ancylostomiasis hookworms ancylostoma duodenale. eman khalifa prof. of parasitology
TRANSCRIPT
ANCYLOSTO
MIA
SIS
HOOKWORM
S
ANCYLOSTO
MA D
UODENALE
.
EMAN
KH
ALIF
A
P RO
F. O
F PA RA S I T
OLO
GY
ANCYLOSTOMA DUODENALE
Diseases: Ancylostomiasis, Hookworm disease Morphology:
Ancylostoma adults. At the anterior end there is
a big cup shaped mouth called buccal capsule.
They have a club shaped oesophagus
The male worm measures nearly 1 cm by 0.5 mm
and is provided with a copulatory bursa at the
posterior end with two free spicules
The female is larger and stouter (1.2 cm by 0.6
mm). The posterior end is straight and pointed.
24-Ancylostoma duodenale adult male
25-Ancylostoma duodenale adult female
The eggs Size: 60 X 40 in diameter ,
Shape: oval with blunt poles, thin-walled ,Colour: colourless
Content: four cell stage (immature).
ANCYLOSTOMA DUODENALE
Life cycle
Habitat: Adults live in the small intestine of man
attached by the mouth capsule to the mucosa. Eggs
passed in faeces mature rapidly, hatch and
produce the first stage rhabditiform larvae (250 )
in 1 to 2 days under favourable conditions
(humidity and temperature 25°C), feed actively
upon organic debris and grow rapidly to a size of
500 second stage rhabditiform larvae in 5 days.
They moult for a second time to become
infective ensheathed filariform larvae
(700 ) after about 7 days.
Mode of infection: Man is infected when
the filariform larva penetrates his intact
skin or mucous membrane of the
mouth.
Miners and farmers may acquire the infection on
the hands chiefly in the interdigital spaces,
dorsum of foot and between toes.
The filariform larva moves towards warmth (+ve
thermotropism), moist areas (+ve hygrotropism) and
host tissues (+ve histotropism) but against gravity (-
ve geotropism). The strong +ve histotropism
facilitates access to the host. The –ve geotropism
helps the larva to move towards the surface to reach
human skin.
The larvae enter the lymphatics or venules and
are carried in the blood through the heart to
the lungs, where they break out of the
capillaries into the alveoli. They ascend the
bronchi and trachea. Finally they are swallowed
and pass down to the intestine. This migration
takes about one week, during which the larvae
undergo a third moult and acquire a temporary
buccal capsule. The fourth moult occurs in the
intestine at about the 13th day. The egg-laying
females are developed in 5 to 6 weeks after
infection.
CLINICAL PICTURE
Invasion stage:
Larval penetration leads to local dermatitis and localized erythema, usually between the toes, dorsal surface of the foot. Itching is often severe. This
condition is known as “ground itch.”
Migration stage:
Passage of larvae in the lungs leads to minute haemorrhages and pneumonitis. There may be cough, expectoration, haemoptysis, fever, leucocytosis and eosinophilia (verminous pneumonia or Loeffler's syndrome).
INTESTINAL STAGE
:
Severe gastroenteritis often develops about 6 weeks after
infection due to ulceration of mucous membrane. The
gastroenteric phase is self-limited.
Symptoms due to the adult worms occur later only if anaemia
develops. An adult hookworm sucks about 0.3 ml blood / day.
The previous points of attachment bleed for sometime after
movement of the worms to new sites because adult secrets
antiplatelet agents that help the continuous oozing of blood,
this blood loss leads to hypochromic normocytic or
microcytic anaemia, which leads to dyspnoea on exertion,
palpitation, pallor, puffiness of the face, weakness and
dizziness .
Diagnosis:I- Clinical picture :
II- Laboratory:Direct :
Final diagnosis depends upon finding the eggs in the faeces
Infective stage of Ancylostoma duodenale is
Filariform larva
Egg containing four cell stage is the diagnostic stage of
Ancylostoma duodenale
Ancylostoma duodenale
Microcytic hypochromic anamia is a complication of
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