Taenia pathology continued

1
Taenia pathology continued

• 2)Cysticercosis or neurological cysticercosis
  (NC) much more severe than Taeniosis T.
  solium eggs are ingested by human (accidental
  intermediate host). Oncosphere penetrates gut,
  spreads in circulatory system, encysts in
  subcutaneous, intramuscular CNS tissues
  headache, meningitis, epilepsy (1 of leading
  causes in developing countries), seizures,
  blindness, death. Taeniosis may occur in humans
  via reverse peristalsis.

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2
Focus on pathogens Taenia cont.

• Diagnosis/ID see table 20-5, pg 1112
• Genus level
• egg spherical, thick walled, radial
  striations,
  oncosphere with paired hooks visible (?vs
  Hymenolepis)
• characteristic adult morphology scolex,
  strobilus
• proglottids longer than they are wide (vs
  Hymenolepis Diphyllobothrium)
• species level
• T. saginata
• scolex unarmed rostellum (slide 58)
• proglottids lateral uterine branches smaller
  more numerous (15-20)
• T. solium scolex armed rostellum
• proglottids branches larger fewer (8-13)
• Rice grain calcifications on x-ray next slide

3
Rice grain calcifications in muscle of patient
suffering from T. solium cysticercosis
4
Focus on pathogens Hymenolepis nana pg 1112

• The Genus is referred to as dwarf tapeworm. H.
  nana is passed fecal-oral from person to person
  (no intermediate host required) in fecal
  contamination water, food, hands, etc. Rodents
  may serve as a resevoir, but are not necessary to
  the life-cycle.
• IH none DH human
• Epidemiology 1 most common tapeworm infection
  diagnosed in the US world wide. Most prevalent
  where hygiene is poor (infrastructure,
  culturally, institutionally, etc.).
• Pathology/symptoms presence of intestinal adult
  worms causes mild intestinal discomfort like
  Taenia, but severe infections
  result in enteritis.

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5
Focus on pathogens H. nana diagnosis/ID

• Genus level
• egg like Taenia, has oncosphere with hooks,
  but unique in that egg has 2 membranes see
  images next slide
• adult small tape (2 inches), with
  proglottids broader than they are long
• species level
• egg 1 slightly oval, smaller (30-60uM),
  ends are poles or polar thickenings where
  filaments spread between the 2 membranes
• adult rarely found in feces not distinctive

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Focus on pathogens Hymenolepis diminuta

• IH meal beetle DH rodent, human as accidental
  host
• Epidemiology insignificant as a human pathogen
• Pathology/symptoms usually asymptomatic
• Diagnosis/ID eggs more round
  than H. nana, larger (70-90uM), no filaments
  present on the membrane, striated outer???
• adult rarely found in species not
  distinctive. The name suggests he is smaller
  than H. nana, but he is not.

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Focus on pathogens Diphyllobothrium latum

• Weird x 2 pseudophyllidean 2 intermediate
  hosts
• Also called the fish tapeworm or broad
  tapeworm, humans become infected by eating raw,
  pickled /or undercooked fish.
• IH copepod then fish DH human
• Epidemiology endemic to areas with cold fresh
  bodies of water such as Scandanavia (pickled),
  Japan (sushi), Canada, Alaska (eskimos). of
  cases???????
• Pathology/symptoms usually mild intestinal
  discomfort like the other tapes, but due to the
  size, severe infections can result in B12
  deficiency leading to pernicious anemia.

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8
Focus on pathogens D. latum diagnosis/ID

• egg oval, operculate (hard to see), with tiny
  knob on opposite end, 40-75uM. Resembles egg of
  Paragonimus (remember the lung fluke?).
• adult 1 largest tape found in man 3-12M with
  over 3000 proglottids
• proglottids are broader than they are
  long
• scolex almond shaped with lateral bothria
  (2 flaps)
• look at the name Diphyllo bothrium
  latum
• distinguished by combined egg adult
  characteristics

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Focus on pathogens Dipylidium caninum

• Also called cucumber tapeworm, D. caninum is
  primarily a pathogen of pets, rarely humans.
  Fleas or lice ingest the egg-containing feces at
  anus of DH (cat or dog). The DH, which can be
  you, then ingests the fleas or lice. YUCK!
• IH fleas or lice DH 1 cats or dogs 2
  humans
• Epidemiology insignificant as a human pathogen
  filth!!!
• Pathology/symptoms not to worry
• Diagnosis/ID very distinctive presence of
  elongated proglottids that resemble rice grains
  (cucumuber?) and characteristic egg packets in
  feces. Adult ½ meter long.

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More Nematode facts

• Review nematode characteristics slide 39
  a few major distinctions
  different phylum (roundworms), non-semented,
  dioecious, complete digestive tract
• See page 1099 table 20-4, pg 1101
• Intestinal nematodes constitute the most
  prevalent helminth infections in humans. By some
  estimates Ascaris, Ancyclostoma, Trichuris
  Necator alone account for nearly 4 billion
  infections. Infection rates by these pathogens
  in the child population of some countries reach
  90.
• Few nematodes of medical importance require an
  intermediate host, although some (ex. Ascaris)
  require a period of egg maturation outside of DH,
  and some (ex. Ascaris) invade tissues other than
  digestive tract at some point in their
  life-cycle.
• See the basic nematode life-cycle on the next
  slide. To help simplify your life, we will put
  any life-cycle specifics in with the Focus on
  pathogens slides. Dont you feel that anything
  we can do to simplify matters at this point is a
  good idea? I thought so.

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Helminth life cycles - Nematodes