Parasitic Diseases in cultured fishes

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Parasitic Diseases in cultured fishes
By
Dr. Mohamed S. Mohamed Marzouk Professor of Fish
Diseases and Management , Faculty of Veterinary
Medicine, Cairo University
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Parasitic Diseases of cultured fishes

Common Parasites in cultured fishes

• Fish Protozoa (unicellular).

• Fish Helminthes (multi-cellular).

• Fish Parasitic Crustaceans.

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Commom protozoa in cultured Fishes
1. Exteranl cilliated protozoa

• Ichthyophthirius multifillis

• Chilodonella spp.

• Trichodina spp.

2. Internal fish protozoa

• Flagellated Hexamita spp.

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Ichthyophthirium multifilis trophozoit (Stained )
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Ichthyophonus multifillis (unstained)
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Stained Trichodina from skin mucus scraping
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Pathogenesis of external protozoa
Protozoal invasion

Skin cellular irritation
1. Abnormal swimming
2. Excessive mucus
Skin cellular destruction
1. Haemorrhages
2. Erosions and ulcers
3. C.T capsules (White spots).
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Life cycle of Ichthyophthiriosis
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Clinical signs

• Abnormal swimming ( Flashing, circling, sluggish
  and itching ).

• Surfacing and gasping ( Asphyxia ).

• Excessive skin mucus ( patchy then generalized ).

• Pathognomonic white spots (Ichthyophthiriosis).

• Skin haemorrhages, erosions and ulcerations.

• Emaciation and death.

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White spot disease
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Cryptocarion irritans infection in marine fish
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Diagnosis of External parasitic Diseases
1. History ( new introduced fish, water
parameters,

2. Clinical signs and lesions.

• 3. Demonstration and identification of the
  causative parasites
• Skin and gill mucus scraping (wet mount).
• Stained skin and gill mucus smears.

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Treatment of External parasitic Fish Diseases

• External chemical treatment
• Dip treatment
• Bath treatment
• Flush treatment
• Indefinite bath treatment
• Non-chemical treatment
• Increase water temperature in White Spot disease
• Use of ultraviolet radiation in re-circulating
  system

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Types of Chemical treatments
1. Disinfectants

• Pot. Permenganate.
• Malachite green.
• Formaline.
• Na Cl.
• Acriflavin.
• Methylene blue.

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2. Pesticides

• Chlorinated Hydrocarbones.
• Organophosphates.

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Control of Fish diseases in infected fish farms

• In infected earthen ponds
• Drainage
• Dryness
• Disinfection using quick lime
• In infected concrete or fiberglass fish tanks
• Drainage
• Disinfection with strong antiseptics

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Hexamitiosis

• Systemic infection caused by an internal
  flagellated protozoa

Causative protozoa

• Hexamita intestinalis

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Mode of infection and transmission
1. Infection through ingestion.
2. Transmission is from dead fish and
contaminated water body.

Pathogenesis
Hexamita is normal inhabitant of intestine
Large numbers
Small numbers
Systemic form
Intestinal destruction
No signs
Intestinal irritation
Hole in head
Excess mucus
Off food emaciation
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Clinical signs
1. Off food.
2. Emaciation and tucked up abdomen.

3. Mucus shreds from the vent.
4. High mortality in severe cases.
5. Hole in the head in systemic form (Fistula
behind the head exuding white material).
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Diagnosis
Clinical signs and lesions (Non-confirmative)
Laboratory ( Confirmative)

Sampling ( Intestinal mucus )
Quantitative (Count/ MF)
Qualitative
0 - 5 Negative 5 15
Mild 15 -30 Moderate 30
100 Severe More than 100 Marked
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Treatment and control
2. Hexamiticides
1. Expulsion

Sulfonamides
Saline purgative (MgSO4)

1. Aresenical (Carbersone).
2. Murcurial (Calomel).

Can be used in food fishes
Not to be used in food fishes
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Fish Helminthosis

Helminthes of fishes

Platy helminthes
Round worms
Trematodes
Cestodes
Larvae
A dults
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Fish Trematodes

1. Monogenea
2. Digeanea
Adults
Gill flukes
Skin flukes
Encysted metacercaria
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Gill flukes

1. Dactylogyridae
2. Cichlidogyridae
Cichilidogyrus tilapiae (C. tilapiae)
Dactylogyrus vastator (D. vastator)
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D. vastator
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C. tilapiae
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Gill fluke attached to fish gill filaments
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G. elegans
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Skin fluke attached to fish skin
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Haemorrhagic granuloma of Lernea copepode
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2 egg sacs
Anchor
Lernea cyprinicae
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Fish lice ( Argulus sp.) attached to fish skin
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Ventral view of Fish Lice
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Thank You