DATE: MIXOBOLUS

PROTOZOAN DISESES OF FISH

Classification

Phylum Class Order Family Genus

Protozoa Myxosporea Myxosporida Myxobolidae Myxobolus

1.M

yxobolus cerebralis is a myxosporean parasite of salmonids (salmon, trout, and their allies) that causes whirling disease .

2. Whirling disease afflicts juvenile fish (fingerlings and fry) and causes

skeletal deformation and neurological damage.

3. Fish "whirl" forward in an awkward, corkscrew-like pattern instead of swimming normally, find feeding difficult, and are more vulnerable to predators.
4. Clinically fish become hyperactive with fish flashing and cutting against rocks or sides.
5. Upon contact with fish hosts and firing of the polar capsules, the sporoplasm

contained within the central style of the triactinomyxon migrates into the epithelium or gut lining. Firstly, this sporoplasm undergoes mitosis to produce more amoeboid cells, which migrate into deeper tissue layers, to reach the cerebral cartilage

6. Cartilage is scarred with lesions in which M. Cerebralis spores develop, weakening and

deforming the connective tissues.

7. Drugs, such as furazolidone, furoxone, benomyl, fumagillin, proguanil and clamoxyquine, have been shown to impede spore development, which reduces infection rates.

TRICHODINIASIS

Classification Phylum Class

Order Family

Genus

Protozoa Ciliata Peritricha Urceolaridae Trichodina

1. This disease is caused by a group of peritrichal ciliated protozoans.
2. The organisms are saucer shaped, 50 microns diameter, with rows of cilia at both ends and a macro and micronucleus.
3. Clinically fish usually exhibit flashing and become lethargic.
4. There is an increase in mucus production causing a white to bluish haze on the skin.
5. The skin may develop ulcers and the fins may fray.
6. Histologically, masses of organisms are attached by adhesive discs and denticles of exoskeleton to the epidermis. The underlying epithelial cells undergo necrosis.
7. There is secondary hyperplasia and hypertrophy of the gill epithelium.
8. Transmission is by direct contact with infected fish and or contaminated water.

1. Epistylis causes red sore disease

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• This ciliated protozoan is primarily a free-living protozoan that lives on aquatic plants and is believed to be an opportunist. Outbreaks have occurred in catfish and salmon that have been maintained in water high in organic content.

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• It appears on the skin of fish
• It is a branched stalked ciliated protozoan with bell like bodies on stalk (Heteropolaria colisarum)
• It is found primarily in wild populations of scaled fish.

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• Ulcers or cotton-like growth is seen on the skin, scales and spine resulting in a red colored lesion.
• In catfish the lesion involves the spines and bones that underlie the skin of the head and pectoral girdle.
• This protozoan parasite has also been observed on eggs.

EPISTYLIS

Classification Phylum Class

Order Family Genus

Protozoa Ciliata Peritricha Epistylidae Epistylisa

ICHTHYOPHTHIRIUS MULTIFILIIS

("Ich" or White Spot Disease)

Classification Phylum

Class

Order Family Genus

Protozoa Ciliiophora Hymenostomitida Ichthyophthiridae Ichthyophthirius

1. It is the largest protozoan parasite of fish.
2. The trophozoite are up to 100 microns diameter, ciliated and contain an oval horseshoe shaped nucleus.
3. This is a disease of hatchery reared fish.
4. Typical behaviors of clinically infected fish include:
1. Anorexia (loss of appetite, refusing all food, with consequential wasting)
2. Rapid breathing
3. Hiding abnormally
4. Resting on the bottom
5. Flashing
6. Rubbing and scratching against objects
7. Upside-down swimming near the surface
5. As the trophozoite enlarge they cause hyperplasia of the epidermis with white spots forming on the skin and gills.
6. Severely infected fish may have respiratory problems and die.
7. Histologically there is epidermal hyperplasia with the encysted trophozoite present in the epidermis.
8. The only way to treat the disease is by interrupting the life cycle of the parasite.
9. One must treat the water to kill the tomites to prevent spread of the disease (Malachite green, formalin, methylene blue, or kmno4).
10. These treatments only kill the tomites and not the trophozoite that are encysted in the

fish.

CHILODONELLA CYPRINI.

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CLASSIFICATION

Phylum: Class: Order Genus

Ciliophora Cryptophoridia Chilodinellidae Chilodenella

1. The parasite is vaguely leaf shaped with a length of 40-70 microns, & a width of some 30- 50 microns. The ventral side of the parasite is covered with cilia.
2. Behavior:Labored breathing, and fish may appear at surface gasping for air. Fish will evidence lethargy, and May from time to time, try to "scratch" of the organisms, by rubbing against an object of some kind in the aquarium. Distress is visibly obvious.
3. Fins. Fins often become clamped or folded
4. Body: Excessive mucous production is typical, & parts of the body wil_l exhibit cloudiness as large numbers of the parasite begin feeding of the epithelial layers.
5. Gills. Gill examination will show large numbers of the leaf shaped organisms.
6. Skin (smear). Should show ciliates once an infection has become established.
7. Treatment: Fortunately if successfully diagnosed, there are several treatments that can

be used. These include the use of formaldehyde used as a bath as well as Acriflavine type drugs along with methylene blue.

ICTHYOBODOIS COSTIASIS

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CLASSIFICATION

Phylum :

Protozoa Class Kinetoplastida Bodonina Ichthyobodo necator

Family Genus: Species:

1. Ichthyobodosis is also called as Costas’s.
2. Costia is a minute flagellate with 3-4 flagella.
3. It affects both the skin and gills of fish.
4. White patches are caused on body due to excess mucus production by the fish in response to a skin irritant.
5. Fish suffering infestations exhibit the classic symptoms of lethargy, clamped fins,

rubbing and flashing and the skin can take on a grey white opaqueness.

6. It looks different from fungus, which usually forms wool-like tufts
7. Gill is pale in colour.
8. The best treatment is with copper at 0.2 mg per liter (0.2 ppm) to be repeated once in a few days if necessary.
9. Acriflavine may be used instead at 0.2% solution (1 ml per liter). As Acriflavine can

possibly sterilize fish and copper can lead to poisoning, the water should be gradually changed after a cure has been affected.

