Non Taenia Cestodes & Trematodes Flashcards
Who and where does Diplylidium caninum infect?
- DH Ca & Fe (people)
- recent molecular evidence shows specialized Ca & Fe strains, but cross infection is possible
- small intestine
What is in Diplylidium caninum egg packets?
- each packet contains up to 30 eggs
- each egg contains a hexacanth larvae
- HEAVY - do not float well
Describe Diplylidium caninum mature segments:
2 sets of genetalia per segment so two lateral genital pores
What is the life cycle of Diplylidium caninum?
- PPP = 2-3 wks
- gravid segments & egg packets are shed in feces -> develop into cysticercoid larvae within flea larvae -> flea larvae develops into an adult flea IH (not vector) (potentially also happens w/ chewing lice) -> flea IH is ingested by DH -> Diplylidium caninum develops into adult in DH
What type of metacestode larvae does Diplylidium caninum have?
cysticercoid
How do we diagnose & control for Diplylidium caninum?
- Dx based on detection of egg packets or segments in feces (most likely) (DONT use fecal floats!)
- several cestocides are labeled for Ca & Fe
- treat all pets in household
- FLEA CONTROL IS IMPERATIVE
What is the epidemiology/ecology of Diplylidium caninum?
- present wherever you have fleas
- more common on coasts & further south
- global distribution
- indirect life cycles: Ca or Fe DH (rarely humans); arthropod IH
- zoonotic but not directly from pets (need to eat flea)
Why are Mesocestoides spp a weird type of Cyclophyllid cestode?
- no rostellum
- ventral genital pore
- 2 IH
who are the DH for Mesocestoides spp?
- DOGS, CATS, wild canids, (people) in coastal North America
Are Mesocestoides spp zoonotic?
yes, but not directly from pets, we need to consume the IH
How do we diagnose Mesocestoides spp in Ca as the DH?
segments, not eggs in feces
What are unique features of Mesocestoides Tetrathyridium and how is it diagnosed?
This is the metacestode larvae stage
- four suckers on an inverted scolex
- can divide asexually
- in Ca, can be diagnosed by ultrasound or abdominocentesis +/- PCR
What is the life cycle of Mesocestoides spp?
- PPP = 16-20 days
- gravid segments passed in feces -> ingested by 1st IH (unknown, potentially an arthropod) -> ingested by second IH (reptile, mammal, Av) & develops into Tetrathyridia Larvae -> ingested by DH & develops into adults
- if Ca ingests 1st IH will have tetrathyrdia larvae in its peritoneal cavity
What is special about Pseudophyllid cestodes?
- 2 IH
- ventral genital pores
where do Pseudophyllid cestodes live?
small intestine
What are the DH of Pseudophyllid cestodes?
Ca, piscivores, people
What are the freshwater Pseudophyllid cestodes?
Dibothriocephalus latum & Dibothriocephalus dendriticum
What are the IHs of Dibothriocephalus latum?
walleye, pike, pickerel, perch, burbot
What are the IHs of Dibothriocephalus dendriticum?
whitefish, burbot, sticklebacks
what are the marine Pseudophyllid cestodes?
Dibothriocephalus ursi & Dibothriocephalus nihonkaiense
what is the IH of Dibothriocephalus ursi & Dibothriocephalus nihonkaiense?
Pacific Salmon
What is the old name for Dibothriocephalus?
Diphyllobothrium
What is this group & structure?
- Dibothriocephalus sp
- scolex w/ bothrium
what are the significant feature of Dibothriocephalus sp gravid segments?
- central coiled uterus
- ventral genital pore
what do adult Dibothriocephalus sp resemble?
a zipper!
What features do Dibothriocephalus sp eggs have?
circular operculum on one end, pimple on the other
What kind of metacestode larvae do Dibothriocephalus sp have?
procercoid in first IH & plerocercoids in second IH/PH
What is the life cycle of Dibothriocephalus sp?
- PPP = 2-4 wks
- adults can liver for years w/in DH intestines
- eggs are passed via feces -> develop into coracidium larvae in environment -> ingested by first IH (crustacean) & develop into procercoid larvae -> ingested by second IH (fish) & develop into plerocercoid larvae -> possibly ingested by paratenic host (pisciverous fish) OR DH -> develop into adults in DH
How do we diagnose & control Dibothriocephalus sp?
