Helminths: Cestodes/Tapeworms (Exam 2)

A cysticercoid is the ______ stage of cestodes/tapeworms.

larval

A cysticercus is the thin walled, fluid filled bladderlike cyst that encloses the ______.

scolex

The oncosphere is the ______ first stage larva of certain cestodes.

motile

An oncosphere is armed with ______.

6 hooklets

Regarding the oncosphere, an ______ is inside the egg.

embryo

Hermaphroditic means having ______ and ______ reproductive organs within the same individual.

male, female

All tapeworms have ______ reproductive organs in each adult segment.

male and female

Hexacanth embryo

A tapeworm egg containing six hooks

The hooklets are found on the external circle of the ______.

sucker hole

Hooklets are clawlike, retractile hooks that line the ______ of certain tapeworms.

rostellum

Hooklets are used for ______ to the intestinal mucosa, with the aid of suckers.

attachment

Proglottid

In female cestodes, each proglottid contains a ______.

uterus (which holds eggs)

Polar filaments are derived from the epithelial covering of the ______.

oncosphere

Rostellum

The ______ attaches to the wall of the intestine of a host by means of suckers and sometimes hooks.

scolex (3)

The suckers are holes found on the sides of the ______.

scolex (C)

The strobila is the ______ of a tapeworm.

entire body

A copepod is a freshwater ______ that can serve as an intermediate host for some cestodes.

crustacean

A coracidium is a ciliated ______.

hexacanth embryo

Taenia solium common name

Pork (porcine) tapeworm

Taenia saginata common name

Beef (bovine) tapeworm

Hymenolepis diminuta common name

Rat tapeworm

Hymenolepis nana common name

Dwarf tapeworm

Dipylidium caninum common name

Dog (cat) tapeworm

Diphyllobothrium latum/Dibothriocephalus latus common name

Broad Fish tapeworm

Echinococcus granulosus common name

Hydatid tapeworm

Specimen of choice for recovery of Taenia solium and Taenia saginata

Eggs or proglottids in feces

Specimen of choice for recovery of Hymenolepid diminuta and Hymenolepis nana

Eggs in feces

Specimen of choice for recovery of Dipylidium caninum and Diphyllobothrium latum/Dibothriocephalus latus

Eggs or proglottids in geces

Specimen of choice for recovery of Echinococcus granulosus

Protoscolices (larva) in hydatid cyst fluid/tissue

What are the three basic morphological forms of the cestodes?

1. Embryo (oncosphere)

2. Larval stage (metacestode)

3. Adult

The ______ stage is the infective stage for an intermediate host.

embryo (oncosphere)

The larval stage (metacestode) develops from the ______ within the intermediate host.

oncosphere

The adult worm is found in the ______ host.

definitive

S/Sx of Taenia solium and Taenia saginata infection

- Asymptomatic

- Abdominal pain

- Diarrhea

- Weight loss

S/Sx of Hymenolepis diminuta infection are ______.

mild

S/Sx of Hymenolepis nana infection

- Asymptomatic

- Heavy burden causes abdominal pain

- Diarrhea

- Headaches

- Dizziness

Dipylidium caninum infection causes mild ______ disturbances.

intestinal

S/Sx of Diphyllobothrium latum/Dibothriocephalus latus infection

- Intestinal obstruction

- Macrocytic anemia due to vitamin B12 deficiency

- Abdominal pain

- Weight loss

S/Sx of Echinococcus granulosus infection

- Humans: Cysts in liver/lung

- Coughing and pain

- Leakage of fluid causes allergy and eosinophilia

What cestodes infect dogs?

- Echinococcus granulosus

- Dipylidium caninum

What cestode infectes cats?

Dipylidium caninum

Where else can Taenia solium be found besides the intestines?

Larval cystss in the brain, muscles, or other tissues

Taenia solium is the only one that has the ______.

cyst

Where else can Echinococcus granulosus be found besides the intestines?

Liver, lungs, and other organs

Taenia solium egg

30-45um

Round

Thick striated dark brown shell

Taenia solium adult

2-8 meters

4 large suckers

Rostellum with hooks

Taenia solium proglottid

Longer than broad

7-12 uterine branches

Lateral genital pore

For Taenia solium, the infectious stage for humans is the ______.

oncosphere

Taenia saginata egg

30-45um

Oncosphere with 6 hooklets

Round

Thick striated dark brown shell

Taenia saginata adult

4-12 meters

4 suckers

Rostellum has no hooks

Taenia saginata proglottid

Longer

15-30 uterine branches

Lateral genital pore

Hymenolepis nana egg

Polar filaments coming off center embryo into dirty space of the outer shell

6 hooklets on embryo (hexacanth)

Hymenolepis nana scolex

4 suckers

Rostellum with hooks

Cone shaped

Hymenolepis diminuta egg

No polar filaments

Clear area around embryo

6 hooklets on embryo (hexacanth)

Hymenolepis diminuta scolex

4 suckers

No hooks

Club shaped

Hymenolepis diminuta proglottid

Dipylidium caninum egg

Dipylidium caninum proglottid

Dipylidium caninum adult

2 egg holes

Dipylidium caninum definitive and accidental hosts

Definitive: Dogs

Accidental: Humans

Diphyllobothrium latum/Dibothriocephalus latus egg

Diphyllobothrium latum/Dibothriocephalus latus proglottid

Rosette uterus in the middle of each

Diphyllobothrium latum/Dibothriocephalus latus adult

2 suckers

Diphyllobothrium latum/Dibothriocephalus latus infectious stage

Plerocercoid larva

Gravid proglottid

Uterus full of eggs

Diphyllobothrium latum/Dibothriocephalus latus intermediate hosts

copepod and fish

Echinococcus granulosus egg

30-38um

Resembles Taenia eggs

Echinococcus granulosus hydatid sand

Diagnostic stage

Protoscolices in hydatid

Echinococcus granulosus scolex

Echinococcus granulosus proglottids

Immature

Mature

Gravid

12-15 uterine branches in each

The hydatid cyst of Echinococcus granulosus is very ______.

strong