely humans)
Arthropod intermediate hosts (IH)
Zoonotic but not directly from pets (eat flea)

Question 28

Life cycle of Dipylidium caninum

Answer 28

Gravid segments and egg packets are passed in feces of DH
Flea larvae with cysticercoid
Adult flea with cysticercoid
IH: fleas
Ingested by dogs
PPP 2-3 weeks

Question 29

Egg packets of Dipylidium caninum

Answer 29

Each packet contains up to 30 eggs
Each eggs contains a hexacanth larvae
Heavy do not float

Question 30

Cyclophyllid cestodes: larval stages

Answer 30

Cysticercoid- single protoscolex, no cyst, in an arthropod
Cysticercus- single protoscolex, fluid filled cyst
Coenurus- many (10s) protoscolices attached to wall of fluid flipped cyst
Strobilocercus- single miniature adult, no cyst
Cystic hydatid- many (1000s) protoscolices free in fluid filled cyst
Alveolar hydatid- many (100s) protoscolices free in multi chambered fluid filled cysts

Question 31

Diagnosis and control of Dipylidium

Answer 31

Diagnosis based on detection of egg packets or segments (most likely) in feces (cucumber seeds)
Several products labelled for dogs an cats
Treat all pets in household
Flea control imperative
Treatment failures generally flea related
Short PPP sometimes makes it look as treatment has failed

Question 32

Helminths of dogs

Answer 32

Small intestine
Pseudophyllid cestodes (2 IH)
Fish or tapeworms: DH dogs, piscivores, people
Fresh water
Diphyllobothrium latum (walleye, pike, pickerel, perch, burbot)
D. dendriticum ( whitefish, burbot, sticklebacks)
Marine
D. ursi (Pacific salmon)
D. nihonkaiense (Pacific salmon)

Question 33

Epidemiology/ecology of Diphyllobothrium

Answer 33

1.3% of 231 shelter dogs in Regine
5% of 259 dogs from remote and northern SK
Indirect life cycles
Dog DH (also humans and bears)
Cetacean 1st IH
Fish 2nd IH +/- PH
Zoonotic from eating fish

Question 34

Life cycle of Diphyllobothrium

Answer 34

Eggs in feces
grow to Coracidum in environment
Curstacean gest infected with procercoids
Fish eats crustacean
IH2 now has plerocercoids
IH2 can be eaten by dog OR
Pisciverous fish PH
PH or IH eaten by DH
PPP 2-4 weeks
adults can live for years

Question 35

Diagnosis and control of Diphyllobothrium

Answer 35

Diagnosed based on detection of eggs ro segments (long strands of gravid segments) in feces
Little clinical significance (gross factor)
Prevent access to raw fish
Cook or deep freeze fish prior to consumption
Prevent dogs from contaminating water

Question 36

Intestinal flukes of dogs and cats

Answer 36

Alaria spp. - dogs (common NW Canada)
Nanophyetus salmincola (BC)- dogs (and cats)

Question 37

Liver flukes of dogs and cats

Answer 37

Metorchus conjunctus- dogs

Question 38

Are dog and cat flukes zoonotic

Answer 38

All potentially zoonotic, but not directly from pets (humans serve as aberrant DH)

Question 39

Alaria spp

Answer 39

DH dohs (cats, wild canids, people)
3% of 231 shelter dogs in Regina, 8% of 62 dogs in SE Sk
Zoonotic but not directly from pets

Question 40

Life cycle of Alaria

Answer 40

Eggs in feces
Miracidium
Snail first IH
cercaria
Tadpole or frog second IH with metacercariae
Can have a small mammal PH
PH or IH eatedn by DH
PPP 1-2 weeks

Question 41

Nanophyetus salmincola is

Answer 41

DH dogs (cats, people)
Fluke infection is harmless to dog but
Transmits neorickettsia helminthoeca, causes salmon poisoning in dogs in BC< NW USA
Rise of body temp, loss of appetite, vomiting, diarrhea, listlessness and/or rapid weight loss
Treat fluke with praziquantel, rickettsia with doxycycline

Question 42

Life cycle of Nanophyetus

Answer 42

Eggs in feces
Mircidium
Snail first IH
Cercariae
Salmon fish second IH with metacercariae
DH eats IH

Question 43

Metorchis conjunctus common in and is it zoonotic

Answer 43

DH dogs (rural, remote and northern)
Cats, fox, mustelids, people
Zoonotic but not directly from dogs

Question 44

Life cycle of Metorchis conjunctus

Answer 44

Eggs in faeces
Miracidium
Snail first IH
Cercariae
Sucker fish seond IH woth metacercariae
DH eats second IH

Question 45

Diagnosis and control of trematodes

Answer 45

Diagnosis on detection of eggs in feces (flotation)
Usually subclinical
Prevent access to raw fish/frogs (PH)
Cook or freeze prior to feeding (or eating)
Prevent dogs from fecally contaminating water