Intestinal Tapeworms

Question 1

Life cycles of pseudophyllydeans involve___ as the 1st intermediate host and____ as the 2nd intermediate host

Answer 1

crustaceans ; fish

Question 2

pseudophyllidean order have a scolex with dorsal and ventral longitudinal grooves called ___, that may vary structurally between different species (aids in taxonomic studies)

Answer 2

bothria

Question 3

Differences between Pseudophyllidean Cyclophyllideans

Answer 3

• In pseudophyllideans, the uterus opens to a pore
• In Pseudophyllideans, Fertilized eggs are shed continuously from the proglottids, rather than accumulating in the uterus as seen in Cyclophyllideans

Question 4

Also called the broad fish tapeworm, this cestode is common in fish-eating carnivores, particularly in northern Europe

Answer 4

Diphyllobothrium latum

Question 5

parasite lacks host specificity, occurring in many canines and felines, bears, and humans

Answer 5

Diphyllobothrium latum

Question 6

____ is 10-20 mm wide, and consist of > 3,000 proglottides, making it the largest human tapeworm

Answer 6

Diphyllobothrium latum

Question 7

____ is anapolytic (retains terminal proglottides) & releases long chains of spent proglottides, showing that the infected person has a secret gues

Answer 7

Diphyllobothrium latum

Question 8

Diphyllobothrium latum eggs are expelled through the __

Answer 8

uterine pore,

Remember pseudophyllideans uterus open to a pore

Question 9

D. latums crustacean intermediate host belong to what two genuses?

Answer 9

genus Diaptomus or Cyclops.

Question 10

Procercoid of D. latum enter the intestinal wall and migrate to the body muscles. There it develops into a long (2-4 cm) pseudosegmented ___

Answer 10

plerocercoid

Question 11

How does infection occur of human host by D. latum?

Answer 11

Infection of definitive host takes place when plerocercoids in raw/poorly cooked/steamed/pickled fish are eaten

Question 12

What are symptoms of infection by D. latum, the BIG sign of infection?

Answer 12

A characteristic anemia is common because D. latum competes with the host in regards to competitive uptake of dietary vitamin B12, a vitamin important in the synthesis of hemoglobin

Question 13

Treatment for D. latum?

Answer 13

Praziquantel given orally as a single dose in the morning is effective.
Vitamin B12 should be given to all patients

Question 14

Infectious stage of Diphyllobothrium latum is___

Answer 14

plerocercoid stage found in fish muscles

Question 15

The largest group of cyclophyllideans is the ___tapeworms

Answer 15

Taenia

Question 16

____(beef tapeworm) is the most common of tapeworms of humans, occurring in nearly all countries where beef is eaten

Answer 16

Taenia saginata

Question 17

How is Taenia saginata diagnosed?

Answer 17

gravid proglottids passed in feces usually brought to physician for diagnosis

Question 18

How do you diagnose T. saginata vs. T solium?

Answer 18

By examining a gravid uterus.
T. saginata has a bilobed ovary and twice as many testes as T. solium.
If entire worm is passed, unarmed scolex leads to accurate diagnosis

Question 19

What is the first sign of infection by Taenia saginata?

Answer 19

The first sign of infection is the presence of gravid proglottids in feces

Question 20

What are symptoms of Taenia saginata infection?

Answer 20

• Saginata taeniasis condition is mostly asymptomatic

- Symptoms associated with this tapeworm: abdominal pain, nausea, headache, diminished appetite and weight loss

Question 21

What is the most important menas of prevention and control of Taenia saginata?

Answer 21

• Meat inspection for the white pin-head sized cysts is the most important public health measure
• adequate treatment of sewage is also very important

Question 22

The most potentially dangerous adult tapeworm of humans, occurring in all countries where pork is eaten, is the pork tapeworm __

Answer 22

Taenia solium

Question 23

Why is Taenia solium dangerous?

Answer 23

Taenia solium is dangerous becasue of self-infection by cysticerci

Question 24

The life cycle of T. solium strongly matches that of T. saginata, except that intermediate hosts are __instead of cattle

Answer 24

pigs

Question 25

What are Taenia solium infection symptoms?

Answer 25

Presence of one adult tapeworm causes no distinct symptoms, which is usually the case. However, the armed scolex may cause vague abdominal pain (irritation of the intestinal lining). There is superficial damage at the site of attachment of the scolex

Question 26

Human infection with the cysticercus (bladderworms) of T. solium is also possible. This condition, called ___

Answer 26

human cysticercosis

Question 27

How do you diagnose T. solium?

Answer 27

Presence of gravid proglottids or eggs in feces

Question 28

Commonly known as the dwarf tapeworm of mice and humans, _____is the most common cestode of humans in the world, especially among children

Answer 28

Hymenolepis nana

Question 29

This is the smallest tapeworm infecting humans

Answer 29

Hymenolepis nana

Question 30

In villi, oncophores of Hymenolepsis shed 6 hooklets; 4 days later, becomes a modified larva called ___

Answer 30

cercocystis

Question 31

How is the life cycle of Hymenolepsis nana unique?

Answer 31

An intermediate host is optional in the life cycle

Question 32

How does infection by Hymenolepsis nana occur?

Answer 32

Direct contaminative infection by eggs is probably the most common route in human cases. However, accidental ingestion of an infected grain beetle or flea cannot be ruled out

Question 33

What is the optional intermediate host of Hymenolepsis nana?

Answer 33

Flour beetle

Question 34

How does autoinfection by Hymenolepsis occur?

Answer 34

Eggs release by the gravid proglottids can hatch in the small intestine and re-infect the same host rather than become excreted in feces

Question 35

Where is the highest rate of infection by Hymenolepsis nana?

Answer 35

Moscow Russia

Question 36

A household shared with rats is likely to have its cereal foods infested by flour beetles, which leads to the infection by ___

Answer 36

Hymenolepsis nana

Question 37

What are symptoms of infection by Hymenolepsis nana?

Answer 37

Hymenolepiasis is asymptomatic during light infections.With > 2000 worms, damage to the intestinal mucosa may produce enteritis
Auto-infection is common in children and immunosuppressed patients
In such cases, diarrhoea, vomiting, dizziness, abdominal pain, and loss of appetite may occur

Question 38

How is diagnosis of Hymenolepsis conducted?

Answer 38

Diagnosis is via identifying eggs in the feces. Gravid proglottids usually break up in the large intestine and releases the eggs

Question 39

What is the treatment for Hymenolepsis nana and why does it require more treatment

Answer 39

Praziquantel is very effective against adult worms but not against young cysticercoids; thus, additional chemotherapy may be necessary like niclosamide etc

Question 40

___is known as the cucumber tapeworm

Answer 40

Dipylidium caninum

Question 41

____is a common parasite of domestic dogs, cats, and humans, especially children, and is universal in distributio

Answer 41

Dipylidium caninum

Question 42

___is easily recognized because each segment has two sets of male and female reproductive systems and a genital pore on each side

Answer 42

Dipylidium caninum

Question 43

How do you diagnose Dipylidium caninum?

Answer 43

The proglotttids of this tapeworm look like cucumber seeds

Question 44

What is the intermediate host of Dipylidium caninum?

Answer 44

larvae of fleas or louse

Question 45

How is Dipylidium caninum an example of hyperparasitism?

Answer 45

The intermediate host, a flea, is itself a parasite carrying a parasite