10. Salt bath 3% solution

HEXAMITIASIS

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HOLE IN THE HEAD DISEASE.

Phylum: Protozoa

Order: Diplomonadida Family: Hexamitidae Genus: Hexamita

1. Hexamitiasis is a parasitic disease that can affect both freshwater and saltwater fish.
2. In some cases, lesions appear on the head and flanks of the fish, hence its alternative name: hole in the head disease.
3. Hexamita infections may also be responsible for head and lateral line erosion (HLLE)
4. Fish infected with Hexamita commonly produce white, stringy feces, and their coloration becomes more subdued than normal.
5. The fish eventually lose their appetite and gradually become emaciated.
6. Often (but not always), lesions appear on the fish’s head. Sometimes, these lesions are also apparent on the fish’s flanks.

MICROSPORIDOSIS COTTON SHRIMP DISEASE MILK SHRIMP DISEASE WHITE OVERY DISESE

Cotton shrimp disease

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Etiological Agent: Microsporidia such as Thelohania spp., Nosema spp., and Pleistophora spp.

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Clinical Signs: Infected shrimps appear opaque and cooked. Gradual and low levels of mortalities are observed. Microsporidia invade and replace gill, muscle, heart, gonads and hepatopancreas, and cause necrosis in these regions

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Ovaries will become white and sterile.

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Prevention and Control: Maintain of good sanitary conditions at the pond bottom and the overall pond area.

EXPERIMENT NO.13 DATE:

VIRAL DISEASES OF FISH

Aim : To study the viral pathogenesis of Fishes

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Introduction:

Important emerging viral pathogens of fish are found among many families of vertebrate viruses that are well-known to include pathogens of humans or domestic livestock. However, there are significant differences between the ecology of viral diseases of fish and those of humans or other terrestrial vertebrates. The most significant amongst these differences are that:

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1. Few fish viruses are known to be vectored by arthropods;

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• Water is a stabilizing medium, but currents are less effective for long range virus transmission than are aerosols;

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• Wild reservoir species are often at very low densities (except for schooling and aggregate spawning stocks);

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• Fish are poikilotherms and temperature has an exceptionally critical role in modulating the disease process by affecting both the replication rate of the virus as well as the host immune response and other physiological factors involved in resistance;

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• Few fish viruses are transmitted sexually between adults, although high levels of some viruses are present in spawning fluids and a few viruses are transmitted vertically from adult to progeny, either intra-ovum or on the egg surface. However, as occurs for avian diseases, migratory fish can serve as carriers for long-range dispersal of viral pathogens.

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Importance :The global expansion of finfish aquaculture and accompanying improvements in fish health surveillance has led to the discovery of several viruses that are new to science. Many of these are endemic among native populations and opportunistically spill-over to infect fish in aquaculture facilities. Other well-characterized fish viruses (e.g., channel catfish virus, Onchorhynchus masou virus) can also cause significant losses in aquaculture but do not seem to be increasing significantly in host or geographic range. In the following sections, we consider the major emerging fish virus diseases that cause significant losses in aquaculture and are expanding in host or geographic range.

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VIRAL DISEASES OF FISH

• Lymphocystis
• Viral Hemorrhagic Septicemia (VHS)
• Infectious Pancreatic Necrosis (IPN
• Infective Hepatic Necrosis (IHN)
• Chinook disease
• Channel Cat Fish Virus Disease

1. LYMPHOCYSTIS:

1. Lymphocystis is a chronic disease of freshwater and marine fishes caused by infection with an iridovirus known as Lymphocystivirus
2. Infection results in the development of pebble or wart-like nodules most commonly seen on the fins, skin, or gills, although other tissues may be affected.
3. Tumor formation is the important character of this viral disease.
4. The external lesions are raised and made up of the growing of granular, nodular tissue which is composed of many greatly enlarged host cells.
5. Matured lesions may become slightly hemorrhagic. Within 6-15 days of infection the tumors grow to 50 thousand times.
6. The only control measure is prevention.

2. VIRAL HEMORRHAGIC SEPTICEMIA (VHS):

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This disease occurs in salmon fishes. Transmission of the disease occurs through the water by flagellates.

1. At a low level of infection, fish might not display any symptoms.
2. As the infection becomes greater, however, fish will display widespread hemorrhages (bleeding) throughout body surface (eye, skin and fins).
3. Hemorrhage is seen within the internal organs also. (swim bladder, intestine, kidney etc). Because of the bleeding, gills and liver might appear pale.
4. Sick fish will often be listless, swim in circles, and are frequently observed at the surface of the water.
5. The symptoms are kidney swelling, reduced appetite, obvious distress, erratic spiral

swimming, multiple hemorrhages in skeletal muscles, change in body colour, reddish fins.

6. The only control measure is prevention.

3. INFECTIOUS PANCREATIC NECROSIS (IPN):

1. This disease is found in trouts.
2. This disease causing high mortality of fry, fingerlings and occasionally larger fishes.
3. Abdominal swelling, anorexia, abnormal swimming, darkening of the skin, and trailing of the feces from the vent are main symptoms.
4. Hemorrhages can be seen in ventral areas including bases of fins.
5. There will be pronounced pancreatic necrosis.
6. On necropsy, internal damage (viral necrosis) to the pancreas and thick mucus in the

intestines often is present

7. Diagnostic methods for the detection of the disease include: characteristic histological pancreatic lesion, PCR, indirect fluorescent antibody testing, ELISA, and virus culture can be used to detect the disease. High virus titers can be isolated from carrier animals.
8. 200 ppm of chlorine is effective for treatment.

INFECTIVE HEPATIC NECROSIS (IHN):

1. This disease occurs more in fry and fingerlings and occasionally in adults.
2. Necrosis is observed in the haemopoitic tissue of kidney in infected fish.
3. The symptoms are pale gills, reddish fins, black colouration of the body, abdomen swelling and huge mortality.
4. Clinical signs of infection with IHNV include abdominal distension, bulging of the eyes,

skin darkening, abnormal behavior, anemia, and fading of the gills.

5. Infected fish commonly hemorrhage in several areas - the mouth and behind the head, the

pectoral fins, muscles near the anus, and (in fry) the yolk sac. Diseased fish weaken eventually floating “belly-up” on the surface of the water.

