• 4-NEMATODES
•
4-NEMATODES
•
Nematodes are known commonly as roundworms
and belong to the phylum Nematoda. The adult
stage is typically elongated and cylindrical in
shape, tapering at each end, and lacks body
segmentation. These outward features
differentiate nematodes from the tapeworms that,
when adult, have flattened and distinctly
segmented bodies. In the case of nematodes the
sexes are separate, and most species are opaque to
white in colour.
•
The life cycles of nematodes are fairly
complex, involving various developmental
stages, and require sequential transmission
through two or three different host species. In
the case of fish parasitic nematodes, the life
cycle may involve transmission, for example,
through a freshwater invertebrate, then through
two fish, the latter typically being a
piscivorous species which is the final
(definitive) host.
•
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•
Cyprinids may be either final or intermediate
hosts, depending on the nematode species. For
example,
Philometra abdominalis
this
nematode requires only two hosts to complete
its life cycle, involving cyprinids as final hosts
and cyclops as the intermediate host. Yet
another host combination is shown by
Eustrongylides mergorum
in which a cyprinid,
e.g. common carp, is the second intermediate
host and a piscivorous bird is the final
•
5-ANNELID WORMS (LEECHES)
•
Leeches are parasitic annelid worms belonging to
the class Hirudinea, which comprises both
terrestrial and aquatic species. Leeches are blood-
feeders that are equipped with suckers at each end
of the body(oral and posterior suckers) enabling
them to maintain a grip on their host.
•
Several species of leech feed on the blood of
cyprinids and other fish, although host-
specificity varies according to the leech
species. One well-known family of freshwater
fish leeches is the Piscicolidae, which includes
Piscicola geometra
, known simply as the fish
leech. This species grows to 30 mm in length,
but some specimens may reach 50 mm. It lives
for less than one year.
•
Most fish leeches are temporary parasites,
detaching from their host after having taken
one or more blood meals. When replete, the
leech will swim in the water, settling on the
substrate where it hides among rocks or plants
to digest its meal. Leeches are more commonly
encountered on wild and pond-cultured
cyprinids but are rare in aquarium maintained
stocks.
•
Health threats of leeches on fish:-
•
1-Leeches themselves are not generally considered to pose serious health
threats to cyprinids, being rarely fatal under normal circumstances.
•
2-In heavy infestations the host may suffer from anaemia and listlessness.
•
3- The leech’s bite wounds are prone to secondary infections for example
by fungi.
•
4- Leeches work as vectors of fish diseases. Leeches are known to be
capable of transmitting certain viruses to fish, such as the spring viraemia
of carp virus (SVCv), leeches may also be natural vectors of some
bacterial fish pathogens, in contrast, their role in transmitting various
species of blood protozoa is well documented. For example, the leeches
Piscicola geometra
and
Hemiclepsis marginata
are both capableof
transmitting the haemoflagellate
Trypanoplasma carassii
to goldfish, carp
and other cyprinids.
•
Life cycle:-
•
The life cycle is direct, with hermaphroditic
adults laying eggs in cocoons that are attached
to aquatic plants or hard surfaces such as the
undersides of rocks. Young leeches hatch from
the cocoons.
•
Clinical signs:-
as most leeches spend
only a proportion of their time attached to the
fish, often the only evidence of a leech
problem is the presence of circular red or white
bite marks on the fish’s skin.
•
Control:-
•
1-remove aquatic plants
•
2- remove the water completely from a lake or
fish pond and apply lime.
•
Treatments
:-
use
1-Dipterex(O.P.C.) 1PPM add for ponds water.
•
2-NaCl 2.5% for 1 h.
•
3-NaCl 30000 PPM for 5-15 sec.
•
4-CuSO
4
0.5 PPM for 5-6 h.
Nematodes, commonly known as roundworms, belong to the phylum Nematoda and have complex life cycles that can impact their cyprinid hosts. Leeches, parasitic annelid worms of the class Hirudinea, feed on blood and use suckers to grip their hosts. Some species of leeches feed on cyprinids, with varying host specificity. Explore these fascinating creatures and their interactions in aquatic ecosystems.
