, Diagnosis an-&& of Shrimp Diseases - Central Institute of ...

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Larval MycosesIt is one of the most devastating diseases in shrimp hatcheries. However, larval mycoseshave been successfi~lly controlled during the recent years with better management practices.Signs and symplorns: Affected larvae appear opaque followed by sudden mortality.protozoeal and mysis stages are highiy susceptible. Within 1-2 day's, whole stock of shrimplarvae may suffer mortality.Cause: Oomycetous fungi, Lagenidilrm spp, Sirolpidium spp,'and Haliphthoros spp. Thesefungi are filamentous, non-septate and coenocytic. Upon infection, the fungal myceliumreplaces the larval tissues and ramifies into various parts of the body. Vegetative propagationof these fungi is through production of bi-flagellate zoospores, which are released into therearing medium. These zoospores further infect fresh shrimp larvae. These fungi can beisolated on peptone yeast extract glucose (PYG) agar or Saboraud's dextrose agar.Dingnosis: Microscopic demonstration of presence of extensively branched non-septate,fungal hyphae within the body cavity of the shrimp larvae.Prevention: Remove bottom sediments and dead larvae periodically. Disinfect the tanks andother equipment in the hatchery from time to time. Treat spawners with 5 ppm treflan bath for1 h.Control: When the disease is detected in early stages, Treflan (Trifluralin) 0.1 -0.2 pp~n bathfor I day may help in reducing Inass mortality.TheOther fungi such as Fusarium spp. cause infections in nauplii, protozoea, juvenilesand adults. Black gill disease is often caused by this fungus. The fungus can be identified bymicroscopic examination of its characteristic canoe shaped micro-conidia. Other oomycetousfungi such as Saprolegnia spp. and Leptolegnia spp. are also known to affect shell of shrimpand produce dark necrotic lesions causing gradual mortality.
PARASiTIC AND NON-INFECTIOUS IIISEASESK. P. JithendranPARASITIC DISEASESAmong the disease causing organisms of shrimp, parasites, especially protozoanparasites form an important group. Although, several diseases caused by parasites have beennoticed in shrimp, often, chronic conditions caused by protozoans play a crucial role inshrimp production. The protozoa, affecting shrimp can be grouped as parasites andcommensals. Following are the major disease problems caused by the protozoa:Protozoan foulingCotton shrimp diseaseEnterozoic cephaline gregarine infectionInvasive protozoan infection"'Protozoan FoulingThis is a serious disease problem commonly encountered both in hatchery and farm.Signs and symptoms: Affected shrimps are restless and their locomotion and respiratoryfunctions are hampered. Heavily infected, larger shrimp often have fuzzy-mat like appearanceon the body surface, appendages and gills. Animals also show brownish discoloration due toalgal filaments or debris entangled with the epibiont.Causative organism: Peritrichous ciliates such as Zoothamniwm, Epistylis, Vorticella,Acinata etc.Diagnosis: Based on gross signs and symptoms. Fresh smear preparation of the surfacescrapping or gill or appendages will reveal the morphology of the protozoan.Prevention: Maintain good water quality, reduce the organic substance, silt and sediment onthe pond bottom, maintaining optimum dissolved oxygen level (5-6 ppm) and frequentexchange of water.Control: Formalin is the chemo therapeutant of choice. Treatment with formalin 15-25 ppmconcentration (single treatment) for ponds or dip treatment of affected animals in 50-100 ppmfor 30 min is useful. Good aeration during treatment is essential.
Page 5 and 6: OVERVIEW OF STRATEGIES FOR PREVENTI
Page 7 and 8: in harmonizing aquatic animal healt
Page 9 and 10: SI-IRXMP DISEASES: GENEIL4L ASPECTS
Page 11 and 12: quantitative level of pathogen is i
Page 13 and 14: presence of prominent eosinophiiic
Page 15 and 16: Disease affected the shrimps of all
Page 19 and 20: BACTERIAL AND FUNGAL DISEASES OF SH
Page 21: Cause: The epibiotic bacteria stich
Page 25 and 26: XOS-INFECTIOUS DISEASESNon-infectio
Page 27 and 28: INVESTIGATING SHRIMP DISEASES: OBSE
Page 29 and 30: lnay be a predisposing factor for b
Page 31 and 32: BACTERIOLOGICAL METHODSS.V. Alavand
Page 34 and 35: In place of ZMA, nutrient agar prep
Page 36 and 37: Interpretation: Positive reaction i
Page 38 and 39: Incubate at 37°C for 1-2 h.Examine
Page 40 and 41: Alkaligens: etc. are resistant. The
Page 42 and 43: Culture Media, Reagents and StainsC
Page 45 and 46: Differential characteristics of Vib
Page 47 and 48: Davidson's Alcohol Formatin Acetic
Page 49 and 50: Paraffin cold impregnationXylene an
Page 51 and 52: ProcedureDe-paraffinise the slid'c
Page 53 and 54: Biochemistry of Nucleic Acids with
Page 55 and 56: DNA e.rl1i6it.v base equivuleizcc!E
Page 57 and 58: hydrolyzed by dilute alkali. The su
Page 59 and 60: Polymerase Chain Reaction (PCR) is
Page 61 and 62: a number of viral, bacterial and pa
Page 63 and 64: from 15-30 bases. Negative controls
Page 65 and 66: PCR Primers for Indian WSVTwo sets
Page 67 and 68: ANTIOXIDANTS IN MANAGEMENT OF OXIDA
Page 69 and 70: Many potent chemical carcinogens ar
Page 71 and 72: cells. It has been shown that possi
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AFB, induced ~nutagenesis in Salmon
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FIGURE 2. An overview of oxygen rad
Page 77 and 78:
were responsible for production los
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for Asiatic region. The participati
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charge of the DNA fragment. The neg
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European countries have in place th
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irth to a new concept to treatment
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