6. Necrosis is common in the kidney and spleen, and sometimes in the liver.^[20] Mortality is very high in young fish.

CHINOOK DISEASE

1. A small size virus is responsible for this disease in Chinook salmon (Oncorhynchus tshawytscha) fingerlings.
2. The symptoms are exophthalmus, distended abdomen, a dull red area on the dorsal surface anterior to dorsal fin.
3. The liver, spleen, kidney, gills and heart are pale.
4. The disease is transmitted by the egg from the carrier female.
5. No treatment.

EXPERIMENT NO. 14 DATE:

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VIRAL DISESES OF SHRIMP AND PRAWN

(1) Monodon

Bacculovirus Disease (MBV)

Etiological Agent

MBV-type or pmsnpv is a type A occluded Monodon Bacculovirus.

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Clinical Signs

Lethargy, anorexia, poor feeding, dark colouration and reduced growth rate.

Infected shrimps are often associated with fouling of gills and appendages by ciliates such as

Zoothamnium spp. And Vorticella spp.

Acute infection leads to loss of epithelial cells of hepatopancreas.

Treatment

No treatment available for MBV infection

Prevention and Control

There is little information on prevention and control of the MBV infection in shrimp pond culture. The prevention method for the MBV infection is possibly through avoidance by screening the PL's before stocking shrimp in the pond.

2) HEPATOPANCREATIC PARVO-LIKE VIRUS (HPV) DISEASE

Etiological Agent

HPV is caused by a small parvo-like virus, 22-24 nm in diameter.

Clinical Signs

1. Reduced feeding,
2. Poor growth rate,
3. Body surface and gill fouling with ciliates and occasional opacity of abdominal muscles.
4. Severe infections may include a whitish and atrophied hepatopancrease,
5. Anorexia and reduced preening activity.
6. Losses may be occurring due to the increased occurrence of surface and gill fouling organisms and secondary infections by the opportunistic Vibrio spp.

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Treatment

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No treatment available for HPV infection.

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Prevention and Control

No information is available on the prevention and control procedures for HPV infection.

However, screening the pals before stocking shrimp by routine histology or the Giemsa- impression smear method is recommended.

(3) YELLOW-HEAD DISEASE (YHD

Etiological Agent

Yellow-headed virus (YHV) is an ssRNA, rod shaped, enveloped virus with two rounded ends.

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Clinical Signs

1. The affected shrimp shows a marked reduction in food consumption.
2. Moribund shrimp will appear swimming slowly near the surface of the pond dike and remain motionless.
3. The animals have pale bodies, swollen cephalothoraxes with a light yellow to yellowish hepatopancreas and gills.
4. A high mortality rate may reach 100% of affected populations within 3-5 days from the

onset of disease.

Treatment

No treatment is available for YHV infection.

Prevention and Control

The reliable method to prevent the occurrence of YHD is possibly through avoidance, such as

careful selection of post larvae, reduction or elimination of horizontal transmission including carriers, disinfection of contaminated ponds or equipment with 30 ppm; and chlorine, providing shrimp with good water quality and proper nutrition.

(4) WHITE SPOT DISEASE (WSD)

1. The disease is caused by the dsDNA virus, Systemic Ectodermal and Mesodernal Bacculovirus (SEMBV).

Clinically affected shrimp were first seen to swim to the water surface and congregate at

the pond dikes.

2. Typical clinical signs include white spots or patches, 1-2 mm in diameter, on the inside of the shell and carapace, accompanied by reddish discoloration of the body.
3. The diagnosis procedure of SEMBV infection is based on the appearance of the

intranuclear hypertrophy in stained histological sections and the presence of virus particles in the nucleus of the infected cells observed under the electron microscope.

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4. PCR technique is recently used to detect SEMBV in shrimp larval and other stages, including brood stock and subclinical virus carriers.

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• No treatment is available for SEMBV infection.

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• Prevention practices through avoidance are strongly recommended for the farmers, involving the combinations of efficient pond management, use of proper feed, selection of good quality of PL, reduction of possible carriers, avoidance of introduction of contaminated water into the pond, and disinfection of all equipment and utensils.

(5) INFECTIOUS HEPATOPANCREATIC AND LYMPHOID ORGAN NECROSIS (IHLN)

Etiological Agent

The primary cause of the disease is attributed to viral etiology.

Clinical Signs

1. Light pinkish to yellowish discoloration of the cephalothorax region.
2. Often fouling by ciliate protozoan Zoothamnium seen. Blackened and necrotic hepatopancreas.
3. Secondary bacterial infection from bacteria such as Vibrio alginolyticus seen.

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Treatment

No treatment is available for IHLN infection.

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Prevention and Control

Keep the physico-chemical condition of pond environment within acceptable levels. To avoid

bacterial and viral pathogen entering from outside, closed culture could be useful in prevention of IHLN disease.

CHANNEL CAT FISH VIRUS DISEASE

1. This disease occurs in fingerling of cat fish (Ictalurus punctatus).
2. Gross pathological signs are:

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• Swollen abdomen
• Exophthalmos (popeye)
• Hemorrhaging of fins and ventral abdomen
• Hemorrhaging of the musculature, liver and kidneys
• Dark and enlarged spleen
• Fluid in the abdominal cavity
• Pale, enlarged kidneys, which may be the only internal indication of disease in infected fish.

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• The symptoms are that the fish show abnormal swimming and rotating..
• There is no treatment for this disease.
• Fish suffering from CCVD often show a decreased interest in food. This is often the first sign and it can be followed by high mortality in fry and juveniles.
• Erratic swimming, brief episodes of hyperactivity followed by extended periods of lethargy and large congregations of fish at the sides of the pond are also symptoms that can be seen.
• Fish may also stay motionless with the head pointing up and their tail down.

Experiment no ; 15 Date :

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BACTERIAL INFECTIONS

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The most common bacterial infections are caused by one of three pathogens: Vibrio, Pseudomonas or Aeromonas. The symptoms (e.g., cloudy eyes, bloody patches, decaying or frayed fins, scratching) of these bacterial infections can be similar, and therefore it can be difficult to determine which pathogen is responsible. Fish with an internal bacterial infection may not show any signs other than a loss of appetite and possibly a swollen abdomen.

