Fungal disease of marine fish

1

• Fungal disease of marine fish
• Fungi, opportunistic, weak pathogen
• Pathogenic, when stressful reduce
• defences
• Uncommon in estuarine marine
• ecosystem
• Pathogenic fungi, Ichthyophonus, ulcerative
• syndrome, redspot disease/epizootic
• ulcerative syndrome

2

• 1. Ichthyophonus
• Fungus-like, systemic infection, cold water
• Pathology depend host, dosage, species
• fungus
• Gross signs, loss equilibrium, abnormal pig-
• mentation,abdominal distention, muscle
• athrophy, spinal curvature, roughening skin,
• ulcers
• Internal, white nodule escp vascular organ
• (kidney,heart,spleen,liver),hyperpigmentation

3

• Muscle liquefaction seen in acute cases
• Early stage mononuclear infiltrate, chronic
• form chronic inflamatory
• Obligate pathogen, transmission by feeding
• spore, water-borne, amoeboid penetrate
• mucosa, entering bloodstream
• 2. Ulcerative mycosis
• Very deep penetrating lesion, commonly
• perforate body wall

4

• Lesion infected by bacteria protozoa
• High mortality, systemic bacterial infection
• Lesion, UM begin as skin infection under-
• lying muscle viscera
• Skin lesion, up to 5 mm, red-yellow foci,
• mononuclear infiltrate
• Fungal infection, near skin surface, invasion
• underlying muscle
• Large ulcers, fungal hyphae, bacteria,
• necrotic muscle

5

• Fungi in UM lesion, Aphanomyces,
• Saprolegnia
• Saprolegniaceous common in freshwater,
• form fuzzy, cottony growth on skin
• 3. Redspot disease/ epizootic ulcerative syndrome
• 1980 EUS reported from Malaysia from frsh
• water fish-estuarine fish
• Caused deep skin ulcers, inflamatory
• Lesion began on skin surface, deep ulcers

6

• Early stages, epithelial edema, loss surface
• epithelium, dermal edema with hyperemia
• hemorrhage
• Vibrio the initiator of RSD later digenean
• trematode
• Miscellaneous pathogens
• from marine to freshwater-- classical oomycete
• skin infection-- superficial foci of cottony
  hyphae
• salmonids, oomycete epidemics associated

7

• with ulcerative dermal necrosis (UDN)
• necrosis consist of oomycete Saproglenia
• diclina-parasitica
• Exophiala responsible in net cage salmon
• other fungal disease, Aureobasidium in
  stingray,
• Sarcinomyces in black seabream, Cladosporium
• in cod, Fusarium in trigger fish and bonnethead
  
• shark