Diagnosis and treatment of bacterial and viral diseases in fish

Grass carp viral hemorrhagic disease

Pathogen: grass carp hemorrhagic virus, which belongs to the family Reoviridae.

Symptoms: viral fish disease, fish body surface is generally dark and slightly red, subcutaneous and muscle bleeding, oral cavity, lower palate, head or orbital congestion, and even exophthalmos, Gill cover, fin base hyperemia.

Prevention and treatment methods: bacterial hemorrhagic disease: can choose "bacterial gram + VK3 powder + Sanhuang powder mixing and feeding internal administration", external use of gold iodine; viral hemorrhagic disease: can choose "rifampicin (methylpirifamycin) + virus nemesis", external use of chlorine dioxide for water disinfection.

The above two formulations are very effective in the treatment of grass carp hemorrhagic disease, and the therapeutic effect of those without a bait machine is more obvious than that of a bait machine, and the pond mouth with a bait machine had better be fed with a small amount of bait downwind, so that those fish that are slightly sick and unable to grab food can be recovered and death can be reduced as quickly as possible.

Bacterial Gill rot

Pathogen: columnar fibrous bacteria (formerly known as Radius columnar).

Symptoms: the body color of the diseased fish is black, especially in the head, so it is also called "aconite plague". Sick fish swim slowly, slow to respond to external stimuli, dyspnea, loss of appetite; there are mud-gray, white or waxy spots on the Gill piece, increased mucus on the surface and the end of the Gill filament, and often adhere to silt, Gill filament swelling, severe Gill filament end defect; the inner epidermis in the center of the operculum is often corroded into a round or irregular transparent window, so it is called "skylight".

Epidemic situation: a widespread fish disease. The main harm to grass carp, herring, common carp, crucian carp, silver carp, bream, bighead carp can also occur. It can occur regardless of the fish species or the adult stage. The disease usually occurs when the water temperature is above 15 ℃. In the range of 15-30 ℃, the higher the water temperature is, the easier it is to break out. The disease is often associated with red skin disease and bacterial enteritis.

Prevention: the fish pond must use fermented manure or finished fertilizer such as Sufeibao, Feishui ointment and soak in hot water for more than half an hour.

Treatment: rifampicin (mepirifamycin) was sprinkled in the whole pool with 0.1~0.2ppm; Sanhuang powder mixed with feed for oral administration, twice a day for 3 to 5 days; aldehyde quick kill, Zhongren gold iodine, chlorine dioxide, traditional Chinese medicine disinfection preparation "Shuanghuang essence" and other series of disinfectants for water disinfection.

Enteritis disease

Pathogen: Aeromonas punctata.

Symptoms: red and swollen anus, severe pressure on abdominal blood or yellow mucus outflow from the anus, some or all of the intestines are inflamed, showing purplish red. In the early stage of the disease, the foregut and hindgut are congested and red, and in severe cases, the whole intestine is congested and inflamed, bleeding, resulting in septicemia. The diseased fish's abdomen is swollen, the anus is red and swollen, sometimes yellow mucus can be extruded, a faecal mass is dragged behind the anus, and sometimes there is stagnant water in the abdomen.

Treatment: every mu of water was sprinkled with Zhongren gold iodine or chlorine dioxide in the whole pool for 2 to 3 days, and rifampicin (mepirifamycin) 2g + VC 2g + appetizer Yingling 2g / kg feed + Sanhuang powder for 3 days could be cured. After stopping the dead fish, take the bait once a day for a week, otherwise the disease will be repeated.

Red skin disease (also known as hemorrhagic corruption)

Pathogen: Pseudomonas fluorescens.

Epidemic situation: when the body surface of the fish is intact, the pathogen can not invade the skin of the fish; only when the fish is damaged by mechanical damage due to fishing, transportation, stocking, mechanical damage, or frostbite, or the body surface is parasitized by parasites, can the pathogen take advantage of the deficiency and cause the disease. Grass carp, herring, common carp, crucian carp, blunt snout bream and other freshwater fish can suffer from this disease. In various fish culture areas of our country, it is popular all the year round, especially after fishing and transportation.

Symptoms: the body surface of the diseased fish is bleeding and inflamed, and the scales fall off, especially on both sides of the fish body and abdomen; the base of the fin or the whole fin is congested, the tip of the fin is rotten, often decaying a section, and the soft tissue between the fins is often destroyed, so that the fin is broomlike, which is called "fin decay"; water mold infection often occurs in the focus of the body surface.