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With most bacterial infections, all fish in the aquarium will be affected to varying degrees, so the entire aquarium may need to be treated. Obviously, if we are dealing with a large aquarium, this could potentially be expensive. If only one fish appears to be infected and you move the infected fish to a quarantine aquarium as soon as possible, you may get lucky and not have to treat the display aquarium. Over the past 25 years, I have used a variety of medications with varying degrees of success; however, in most cases, tetracycline has been the most effective treatment for infections caused by both Vibrio and Aeromonas, though there are other antibiotics that you can use. Remember to follow the manufacturer's directions and

remove any activated carbon from your filter before treating the aquarium. Another option is the use of medicated foods if the fish are eating well.

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1) LUMINOUS VIBRIOSIS

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Etiological Agent

Vibrio harveyi, Vibrio vulnificus

Clinical Signs

High mortality rate in young juvenile shrimp (one month syndrome). Moribund shrimp hypoxic often come to the pond surface and edges of pond. Vertical swimming behavior immediately before onset of acute mortality. Presence of luminescent shrimp in ponds.

Treatment

Disinfection of intake water with Formalin (100-200 ppm). Administration of Oxolinic acid (0.6 ppm) and Sarafloxacin (5mg/kg) through feed for 5 days.

Prevention and Control

Proper pond and water management. Utilization of reservoir for intake water.

(2) VIBRIOSIS

Etiological Agent

Vibrio vulnificus, V. Parahemolyticus, V. Alginolyticus, V. Anguillarum, V. Damsella, V. Fluvialis and V. Mimicus.

Clinical Signs

High mortality rates, particularly in young juvenile shrimp. Moribund shrimp with corkscrew

swimming behavior appear at edge of pond. Reddish discoloration of juvenile shrimp. External Fouling

Black spots, chronic soft shelling.

Treatment

Disinfection of intake water i.e. Formalin 100-200 ppm. Anti-microbial preparation application

through feeds (Oxolinic acid 0.6 ppm and Sarafloxacin 5 mg/kg).

Prevention and Control

Proper pond and water management and utilization of reservoir for intake water.

3. DROPSY

1. Dropsy is not a specific disease, but rather a symptom of a deteriorated health condition.
2. With dropsy, the fish will have visible swelling and projected scales. This is the result of a fish not being able to regulate the amount of fluid in a part of its body.
3. The affected area is typically the abdomen; specifically, it is most often the visceral

cavity that houses a number of organs, such as the stomach, intestines, gall bladder and kidneys.

4. The failure to regulate fluids is a symptom; therefore, there is usually some other disease involved that starts the process (caused by poor water quality, stress, internal bacterial infections, parasites, viruses and tumors).
5. Although dropsy is fairly easy to diagnose, the cause is much harder to determine; however, the primary cause is usually attributed to a bacterial infection.
6. The causative agent can be introduced to the aquarium through food, poor water quality or through the introduction of other fish to an established aquarium.
7. Although dropsy is not highly contagious, the affected fish should be removed and

placed in a quarantine aquarium. Dropsy can be spread from the affected fish, which can possibly produce stress among the other fish and make them more vulnerable to dropsy or other conditions

8. Although there are no present medications that can effectively cure fish stricken with dropsy, your first line of defense is to administer a wide-spectrum antibiotic in the condition's early stages.
9. In addition, you might add Epsom salts to your aquarium (20 milligrams per liter or 75.2 milligrams per gallon), which will aid the affected fish in expelling unnecessary fluids

from its body.

Unfortunately, the prognosis of fish affected with dropsy is not very good. By the time the fish has swollen up and the scales project outward, the internal damage may be

too expensive to repair and for the fish to recover. Most cases of dropsy are fatal.

TUBERCULOSIS

1. If a fish has a bent or curved spine, it is most likely infected with a Gram-positive mycobacterium (Mycobacterium marinum or M. Fortuitum). This is commonly referred to as fish tuberculosis, piscine tuberculosis, acid-fast disease or granuloma disease.
2. Symptoms include lethargy, emaciation, fin and scale loss, exophthalmia (bulging eyes), skin inflammation and ulceration, edema (dropsy), peritonitis (parasite infestation) and nodules in muscles that may cause deformation of the fish.
3. Infected fish should be removed and quarantined immediately for four weeks or more.

To prevent this infection, do not overcrowd, and provide good water quality. Remove any fish that appear affected.

4. Some successful treatments have been described using chloramine-B or -T, cyclosporine, doxycycline, ethambutol, ethionamide, isoniazid, kanamycin,

minocycline, penicillin, rifampin, streptomycin, sulfonamides and tetracycline. In addition, you might try using

5. Streptomycin for the first four days at a dose of 10.6 mg/L (40 mg/gallon). After the streptomycin treatment is completed, feed the affected fish with food that has been

treated (soaked in) with rifampin at a rate of 10 milligrams per 100 grams of food for about two months. At the same time, treat the aquarium with isoniazid twice a week at a

10.6 mg/L (40 mg/gallon) dosage for one month.

6. If all fish become infected and eventually die, the entire pond should be sterilized using a mild bleach solution and rinsed with liberal amounts of water before adding any new fish.

FURANCULOSIS

Furunculosis is highly contagious disease that affects fish of all ages.

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Also known as infection with Aeromonas salmonicida, the infection causes high mortality in salmonids, though some other species of fish are affected.

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Gross pathological signs are:

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1. Furuncles (or boils) involving skin and/or muscle, progressing to crater lesions (usually restricted to the sub acute or chronic phase in adult fish)
2. Hemorrhages on the skin, mouth and fin bases (mainly of paired fins)
3. Darkening of body colour and pale gills
4. Bloody discharge from vent
5. Exophthalmoses (Popeye)
6. Hemorrhages in muscle and internal organs
7. Enlarged spleen and focal necrosis of the liver
8. Stomach filled with mucus, blood and sloughed epithelial cells
9. Congested intestine
10. Death without any clinical signs other than darkening of the skin, which can occur in per acute infections in juvenile fish.