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Presentation Transcript
4-NEMATODES Nematodes are known commonly as roundworms and belong to the phylum Nematoda. The adult stage is typically elongated and cylindrical in shape, tapering at each end, and lacks body segmentation. These differentiate nematodes from the tapeworms that, when adult, have flattened segmented bodies. In the case of nematodes the sexes are separate, and most species are opaque to white in colour. outward features and distinctly
The life cycles of nematodes are fairly complex, involving various developmental stages, and require sequential transmission through two or three different host species. In the case of fish parasitic nematodes, the life cycle may involve transmission, for example, through a freshwater invertebrate, then through two fish, the latter piscivorous species (definitive) host. typically which being the a is final
Nematodes are rarely life threatening to their cyprinid hosts. They may however damage the parasitised organs and cause general poor health such as emaciation, reduced growth and reduced fecundity. The range and degree of these detrimental effects varies depending upon the nematode species involved, the intensity of infection, and whether the host is final intermediate. or
Cyprinids may be either final or intermediate hosts, depending on the nematode species. For example, Philometra nematode requires only two hosts to complete its life cycle, involving cyprinids as final hosts and cyclops as the intermediate host. Yet another host combination Eustrongylides mergorum in which a cyprinid, e.g. common carp, is the second intermediate host and a piscivorous bird is the final this abdominalis is shown by
5-ANNELID WORMS (LEECHES) Leeches are parasitic annelid worms belonging to the class Hirudinea, terrestrial and aquatic species. Leeches are blood- feeders that are equipped with suckers at each end of the body(oral and posterior suckers) enabling them to maintain a grip on their host. which comprises both
Several species of leech feed on the blood of cyprinids and other fish, although host- specificity varies according to the leech species. One well-known family of freshwater fish leeches is the Piscicolidae, which includes Piscicola geometra, known simply as the fish leech. This species grows to 30 mm in length, but some specimens may reach 50 mm. It lives for less than one year.
Most fish leeches are temporary parasites, detaching from their host after having taken one or more blood meals. When replete, the leech will swim in the water, settling on the substrate where it hides among rocks or plants to digest its meal. Leeches are more commonly encountered on wild cyprinids but are rare in aquarium maintained stocks. and pond-cultured
Health threats of leeches on fish:- 1-Leeches themselves are not generally considered to pose serious health threats to cyprinids, being rarely fatal under normal circumstances. 2-In heavy infestations the host may suffer from anaemia and listlessness. 3- The leech s bite wounds are prone to secondary infections for example by fungi. 4- Leeches work as vectors of fish diseases. Leeches are known to be capable of transmitting certain viruses to fish, such as the spring viraemia of carp virus (SVCv), leeches may also be natural vectors of some bacterial fish pathogens, in contrast, their role in transmitting various species of blood protozoa is well documented. For example, the leeches Piscicola geometra and Hemiclepsis marginata are both capableof transmitting the haemoflagellate Trypanoplasma carassii to goldfish, carp and other cyprinids.
Life cycle:- The life cycle is direct, with hermaphroditic adults laying eggs in cocoons that are attached to aquatic plants or hard surfaces such as the undersides of rocks. Young leeches hatch from the cocoons.
Clinical signs:- as most leeches spend only a proportion of their time attached to the fish, often the only evidence of a leech problem is the presence of circular red or white bite marks on the fish s skin.
Control:- 1-remove aquatic plants 2- remove the water completely from a lake or fish pond and apply lime. Treatments:-use 1-Dipterex(O.P.C.) 1PPM add for ponds water. 2-NaCl 2.5% for 1 h. 3-NaCl 30000 PPM for 5-15 sec. 4-CuSO40.5 PPM for 5-6 h.
