CATDOLL : CATDOLL: Cryptosporidiosis in fish? How is cryptosporidiosis treated?

1. Sporozoan disease in fish?

First, we need to distinguish the type of disease and the type of fish we are raising. Sporozoa are a large class of pathogenic protozoa, and there are many types. There are many fish disease sporozoa, which can parasitize the mesentery, gills, brain, spinal cord, and internal organs. Iodine bubble worms are the main pathogenic organisms of carp. Generally, prevention and treatment are the main measures. It is too late to infect the fish. Prevention and control methods:

1. Thoroughly clean the pond with quicklime, etc. to inhibit the massive reproduction of spores and reduce the occurrence of this disease;

2. Before stocking the fish, add 500g of potassium permanganate to 1 cubic meter of water, stir to fully dissolve it, and make a solution with a concentration of 500mg/L. Soak the fish for 30 minutes, or add 500g of lime nitrogen to 1 cubic meter of water, stir to make a suspension, and soak the fish for 30 minutes. Treatment of myxosporean disease This disease is caused by myxosporeans parasitizing the skin, gills, intestines and nervous system of fish. The parts of the fish disease have cysts, which are grayish white dots and tumors. Common myxosporeans include pancake-shaped iodine spores, wild carp sulfonium spores, crucian carp iodine spores, silver carp iodine spores, etc. Symptoms: The sick fish are emaciated, the body color is black, they swim alone or restlessly and wildly, and they are extremely harmful to the fish from October to February of the following year. Treatment methods: 1. Sprinkle 1 jin of 90% crystal trichlorfon per mu of water in the whole pond, and sprinkle it again after 3 to 4 days. 2. For every 10,000 fish or 100 jin of fish, mix 75 grams of edible sulfur powder with feed and feed it for one week. 3. Add 10 grams of 90% crystal trichlorfon to each jin of feed to feed fish, which can cure intestinal parasitic myxosporeans. This method is also effective for ringworm disease. Compare the following information, and it is best to consult an expert for specific practices. Other classifications 1. Madness disease is also known as silver carp madness disease, crazy knife, and silver carp iodine bubble disease. It is caused by silver carp iodine bubble parasitism in various organs and tissues of silver carp, especially the nervous system and sensory organs, such as the brain, spinal cord, parasitic lymph fluid in the cranial cavity, nerves, olfactory system, balance, and auditory systems. Silver carp fry can be infected as soon as they emerge from the membrane. At present, in production, it mainly harms silver carp of full age. When the disease is serious, it can cause a large number of sick fish to die; the meat of sick fish is not fresh and has a strong fishy smell, and it is very thin, so the commercial value of the fish that have not died is also seriously affected. This disease occurs in rivers, lakes, reservoirs, and ponds across the country, especially in Hangzhou, Zhejiang. When seriously infected, the sick fish are extremely emaciated, with a large head and a small tail, with an upturned tail. The weight is only about half of that of a healthy fish. The length of the head is 2.95 times the height of the tail stalk (2.2-2.3 times for healthy fish), and the body color is dull and lusterless. The sick fish swim alone in the water, often jumping out of the water and diving back into the water, repeating this many times and dying. When dying, the head often burrows into the mud. Some swim sideways and die due to loss of balance and feeding ability, so it is called crazy disease. When the fish body is cut open, white cysts of varying sizes visible to the naked eye can be seen at the place where the silver carp iodine vesicles parasitize; the liver and spleen are atrophied, there is ascites in the abdominal cavity, and the vagus lobe of the cerebellum is significantly congested; the sick fish are severely anemic. 2. Pancake iodine vesicle disease is a serious fish disease during the grass carp seedling breeding period. It is caused by the parasitism of the pancake-shaped iodine bubble worm, which mainly parasitizes the intestinal wall of grass carp, especially the lamina propria and submucosa of the foregut. It occurs in all fish farming areas across the country, with Fujian, Guangdong, Guangxi, Hunan, Hubei and other places being the most serious. The mortality rate can be as high as over 90%. The fry are infected 12 days after being put into the pond, causing a large number of deaths. When the water temperature is 27-30℃, it takes 12-15 days for the worm to develop a generation in the body of grass carp. When the spores aged for 6-8 months are used to artificially infect grass carp fry, 100% of them will become ill. It mainly harms grass carp with a total length of less than 5 cm, and bighead carp, silver carp and black carp mixed in the same pond are not affected. The disease is prevalent from May to July, especially from May to June. Many small white cysts are formed at the parasitic sites of the pancake-shaped iodine bubble worm, and the cysts are surrounded by connective tissue membranes formed by the host. The body color of the sick fish is black; the fish is emaciated, with a slightly swollen abdomen, light red gills, anemia, no food in the intestines, thickened foregut, and degeneration and necrosis of the intestinal wall tissue; when a large number of pancake-shaped iodine bubble worms parasitize on the spine, the fish body may bend. According to reports from Sichuan Province, pancake-shaped iodine bubble worms parasitize in the muscles of carp fry, forming white cysts. The body surface of the sick fish is uneven, and the fish grows slowly. In severe cases, the disease causes a large number of deaths. 3. Wild carp iodine bubble worm disease Wild carp iodine bubble worms parasitize on the skin and gills of dace fry and summer carp, forming many gray-white tumor-like or dot-like cysts, especially on the body surface. In severe cases, it affects the breathing and swimming of the sick fish.

