Hookworms

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Hookworms
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Hookworms

• The hookworms cause hookworm disease,
  which is one of the five major parasitic disease
  in China(malaria, shistosomiasis, filariasis,
  kala- azar and hookworm disease). At least two
  species of hookworms infect man, Necator
  americanus and Ancylostoma duodenale. They live
  in small intestine.

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I.   Morphology

• 1. Adults They look like an odd piece thread and
  are about 1cm. They are white or light pinkish
  when living. ?is slightly larger than?.The males
  posterior end is expanded to form a copulatory
  bursa.
• 2. Eggs 6040 µm in size, oval in shape, shell
  is thin and colorless. Content is 2-8cells.

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Differences between two hookworms
Adults of A. duodenale
Adults of N. americanus
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• Scanning electron micrograph of the mouth capsule
  of Ancylostoma duodenale, note the presence of
  four "teeth," two on each side.

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• Scanning electron micrograph of the mouth capsule
  of Necator americanus, another species of human
  hookworm.  Note the presence of two cutting
  "teeth.

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• Ancylostoma duodenale - copulatory bursa and
  spines of male(a side view)

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• Copulatory bursa of N. americanus(a side view)

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• Left picture Copulatory bursa and spines of N.
  americanus(a side view)
• Right picture copulatory bursa of A. duodenale(a
  top view)

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• Morphologically it is not possible to
  differentiate between A. duodenale and N.
  americanus. Interference contrast. 400.
  Enlarged by 5.4.

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3.The Morphological Differences between Two
species of Hookworms

• __________________________________________________
  ___
• A. duodenale
  N. americanus
• __________________________________________________
  ____
• Size larger
  smaller
• __________________________________________________
  ____
• Shape single curve, looks like C
  double curves, looks like S
• __________________________________________________
  ____
• Mouth 2 pairs of ventral teeth
  1peir of ventral cutting plates
• __________________________________________________
  __________
• Copulatory circle in shape
  oval in shape
• Bursa (a top view)
  (a top view)
• __________________________________________________
  __________
• Copulatory 1pair with separate
  1pair of which unite to form
• spicule endings
  a terminal hooklet
• __________________________________________________
  _____
• caudal spine present
  no
• __________________________________________________
  _____
• vulva position post-equatorial
  pre-equatorial
• __________________________________________________
  _____

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II. Life Cycle

• 1.  Final host man
• 2.  Inf. Stage Larva 3 or filariform larva
• 3.  Inf. Route by skin
• 4.  Food blood and tissue fluid
• 5.  Site of inhabitation small intestine
• 6.  Life span Ad 15years, Na 3-7years
• 7. Blood-lung migration
• skin, cavum, right heart, lungs

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Life cycle of hookworm
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III. Pathogenesis and Clinical Manifestations

• 1. Larval migration
• (1) Dermatitis, known as "ground itch" or
  "stool poison".The larvae penetrating the skin
  cause allergic reaction, petechiae 0r papule
  with itching and burning sensation. Scratching
  leads to secondary infection.
• (2) pneumonitis (allergic reaction),
  Loeffier's syndrome cough, asthma, low fever,
  biood-tinged sputum or hemoptysis, chest-pain,
  inflammation shadows in lungs under X-ray. These
  manifestations go on about 2 weeks.

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• 2. Adults in small intestine
• (1) Epigastric pain as that of a duodenal
  ulcer.
• (2) A large worm burden results in
  microcytic hypochromatic anemia (character
  manifestation). The symptoms are lassitude,
  edema, palpitation of the heart. In severe case,
  death may result from cardiac failure or physical
  exhaustion.
• (3) Allotriophagy (orpica) is due to the
  lack of trace element iron .
• (4) Amenorrhea, sterility, abortionmay take
  place in women.
• (5) Gastrointestinal bleeding
• (6) Infantile hookworm disease

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Adults in intestinal mucosa
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Iv. Diagnosis

• Criterion 1. hemoglobin is lower than
  120g/L in man, 110g/L in woman. 2. find hookworm
  egg
• Method
• 1. saturated brine flotation technique
• 2. direct fecal smear
• 3. culture of larvae
• V. Treatment
• 1. Albendazole 2. Mebedazole
• VI. Epidemiology
• worldwide distribution. 22-26? is the optimal
  temperature for Ancylostoma duodenale
  development, Ancylostoma duodenale mainly
  prevalent in north of China. 31-35? is suitable
  for Necator americanus, it is mainly prevalent in
  south of China
• VII. Prevention
• Unified measures 1. sanitary disposal of night
  soil, 2. individual protection, 3. health
  education, 4. cultivate hygienic habits, 5.
  treat the patients and carriers.