Intestinal Tapeworms Flashcards
Life cycles of pseudophyllydeans involve___ as the 1st intermediate host and____ as the 2nd intermediate host
crustaceans ; fish
pseudophyllidean order have a scolex with dorsal and ventral longitudinal grooves called ___, that may vary structurally between different species (aids in taxonomic studies)
bothria
Differences between Pseudophyllidean Cyclophyllideans
- 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
Also called the broad fish tapeworm, this cestode is common in fish-eating carnivores, particularly in northern Europe
Diphyllobothrium latum
parasite lacks host specificity, occurring in many canines and felines, bears, and humans
Diphyllobothrium latum
____ is 10-20 mm wide, and consist of > 3,000 proglottides, making it the largest human tapeworm
Diphyllobothrium latum
____ is anapolytic (retains terminal proglottides) & releases long chains of spent proglottides, showing that the infected person has a secret gues
Diphyllobothrium latum
Diphyllobothrium latum eggs are expelled through the __
uterine pore,
Remember pseudophyllideans uterus open to a pore
D. latums crustacean intermediate host belong to what two genuses?
genus Diaptomus or Cyclops.
Procercoid of D. latum enter the intestinal wall and migrate to the body muscles. There it develops into a long (2-4 cm) pseudosegmented ___
plerocercoid
How does infection occur of human host by D. latum?
Infection of definitive host takes place when plerocercoids in raw/poorly cooked/steamed/pickled fish are eaten
What are symptoms of infection by D. latum, the BIG sign of infection?
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
Treatment for D. latum?
Praziquantel given orally as a single dose in the morning is effective.
Vitamin B12 should be given to all patients
Infectious stage of Diphyllobothrium latum is___
plerocercoid stage found in fish muscles
The largest group of cyclophyllideans is the ___tapeworms
Taenia
____(beef tapeworm) is the most common of tapeworms of humans, occurring in nearly all countries where beef is eaten
Taenia saginata
How is Taenia saginata diagnosed?
gravid proglottids passed in feces usually brought to physician for diagnosis
How do you diagnose T. saginata vs. T solium?
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
What is the first sign of infection by Taenia saginata?
The first sign of infection is the presence of gravid proglottids in feces
What are symptoms of Taenia saginata infection?
- Saginata taeniasis condition is mostly asymptomatic
- Symptoms associated with this tapeworm: abdominal pain, nausea, headache, diminished appetite and weight loss
What is the most important menas of prevention and control of Taenia saginata?
- Meat inspection for the white pin-head sized cysts is the most important public health measure
- adequate treatment of sewage is also very important
The most potentially dangerous adult tapeworm of humans, occurring in all countries where pork is eaten, is the pork tapeworm __
Taenia solium
Why is Taenia solium dangerous?
Taenia solium is dangerous becasue of self-infection by cysticerci
The life cycle of T. solium strongly matches that of T. saginata, except that intermediate hosts are __instead of cattle
pigs
What are Taenia solium infection symptoms?
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
Human infection with the cysticercus (bladderworms) of T. solium is also possible. This condition, called ___
human cysticercosis
How do you diagnose T. solium?
Presence of gravid proglottids or eggs in feces
Commonly known as the dwarf tapeworm of mice and humans, _____is the most common cestode of humans in the world, especially among children
Hymenolepis nana
This is the smallest tapeworm infecting humans
Hymenolepis nana
In villi, oncophores of Hymenolepsis shed 6 hooklets; 4 days later, becomes a modified larva called ___
cercocystis
How is the life cycle of Hymenolepsis nana unique?
An intermediate host is optional in the life cycle
How does infection by Hymenolepsis nana occur?
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
What is the optional intermediate host of Hymenolepsis nana?
Flour beetle
How does autoinfection by Hymenolepsis occur?
Eggs release by the gravid proglottids can hatch in the small intestine and re-infect the same host rather than become excreted in feces
Where is the highest rate of infection by Hymenolepsis nana?
Moscow Russia
A household shared with rats is likely to have its cereal foods infested by flour beetles, which leads to the infection by ___
Hymenolepsis nana
What are symptoms of infection by Hymenolepsis nana?
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
How is diagnosis of Hymenolepsis conducted?
Diagnosis is via identifying eggs in the feces. Gravid proglottids usually break up in the large intestine and releases the eggs
What is the treatment for Hymenolepsis nana and why does it require more treatment
Praziquantel is very effective against adult worms but not against young cysticercoids; thus, additional chemotherapy may be necessary like niclosamide etc
___is known as the cucumber tapeworm
Dipylidium caninum
____is a common parasite of domestic dogs, cats, and humans, especially children, and is universal in distributio
Dipylidium caninum
___is easily recognized because each segment has two sets of male and female reproductive systems and a genital pore on each side
Dipylidium caninum
How do you diagnose Dipylidium caninum?
The proglotttids of this tapeworm look like cucumber seeds
What is the intermediate host of Dipylidium caninum?
larvae of fleas or louse
How is Dipylidium caninum an example of hyperparasitism?
The intermediate host, a flea, is itself a parasite carrying a parasite
