This document describes the general characteristics, morphology, and life cycle of Ancylostoma duodenale, commonly known as the Old World hookworm. It notes that the adult worm is pinkish or creamy gray in color, with a buccal capsule containing 6 teeth used to latch onto the intestinal mucosa. The female worm is 12.5 mm long and lays eggs that pass in feces, while the males are 8 mm long. It also describes the rhabditoid and filariform larval stages that develop outside the host.

1. Ancylostoma
doudenale

2. GENERAL CHARACTERISTICS
• SYNONYM: Old World Hookworm
• DISEASE: Ancylostomiasis
• GD: Cosmopolitan

3. Morphology
• Adult Worm:
Generalities:
Relatively stout, somewhat cylindrical, slightly
constricted anteriorly, has ventral curvature so
anterior end is directed dorso-anteriad
- Pinkish or creamy gray in color, covered with tough
cuticle
- provided with cervical papillae
- circumesophageal nerve ring
Oral aperture is not terminal, but directed towards
dorsal surface
Conspicuous, large buccal capsule provided with 6
teeth – (3 pairs), 4 hoollike in ventral surface, and 2
knoblike triangular plate on dorsal surface
5 glands connected with digestive system: one is
esophageal gland which secrets a ferment to prevent
blood clots
 tripartite valve
Midintestine extends from esophagus to rectum
Food of the worm is mucous membrane plasma
Y-shaped figure during copulation
Insemination: bursa copulatrix to vulva and insert a
pair of copulatory spicules and secrete cementum
(amoeboid spermatozoa)

4. MORPHOLOGY
• MALE WORM
8mm long
 Genital opening posteriorly
opens with cloaca
 Campanulate bursa with 3
lobes (tripartite) : 1 dorsal, 2
lateral supported by chitinous
rays
 Total number of rays: 13
 2 bristle like spicules and
cloaca
 Gubernaculum regulates
spicules

5. MORPHOLOGY
• FEMALE WORM
- 12.5mm long
 Genital opening (1/3 of body)
 Conoidal posterior with
subterminal anal opening
 Vulva situated midventrally at
distal third of body
 2 sets of reproductive organs
which open into vulva (oviducts,
seminal receptacles, vagina)

6. MORPHOLOGY
• EGGS:
Passed out with feces and are
oval or elliptical
 Colorless (not bile stained)
 Surrounded by transparent
hyaline shell membrane
 Segmented protoplasm with 4
blastomeres
 Floats in saturated solution of
common salt
 Not infective to man
 Average: 25,000 – 30,000 eggs
daily

7. MORPHOLOGY
• RHABDITOID LARVAE
Larger
 More attenuated posteriorly
 Longer buccal cavity
 Smaller genital primordium

8. MORPHOLOGY
• FILARIFORM LARVAE
• Third-stage larva
 Larger
 Pointed posterior end
 Infective to man, and viable in
soil for weeks
 Close mouth
 Old cuticle may be shed or
remain for some time