A small work on fish pathology.

1. Md.Atick Chowdhury

2. Systemic Pathology of Teleost
The Integumentary System
The Respiratory System
The Digestive System
The excretory System

3. The Digestive System
 Digestion is the process of converting food into
smaller compounds that can be used by the body.
 Mouth Buccal Cavity Phyrynx
Oesophagus Stomach Pyloric caeca
Intestine The Pancreas Liver Rectum
Anus

4. The Digestive System
Figure: Teleost Digestive System

5. Oral Cavity
 The oral cavity of the teleost is a hard, bony structure,
which is well adopted to prehension of rough
materials.
Common Diseases:
Lesions:
 Caused by fishing hook & developed into infected ulcers.
Necrotic fungal infection:
 Occur in upper jaw.
Neoplasia:
 Lesion of the lips or of pharynx.
 Caused by polluted water.

6. Oral Cavity
Figure: Normal Structure of Oral Cavity
Figure: Pathology of Oral Cavity

7. Oesophagus
Oeosophage is situated after pharynx, a muscular tube
that leads to the stomach.
Common Diseases:
Degenerative myopathy:
o Develop in muscle of oesophagus.
o Occurs due to vitamin E.
Figure: Normal Structure of Oesophagus Figure: Pathology of Oesophagus

8. Swim Bladder
 A gas-filled structure in many fishes that functions to
maintain buoyancy & helps in respiration.
 Common Diseases:
 Oedema:
 Caused by chronic bacterial infection.
 Inflammation:
 Due to raise of temperature.
 Distension:
 Assosiated with pathological lesions.
 Due to feeding on dusty food.

9. Swim Bladder
Figure: Normal Structure of Swim Bladder
Figure: Pathology of Swim Bladder (1: Inflammation, 2: Distention, 3: Oedema)
1
2 3

10. The Stomach
After oesophagus true stomach is found.
Common diseases:
Bacterial lesions:
 Occurs occasionally within the muscular is of the stomach
and external serous.
Ascites:
 Increased fluid found in stomach cavity.

11. The Stomach
Figure: Normal Structure of Stomach
Figure: Pathology of Stomach

12. The Intestine
The intestine is a long thin tube with a thin double
layer musculature.
Common diseases:
IPN (Infectious Pancreatic Necrosis):
 Infectious Pancreatic Necrosis Virus
 Does not take food
 Fish show abnormal distension
IHN (Infectious Haematopoietic Necrosis):
 Infectious Hematopoietic Necrosis Virus (IHNV)
CCVD (Channel Catfish Viral Disease):
 Channel Catfish Virus (CCV)
 Abnormal movement
 Swelling

13. The Intestine
VHS (Viral Hemorrhage Septicemia):
 VHSV (Viral Hemorrhage Septicemia Virus)
 Dark color on intestine skin
 Swollen structure
Chronic infection:
 Caused by fungus such as Mycrobacterium or Nacardia
asteroides.
 Focal granullomatous infecton of the gut wall

14. The Intestine
Figure: Normal Structure of Intestine
Figure: Pathology of Intestine

15. Liver
 It has no specific shape and has 2 or 3 tissues.
 Common diseases:
 Hepatic Necrosis:
 Diphyllobothrium sp., Aeromonas salmonicida
 Nausea, weakness, abdominal pain.
 Lipid infiltration:
 Fatty infiltration of liver cell is common in farmed fishes.
 Liver enlarges
 Yellow or light brown color
 Loses its sharp edge of its lobes.
 Hepatic granuloma:
 Caused by a wide range of pathogen.
 Renibacterium salmoninarum, Mycobacterium fortuitum.

16. Liver
 Euclinostomum:
 Caused by Digenean parasites.
 Blood vessel degeneration:
 Blood vessel degenerates rapidly.
 Vaccume:
 Cell reduced causing vaccume condition.
 Bacterial colony:
 Several bacteria attacks & forms colony.

17. Liver
 Pigment accumulation:
 Most common is accumulation of ceroid and lipofuscin
 These byproduct catabolism are seen in liver cells &
hemopoietic tissue.
 The biliary system:
 It includes gallbladder, bile ducts and certain cells inside the
liver & bile duct outside the liver.
 Protozoan parasites are frequently observed in the gallbladder.
 Pathological changes resulting from biliary disease depend on
the level of the lesion.

18. Liver
Figure: Normal Structure of Liver
Figure: Pathology of Liver
Figure: Digenean sp.

19. Pancreas
Pathology of the teleost pancreas is complex.
Pancreatic tissue located in externa around the portal
vein system within the liver.
Common diseases:
 IPN (Infectious Pancreatic Necrosis):
 Infectious Pancreatic Necrosis Virus
 Responsible for acute & chronic exocrine pancreatitis.
 Affected fish have massive necrosis of the pancreas and
mortalities can be 20-30%
 CCVD (Channel Catfish Viral Disease):
 Channel Catfish Virus (CCV)
 IHN (Infectious Haematopoietic Necrosis):
 Infectious Haemopoietic Necrosis Virus

20. Pancreas
Figure: Normal Structure of Pacreas
Figure: Pathology of Pancreas

21. Thanks
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