2. How to treat cryptosporidiosis?

Cryptosporidiosis is treated as an intestinal infectious disease and should be isolated. Patients with severe symptoms should be hospitalized. Severe diarrhea may cause electrolyte imbalance, which must be corrected. Supportive treatment should be strengthened for those with low immune function. Avoiding foods high in fat and sugar during an attack can help relieve symptoms.

3. Can we eat fish that have spore diseases?

Can

People with rhinosporidiosis can eat fish. There are no special dietary restrictions. You can eat any food that helps improve immunity. There is no problem.

Fish spore diasis (same as myxospore diasis, the same below) is a fish disease with a very high incidence in recent years, causing great economic losses to aquaculture production.

There are many species of myxosporeans that harm fish. The worms are relatively small and produce spores during their development. Moreover, myxosporeans parasitize a wide range of organisms, infecting almost every type of fish and various organs. Even several types of myxosporeans may parasitize the same organ of the same fish.

Myxosporeans often cause serious epidemics in fish. In North America, Europe and Japan, there is a salmon and trout spinning disease, which is caused by myxosporeans and causes a large number of salmon and trout deaths. In various fish farming areas in China, there is also a silver carp madness disease similar to salmon and trout spinning disease (the sick fish are thin, their tails are upturned, they spin up and down, and soon die).

4. How to kill sea bass spores?

First, clean the pond thoroughly with quicklime, etc., which can inhibit the massive reproduction of sea bass spores and reduce the occurrence of this disease.

Secondly, fish with spore diasis have poor appetite due to the disorder of internal mechanism, damage to the skin or gill tissue of the fish, infection and rot of bacteria, which hinders the respiratory function of the gill tissue and eventually kills the sick fish. Finally, spore diasis has become a major obstacle to fish farming, so prevention is the priority.

5. How to deal with shrimp sporozoans?

1. The shrimp pond should be thoroughly desilted and disinfected to kill the spores in the bottom mud;

2. Sick and dead shrimps should be destroyed promptly to prevent healthy shrimps from getting infected after eating them;

3. Try to use fumagillin as bait for feeding. Use 50 mg per kilogram of shrimp per day for 12-20 consecutive days.

6. How to treat fish printing disease?

Measures for treating fish printing disease: (1) 1 mg/L of bleaching powder or 0.3-0.5 g/m3 of trichloroisocyanuric acid, spray all over the pond for 2-3 times; (2) When the broodstock are sick, the affected area can be cleaned with 1% potassium permanganate solution, or the moisture on the lesion can be absorbed with gauze, and then smeared with chlortetracycline or tetracycline ointment. (3) When the disease is serious, it is necessary to inject streptomycin sulfate intramuscularly or intraperitoneally, 20 mg per kilogram of fish; or chlortetracycline, 5,000 international units per kilogram of fish.

7. Spore killer?

Copper Sulfate

1. The ability of copper sulfate to kill pathogens varies with the changes in the water environment. If the water quality is rich and the water temperature is low, the dosage can be appropriately increased, otherwise, the dosage can be reduced. At the same time, do not apply the medicine in the morning when fish float to the surface and the water temperature is high in the morning. It is best to use it between 16:00 and 18:00 in the afternoon.

2. The safe concentration range of copper sulfate is relatively small. When copper sulfate is actually used, the appropriate concentration should be selected according to different aquaculture species. Generally, copper sulfate with a concentration of 0.5×10-6-0.7×10-6 is sprayed throughout the pond or copper sulfate with a concentration of 8×10-6 is used for immersion for 20-30 minutes.

3. Copper sulfate is often used in a mixture with ferrous sulfate in a ratio of 5:2. Ferrous sulfate is mainly used to remove fixatives, clearing obstacles for copper sulfate to kill parasites.

4. The water temperature for dissolving copper sulfate should not exceed 60℃, otherwise the solution will easily become ineffective.

8. How to determine whether shrimps have sporozoa?

We applied PCR technology to amplify the 18SrRNA gene of EHP, and then used a probe labeled with dicoxin to detect EHP infected in cells by in situ hybridization. Finally, we developed a new PCR technology to detect EHP in shrimp tissues, excrement and water.