Treatment: sprinkle chlorine dioxide externally, with 100g / mu rice, take orally with the mixture of fungus and Shuanghuang essence for 5 days, sprinkle with aldehyde quick kill or Shuanghuang essence whole pool, or sprinkle with Zhongren gold iodine 125ml/ mu whole pool for three days. With the combination of the above three methods, the cure rate can reach more than 90%; rifampicin (mepirifamycin) 2g + VC 2g + appetizer Yingling 2g / kg feed + Sanhuang powder, taken for 3 days, can be cured. After stopping the dead fish, take the bait once a day for a week, otherwise the disease will be repeated.

Bacterial septicemia (fulminant hemorrhagic disease)

Pathogens: Aeromonas, Vibrio.

Epidemic season: from the end of February to November, the disease was the most serious when the water temperature was about 28 ℃. The freshwater fish endangered are crucian carp, silver carp, bighead carp, common carp, grass carp and so on. The prevalence rate is more than 60%, and the mortality rate is 10% to 80%.

Main symptoms: in the early stage of the disease, the diseased fish mainly showed mild hyperemia in the mouth, abdomen, operculum, orbit, fin and both sides of the fish body. With the development of the disease, the above body surface congestion intensified, flesh and bone showed bleeding symptoms, orbital congestion, exophthalmos, abdominal swelling, redness and swelling. The Gill filaments are gray and show anemia, and in severe cases, the ends of the Gill filaments rot. Open abdominal cavity, cavity accumulation of yellow or red ascites, liver, spleen, kidney enlargement, intestinal wall congestion, inflation and no food.

Treatment: sprinkle with Shuanghuang essence 200ml or chlorine dioxide 150g whole pool per mu of water surface; aldehyde quick kill or Zhongren Jin iodine whole pool sprinkle, dosage is 250ml/ mu rice, continuous use for three days; Mieke + rifamycin + VK3 powder + Sanhuang powder mixture for 5 days, can be cured.

White head and mouth disease

Pathogen: a myxococcus.

Symptoms: the skin of the diseased fish is milky white from the end of the kiss to the front of the eyes. The lips seem to be swollen and the mouth is closed inflexibly, resulting in difficulty breathing. The skin around the mouth ring is rotten, and a little floc adheres to it, so the symptoms of "white head and white mouth" can be clearly seen by observing the sick fish swimming on the water surface at the edge of the cylinder. The sick fish are thin and black, slow to respond, float weakly, often stay by the pool, and will die soon.

Treatment: 150g chlorine dioxide per mu of water or Zhongren gold iodine 150ML whole pool for 2g for 3 days; rifampicin (mepirifamycin) 2g + VC 2g + appetizer Yingling 2g / kg feed + Sanhuang powder, 3g for 5 days, can be cured, after stopping dead fish, bait once a day for 1 week, otherwise the disease will be repeated.

White skin disease

Pathogen: Trichoderma albicans.

Symptoms: at the beginning of the disease, some whitening at the end of the caudal fin, with the development of the disease, quickly spread to the back half of the fish torso, the spread of the part appeared white, so it is also known as white tail disease. The caudal fin of the seriously diseased fish was rotten or incomplete, and soon the diseased fish struggled to swim in the water with its head down and tail up, and soon died.

Epidemic situation: the disease is highly contagious, and the epidemic season is from June to July. Due to careless operation at ordinary times, the fish is injured and the bacteria take the opportunity to invade, causing the epidemic of the disease. The general mortality rate is about 30%, and the highest mortality rate can reach more than 45%. The course of the disease is relatively short, and it takes only 2 to 3 days from onset to death, which is a great threat to fish.

Treatment: 150g chlorine dioxide per mu of water or Zhongren gold iodine 150ml can be sprinkled in the whole pool for 2 to 3 days.

Printing disease

Pathogen: Aeromonas punctata.

Symptoms: the focus mainly occurs in the trunk behind the dorsal and ventral fins, followed by both sides of the abdomen, and a few in the anterior part of the fish body. The diseased part first appeared round erythema, which was like a red seal on the skin of the fish, then the epidermis rotted, the middle part of the scales fell off, the rotten epidermis also collapsed and fell off, and exposed the white dermis, the scales around the focus were embedded in the decayed epidermis, and the peripheral scales were loose and inflamed, forming a distinct outline. In the middle and later stages of the disease, the bottom of the pot is formed, and in severe cases, the muscles rot, exposing bones and internal organs, and the diseased fish die immediately.

