VT 113 Lecture Exam Accumulative

1st intermediate host: A planktonic crustacean

2nd intermediate host: Freshwater fish

Definitive Host: Humans (eating fish eating mammals such as bears, wolves, foxes)

Diphyllobothrium latum

Diphyllobothrium latum ova

Diphyllobothrium latum

This cestode (the broad fish tapeworm) is found in fresh water regions

• Adult tapeworm worm reside in the small intestine of humans or other mammals where they release the eggs(ova) via feces in the water

• Eggs hatch in the fresh water into free-swimming larvae called coracidia which is ingested by crustaceans

• While inside the crustaceans the larvae develop into procercoid larva then small freshwater fishes consume the infected crustaceans

• The procercoid larvae migrate into the fish’s tissues and develop into the plerocercoid larva that gets ingested by humans by eating raw or uncooked fish

The prepatent period (time between it infects the host and before it can become detected) of Diphyllobothrium latum

3-4 weeks

Dipylidium caninum ovum

The flea tapeworm affects dogs, cats and humans

Dipylidium caninum

This cestode grows in the small intestine of dogs, cats and can affect humans

Collection: Segments in feces or found in perianal region

Diagnostic: Fecal Flotation

Intermediate host: fleas (Ctenocephalides)

Definitive host: Dogs, Cats, and even Humans

Dipylidium caninum adult stage

Type of Life Cycle:

Direct or Indirect?

The Dipylidium caninum life cycle

Indirect Life Cycle

The prepatent period (time between it infects the host and before it can become detected) of Dipylidium caninum

14-21 days (2-3 weeks)

Taenia sp

Cestode (Tapeworm) located in the small intestine that contains scolexes with 2 rows of hooks one lateral genital pore

Eggs have striated shell with 6 hooks inside the ova

This cestode has the

Intermediate host: Rabbit

Found in the rabbit’s organs

Definitive host: Dogs, Coyotes, Foxes

Taenia pisiformis

The prepatent period (time between it infects the host and before it can become detected) T. pisiformis

2 months

This cestode has the

Intermediate host: Pigs

Found in the striated muscles, heart, tongue, and sometimes brain of infected pigs

Definitive host: Humans

Taenia solium

This cestode has the

Intermediate host: Cattle

Found in the striated muscle tissues of cattle, primarily the heart, masseter muscles (jaw), diaphragm, and tongue

Definitive host: Humans

Taenia saginata

This cestode has the

Intermediate host: Sheep

Definitive host: Dogs, Coyotes, Foxes (Wild Canids)

Taenia ovis

Taenia spp. ova

This cestode is

Intermediate host: Ruminants (harboring the larval stage)

Definitive host: Canids (commonly harboring the adult stage)

Taenia hydatigena

Type of Life Cycle:

Direct or Indirect?

The Taenia pisiformis life cycle

It’s an Indirect Life Cycle

M. multiceps

Adult lives in small intestines of canids

Diagnostics: Eggs in fecal flotation, segments found in feces or perinatal region

The prepatent period (time between it infects the host and before it can become detected) of Taenia multiceps

7-9 weeks

Coenurus

The larval stage of M. multiceps

The intermediate host of M. multiceps:

Sheep

The intermediate host of M. serialis:

Rabbits

M. multiceps coenurus produces space occupying lesions in the ___

Brain

M. serialis coenurus produces space occupying lesions in ____ of rabbit

Subcutaneous tissues

Echinococcus granulosus

Intermediate host is ruminant

This is _____

Echinococcus granulosus ova

True or False: Echinococcus granulosus is highly zoonotic

True

Echinococcus granulosus is ___

Tapeworm (Cestode)

Does Echinococcus an Indirect or direct life cycle ?

Indirect life cycle

Echinococcus granulosus

The hydatid cyst forms in the intermediate host (ruminants) and it’s Unilocular hydatid cyst form is found in the liver, lung, brain.

Echinococcus granulosus

Hydatid cyst has thick walk with a germinal membrane inside of it

Brood capsules containing protoscolices bud from germinal membrane

Echinococcus granulosus

In _____ every protoscolex when ingested can develop into an adult tapeworms

Echinococcus multilocularis

The intermediate host for ______ is the microtine rodent

E. multilocularis

____ lacks the thick cyst wall (key difference)

Looks alveolar or like a bunch of grapes

Very invasive and replaces normal tissues

E. multilocularis

This tapeworm comes about via the cat eating rodents with hydatid cyst and each protoscolex develops into the adult tapeworm intestine

Mesocestoides

Found in the small intestine of carnivors

This is the ONLY tapeworm that uses 2 intermediates hosts

1st intermediate host: oribatid mite that ingest the proglottids which will then develop into the cysticercoid

2nd intermediate host: rodents, birds, reptiles, or amphibians that ingest the mite then the cysticercoid inside develops into the Tetrathyridium (larval tapeworm)

Definitive Host: Canids (Dogs, foxes, coyotes)

the tetrathyridial larvae multiply exponentially - huge numbers are of larvae are infective to the dogs and cats which are the definitive hosts.

Pseudotapeworms

• Spirometra

• Diphyllobothrium

Spirometra

First Intermediate Host: Tiny freshwater crustaceans ingest the hatched parasite embryos in the water, which then develop into procercoids.

Second Intermediate Host: Vertebrates such as frogs, snakes, birds, or mammals. When the copepod is eaten, the larvae migrate to the muscles and tissues, developing into a stage called a plerocercoid (sparganum).

Definitive host of this pseudotapeworms is cats, raccoons, dogs and other carnivores.

Diphyllobothrium

“Fish tapeworm”

Intermediate host: Fish

Definitive host: Dogs get infected by eating raw fish