Intestinal Nematodes

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Intestinal Nematodes
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Classification of Parasites
helminths Protozoa
Mulicellular Specialized cells Unicellular Single cell for all function
Round worms (Nematodes) cylindrical, unsegmented Flat worms 1-Trematodes leaf-like, unsegmented. 2-Cestodes tape-like, segmented Amoebae move by psudobodia. Flagellates move by flagella. Ciliates move by cilia Apicomplexa (sporozoa) Tissue parasites

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Nematodes General features

1. Elongated worm, cylindrical, unsegmented and
   tapering at both ends.
2. Variable in size, measure lt1 cm to about 100cm.
3. Sex separate and male is smaller than female

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• Nematodes Location in the human body

• Intestinal nematodes
• Tissue nematodes

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Nematodes common intestinal infections

• Common intestinal nematode infections
• Enterobius (Oxyuris) vermicularis
  (Pinworm,seatworm,threadworm)
• Trichuris trichiura (whipworm)
• Ascaris lumbricoides (roundworm)
• Ancylostoma duodenale Necator americanus
  (hookworms)
• Strongyloides stercoralis

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Enterobius vermicularis (Oxyuris)

• (Common names Pin worm, seat worm, thread worm(
• Found all over the world.
• adult in lumen of cecum and appendix from which
  adult female migrate to rectum.
• It can be seen by naked eye as white thread
  1cm.
• Male is smaller than female 0.5cm, with coiled
  end.

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Enterobius vermicularis (Oxyuris)
LIFE CYCLE
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Enterobius vermicularis (Oxyuris)

• Pathology
• Majority of infections are asymptomatic.
• Main clinical presentation pruritus ani
• perianal excoriation
• Ectopic enterobiasis occurs in female when invade
  vulva and vagina result in valvovagintis
• Usually accompanied by insomnia, anorexia,
  loss of weight and concentration (Side effect)

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Enterobius vermicularis (Oxyuris)
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Enterobius vermicularis (Oxyuris)
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Enterobius vermicularis (Oxyuris)

• Treatment
• ??Albandazole , Mebendazole
• for whole family

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Ascaris lumbricoides
(roundworm)
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Ascaris lumbricoides
(roundworm)
Ascaris adult
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Ascaris lumbricoides
(roundworm)

• The commonest human helminthes infection.
• Found in jejunum and upper part of ileum.
• Female 20 cm longer than male 10 cm
• Feed on semi digested food.

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Ascaris lumbricoides
(roundworm)
LIFE CYCLE
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Ascaris lumbricoides
(roundworm)
Ascaris egg (embryonated)
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Ascaris eggs
Ascaris larva emerging from egg
Ascaris egg (embryonated)
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Ascaris lumbricoides
(roundworm)

• Pathology
• 1-Adult worm
• Light infection asymptomatic.
  
• Heavy infection intestinal obstruction
• Migrating adult to bile duct -jaundice
• 2-Larvae Loefflers syndrome (imp)
• Pneumonia, cough with bloody sputum
  
• Eosinophilia, urticaria

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Ascaris lumbricoides
(roundworm)
Loefflers syndrome Larvae in lung
pnumonia,cough ,bloody sputum
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Ascaris lumbricoides
(roundworm)
Ascaris larva in lung
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Ascaris lumbricoides
(roundworm)

• Diagnosis
• -eggs in stool.
• -larvae in sputum.
• -adult may pass with stool.

• Treatment Albendazole , Mebendazole

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Trichuris trichiura (Whipworm)
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Trichuris trichiura (Whipworm)
LIFE CYCLE
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Trichuris trichiura (whipworm)

• World wide ,common in poor sanitation.
• It coexists with Ascaris because of similar
  requirement.
• Adult live in large intestine especially caecum
  and appendix in heavy infection the whole
  length of large intestine affected.
• Male and female worm have narrow anterior
  portion penetrate the intestinal mucosa

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Trichuris trichiura (Whipworm)

• Pathology
• light infection asymptomatic
• heavy infection abdominal pain ,bloody
  diarrhea. Rectal prolapse in children is a common
  complication.
• -

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Trichuris trichiura (Whipworm)
Embryonated egg Unembryonated egg
Infective stage Diagnostic stage
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Trichuris trichiura (Whipworm)

• -Diagnosis egg in stool characterized by its
  barrel shape with mucoid plugs at each pole .
• Treatment Albendazole.

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Hook worms Ancylostoma dudenale Necator
americanus
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Hook worms
Buccal cavity attached to intestinal mucosa
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Hook worms Ancylostoma dudenale Necator
americanus
LIFE CYCLE
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Hook worms Ancylostoma dudenale Necator
americanus

• A common cause of anemia.
• Found in small intestine mainly jejunum.
• Its buccal capsule (mouth) lined with hard hooks,
  triangular cutting plates and anticoagulant
  glands.

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• Hook worms
• Pathology clinical picture

• - larvae
• At the site of entry of larvae (ground
  itch).
• Migration phase
• cough with bloody sputum
• pneumonia, eosinophilia,u rticaria.
• - adult worm
• low worm burden no symptoms.
• Moderate to heavy burden
• Epigastric pain, vomiting , hemorrhagic
  enteritis.
• Protein loss hypoproteinaemia edema.
• Anemia due to withdrawal of blood by parasites
  and hemorrhage from punctured sites lead to
  sever anemia microcytic hypochromic .

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Hook worms Diagnosis and treatment

• Diagnosis
• -Eggs in stools.
• -occult blood ()

Treatment Albendazol, Mebendazole
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Strongyloides stercoralis

• Widely distributed in tropical region worldwide .
• fetal opportunistic in immuno-compromised host.
• It is smallest pathogenic nematodes
• 2.5mm.
• adult live in mucous membrane of duodenum jejunum
  rarely m.m.of bronchus.

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Strongyloides stercoralis
LIFE CYCLE
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Strongyloides stercoralis Pathology and
clinical picture

• Cuteneous little reaction on penetration.
• sever dermatitis at perianal region in
• case of external autoinfection.
• Migration same as hook worms .
• Intestinal inflammation of upper intestinal
  mucosa, diarrhea, upper abdominal pain clocky in
  nature.
• Disseminated strongyloidiasis in patient with
  immunodeficiency ,uncontrolled diarrhea
  granulomatus changes necrosis--perforation--peri
  tonitis--death.

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Strongyloides stercoralis

• Diagnosis
• rhabditiform larvae diagnostic stage in
• -Stool examination
• -Duodenal aspirate
• Treatment Albandazole, Mebendazole