Treatment: 150g/ per mu of rice with chlorine dioxide, sprinkled for 2 times for 3 times, and rifampicin (mepirifamycin) 2 g + VC 2 g + appetizer Yingling 2 g / kg feed + Sanhuang powder for 3 days, can be cured. After stopping the death of fish, bait was given once a day for 1 week, otherwise the disease would be repeated.

Gill mildew

Pathogen: Gill mold belonging to molds.

Symptoms and diagnosis: the diseased fish do not eat, swim slowly, and the gills are congested and bleeding. As the spores produced by the mycelium come into contact with the fish, they attach to the gills and develop into hyphae. The hyphae continue to grow into the tissue, branching through the tissue like an earthworm, branching along the Gill blood vessels or penetrating into the cartilage, destroying the tissue, blocking the microvessels and blocking the blood flow. The Gill filament showed gangrenous disintegration, and obvious defects could be seen in the necrotic site.

Epidemic and harm: the prevalence of this disease is closely related to the deterioration of pond water, especially in ponds with high content of organic matter and dirty water quality.

Treatment: sprinkle with 50ml/ mu rice whole pool or choose chlorine dioxide 150g/ mu rice whole pool, or use aldehyde to kill 250ml/ mu rice whole pool.

Grass carp "old three diseases" (red skin disease, Gill rot disease, enteritis)

The main results are as follows: 1. symptoms of red skin disease: local or most of the body surface of the diseased fish is bleeding, hyperemia, inflammation and scale falling off, especially on both sides and abdomen of the fish, the base of some or all fin is congested, and the end of the fin is rotting in the shape of a broom. at low temperature, there are often secondary water mold in the focus, and red plaques often appear in the Gill cover and the upper and lower jaw of the fish. Sick fish often swim on the water alone and move slowly. Also known as hemorrhagic corruption, commonly known as "red skin plague".

Prevention and control methods: fish disease injury should be prevented in fishing, transportation, stocking and other operations. Soak in 5~10PPm bleach solution for half an hour before stocking. Sulfathiazole was added to the feed, the dosage was calculated according to the weight of 100 jin fish, and fed continuously for 6 days. In vitro disinfection can be sprinkled with bleach in the whole pool.

2. Symptoms of Gill rot disease: the diseased fish often swim alone, move slowly, and the body color is black, especially the head is the most severe. Opening the Gill cover shows that the epidermis of the inner wall of the operculum bone of the diseased fish is congested, inflamed and ulcerated; the end of the Gill is rotten and defective, the color is white, and the tip cartilage of the Gill is exposed. In severe cases, the edge of the Gill is rotten into a mass, and the edge is white with mud. The center of the epidermis on the inner surface of the operculum is corroded to appear irregular transparent holes, commonly known as "open skylight" and "aconite plague".

Prevention and control methods: when the fish are released, wash them with 1/100000 bleach solution for 30 minutes. Sprinkle the whole pool with bleach.

Treatment: erythromycin (poultry, containing 1 million units per gram), the first day the whole pool sprinkled 0.07ppm, the second day powder mixed bait, 0.5g per 100jin of fish, 2 days half; gallnut, furazolidone treatment of enteritis, Gill rot complications, medication: gallnut boiled liquid with residue sprinkled throughout the pool, so that the pool water into 1.4~3.0ppm, while feeding furazolidone for 6 days, 0.5mg per 100jin every day.

3. Symptoms of enteritis: the diseased fish have black body color, red and swollen anus, slow response, dilated abdomen, accumulation of light yellow ascites, partial or total congestion and inflammation of the intestinal wall, poor elasticity of the intestinal wall, thinning of the intestinal wall, no food in the intestine, yellowish mucus or purulent mucus, light pressure on the abdomen, blood or yellow mucus outflow from the anus, and the intestines are red or purplish red in the later stage of the disease. Commonly known as "white dew plague".

Prevention and treatment: add 10 grams of Litalin for every 100 jin of feed and feed it with bait once a day for 5 days continuously.

Grass carp "new three diseases" [bacterial complications (red skin, rotten Gill, enteritis)], viral hemorrhagic disease, hepatobiliary syndrome and so on.

