Hookworms such as Ancylostoma duodenale and Necator americanus infect humans and cause hookworm disease. They live in the small intestine where the female lays eggs that are passed in feces. When the eggs hatch in soil, they release larvae that can penetrate human skin, enter the bloodstream and mature into adult worms in the intestine. Symptoms include abdominal pain, diarrhea, and iron-deficiency anemia. Diagnosis is by finding eggs in stool samples under microscopy. Treatment involves anthelmintic drugs while prevention focuses on proper sanitation and hygiene.

1. Hook worm
Ancylostoma Duodenale
Necator americanus
Prof Dr Naael H Ali
College of Medicine
University of Basrah
Basrah, IRAQ
naael.Ali@uobasrah.edu.iq

2. The hookworms cause hookworm disease,
At least two species of hookworms infect man,
Necator americanus and
Ancylostoma duodenale.
They live in small intestine.

3. Ancylostoma duodenale
Disease: ancylostomiasis .
Distribution: Worldwide especially in tropical and subtropical areas.
Definitive host: Man only.
Habitat: Small intestine, particularly in the jejunum and less often in the
duodenum.
Infective stage: Third stage filariform larva.
Life cycle:
•Adult worm inhabiting the small intestine of man .
•Female worm lays eggs which are not infective for humans.
•When deposited in the soil, the embryo develops inside the eggs.

5. •Rhabditiform larva, hatches out of the egg, molts twice, to
become the third-stage infective filariform larva.
•When a person walks barefooted on soil containing the filariform
larva, they penetrate the skin and enter the subcutaneous tissue.
•Larvae are carried along the venous circulation to the right side
of the heart and to the lungs. Here, they escape from the
pulmonary capillaries into the alveoli, migrate up the respiratory
tract to the pharynx, and are swallowed, reaching the small
intestine.
•During migration or on reaching the esophagus, they undergo
third molting. They feed, grow in size, and undergo a final molting
in the small intestine and develop the buccal capsule, by which

6. Morphology
1. Adults: They look like an odd piece thread and are about
1cm. They are white or light pinkish when living. Female is
slightly larger than male .The male’s posterior end is
expanded to form a copulatory bursa.
2. Eggs: 60×40 µm in size, oval in shape, shell is thin and
colorless. Content is 2-8cells

7. Ancylostoma
duodenaletoma :
1-Buccal capsule:
in male & female
 anterior end, enlarged,
with:
• 2 pairs of subequal
ventral teeth-like
thickenings,
 1 pair of dorsal small
tooth-like thickenings

9. 2-Capulatory bursa in male:
 Fan-like expansion of posterior part of
cuticula,
 With rib-like thickenings and 2 thin
separated copulatory bursa.
2 separated spicules

10. posterior end in
male (Bursa) of
A. duodenale

11. Necator
americanus:
1-Buccal capsule:
in male and
female
• anterior end,
enlarged,
• chitinized with 2
cutting plates on
the ventral side.

13. Capulatory
bursa in male:
 Fan-like
expansion of
posterior part of
cuticula,
 with rib-like
thickenings &
2 thin fused
copulatory barbs.

14. posterior end in male (Bursa) of N. americanus

15. Egg:
►Thin shelled transparent, ovoid & measures
64-76 µm in early stages(4-celled) of cleavage
when laid in several hours may reach the early
larval stage, then hatching in 24-48 hrs. to L1.
4- celled
1- celled

16. Eggs of hookworms in unstained wet mount

17. Open mouth
Bulb
C- Rhabditoid larva:
Mouth open
Esophagus short with
bulb

18. D- Filariform larva:
more delicate
closed mouth
long esophagous

19. Bulb
Closed mouth
Ancylostoma duodenale Filariform Larva in
sputum

20. The Human Hookworms
Necator americanus
Ancylostoma duodenale

21. 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
_______________________________________________________
The Morphological Differences between Two species of
Hookworms

22. Pathogenesis and clinical features:
•Hookworm may produce a local irritation at the site of
infection.
•As the worms mature in the jejunum, patients may have
vague colicky abdominal pain, flatulence, nausea,
anorexia, vomiting and diarrhea with red to black stools.
•Each Ancylostoma worm ingests 0.15-0.2 mL of blood
daily leading to anemia.

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

24. 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

26. • D.H:- Man.
• Habitat:-Small
intestine (jejunum)

27. Loeffler’s syndrom

28. Diagnosis:
1.Clinical picture in an endemic area.
2.Demonstration of characteristic oval segmented hookworm eggs in feces by
direct wet microscopy or by concentration methods is the best method of
diagnosis
3.Stool culture: Harada Mori method of stool culture is carried out to
demonstrate third stage filariform larvae
4.Blood examination reveals microcytic, hypochromic anemia and eosinophilia.

29. Treatment:
•Albendazole (400 mg single dose) or mebendazole (500 mg once).
•Treatment of hookworm disease also includes relief of anemia.
Prevention and control:
•Prevention of soil pollution with feces and proper disposal of night soil
and use of sanitary latrines.
•Use of footwear and gloves.
•Treatment of cases.
•Health education.