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Control/ Treatment

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The disease is controlled on farms by medication or vaccination.

Iodine is also used to decontaminate the surface of fertilized eggs to prevent vertical transmission (passage of infection from parent to offspring).

COLUMNARIS

1. Columnaris (also referred to as cottonmouth) is a symptom of disease in fish which results from an infection caused by the Gram-negative, aerobic, rod-shaped bacterium Flavobacterium columnare. It was previously known as Bacillus columnaris, Chondrococcus columnaris, Cytophaga columnaris and Flexibacter columnaris.
2. An infection will usually first manifest in fish by causing frayed and ragged fins.
3. This is followed by the appearance of ulcerations on the skin, and subsequent epidermal

loss, identifiable as white or cloudy, fungus-like patches – particularly on the gill filaments.

4. Mucus often also accumulates on the gills, head and dorsal regions.
5. Gills will change colour, either becoming light or dark brown, and may also manifest necrosis.
6. Fish will breathe rapidly and laboriously as a sign of gill damage. Anorexia and lethargy are common, as are mortalities, especially in young fish.

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Treatment

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As Flavobacterium columnare is Gram-negative, fish can be treated with a combination of the antibiotics furan-2 and kanamycin administered together. A medicated fish bath (using methylene blue or potassium permanganate and salt),^[3] is generally a first step, as well lowering

the aquarium temperature to 75°F (24°C) is a must, since columnaris is much more virulent at higher temperatures, especially 85-90°F.

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Medicated food containing oxytetracycline is also an effective treatment for internal infections, but resistance is emerging. Potassium permanganate, copper sulfate, and hydrogen peroxide can also be applied externally to adult fish and fry, but can be toxic at high concentrations. Vaccines can also be given in the face of an outbreak or to prevent disease occurrence.

FIN ROT

1. Fin rot can be the result of a bacterial infection (Pseudomonas fluorescens, which causes a ragged rotting of the fin), or as a fungal infection (which rots the fin more evenly and is more likely to produce a white 'edge').
2. Sometimes, both types of infection are seen together. Infection is commonly brought on by bad water conditions, injury, poor diet, or as a secondary infection in a fish which is

already stressed by other disease.

3. Fin rot starts at the edge of the fins, and destroys more and more tissue until it reaches the fin base. If it does reach the fin base, the fish will never be able to regenerate the lost

tissue. At this point, the disease may attack the fish's body directly.

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Symptoms

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1. Fin edges turn black / brown
2. Fins fray
3. Base of fins inflamed
4. Entire fin may rot away or fall off in large chunks
5. Fins have white dots

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Treatment

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1. Change the water and check the filter
2. Treat with a suitable treatment such as phenoxyethanol, malachite green methylene blue or other proprietary agent^[2]
3. Use aquarium salt, 1 tbsp per 5 U.S. gallons
4. Find out the ph and correct it if necessary.
5. Use antibiotics if the rotting is jagged.

SURFACE FOULING DISEASES

Etiological Agent:

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Many species of bacteria, algae and protozoa such as filamentous bacteria, Leucouthrix sp.,

Flavobacterium sp. And Zoothamnium sp.

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Clinical Signs:

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Infected shrimps show black/ brown gills or appendage discoloration or fuzzy/cottony appearance due to a heavy colony of the organisms. In some cases, the severely affected shrimp die during the molting period.

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Treatment:

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Chlorine and formalin are often used to treat those commensal organisms if shrimp display heavy infection. Changing water is the most preferable management, which stimulates molting of the shrimp in order to reduce the infestation.

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Prevention and Control:

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Prevention and control of the occurrence of surface fouling are usually done through maintenance of good sanitary conditions at the pond bottom and the overall pond area. Organic matters and suspended solids in the pond should be reduced to prevent the attachment of those fouling organisms.

EXPERIMENT NO. 16 DATE;

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HELMINTH PARASITES OF FISH AND PRAWN

Platy helminthes

Monogenean Parasites of Fish

1. Dactylogyrus
2. Gyrodactylus
3. Ancyrocephalids
4. Capsalids Trematodes
5. Diplostomum spathaceum
6. Posthodiplostomum minimum: Nematihelmithes
1. Camallanus
2. Capillaria
3. Contracaecum
4. Eustrongylides

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Monogenean Parasites of Fish

Monogenean are a class of parasitic flatworms that are commonly found on fishes and lower aquatic invertebrates. Most Monogenean are browsers that move about freely on the fish’s body surface feeding on mucus and epithelial cells of the skin and gills; however, a few adult Monogenean will remain permanently attached to a single site on the host. Some Monogenean species invade the rectal cavity, ureter, body cavity, and even the blood vascular system. Between 4,000 and 5,000 species of Monogenean have been described. They are found on fishes in fresh and salt water and in a wide range of water temperatures.

Classification and Identification of Monogenean

There are 13 families of Monogenean; of these, four are frequently diagnosed on aquaculture fishes. These four families are Gyrodactylidae, Dactylogyridae, Ancyrocephalidae, and Capsalidae, and parasites of these families are commonly called gyrodactylids, dactylogyrids, ancyrocephalids, and capsalids, respectively.

1. DACTYLOGYRUS (GILL FLUKE)

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Classification:

Phylum Platyhelminthes

Class Trematoda. Order Monogenea

Genus : Dactylogyrus

1. Dactylogyrus is a genus of the Dactylogyridae family of Platyhelminthes. They are commonly known as gill flukes like other Monogenean, Dactylogyrus only has one host required to complete its life cycle.
2. In heavily infected fish, Dactylogyrus can also be found on the buccal cavity.
3. Other characteristics of the Dactylogyrus include the appearance of four eye-spots, 14 marginal hooks, one to two connective bars and two needle-like structures and spindle-shaped dactylogyrid-type seminal vesicles.
4. Symptoms that include inflamed gills, excessive mucous secretions and accelerated respiration.
5. The infected fish also becomes lethargic, swims near the surface, and its appetite decreases.
6. Additionally the infected fish may hold its gill covers open and scratch its gills on rocks.
7. In severe infections, Dactylogyrus can cause hemorrhaging and metaplasia of the

gills which can lead to secondary bacterial infections and death.