1. The symptoms of bacterial complications (red skin, rotten Gill, enteritis): the symptoms of diseased fish include red skin, rotten Gill and enteritis; local or most of the body surface of diseased fish is bleeding, hyperemia, inflammation and scale shedding, which is most obvious on both sides and abdomen of the fish. the base of some or all fin is congested, and the end of the fin is rotting in the shape of a broom. at low temperature, there are often secondary water mildew in the focus, and red plaques often appear in the Gill cover and the upper and lower jaw of the fish. Sick fish often swim on the water alone and move slowly.

The diseased fish often swim alone, move slowly, and the body color is black, especially the head is the most severe. Opening the Gill cover shows that the epidermis of the inner wall of the operculum bone of the diseased fish is congested, inflamed, and fester; the end of the Gill filament is rotten and defective, the color is white, and the tip cartilage of the Gill filament is exposed. In severe cases, the edge of the Gill flap rotates into a ball, and the edge is white with mud. Irregular transparent holes appear in the center of the epidermis on the inner surface of the operculum, commonly known as "skylight".

The diseased fish have black body color, red and swollen anus, slow response, dilated abdomen, light yellow ascites, partial or all hyperemia and inflammation of the intestinal wall, poor elasticity of the intestinal wall, thinning of the intestinal wall, no food in the intestine, yellowish mucus or purulent mucus, light pressure on the abdomen, blood or yellow mucus outflow from the anus, and the intestines are red or purplish red in the later stage of the disease.

Prevention and control methods: thoroughly clear the pond and disinfect, carry out "Sixiao" and "Siding", do not directly use unfermented animal feces, do not feed rotten and deteriorated feed, and soak fish fry with 3% salt water before stocking.

Treatment: disinfectants such as 0.2ppm chlorine dioxide or 0.3ppm bromochlorohydantoin or 0.4ppm strong chlorine were sprinkled regularly in the whole pool, garlicin 100g for every 40kg feed for 7 days and enrofloxacin 100g for 3 days for 3 days, doubling the first day.

2. symptoms of viral hemorrhagic disease: the body surface color of diseased fish is black and slightly reddish, travel alone from the group, feeding stops, there are three types of disease.

A, red muscle type: obvious hyperemia and bleeding in the epidermal muscle of diseased fish.

B, red fin red Gill cover type: Gill cover, base of fin, mouth, upper and lower jaw, top of head, hyperemia around orbit, and even exophthalmos

C, enteritis type: the body surface epidermis of the diseased fish is basically asymptomatic, but after dissection, the intestinal tract of the diseased fish is congested and red, the internal organs have some bleeding, and the intestinal wall is elastic and free of decay and edema.

From March to April, the symptoms of inflammation and congestion on the body surface of diseased fish are as follows: head, mouth, operculum, orbit, both sides of body surface, ventral fin and caudal stalk, etc. exophthalmos, Gill anemia, internal organs with varying degrees of inflammation can be seen in some diseased fish. sometimes inflation and expansion of the intestinal tract can be seen.

The symptom of diseased fish after 5 months is that the body surface is inflamed by congestion of the lower margin of the operculum, fin base and internal organs, and sometimes the flesh and bones of the mouth are also congested and inflamed at the same time. The disease is widely prevalent in grass carp culture. The water temperature may occur between 9 and 36 ℃, especially at 28 ℃.

Prevention and treatment methods: inactivated vaccine is used to inject fish species, which can be prevented; every 100 jin of fish is pulped with 8 jin of water peanuts, 0.5 jin of garlic and salt, and mixed with 3 jin of rice bran to make bait, once a day for 5 days; at the same time, 1 meter per mu of water is sprinkled in the whole pond with 0.6 jin of copper sulfate and sprinkled continuously for 5 days. Every ten thousand fish species were ground into powder with 0.5 kilogram of rhubarb or maple incense leaves, decocted or soaked in hot water overnight, mixed with feed for 5 consecutive days, and applied with 0.7PPm depth of copper sulfate, or copper acetate, or copper chloride for 2 days.

3. Symptoms of hepatobiliary syndrome: in the early stage of the disease, the diseased fish drifted by the pool, the reaction was slow, the food intake was reduced, and there were no obvious symptoms on the visual body surface, only a small number of fish had red eyeballs and orbits, Gill filaments swelled, and there were no parasites under microscope; anatomy found no food in the intestines and swelling of the liver. The color is light, the light bile color is dark, becomes brittle and fragile, the liver is obviously enlarged, yellowed and whitish in the middle and later stage of the disease, forming "flower liver" or even part or most of it becomes "green liver". The severe liver adheres to intestinal mucosa and fat and fills up in the chest, the gallbladder sometimes swells and blackens, sometimes the gallbladder becomes absent, and the ascites is serious.

