Lyudmila Leonidovna Kiseleva
Svetlana Ernstovna Mogilevtseva
Alexey Romanovich Lyashuk
Task 5.
Topic: Medical helminthology. Phylum
Flatworms. Class Flukes.
,1. Medical helminthology as a science. Classification
of helminthes
• Medical helminthology studies the morphology, biology and
ecology of worms that parasitize in humans, as well as the
epidemiology, pathogenesis, clinical manifestations, diagnosis,
treatment and prevention of the diseases caused by them.
• Humans can be infected by the helminthes belonging to two phyla
of animal kingdom:
1) Flat worms (Plathelminthes) 2) Round worms(Nemathelminthes).
,Epidemiological classification of helminthes is based on the biological features
of their life cycles :
• Geohelminthes (soil-transmitted) are
worms the development of which occurs
in the external environment without
intermediate hosts.
• Biohelminthes (host-transmitted) - these
are worms the development of which
occurs with the change of hosts (i.e., in
their life cycle there is a definitive host
and intermediate hosts).
• Contact helminthes - these are worms
the eggs of which mature quickly (within
several hours) and infection most often
occurs through the contact of a healthy
person with a sick person. Autoinfection is
Карликовый цепень
also possible.
, 2. General characteristics of the phylum Flatworms.
Characteristic features of the class Flukes. Features of life cycles.
Phylum Flatworms (Plathelminthes).
Characteristic features of animals of this phylum:
1. triploblastic, their organ systems have developed from the
ectoderm, endoderm and mesoderm;
2. bilateral symmetry;
3. leaf-shaped or ribbon-shaped body which is dorsally-ventrally
flattened;
4. no body cavity, the space between the internal organs is filled
with parenchyma of mesodermal origin which performs
supporting, excretory and storage functions;
5. presence of the dermomuscular tube which in parasites
consist of the tegument, hypodermis and three layers of
muscles (circular, longitudinal and oblique);
6. nervous system represented by the peripharyngeal nerve ring
connecting the suprapharyngeal and subpharyngeal ganglia,
and longitudinal nerve cords extending from it, the lateral
nerve cords are the most developed; the nerve cords are
connected by commissures (ladder type). Such a nervous
system is called an orthogon.
Svetlana Ernstovna Mogilevtseva
Alexey Romanovich Lyashuk
Task 5.
Topic: Medical helminthology. Phylum
Flatworms. Class Flukes.
,1. Medical helminthology as a science. Classification
of helminthes
• Medical helminthology studies the morphology, biology and
ecology of worms that parasitize in humans, as well as the
epidemiology, pathogenesis, clinical manifestations, diagnosis,
treatment and prevention of the diseases caused by them.
• Humans can be infected by the helminthes belonging to two phyla
of animal kingdom:
1) Flat worms (Plathelminthes) 2) Round worms(Nemathelminthes).
,Epidemiological classification of helminthes is based on the biological features
of their life cycles :
• Geohelminthes (soil-transmitted) are
worms the development of which occurs
in the external environment without
intermediate hosts.
• Biohelminthes (host-transmitted) - these
are worms the development of which
occurs with the change of hosts (i.e., in
their life cycle there is a definitive host
and intermediate hosts).
• Contact helminthes - these are worms
the eggs of which mature quickly (within
several hours) and infection most often
occurs through the contact of a healthy
person with a sick person. Autoinfection is
Карликовый цепень
also possible.
, 2. General characteristics of the phylum Flatworms.
Characteristic features of the class Flukes. Features of life cycles.
Phylum Flatworms (Plathelminthes).
Characteristic features of animals of this phylum:
1. triploblastic, their organ systems have developed from the
ectoderm, endoderm and mesoderm;
2. bilateral symmetry;
3. leaf-shaped or ribbon-shaped body which is dorsally-ventrally
flattened;
4. no body cavity, the space between the internal organs is filled
with parenchyma of mesodermal origin which performs
supporting, excretory and storage functions;
5. presence of the dermomuscular tube which in parasites
consist of the tegument, hypodermis and three layers of
muscles (circular, longitudinal and oblique);
6. nervous system represented by the peripharyngeal nerve ring
connecting the suprapharyngeal and subpharyngeal ganglia,
and longitudinal nerve cords extending from it, the lateral
nerve cords are the most developed; the nerve cords are
connected by commissures (ladder type). Such a nervous
system is called an orthogon.