8. Heavily infected fish are also anorexic and can be found gasping for air and exhibiting abnormal behavior such as jumping out of the water.

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Treatment

A primary method for control of Dactylogyrus is the application of chemicals. Treatments include Praziquantel, salt baths, formalin or organophosphates, Bromex-50 and potassium permanganate.

2. GYRODACTYLIDS

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Classification:

Phylum Platyhelminthes

Class Trematoda. Order Monogenea Genus : Gyrodactylus Species: elegans,

1. Gyrodactylus is a broad group of parasites commonly called "Flukes". These are in fact skin or gill flukes, which attach themselves to the skin or gills of the fish, and can cause a great deal of damage.
2. These worms, as in fact they are, obtain nourishment by "eating" skin fragments as well as the sucking the blood of the victim which contributes to the pale appearance in chronic infestations.
3. Gyrodactylids have a pair of anchors with both dorsal and ventral bars and 16

marginal hooks, and do not have eye spots.

4. Attachment to the fish is made with the marginal hooks; the anchors are used as a spring-like device to assist attachment with the marginal hooks.
5. These gyrodactylids use an adhesive material to “glue” their eggs to the skin of

the catfish. Gyrodactylids may be found on freshwater, marine, and brackish water fishes.

2. ANCYROCEPHALIDS

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Classification:

Phylum Platyhelminthes

Class Trematoda. Order Monogenea Genus : Enterogyrus,

1. They are usually found on gills of freshwater, marine, and brackish fishes.
2. However, some genera (Neodiplectanotrema and Paradiplectanotrema) were reported in the esophagus of marine fishes, and one genus, Enterogyrus, lives in the stomach of African and Asian cichlid species.
3. Ancyrocephalids have two pairs of eye spots, and two pairs of anchors
4. Each pair of anchors has a transverse bar.
5. Marginal hooks usually number 12–14, but may be absent in some species.
6. Some species produce an adhesive substance to assist in attachment to the fish host.
7. Ancyrocephalids are oviparous, and eggs are occasionally seen in mucus when examining gill tissue with a microscope.

4. CAPSALIDS

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Classification:

Phylum Platyhelminthes

Class Trematoda. Order Monogenea Genus : Neobenedenia

1. Capsalids are primarily found on the skin and occasionally the eyes of marine fishes, and occasionally on brackish fishes.
2. The capsalids primarily rely on an adhesive substance for attachment to the host, but

they do have two pairs of anchors, a pair of accessory sclerites, and 14 marginal hooks. Many also have two circular attachment organs at their anterior ends. They also have

two pairs of eye spots, but these are not easily discerned in adults.

3. As capsalids reach maturity, their bodies tend to spread out to accommodate their extensive digestive system. Consequently, an infected fish may have capsalids at different stages of maturity that do not appear to be related. The eggs of capsalids usually have long thread-like appendages with adhesive droplets . Mature capsalids and egg masses are often large enough to be seen with the unaided eye.
4. Extensive skin wounds caused by severe infestation of capsalids Monogenean and secondary bacterial infection in lookdown Selene vomer. Inset: Numerous capsalids (white) and an capsalids egg mass (brown) on skin of pompano Trachinotus carolinus.
5. Fishes infested with Monogenean may become lethargic, swim near the surface, have clamped fins, seek the corners of aquaria or the sides of the pond, and have diminished

appetite.

6. They may be seen rubbing the bottom or sides (flashing) of the tank. Scale loss may occur where the Monogenean are attached, and the skin may vary in color where the

parasites have fed. Heavy gill infestations result in respiratory disease . Gills may be swollen and pale, respiration rate may be increased, and fish will be less tolerant of low-

oxygen conditions.

7. Piping (gulping air at the water surface) may be observed in fish in severe respiratory distress. Large numbers of Monogenean on either the skin or gills may result in

significant damage and mortality.

DIPLOSTOMUM SPATHACEUM:

Classification:

Phylum Platyhelminthes

Class Trematoda. Order Monogenea

Genus : Neobenedenia

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1. Diplostomum are digenean trematodes that have complex life cycles that involve birds (usually gulls), snails and fish.
2. In fish, the parasite infects the eye and can led to modifications of the host's behavior, which can make it more likely to be eaten by the parasite's next host (a fish-eating bird).
3. The parasite also affects marketability of the fish, affecting its feeding and growth, cosmetic appearance and causing blindness.
4. There have been cases of blindness in hatchery populations.
5. The body of the adult is 0.3-0.5 cm in length and distinctly divided into a flattened anterior forebode and a cylindrical and narrower hind body.

Eggs are shed and passed in the feces of the bird to the water.

6. Primary host fish which ingest the initially infected fish (second intermediate host) become infected and the life-cycle is completed when the host fish are ingested by fish- eating birds.

POSTHODIPLOSTOMUM MINIMUM: (BLACK SPOT DISEASE)

Classification:

Phylum Platyhelminthes

Class Trematoda. Order Monogenea Genus :

1. The metacercariae within the skin results in increased melanin deposition, hence the term “black spot disease”.( "black grub" in the fin of an affected fish).
2. Visible white or yellow spots in the visceral organs, usually no larger than 1 mm in diameter are often referred to as “white grubs” or “yellow grubs” "yellow grub" in muscle tissue of affected fish) and could be caused by several trematode species
3. Diagnosis of digenetic trematode infections is dependent upon identification of the genus and species of the trematode within infected fish.
4. Metacercariae are located in any organ of the fishes’ body, but are generally more numerous in the liver, kidney, heart, spleen and other organs of abdominal viscera. .

LIGULA INTESTINALIS:

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BELTWORMS”

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Classification:

Phylum Platyhelminthes

Class Cestoda. Order

Genus :

1. Clinical signs of cestodiasis include emaciation, anemia, discoloration of the skin
2. They are susceptibility to secondary infections.
3. Low numbers of pleurocercoids may be located in vital organs such as the brain, heart, spleen, kidney, or gonad and have a devastating effect on the fish.
4. This group of parasites is distinct for three reasons: (a) they are not highly host-specific, but can develop in a wide variety of second intermediate host fishes,
5. Pleurocercoid stage develops sexually in the second intermediate host, and (c) these

cestodes are very broad in shape and for this reason have also been known as “beltworms”.

