Hookworms are intestinal parasite of man and
other vertebrates. The term hook worm was coined either on the basic of the curved
or bent front end of the worm or on the basis of the hook like supporting
structure found in the posterior
extremity of male worms the bursa ( a corpulatory structure of the male). There
are two major species of hookworm nematodes namely;
other vertebrates. The term hook worm was coined either on the basic of the curved
or bent front end of the worm or on the basis of the hook like supporting
structure found in the posterior
extremity of male worms the bursa ( a corpulatory structure of the male). There
are two major species of hookworm nematodes namely;
Necator Americanus (new world)
Ancylostomg duodenale (old world) with respect
to mode of transmission life cycle and pathology, they are usually lumped
together
to mode of transmission life cycle and pathology, they are usually lumped
together
Geographical Distribution
It is chiefly found in
Africa, Europe, United States. Tropics and subtropics regions
Africa, Europe, United States. Tropics and subtropics regions
Mode of transmission
The larva hatch outside the body, and infect by
penetrating the skin through infected soil and ingestion of contaminated water
penetrating the skin through infected soil and ingestion of contaminated water
Characteristics
ü Adult male is about 8 –
11mm long and female about 10 – 13mm long
11mm long and female about 10 – 13mm long
ü Male possess an expanded
posterior end to form a corpulatory bursa.
posterior end to form a corpulatory bursa.
ü Ancylostoma duedenale has
two pairs of hook (teeth) and necator americanus two crescentric cutting plates
for attaching itself to the wells of the small intestine in order to et up the
tissue of the host.
two pairs of hook (teeth) and necator americanus two crescentric cutting plates
for attaching itself to the wells of the small intestine in order to et up the
tissue of the host.
ü Female has a sharply
defined spine posterior while male posterior end has a burser copulatrix provided
with a pair of spicules larva hatch outside their host and undergo three
development satges (i.e. habditiform, larva, stronsliform larva and filariform
larva) which is the infective form
defined spine posterior while male posterior end has a burser copulatrix provided
with a pair of spicules larva hatch outside their host and undergo three
development satges (i.e. habditiform, larva, stronsliform larva and filariform
larva) which is the infective form
Differences Between A. duodenale
and N. americanus
and N. americanus
|
parameters
|
A.
Duodenale |
N.americanus
|
|
Buccal capsule plates
|
4 hooks (teeths)
|
2 halfmoon shaped
crecentric cutting plates |
|
Spicules of the
copulatory bursa |
Diverging from each other
(pointed tips) |
Lying close besides one
another ending in barbed hooks |
|
Posterior end of female
|
With small terminal
rodlike process (the mucron |
No terminal mucron
|
|
Disease
|
Old world hook worm
infestation |
New world hook worm
|
Life cycle
The two hookworm species A. duodenale and N.
Americanus have the same general life cycle. The egg of hookworm are passed in
the faecal matter of an infected person. These eggs develop in the soil and
give rise to rhabdiform larvae, after 1 – 2 days. These rhabdiform within 5 – 6
days under goes two ecdyses to become the sheathed filariform larvae. Under
favourable conditions the larva may live for several months in the soil. The
larva instinctively climb onto grass or other vegetation to improve the
probability of contact with a host. On contact to the skin of man, the larva
actively penetrates through the sole of the feet after several hours, they
reach the immediate carried into the heart and lungs. The larva proceeds up the
bronch and trachea to the throat. Although some larva are ejected by spitting,
most are swallowed with sputum and arrive in the small intestine, where they
mature into adult male and female lays eggs (which are passed out with the host
faeces) and the cycle begins
Americanus have the same general life cycle. The egg of hookworm are passed in
the faecal matter of an infected person. These eggs develop in the soil and
give rise to rhabdiform larvae, after 1 – 2 days. These rhabdiform within 5 – 6
days under goes two ecdyses to become the sheathed filariform larvae. Under
favourable conditions the larva may live for several months in the soil. The
larva instinctively climb onto grass or other vegetation to improve the
probability of contact with a host. On contact to the skin of man, the larva
actively penetrates through the sole of the feet after several hours, they
reach the immediate carried into the heart and lungs. The larva proceeds up the
bronch and trachea to the throat. Although some larva are ejected by spitting,
most are swallowed with sputum and arrive in the small intestine, where they
mature into adult male and female lays eggs (which are passed out with the host
faeces) and the cycle begins
Prevention and control
i. Use of footwear (safely
boot) in endemic areas
boot) in endemic areas
ii. Improvement of general
sanitation.
sanitation.
iii. Provision of adequate
latrine accommodation
latrine accommodation
iv. Use of antihelminttic drugs
v. Health education
