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7.1.3.Normally found external signs in fish and causes
Level I Gills necrotic – Bacterial, parasitic, fungal Gills with excess mucus – Bacterial, parasitic, environmental or nutritional Gills pale – Viral, bacterial, nutritional Skin with excess mucus – Parasitic, environmental Re-pigmented areas in skin – Bacterial or parasitic Dark skin pigmentation – Viral, bacterial, nutritional, eye parasite Haemorrhage, erythemia – viral, bacterial, parasitic, toxicants Frayed, eroded, erythemia in fins – Bacterial, parasite, mechanical, physiological disorder Exophthalmia, haemorrhaged opaque eyes – Viral, bacterial, parasitic, gas super saturation Ulceration, necrotisation – Bacterial, parasitic Dropsy – Bacterial, viral, metazoan parasite. Enlarged abdomen (fluid accumulation) – Viral, bacterial, parasitic Growth, nodules, raised spot on skin – Viral, parasitic, neoplasmic, fungal. Clinical signs observed in shrimps Major behavioural changes that can be observed in shrimp are:
Morphological abnormalities observed in shrimps Ø surface fouling of appendages and cuticle for filamentous bacteria and protozoans. Ø oral region for bacterial "plaques" (presumptive for Vibrio spp.). Ø larval mycosis - diagnosed by demonstration of hyphae, discharge tube, and motile zoospores. Ø muscle atrophy in abdomen, especially in 6th abdominal segment (muscle should fill half of space available). Ø hepatopancreas atrophy, vacuolisation, lipid droplets and BP inclusion bodies. Ø cuticular deformities: bent or broken setae or spines Ø melanized appendages tips or foci. |