EXPERIMENT NO: 17

Date:

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NEMATODE INFESTATION IN FISH

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1. Camallanus

1. Camallanus resides in the intestinal tract of the fish
2. It is smooth, reddish cylindrical elongated worm
3. It will grow up to 1 cm
4. It will make serpentine movements.
5. Often protrudes from anus;
6. Larvae may be seen in adult;( live-bearer)
7. Indirect life cycle (requires intermediate invertebrate host)

CAPILLARIA

1. Capillaria resides in the intestinal tract of the fish
2. It is smooth, elongated worm.
3. It will grow up to 1 cm
4. Double-operculated barrel-shaped eggs may be seen in females; may see eggs only in fish tissues
5. It will make serpentine movements.

3, CONTRACAECUM

1. It resides in the Body cavity, liver, muscle, heart, swim bladder
2. It is smooth, visible, semi coiled elongated worm.
3. It will grow up to 0.8-2.0 cm
4. It will make no movements.
5. Fish is intermediate host;

4. EUSTRONGYLIDES

1. It is smooth, visible coiled elongated worm.
2. It will grow up to 8-10 cm
3. It will make no movements.
4. Fish is intermediate host; definitive host is wading bird; oligochaete worm required as intermediate host in some species

PISCICOLA GEOMETRA

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LEECH

1. The adult fish leech is clearly visible without magnification, measuring up to 25mm in length.
2. The fish leech can affect any part of the fish, firmly attaching itself with the sucking disc

and feeding by piercing the skin and sucking blood with its specialized mouthparts

3. Wounds left by feeding leeches may become infected with secondary bacterial

infections or fungus.

4. There is also a risk of spreading viral diseases; the fish leech is known to be a factor in the spread of SVC (Spring Viremia of Carp). Life Cycle Reproduction occurs after several meals.
5. Heavily infested fishes have been observed to swim primarily at the water surface, often with their dorsum exposed.
6. Fishes exhibiting this behavior also suffer from ulcerative lesions of the exposed skin.
7. Organophosphates (0.25 mg/L, prolonged bath) are somewhat effective but not approved for use in food fish.

Experiment No 18 Date:

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COPEPODS FISH LICE

ANCHOR WORMS

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LEPEOPHTHEIRUS

1. L. Salmonis is an Epizootics cause great damage to salmonids .
2. They resort through feeding on host skin.
3. The dermis is edematous
4. Hemorrhage occurs and blood seeps between scales;
5. Deaths probably result from osmoregulatory failure.
6. A bath treatment for 1 h with 1 ppm of the organophosphorus compound Dichlorvos is effective against post-thalamus stages of L. Salmonis . Side effects are

minimal and clearance rates from fish tissues satisfactory, but treatment may be required every 3–4 weeks

CALIGUS

1. Sea lice cause physical and enzymatic damage at their sites of attachment and feeding.
2. Sea lice infection itself causes a generalized chronic stress response in fish.
3. Changes in the mucus consistency and damage to the epithelium results in loss of blood and fluids, electrolyte changes, and cortisol release.
4. This can decrease salmon immune responses and make them susceptible to other diseases and reduces growth and performance.^[26][27]
5. The degree of damage is also dependent on the species of sea lice, the developmental stages that are present, and the number of sea lice on a fish.

ARGULUS.

1. Arugulas is a common parasite of ornamental fish, particularly koi and goldfish.
2. The fish louse is visible to the naked eye, and has a broad, flat, oval-shaped body, with a shell and four pairs of swimming legs. Argulids are extremely irritating and infested fish rub on submerged objects or bottom substrates in an attempt to dislodge the parasite from their skin.
3. Argulids attach by a pair of hooks and two large anterior suckers, but remain free- swimming throughout their life
4. Aaffected fish flash and jump, dive to the bottom of a tank and roll onto their side.
5. The fish will not eat, and may hide and lose their color due to all of the stress involved with a fish lice infestation.
6. The feeding activities of argulids are highly damaging to fish.
7. The fish louse possesses a long stylet that pre-digests the fish tissue and musculature into food for itself.
8. Heavy infestations typically result in gradual loss of physical condition and weakening of the host to such an extent that it becomes susceptible to secondary bacterial

infections, especially where the argulid injected the fish with its stylet.

9. Argulids are also capable of transmitting certain viruses, bacteria, and blood parasites as they feed.
10. The best treatment we offer for this parasite is De-Los.

LERNAEA

Lernaea (also incorrectly spelled Lernea) is a genus of copepod crustaceans commonly called

anchor worms, parasitic on freshwater fishes.

They mate during the last free-swimming (copepod) stage of development. After mating, the female burrows into the flesh of a fish and transforms into an unsegmented, wormlike form, usually with a portion hanging from the fish's body.

Diagnosis

Symptoms of anchor worm can be as follows:

1. Anchor worms (Lernaea) can be seen with the naked eye
2. Red pustule on or near base of fins
3. Frequent rubbing or "flashing"
4. Localized redness can be found on body
5. Inflammation on the body of the fish
6. Tiny white-green or red worms in wounds
7. Breathing difficulties will occur

8. General lethargy is found in fish

Treatment

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There are several treatments for anchor worm in the aquarium/pond. Potassium permanganate is usually considered the best treatment and can be used

ERGASILUS

1. Ergasylus causes increased respiratory rate
2. Gross lesions are observed on the gills.
3. Occasionally gill necrosis and hemorrhage are observed.
4. It can be diagnosed by : wet mounts, histology
5. For treatment: emamectin benzoate (SLICE) is used.
6. White, cream, or yellow cysts or sacs are seen on gills or in mouth
7. V-shaped white egg sacs are found on inner edges of gills

Experiment No.16 Date:

FUNGAL DISEASES

SAPROLEGNIASIS WATER MOLDS

1. Saprolegniasis is a fungal disease of fish and fish eggs most commonly caused by the

Saprolegnia species called "water molds."

2. The disease will attack an existing injury on the fish and can spread to healthy tissue.
3. Poor water quality (for example, water with low circulation, low dissolved oxygen, or high ammonia) and high organic loads, including the presence of dead eggs, are often

associated with Saprolegnia infections.

