BACTERIAL DISEASES

Dr. BUNDIT TENGJAROENKUL

Department of MedicineFaculty of Veterinary Medicine

Khon Kaen University

Fish

Pathogens Environment

Diseases

Diseases

Diseases• Fish: Poikilothems• Pathogens: Bacteria, Protozoa, Fungi• Environments: Water-Soil quality, Diet,…General signs

• Emaciation, Stunting, Lethargy, Ascites• Exophthalmos, Corneal opacity, Hemorrhage• Erratic swimming, Gulping, Gill-Fin rots• White spot, Pale gill

Bacterial Diseases

• Cause: Aeromonas hydrophila (G-, Bacillus; Flora)

+ Poor water quality (Predisposing)• Transmission: Mouth, Skin (damage), Gill• Signs:

• Peracute: Overnight, No/Little Sign, Congestion,

Internal organs (pale, swollen, fribble)

• Acute: 1-2 days, dropsy -popped scale &ascites, exophthalmos, hemorrhage

Motile Aeromonas (d) Septicemia

• Signs (cont.): • Chronic: ulcers, hemorrhage, lethargy, erratic

swimming, ascites, fin-gill rots, exophthalmos, K-Li enlarge, corneal opacity

• Latent: no signs, immune +, reservoir* Human: diarrhoea• Isolation: BHI, TSA

Motile Aeromonas (d) Septicemia

•Prevention: 0.1-0.5% NaCl @ transportation

Density…appropriate Water quality…good Vaccine ?• Treatment:

• Oxytetracyclin 55-75 mg/kg fish ppm, 7-10 d • Oxolinic acid 10 mg/kg fish ppm, 7-10 d • Amoxycillin 40-80 mg/kg fish ppm, 10 d

Motile Aeromonas (d) Septicemia

Bacterial Diseases

• Cause: Aeromonas salmonicida (G-, , non-motile)• Transmission: Mouth, Skin (damage), Gill• Furuncle = Necrosis + Exudate + Macrophages• Signs: • Peracute: fingerlings, dark in color, death• Acute: subadult-adult, anorexia,

hemorr. (skin-fins-gut), death

Furunculosis

• Signs (cont.): • Chronic: furuncles + ulcers, internal hemorr,

survivals = carriers • Predisposing causes:

• Stress, Temp, Overcrowding, Trauna-wound

Furunculosis

•Prevention: 0.1-0.5% NaCl @ transportation

Density…appropriate Water quality…good• Treatment:

• Oxytetracyclin 75 mg/kg, OID 7-10 d • Sulfamerazine 265 mg/kg , OID 14 d • Chloramphenicol 55 ppm 10 d• Furazolidone 35 ppm 20 d• Nor-, Enrofloxacin 2-3 ppm 7-10 d

Furunculosis

Bacterial Diseases

• Vibrio (G-, motile, comma rods) “red boil, red pest” •V. anguillarum (common)•Transmission: Mouth, Skin (damage), Brooders• Signs: marine-estuarine water• Redness: Base of fins, mouth, skin, anus

Boil like lesion (s/c, m) pus

• Anemia, Skin ulcer • Hemorrhage: skin, fin, gill, internal organs• Abdominal fluid, # Heart

Vibriosis

• Prevention : • Reduce stress (Appropriate density)• Good water quality: DO, pH, NH3, NO2

-, etc.• Treatment: 0.1-0.5% NaCl @ transportation

• Oxytetracyclin 77 ppm, 10 d • Sulfamerazine 265 ppm 3 d & 154 ppm 11d• Nitrofurazone 56 ppm 10 d• Furanaze 500-1000 ppm 10 d• Oxolinic acid 10 ppm 10 d• Amoxycillin 40-80 ppm 10-12 d• Nor-, Enrofloxacin 3-5 ppm 7-10 d

Vibriosis

Bacterial Diseases

• Cause: Flexibacter columnaris (G- long rod; Hay-stack appearance)• Transmission: to skin-gill of freshwater fish• Signs: • Skin: mucous, change color w petechial hemorr.

