Intestinal Cestodes Flashcards
Region of growth in cestodes
Neck
Body of the cestode
Strobila
- Proglottids - segments of strobila
- Anterior part - Contains the essential digestive parts
- Middle part - Reproductive parts
- Terminal portion - Gravid eggs
Attachment and anterior part of cestodes
Head / Scolex
* Houses the cephalic ganglion
The common name of Diphyllobotrium latum
Freshwater Broad fish tapeworm
The common name of Taenia solium
Pork tapeworm
The common name of T. saginata
Beef tapeworm
The common name of T. asiatica
Taiwan taenia
The common name of E. granulosus
Hydatid worm
The common name of Dipylidium caninum
Dog tapeworm / Double pored tapeworm
The common tapeworm of rats
Raillietina garisoni
Chain of egg-producing units
Progglotids
> They develop posteriorly from the neck region of the scolex
Cestodes are otherwise known as
Tapeworms
Characteristic body of cestodes
Ribbonlike
The crown of the scolex
Rostellum
* may be armed with hooks/ unarmed
The mature cestode is _ which means it contains both female and male reproductive organs
Hermaphroditic
Food is absorbed from the house through the cestode’s _
Integument
Outer covering/skin of the organism through diffusion
Oncosphere
Larva tapeworm within an embryonic envelope
The infective stage of cestodes
Hexacanth embryo / Oncosphere
The largest human tapeworm
Diphyllobothrium latum (Adults=15 m in length with 3000-4000 proglottids)
Uterine structure of D. latum
Rosette-shaped uterine structure
Number of sucking grooves/ bothria in D. latum
Two (shallow sucking grooves)
Only cestode to have an aquatic life cycle
D. latum
Reservoir host and Definitive host of D. latum
Reservoir: fish
Definitive: humans
How many intermediate hosts does D. latum require?
2
1st: Copepods (houses the first larval stage: coracidium and produces procercoid through shedding)
2nd: Fish / Crustaceans (ingests INFECTIVE procercoid larva, and develops to plerocercoid)
Infective stage of D. latum
Plerocercoid
Difference of coracidium, Procercoid, and plerocercoid
Coracidium: Has epithilium, ciliated, and bears 6 terminal hooks
Procercoid: Does not have epithelium (shedded coracidium)
Plerocercoid: Ribbonlike organism with an undivided scolex
D. latum matures into an adult tapeworm within the human _
Small intestine
D. latum eggs are sometimes confused with _ eggs
Paragonimus eggs
Cestode infection that is transmitted to humans through the ingestion of dog and cat fleas
Dipylidium caninum
Also known as the dwarf tapeworm
Hymenolepis nana
Only cestode that requires 2 intermediate hosts
D. latum
Identify the parasite:
Cucumber seed appearance/resemblance to a dried grain of rice
Dipylidium caninum
Intermediate host of D. caninuum
Intermediate host: Dog/cat flea
*Reservoir hosts: humans, cats, dogs
Since D. latum proglottids may be shed in the feces, and may stick to the skin around the anal area, they may be misdiagnosed as an infection of _
Enterobius vermicularis
- symptoms of D. caninum are also very similar to pinworm infection
Infective stage of D. caninum
Cysticercoids
Identify:
Patient has an appearance of seedlike particles in the stool and undergarments of the patient
D. caninum
The most common tapeworm with worldwide distribution
Hymenolepis nana
Cestode infection wherein intermediate host is NOT required, allowing person-to-person spread possible
H. nana
Humans are _ host in H. nana infection
Intermediate AND Definitive
Refers to a large parasitic burden within the host
Hyperinfection
T/F
H. nana is capable of autoinfection and Hyperinfection
TRUE
*Autoinfection- constant reproduction of the parasite within the host
Difference of nana and diminuta eggs
H. nana eggs are smaller and have 4-8 POLAR FILAMENTS present in the space between the oncosphere and the eggshell
Also known as the rat tapeworm
Hymenolepis diminuta
Humans are the _ host in T. solium
Definitive & intermediate host
** presence of both adult and larval stages
Intermediate host of T. solium
Pigs
Can t. solium invade the CNS?
Yes (severe form)
The major complication (patholgy) of T. solium
Cysticercosis
T/F:
T. solium and T. saginata can be differentiated on the basis of egg morphology
FALSE. T. solium and T. saginata CANNOT be differentiated on the basis of egg morphology
Number of lateral uterine branches in T. saginata and T. solium
T. saginata: >13 uterine branches
T. solium: 7-13 uterine branches
Stain for uterine braches
India ink
DOC for cestode infections
Praziquantel
Cysticerci do not survive temperatures below _ or above _
below -10C
above 50C
What is the 3rd taenia spp?
Taenia asiatica
D. latum is previously known as _
Dibothriocephalus latus
Most common parasitic disease of the CNS
Cysticercosis
Longest cestode
T. saginata
Smallest cestode
H. nana
Shortest cestode
E. granulosus
Tapeworm that can cause megaloblastic anemia
D. latum