4. Saprolegniasis is often first noticed by observing fluffy tufts of cotton-like material-- coloured white to shades of grey and brown--on skin, fins, gills, or eyes of fish or on fish

eggs.

5. These areas are scraped and mounted on a microscope slide for proper diagnosis. Under a microscope, Saprolegnia appears like branching trees called hyphae.
6. With progression of infection fish usually becomes lethargic and less responsive to

external stimuli..

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Management and Control

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1. Saprolegniasis is best prevented by good management practices--such as good water quality and circulation, avoidance of crowding to minimize injury (especially during spawning), and good nutrition.
2. Common treatments include potassium permanganate, formalin, and povidone iodine solutions. Over treatment can further damage fish tissue, resulting in recurring infections. Environmental management is essential for satisfactory resolution of chronic problems.
3. Bath treatment in NaOH (10-25g/lit for 10-20min), KmNO4 (1g in 100lit of water for 30-90

min), CuSO 4 (5-10g in 100 lit water for 10- 30min).

Experiment No.19 Date:

FUNGAL DISEASES

SAPROLEGNIASIS WATER MOLDS

Saprolegniasis is a fungal disease of fish and fish eggs most commonly caused by the

Saprolegnia species called "water molds."

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1. The disease will attack an existing injury on the fish and can spread to healthy tissue.
2. Poor water quality (for example, water with low circulation, low dissolved oxygen, or high ammonia) and high organic loads, including the presence of dead eggs, are often associated with Saprolegnia infections.
3. Saprolegniasis is often first noticed by observing fluffy tufts of cotton-like material-- coloured white to shades of grey and brown--on skin, fins, gills, or eyes of fish or on fish eggs.
4. These areas are scraped and mounted on a microscope slide for proper diagnosis. Under

a microscope, Saprolegnia appears like branching trees called hyphae.

5. With progression of infection fish usually becomes lethargic and less responsive to external stimuli..

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Management and Control

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1. Saprolegniasis is best prevented by good management practices--such as good water quality and circulation, avoidance of crowding to minimize injury (especially during spawning), and good nutrition.
2. Common treatments include potassium permanganate, formalin, and povidone iodine

solutions. Over treatment can further damage fish tissue, resulting in recurring infections. Environmental management is essential for satisfactory resolution of chronic problems.

3. Bath treatment in NaOH (10-25g/lit for 10-20min), KmNO4 (1g in 100lit of water for 30-90

min), CuSO 4 (5-10g in 100 lit water for 10- 30min).

BRANCHIOMYCOSIS GILL ROT

1. Branchiomyces demigrans or "Gill Rot" is caused by the fungi Branchiomyces sanguinis

(carps) and Branchiomyces demigrans (Pike and Tench).

2. Both species of fungi are found in fish suffering from an environmental stress, such as low pH (5.8 to 6.5), low dissolved oxygen, or a high algal bloom. Branchiomyces sp. The main sources of infection are the fungal spores carried in the water and detritus on pond bottoms.
3. Branchiomyces sanguinis and B. demigrans infect the gill tissue of fish.
4. Fish may appear lethargic and may be seen gulping air at the water surface (or piping).
5. Gills appear striated or marbled with the pale areas representing infected and dying

tissue.

6. Damaged gill tissue with fungal hyphae and spores will be present. As the tissue dies and falls off, the spores are released into the water and transmitted to other fish. High mortalities are often associated with this infection.

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Management and Control

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Formalin and copper sulphate have been used to help stop mortalities; however, all tanks, raceways, and aquaria must be disinfected and dried.

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Ponds should be dried and treated with quicklime (calcium oxide). A long term bath in Acriflavine Neutral or Forma-Green for seven days helps this condition. Ponds should be dried and treated with quicklime (calcium oxide) and copper sulphate (2-3kg / ha). Dead fish should be buried.

ICTHYOPHONUS DISEASE SWINGING DISEASE.

1. Icthyophonus disease is caused by the fungus, Icthyophonus hoferi.
2. The disease is spread by fungal cysts which are released in the faeces and by cannibalism of infected fish.
3. Mild to moderate infection will show no external signs of the disease.
4. In severe cases, the skin may have a "sandpaper texture" caused by infection under the skin and in muscle tissue.
5. Some fish may show curvature of the spine. Internally, the organs may be swollen with white to grey-white sores.
6. Diseased fish shows curious swinging movements hence the disease is called as

swinging disease.

7. Along with liver, particularly severely affected organs are:- spleen(salmonids), heart(herring), kidney(salmonids), gonads, brain(salmonids), gills(salmonids), and musculature and nerve tissue behind the eyes(sea fish).

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Management and Control

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There is no cure for fish with Icthyophonus hoferi; they will carry the infection for life. Prevention is the only control. To avoid introduction of infective spores, never feed raw fish or raw fish products to cultured fish. Cooking helps destroy the infective life stage. If Icthyophonus disease is identified by a trained diagnostician, it is important to remove and destroy any fish with the disease. Complete disinfection of tanks, raceways, or aquaria is encouraged. Ponds with dirt or gravel bottoms need months of drying to totally eliminate the fungus.

BLACK GILL DISEASE

Black gill disease

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Etiological Agent: Fusarium spp

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Clinical Signs: Brownish to blackish discoloration on the gills of juvenile shrimp.

Treatment: No treatment is available for fungal infestation without harming the shrimp. Prevention and Control: No information on prevention and control. However, good

management of the pond bottom and prevention of the entry of wild crustaceans into the pond, which may carry pathogen, can be effective control practices.

LARVAL MYCOSIS

Etiological Agent: Filamentous fungi of genus Lagenidium

fungi, such as Sirolpidium spp. and Haliphthoros spp.

spp. and other filamentous

Clinical Signs: Eggs and larve are weak and appear whitish. Moratlities may reach 100% within two days. Fungal mycelium replaces the larval tissues and ramifies into all parts of the body and protrudes out of the body and develops into sporangia.

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Prevention and Control: General hatchery management practices such as use of UV sterilised and filtered seawater, adequate water exchange etc., must be strictly followed. Rearing water, equipment used in the hatchery and all hatchery facilities must be thoroughly disinfected before retarting the hatchery operations.