-erosion-necrosis• Eye: corneal opacity• Fins: rots, petechial hemorr.• Gill: congestion, hemorr., necrosis

Columnaris Disease

• predisposing causes:• low O2, NH3, handling• Prevention : • Avoid skin damage• Appropriate density (reduce stress)• Good water quality: DO, pH, NH3, NO2

-, etc.• Chemicals: CuSO4 10 ppm 20 min (500 ppm 1 min)

• Treatment: • 0.1-0.5% NaCl • Furanaze 1.5 ppm 3 hr

Columnaris Disease

Bacterial Diseases

• Cause: Edwardsiella ruckeri (G-, motile, short rod)

“Enteric Redmouth Disease”• Horizontal transmission• Signs:

• Lethargy, anorexia, exophthalmos• Hemorrhage (mouth, eye, base of fins, gill) • Hemorrhage (liver, gonad, bladder, m)• Spleen (swollen, friable)

Yersinia ruckeri

• Predisposing causes:• Carriers (survivors)• stress, poor water quality

• Tx: Sulfamerazine 265 ppm 3d, 154 ppm 11d

OTC 55 ppm 10 d• Prevention: • Vaccine

Yersinia ruckeri

Bacterial Diseases

• Cause: Edwardsiella tarda (G-, motile, rod) “Emphysematous putrefactive of Catfish”• Transmission: Fece• Signs: • Lethargy, abnormal swimming• Small cutaneous ulcer deep necrotic ulcer• Deep m abscess, ascites, gill inflame• Necrotic nodules in K, Li, Spleen

Edwardsiella tarda

• predisposing causes:• Low temp, Density• poor water quality• Prevention : • Appropriate density (reduce stress)• Good water quality: DO, pH, NH3, NO2

-, etc.• Tx: OTC 55 ppm, Oxolinic acid, Chloram.

Edwardsiella tarda

Bacterial Diseases

• Cause: Edwardsiella ictaluri. (G-, motile, rod)

“Hole in the head”“Enteric Septicemia of Catfish, ESC”• Signs:

• Anorexia, swimming (spiral) • Depigmentation, ”Chin rash” • Ulceration in the frontal bone• Pale gill, ascites, exothalmos

Edwardsiella ictaluri

• Transmission: water to nose to brain• predisposing causes:• Temp, stress• Tx: OTC, Sulfonamide• Prevention: • Avoid skin damage• Appropriate density (reduce stress)• Good water quality: DO, pH, NH3, NO2

-, etc.

Edwardsiella ictaluri

Edwardsiella ictaluri

Bacterial Diseases

• Cause: Pseudomonas spp. (G-, motile, rod)• Signs: • Mass hemorrhage (mouth, opercula, ventral body)• w poor sanitation, high temp

Pseudomonas infection

• Prevention: • Avoid skin damage• Appropriate density (reduce stress)• Good water quality: DO, pH, NH3, NO2

-, etc.• Treatment: • Erythromycin ppm, d • Amoxycillin ppm, d

Pseudomonas infection

Bacterial Diseases

• Cause: Streptococcus spp. (G+)...Hemolytic strains• Transmission: contact, oral• Signs: • Lethargy, Erratic swimming• Skin: hemorrhage, ulcer• Fins: hemorrhage• Eye: exophthalmos, hemorr.

Streptococcosis

Bacterial Diseases

• Cause: Mycobacterium spp. (G+ rod acid fast)• Transmission: skin abrasion, oral• Signs: depend on spp, route, stress, temp• Anorexia, Lethargy, Emaciation, • Fin rots (general), Deformity (Vertebrae)• Skin ulcer: Non-healing,, Shallow, Irregular• Nodules: Liver, Spleen, Kidney, M.

Mycobacterium

• Prevention : • Culling• Avoidance of infection (water, fece, skin eruption)• Treatment: • Kanamycin • Streptomycin • Rifampicin

Mycobacterium

Bacterial Diseases

• Clostridium botulinum• Pasteurella spp.• Renibacterium (BKD)• Enterococcus spp.• Nocadia spp.

Miscellaneous