March 14, 2020
The infectious diseases are further classified into 6 types based on the type of external organism causing it. They are
1. Bacterial Diseases
2. Viral diseases (Not found in India)
3. Fungal Diseases
4. Protozoal Diseases
5. Crustacean Diseases
6. Helminth Diseases
1. BACTERIAL DISEASES:
a) COLUMNARIS: Reddish Peripheral zones on the fish body and hemorrhagic ulcers. caused by Flexibacter Columnaris.
b) GENERAL SEPTICEMIA: Caused due to Aeromonas Hydrophila. This
disease shows ulceration of skin, distended abdomen and inflamed fins and fins bases.
c) FIN & TAIL ROT: Caused by Pseudomonas Bacteria. The infection during its early stage appears as a white line on the margin of the fin. Fin rays become brittle and start breaking.
d) FURUNCULOSIS: caused by Aeromonas Salmonicida. Erractic Behaviour, loss of appetite are observed in the infected fish
e) POP EYE DISEASE: caused by Aeromonas Punctata. Cornea of eye becomes vascularized and later becomes opaque, eyeballs gets decayed.
f) DROPSY: kidney failure in fish, where the fish body balloons outward from excess water.
g) Bacterial Kidney Disease (BKD) - It is a bacterial disease caused by Renibacterium salmoninarum. The source of infection can by contaminated feed and water. Clinical signs of BKD is darkness of the skin, gills are pale in colour, swelling of the kidney.
h) MYCOBACTERIOSIS: also called fish tuberculosis. it is caused by
Mycobacteria chelonian. The most common symptoms are poor body condition, skin ulcers, scales loss.
i) Cold water Disease (CWD) - Cold water disease caused by Flavobacterium psychrophilia. This is rare and it is transmitted from parent to child vertically, not contagious disease.
2. VIRAL DISEASES: 6types not found in INDIA
Spring viremia, Carp Pox, Lymphocystis, Viral Nervous Necrosis (VNN), Infectious Hematopoietic Necrosis (IHN), Viral Hemorrhagic septicemia (VHS).
3. FUNGAL DISEASES:
a) Saprolegniasis: (cotton wool disease)It typically starts on the fins or head and often spreads over the entire body, being visible as white or grey mycelial patches. Spores commonly enter the fish body via damaged gills.
b) Branchiomycosis(gill rot): It is a fungal disease involving gill tissues, affecting the most species of freshwater fish. Symptoms and Causes of Fin Rot. The most common causes of fin rot are poor water quality and improperly low water temperature.
c) Icthyophonus Disease: Icthyophonus disease is caused by the fungus, Icthyophonus hoferi. It grows in fresh and saltwater, in wild and cultured fish, but is restricted to cool temperatures (36° to 68°F). The disease is spread by fungal cysts which are released in the faeces and by cannibalism of infected fish.
4. PROTOZOAL DISEASES
a) Costiasis: Caused by Costia Necatrix. Disease is characterized by blueish of the skin and
respiratory manifestation. symptoms are the gills are usually swollen and sometimes covered with mucous lead to respiratory distresses.
b) Epistylis: It is caused by Heteropolaria Colisarum. Gills shows
very obvious white spots on and around them, bloody hemorrhages are apparent over several parts of the skin, the head of the fish has one or more bleeding areas and also gills shows fungal growths.
c) Ichthyophthiriasis (ICH) - It is caused by Ichthyophthirius Multifilis. The disease is characterized by appearance of white spots on the skin, gills, fins and cornea of the eye.
d) Myxosporidians infestation- It is caused by Myxosporidians genera. most gernerally called as Myxobolas. falling of scales, raising of the scales along their posterior margins are observed.
e) Pox Disease- It is caused by sprozoans. Clinical symptoms is small milky white spots raised 1-2 mm above the surface of skin
f) Trichodiniasis- It is caused by Trichodina Truttae protozoans. This protozoans are saucer shaped, 50 micros diameter.
5. CRUSTACEAN DISEASE: Two types of crustacean disease shows in freshwater fish’s. They are anchor worm infection
and arugulas infestation.
Anchor worm infection is caused by Lernaea Cyprinacea
Argulus infestation is mainly effected on Labeo Rohita
6. HELMINTH DISEASE: The common parasitic worms are Dactylogyrus, Gydrodactylus and neobenedenia. The clinical symptoms are swollen and pale gills that make breathing difficult for the infected fish. Neobenedenia is a large parasite which infects fishes and destroys their gills, leading to breathing problems.
NON INFECTIOUS DISEASES: Non-Infectious are caused due to the deficiencies of the vital Vitamins in the feed.
a) Vitamin C deficiency: Reduced growth/wound repair, internal/external hemorrhage, caudal fin erosion, exophthalmia, anemia, reduced egg hatchability.
b) Vitamin E Deficiency: Depigmentation, fatty liver, anemia, atrophy of pancreatic tissue, mortality, ceroid deposition in liver/blood vessels, splenic haemosiderosis.
c) Folic Acid Deficiency: -Anorexia, reduced growth, fading of body colour, pale gills and liver.
d) Phosphorus Deficiency: Reduced growth, poor feed efficiency, bone demineralization, skeletal deformity, and abnormal calcification of ribs and the soft rays of the pectoral fin cranial deformity increased visceral fat.
e) Pantothenic Acid Deficiency: Anorexia, reduced growth, sluggishness, anemia, skin haemorrhage, and exophthalmia.