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XVI. Sanitation and fish health

1. Pond sanitation

Influence of pond sanitation on fish health and public health; importance of fish health in aquaculture; malaria and bilharzia, and their control measures; factors favouring occurrence of diseases among cultivated fishes and shellfishes (overcrowding, malnutrition and unfavourable water quality).

2. Fish kills

Fish kills due to toxic algae (blue-green algae and dinoflagellates); their control measures.

3. Classification of diseases

According to groups or species of cultivated fish and shellfish affected, organs affected, age of fish, seasons, causative agents and extent of incidence (isolated or epizootic).

4. Causes of diseases

Parasitic (bacteria, virus, fungi, protozoans, worms, crustaceans and mussel larvae), environmental, nutritional and constitutional.

5 Diseases - their aetiology, symptoms and species affected

5.1 Bacterial diseases

"Obligate" and "facultative" bacterial pathogens; important groups of pathogenic bacteria (Aeromonas, Pseudomonas, Corynebacteria, Enterobacteria, Hemophilus, Mycobacteria, Nocardia, Myxobacteria, Streptomyces and Vibrio); common diseases - infectious abdominal dropsy of carps, furunculosis, bacterial kidney disease, "redmouth" disease, ulcer disease, tuberculosis, columnaris disease, tail- and fin-rot, peduncle disease, red pest disease, red spot disease, septicaemia, coldwater disease, exophthalmus, botulinum disease, blue sac disease, nocardia, etc.

5.2 Viral diseases

Infectious haematopoietic necrosis, infectious pancreatic necrosis, viral haemorrhagic septicaemia, ulcerative duermal necrosis, spring viremia of carp, pox disease, kyro-ichthyozoosis, lymphocystis disease, cauliflower disease, swim bladder inflammation, etc.

5.3 Fungal diseases

Saprolegnia infection or dermatomycosis, gill rot or branchiomycosis, "cotton cap" disease and Ichthyophonus disease.

5.4 Diseases caused by protozoans

Costiasis, chilodonelliasis, cyclochaetiasis, whirling disease, ichthyothiriasis, pillularis disease, lenot or pimple disease, milky flesh disease, etc.

5.5 Diseases caused by worms

Ligulosis, gyrodactyliasis, grey pearl disease, worm cataract, diseases due to Dactylogyrus, Cichlidogyrus, Bucephalus, bloodworm nematodes, alanthocephalans, etc.

5.6 Diseases caused by crustaceans

Causative agents - Argulus spp., Lernaea spp., Ergasilus spp., Caligus lacustris, etc.

5.7 Infection by glochidia larvae of freshwater mussels

5.8 Environmental diseases

Causative factors - oxygen deficiency or oversaturation, high acidity, high alkalinity, temperature variations, toxic substances from industrial and sewage effluents, etc.: gas edema, water edema, sunburn, blue sac disease, "pop-eye" or exophthalmus, etc.

5.9 Nutritional diseases

Lipoid hepatic degeneration, enteritis, hepatoma, botulism, aertaminoses, mineral and trace element diseases, and softwater diseases (visceral granuloma, nephrocalcinosis and proliferative kidney disease).

5.10 Tumours in fishes

Benign and malignant tumours; hyperplasia, neoplasia, anaplasia and metaplasia; causes of tumours (adverse chemical or physical stimuli, presence of parasites and hormonal disturbances).

6. Common diseases affecting main cultivated species

7. Common diseases of main organs - skin, eyes, gills and internal organs

8. Effects of diseases

Economic loss through mortality; adverse effect on growth, condition factor, fatigue and reduced fecundity, vulnerability to predation, susceptibility to sub-optimal environmental factors, blood changes.

9. Control techniques for communicable diseases

Immunization, increase of natural and genetic resistance, manipulation of environment (hygiene, prophylaxis and disinfection), and therapy after onset of disease, regular health inspection and certification of eggs, fry and adults for export.

10. Treatment of diseases

10.1 Methods of treatment

(a) Chemical treatment through water (dip, bath or flush treatment);
(b) Chemical treatment through feed, and
(c) Treating fish with chemicals directly.

10.2 Criteria for selection of chemicals for disease control

Ratio between lethal dose for pest and fish, safety of handling, effect on pond's productivity, fish, nearby crops and consumers of fish, duration of half-life, cost, etc.

10.3 Commonly employed chemicals

Copper sulphate, formalin, malachite green, potassium permanganate, hyamine 3500, organophosphorus compounds, antibiotics, sulphonamides, nitrofurans, di-n-butyl tin oxide, euheptin, magnesium sulphate, ammonia, benzalkonium, chloride, acriflavine, iodine, hydrogen peroxide, methylene blue, ozone, sodium chloride, silver nitrate, etc.; their dosages and methods of administration for different diseases; precautions needed.

10.4 National and international aspects of disease control

Coordination and arrangements (International Office of Epizootics, EIFAC, FAO, and other international and national health organizations, etc.); significance of preventive, regulatory and control measures of communicable diseases; importance of health inspection and certifications.

11. Methods of isolation, culture and identification of pathogens


Diagnosis of common diseases of selected fish and shellfish, including isolation, culture and identification of the more common bacterial and fungal pathogens; treatment procedures for common diseases.

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