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8/14/2019 Parasites Study22
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A parasites lives in a close relations
another organism, its host, and cau
harm.
Dependent on its host for its life fun
Extremely common, virtually all ani
a variety of parasitic organisms fro
to helminths.
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Parasites generally don't kill their hosts (parasite that kills its free lunch), but somseverely stress fish populations to the pobecoming biological and economical con
Parasites have a stake in the survival of
Sometimes, when parasites are numeroufish is stressed from another cause, the f
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Destroying
tissue
Rem
and
Allowinginfection
develop
Diverting part of its nutrient
supply
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Yes, in fact, parasitism is natural an
It occurs throughout the plant kingd
in every major group of the animal
Usually, fish parasites aren¶t notice
sometimes anglers will catch a fishobvious signs of infection or parasi
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Type of Parasites
Cestrodes
Acanthocehalans
MolluscsIsopods
Leeches
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The worm's scolex ("head") attaches tintestine of the definitive host.
suction cups
The body is composed of successivesegments ( pr oglottids).
Adults in gastrointetinal,larvae in any
Approx. 3mm up to 200 mm in length
Larvae may move within cryst,limitedmovement in adult
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This group of parasites is comprised of woranterior proboscis covered with many hook
Referred to as ³thorny-headed worms´.
The body is composed of a presoma (proboassociated structures) and a cylindrical trun
The intestinal tract of the affected fish may blood-tinged fluid, and histologically, the prothese parasites will be firmly attached to the
mucosa.
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Only one pair of uropods and lack stron
first thoracic legs.
The carapace is lacking which reveals thsegmented body composed of a head, a
(thorax) of 7 somites (segments) and a
(abdomen) of 6 somites.
scavengers feeding on dead fish parasitic on live fish
Greatest diversity is seen in the deep pa
ocean basins at 1000-5000 metres dept
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Produce larvae (glochidia) which unde
obligatory phase in the gills, fins or sk
the fish host. The parasitic phase may last for seve
months.
The host tissue surrounds the parasit
is shed from the fish, and grows into aliving adult mollusc.
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Marine leeches, 8 to 12 mm long, are
characterized by segmented bodies w
muscular body walls.
They are equipped with anterior and
posterior suckers.
Free moving;worm like movement,fixe
when feeding
Direct life cycle
Parasitic on host blood
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The parasites that be present in la
numbers, typically so as to cause d
disease.
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Tapeworms crawling out of the pyloric caeca of a yearling rainbow trout.
Gross
Slug
Stop
Effect o
Resul
enterit
Reduc
(interfe
absorp
Diagno
Dissec
Preven
Eliminhosts
Quick
cestod
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Photomicrograpdemonstrates th(top) of an Acan
parasite which hinto the intestina(bottom) of an afish. Affected fiemaciation, lethanemia, and po
with a marked i
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Observed salmonids from the Great Lakes
with marked infestation of this parasite with
literally hundreds of these parasites
embedded in the intestinal mucosa .
Gross si
Emaciat
Darkene
Effect on HNecrotic h
the intestin
Growth ret
mortality
Preventation
Quicklimethe water sup
suspected sto
quarantined.
Diagnosis
Gross examielongated and
with retractile
with spines
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Inflamed and
necrotic gills
(left)
Pullus II stage
C er atothoa
oest r oides larvae
on the gills of a
sea bass
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The adult isopods are haematophagus (feblood) and cause anaemia.
Adult isopods can cause considerable dammouth tissues with their biting and suckingparts, or their copulation activity.
Their large size (up to 6 cm in length) mayatrophy of the tongue, dysplasia of teeth aslackening of the cartilagenous tissues lea"bag-shaped" lower jaw. Invariably, the prelarge adult parasites in the buccal cavity inwith feeding, causes chronic stress and regrowth retardation and a predisposition toand/or endo-parasitic invasions.
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Preventation
Removed m
1. Bath in 2
until the
from the
2. Dry the p
several w
liming to
adults.
3. Kill the d
by crush
physical
Diagnosis
Gross exa
microscop
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G
s
f
Effect on Host
Anemia & may show
secondary bacterial infectionsact as vectors of viruses,
bacteria, and protozoan blood
parasites
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Preventation
1. Leeches may b
the culture wat
2. the manual rem
leech using a w
3. A bath of 100 phr is effective.
4. Treated fish mu
to a clean, para
5. Culture facilitie
cleaned proper
intense sunligh
weeks prior to
Diagnosis
Gross examina
microscopic e
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Gross sign
Attached
& Outer s
Effect on Ho
Gill tissue i
Lead to sec
and fungal i
Disruption
function
Preventation
Filter the cultu
Diagnosis
Gross exami
microscopic
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It is impossible to avoid dealing witparasitic organisms that fish acquirthe normal course of their lives.
The majority of this parasites are ninfective to human or to other home
Fishes feeding heavily on parasitesintermediate hosts, probably carry
infections than will fishes that acquinfections at higher level.
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