2. Materials and Methods

2.1 Prawn

Penaeus vannamei infected with Enterosporidium penaeidum (EHP) were collected in Brunei in 2006. Penaeus vannamei infected with EHP were collected from shrimp ponds in Vietnam in 2014 and 2015. In 2014, a batch of Penaeus vannamei from Thailand was sent to our laboratory at the University of Arizona for quarantine and testing. These shrimp were later tested for EHP infection and their hepatopancreas, feces, and water were sampled and tested using PCR technology.

To test the specificity of EHP by in situ hybridization (ISH) and by PCR, samples of Penaeus monodon with clinical signs of cotton shrimp disease from Madagascar in 2005 (fixed tissue) and 2006 (frozen tissue) were used. P. vannamei infected with A. crocodileus, collected in 2014, were also used. For PCR analysis, hepatopancreas tissue or whole shrimp were preserved in 95% alcohol or air-dried and sent to our laboratory. For ISH, shrimp were fixed using Davidson fixation.

DNA extraction

Hepatopancreas was removed from EHP-infected shrimp and placed in one sample (4-5 shrimp). Feces and water were sampled from shrimp tanks carrying EHP-infected shrimp. Water from shrimp tanks was concentrated 150-fold using Microsep Advance centrifugal devices (PALL) for DNA extraction. DNA was purified using a high-purity DNA template preparation kit (Roche Bioscience) or the Maxwell-16 Cell LEV DNA purification kit (Promega).

To test the specificity of the EHP primers, PCR amplification was performed to detect DNA from two parasitic diseases:

(1) Cotton shrimp disease: In 2006, Penaeus monodon were collected from Madagascar. The muscles of these shrimp turned white. Through rRNA gene sequencing, it was found that their DNA was negative because of the presence of microsporidia similar to Pieris (GenBank kp825331);

(2) Amoebiasis: A large number of these whiteleg shrimp died. Through histological examination, it was finally found that these shrimp were infected with amoeba (the species is uncertain).

To ensure that the EHP primers have no reaction with the host genome, prepare the DNA template:

(1) Specific pathogen-free (SPF) whiteleg shrimp (>10 samples) and giant tiger shrimp (3 samples) from Hawaii, USA;

(2) Indian shrimp from Saudi Arabia (2 samples);

(3) Penaeus vannamei cultured in New Caledonia (2 samples);

(4) Macrobrachium rosenbergii from the Philippines (2 samples);

(5) Crabs collected from shrimp ponds near Saudi Arabia (7 samples, unknown species);

(6) Hairy

9. How to eliminate sporozoites?

With copper sulfate

1. The ability of copper sulfate to kill pathogens varies with the changes in the water environment. If the water quality is rich and the water temperature is low, the dosage can be appropriately increased, otherwise, the dosage can be reduced. At the same time, do not apply the medicine in the morning when fish float to the surface and the water temperature is high in the morning. It is best to use it between 16:00 and 18:00 in the afternoon.

2. The safe concentration range of copper sulfate is relatively small. When copper sulfate is actually used, the appropriate concentration should be selected according to different aquaculture species. Generally, copper sulfate with a concentration of 0.5×10-6-0.7×10-6 is sprayed throughout the pond or copper sulfate with a concentration of 8×10-6 is used for immersion for 20-30 minutes.

3. Copper sulfate is often used in a mixture with ferrous sulfate in a ratio of 5:2. Ferrous sulfate is mainly used to remove fixatives, clearing obstacles for copper sulfate to kill parasites.

4. The water temperature for dissolving copper sulfate should not exceed 60℃, otherwise the solution will easily become ineffective.

5. Some parasites (protozoa and sporozoans that form cysts on the bodies of aquatic animals) cannot be treated with copper sulfate. For example, Ichthyophthirius punctatus disease is not only ineffective, but will cause Ichthyophthirius punctatus to form cysts and reproduce in large numbers, aggravating the disease.

6. Copper sulfate aqueous solution is corrosive to metals. When dissolving or spraying drugs, do not use metal utensils. Use plastic, wood, ceramic, or glass utensils instead.

10. How long does it take for a sporozoite outbreak to occur?

July to September

Sporozoites can occur from May to October, but outbreaks usually occur from July to September.

Sporozoite outbreaks are mainly caused by:

1. The seedlings themselves carry sporozoans;

2. The pond is not cleaned thoroughly, and the water quality and bottom quality are poor;

3. During the breeding process, attention was not paid to protecting the liver and gallbladder and strengthening the physique of the fish;

4. Failure to prevent spore parasites in advance, use of cheap drugs or inadequate use of drugs;