After a period of time, the number of dead fish increased sharply; the cause of the disease is more complex, feeding metamorphic feed, excessive fat content in feed or long-term feeding of quinolinol feed, fish culture water polluted by copper, ammonia and other substances will cause liver disease.

Prevention and control methods: pay attention to reasonable stocking density, do not feed rotten and deteriorated feed, do not directly apply unfermented animal feces, often inject new water or use biological agents to improve water quality, often remove feed residues and establish an inspection system for fish feed, keep feed fresh and prevent protein and fat oxidation in feed.

The principle of treatment is detoxification, tonifying the liver, strengthening the liver, dredging and detumescence, promoting the regeneration of hepatocytes and the recovery of biliary function, and eliminating pathogenic bacteria in the body at the same time.

(1) cultivate good water quality, prepare feed with rich nutrition and good overall quality, and feed it scientifically. Avoid excessive feeding, prevent protein deterioration and fat oxidation, prevent feed from damp and mildew deterioration.

(2) do not add low-dose long-term drugs that are harmful to the liver of fish, such as furazolidone, chloramphenicol, sulfonamides, olaquindox, tetracycline antibiotics, etc., and use less fish drugs with high side effects and high residues, such as deltamethrin, dichlorvos, trichlorfon, copper sulfate, dichlorvos, lindane, etc., let alone use pesticides instead of fish drugs in the water.

(3) supplement vitamins, mainly VC, VK and VE.

(4) adding appropriate amount of betaine, choline chloride, carnitine, methionine and phosphorus to the feed can promote the fat metabolism of fish liver, reduce the content of fat in the liver, and prevent the formation of fatty liver.

(5) traditional Chinese medicine: the prescription of traditional Chinese medicine with detoxification and protecting liver, soothing liver and regulating qi and promoting liver cell regeneration is selected for the prevention and treatment of liver disease. the following prescriptions can be used for reference: Angelica sinensis, Radix Paeoniae Alba, Salvia miltiorrhiza, turmeric, Bupleurum, Radix Astragali, Radix Codonopsis, Radix Isatidis, Hawthorn, licorice, etc. The prescription has anti-fatty liver, detoxification, anti-liver injury, promoting liver cell regeneration and functional recovery. Inhibit the occurrence of liver cirrhosis and so on.

(6) liver powder and feed phospholipids: the liver powder of cattle, pigs and other animals contains a variety of vitamins and liver protective factors. It helps to promote the regeneration, detoxification and protein synthesis of damaged hepatocytes. Can improve the symptoms of fish, increase appetite.

Treatment:

A, disinfectants such as 0.2ppm chlorine dioxide or 0.3ppm bromochlorohydantoin or 0.4ppm strong chlorine were sprinkled in the whole pool regularly, and the bait was made by feeding 40kg with 100g Gandanning and 100g allicin for 5 days.

B, stop eating for 1-2 days, oral administration: Gandanlikang powder + Shidukang + Sanhuang powder + andrographis paniculata powder + polypeptide, one meal of bait in the morning and evening every day, and the other two meals were fed with normal bait for four days.

The first course of treatment is any one of florfenicol, doxycycline and Silikang + Yingzhiling + garlicin + multidimensional + Vk3+ Gantai bait; the second course of treatment is Gantai + Yingzhingling + Sanhuang Powder

D, external use of superior iodine, refined iodine, aldehyde poisoning, bacterial poisoning, chlorine dioxide, bromochlorohydantoin, strong chloride any one of, the condition is serious. One time in the morning and afternoon, 9: 00 a.m. at 10: 00 a.m., 4: 00 a.m., 5: 00 p.m., and patrol the pond. If you find something unusual, immediately add new water and start the oxygenation facility. Repeat every 3-5 days.

The treatment method of internal and external splashing is generally adopted, which is mainly treated with disinfectants such as bleach, chlorine dioxide, bromochloro-hydantoin and dibromohydantoin for 3 days, and the effect of "Sanhuang powder" bait is better. Every 100 jin of fish reuse Sanhuang powder (50% of rhubarb, 30% of Cortex Phellodendri, 20% of Scutellaria baicalensis, mix 0.6 jin of flour paste and mix it into feed for 3 days.