Helminthes (worms)

Helminthes

sub kingdom metazoaPhylum Nemathelminthes

(round worms)

class Nematodae

(intestinal round worm)

class Filariea

(tissue round worm)

PhylumPlatyhelminthes

(flat-worms)

classCestodea

(tape worm)

classTrematodea

(Flukes)

Nematodes (round worm)

General characteristics• -bilaterally symmetrical, unsegmented and elongated, • -The body is covered with a non cellular cuticle.• -The sex is separated ( bisexual the )female is longer

than the male.• -Size varies from less than one mm to several

centimeters. • -Digestive system is complete with mouth, gut &

anus. • -Nervous system is very simple.• -Reproductive system is well developed. • The fundamental stages in are the egg , larva & the

adult..

Enterobius vermicularisThreadworm, Pinworm, Seatworm, or Oxyuris vermicularis.

(entero = intestine, bius = live) , (oxy = sharp, uris = tail).

Epidemiology

• -It is cosmopolitan. • -It is more common in cold, temperate than in

tropical and subtropical climates.

• (decrease bathing and less change of the (underwear, so more chance to infection.

Morphology

Mode of transmission

1-Anus to mouth by: a-contaminated finger: (reinfection). b-contaminated night clothes, bed linen, etc.2-Airborne.3-Retroinfection.4-People sleeping in the same bed or bedroom, also contaminated toilet seat and wears.

Pathology and clinical manifestations • Majority of infections are asymptomatic.• -Pruritis ani is main clinical manifestation, which

results from:• 1-tickiling sensation from the emergence of the

adult female worm.• 2-biproduct of adult worms.• 3-sticky albumin material coated the eggs.• -Perianal excoriation, abdominal pain,

appendicitis and eosinophilia are other manifestations.

Behavioral changes

• -nail biting, • -nose picking, • -grinding of teeth during night, • -inattention and poor cooperation

• nervousness, night mare, insomnia, anorexia, loss of weight, tiredness and dark shadow under the eye.

Ectopic enteropiasis

•-Ectopic migration of worms may cause•-vaginitis ,•-omentiti ,•-cervisitis ,

•-peritonitis and •-recurrent UTI.

Diagnosis

1-History and clinical finding:2-Specific diagnosis by detection of: -Adult worms in a-stool (on the surface). b-peri-anal area -Eggs: by

• a-Scotch tape slide method: 95% of infected cases.

• b-Stool examination :• 5% of infected cases

Treatment

-Mebendazole (vermox) repeated after 7-10 days.

-All family must be treated.-All bed lines & towels washed in hot water &

the home must be cleaned.

Trichuris trichiura (Whipworm)

• -It occurs worldwide.• -most common in warm moist climates and

areas where sanitation is poor.

Trichiuris trichiura: adult worms (female and male)

Egg of Trichiuris trichiura

Pathogenesis and clinical features

• -Abdominal pain, weight loss, or epigastric pain.• -Rectal prolapsed (probably due to toxic

irritation of nerve endings).• -Anaemia due to heavy worm load.• -Malnutrition.• -Bloody diarrhea.• -Acute appendicitis due to mechanical blockage.• -Eosinophilia

Diagnosis

1-Stool examination a-typical barrel shaped eggs. b-occasionally an adult worm may appear in

stool.2-Sigmoidoscopy• In heavy infection, sigmoidoscopy may show the

white bodies of the worm hanging from the inflamed mucosa- the so called coconut cake rectum.