ANCYLOSTOMA DUODENALE:  

Phylum: Nemahelminthes

Class: Nematodes

Common Name: Hookworm


HABITAT:-

The adult parasite lives in the small intestine of man, mostly in the jejunum.

MORPHOLOGY:-

It exists in two forms-
i. Adult.
ii. Larva 

ADULT WORM:-

  • They are reddish-brown in color.
  • Anterior end is bent - dorsally hence the name is hookworm.
  • Mouth has 4- pointed teeth, two on the ventral aspect, and two on the dorsal aspect.


MALE:-

  • It measures about 8-11 mm and the posterior end has umbrella-like copulatory bursa.
  • It has 3 membranous lobes (2- ventral & 1- dorsal).

  

FEMALE:-

  • It measure about 10-13 mm.
  • Its posterior is tampering and vulva open at the junction of the posterior and middle a third of the body. 
  • Female are oviparous and produce up to 10,000 - 25,000 eggs per day with stool.


EGG:-

  • Eggs are oval 60×40 um. They are colorless and covered with the transparent hyaline cell membrane.
  • Ovum present in the segmented with four blastomeres, freshly passes eggs are not infective to humans.
  • The further development of eggs occurs in the soil. The eggs hatch to produce the Rhabditiform larva. 
  • There is a clear space between the Eggshell and segmented ovum.


LIFE CYCLE:-

Hookworm has a simple life cycle. No intermediate site is required like other helminths. It doesn't multiply inside the human body. Man is the definite host. The infective host is the filariform larva.

Filariform larva infect the human by penetrating the skin
They invade the bloodstream.
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Reaches to the lungs.
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In the lungs, they penetrate through the capillaries & reach the alveoli.
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From here larva ascends to bronchial tree, trachea, larynx, pharynx. (In pharynx organs are developed)
 ⇓
The larva then crawls over the epiglottis & swollen with saliva.
 ⇓
It reaches the small intestine where it attached to the mucosa & grows into an adult in 3-4 weeks.
 ⇓
After 5 weeks, the worms attain sexual maturity, fertilization occurs & female lay eggs that pass along with the stool.
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Further development of the eggs takes place in the soil.
 ⇓
Rhabditiform larva hatches out from the eggs in 48 hours.
 ⇓
Rhabditiform larva moulds twice to develop into infective filariform larva in 8-10 days.
 ⇓
Thus, the life cycle is repeated again.

PATHOGENESIS/CLINICAL FEATURES:-

I. Due to larva:- It causes pruritic micropapillary dermatitis or ground itch at the side of the skin penetration. It lasts up to 2-4 weeks. 

II. Due to adult worm:- It causes- 
  • Microcytic Hypochromic Anaemia:- Adult worm suck the blood through the wound When it attached to the intestinal villi. 
  • Development of Iron Deficiency Anaemia:- It is related to the intensity and duration of the infection.
  • Epigastric pain.
  • Diarrhea.
  • Vomiting.


LAB DIAGNOSIS:- 


i. Stool Examination:- for the identification of eggs .

ii. Blood Examination: Eosinophilia and microcytic Hypochromic Anaemia. 

TREATMENT:- 

i. Antihelmintic Drugs:- It includes - 
  • Mebendazole.
  • Albendazole.
  • Pyrantel pamoate.

ii. Oral iron replacement.
iii. Nutritional support. 

PREVENTION:- 

  • Proper disposal and treatment of sewage to avoid soil pollution. 
  • Avoid walking barefoot.
  • Education on personal hygiene.