- diagnosis based on detection of eggs or segments in feces
- little clinical significance (gross factor)
- off label, high dose of praziquantel (7.5 mg/kg SID for 2 days, up to 35 mg/kg!)
- prevent access to raw fish (cook or deep freeze fish prior to consumption)
- prevent Ca from contaminating water w/ fecal matter
What kind of life cycle do trematodes have?
aquatic life cycles
What is the epidemiology / ecology of Dibothriocephalus sp?
- not detected in national survey in Canada
- distribution is determined by wildlife reservoirs
- indirect life cycles (Ca DH (also humans); crustacean IH1; Fish IH2; +/- paratenic host
- zoonotic from eating fish: rarely can lead to Vitamin B12 deficiency = pernicious anemia in children (only tapeworm where you can see issues coming through)
What are the different types of flukes?
- intestinal flukes
- liver flukes
What are the different types of intestinal flukes?
- Alaria spp - common in Northwestern Canada
- Alaria marcianae - not in Canada
- Nanophyetus salmincola
What type of liver fluke is there?
- Metorchus conjunctus
Are trematodes zoonotic?
all are potentially zoonotic, but not directly from pets (humans serve as an aberrant DH from ingestion of IH)
why were no trematodes detected in dogs & cats in the national survey?
b/c they used fecal floats which dont detect trematodes
What are the DH of Alaria spp?
DOGS, (cats, wild canids, people)
What is unique about Alaria spp. in terms of trematode eggs?
float well
What is the life cycle of Alaria spp?
- PPP = 1-2 wks
- eggs are passed in feces -> become myracidium in environment -> ingested by first IH (snail) & develops sporocysts, redia, & cercaria allowing for asexual reproduction for amplification -> cercaria leave snail & are ingested by second IH (tadpole or frog) & develop into metacercariae (mesocercariae) -> either get ingested by paratenic host (small mammal) OR DH -> develop into adults in DH
- transmammary transmission in Fe
What are the DH for Nanophyetus salmincola?
DOGS, (cats, people, mesocarnivores)
What does Nanophyetus salmincola transmit & what does it cause in who?
Neorickettsia helminthoeca which causes salmon poisoning in Ca in BC, NW, & USA
How do you treat for Nanophyetus salmincola and Neorickettsia helminthoeca?
praziquantel for fluke & doxycycline for rickettsia
characteristics of adult Nanophyetus under the microscope?
- v tiny
- ventral & oral suckers
- little egg “fins” (eggs)
what is the life cycle of Nanophyetus?
eggs passed in feces -> become miracidium in enviro -> ingested by first IH (snail) & develops into cercariae larvae -> cercariae larvae released into environment -> ingested by second IH (salmonid fish) & develops into metacercariae -> ingested by DH & develops into adults
- Neorickettsia helminthoeca present throughout entire lifecycle
Who are the DH of Metorchis conjunctus?
Ca (rural, remote, & northern)
(also Fe, fox, mustelids, people)
Are Metorchis conjunctus zoonotic?
yes, but not directly from Ca (need to ingest IH)
What are the defining features of Metorchis conjunctus?
ventral & oral suckers
Where can Metorchis conjunctus sometimes be found & what disease can this lead to?
- bile duct (pancreatic duct), leading to pancreatitis
What are the defining characteristics of Metorchis conjunctus eggs?
- looks like they have a little crown
- made up of Operculum & lip (lip is characteristic)
what is the life cycle of Metorchis?
- eggs passed in feces -> develop into miracidium in environment -> ingested by first IH (snail) -> leave host as cercariae -> ingested by second IH (sucker fish) & develop into metacercariae -> ingested by DH & develop into adults
How do we diagnose & control trematodes?
- diagnosis is based on detection of eggs in feces (ideally using sedimentation (not floatation))
- usually subclinical, so goal is to break life cycle
- off label praziquantel
- prevent access to raw fish/frogs (PH; cook or freeze solid prior to feeding (or eating))
- prevent Ca from contaminating water w/ feces
