In recent years, a strange disease has emerged in the process of shrimp farming in the north and south: a large number of shrimp diseases, even flakes, many shrimp have symptoms of red body, liver and pancreas atrophy, lighter color, jejunum and empty stomach, and some black feet can be seen. Suddenly, there were a large number of deaths, and after several research units tested the diseased shrimp, it was found that it was caused by the iridescent virus.
Shrimp infected with iridescent virus do not have too typical single symptoms, so they are not easy to judge by symptoms. Without accurate test results, it is impossible to determine whether it is caused by an iridescent virus. However, judging from the monitoring of the epidemic situation in previous years, the prevalence rate in Guangdong, Zhejiang, Guangxi, Hebei and other provinces is relatively high. Most shrimp with the above symptoms have a high drainage rate.
"From the perspective of the symptoms of the red body alone, the red body caused by the infection with the iridescent virus is not obvious from the red body caused by Dora virus, leukoplakia virus, Vibrio, etc., and it needs to be judged by combining the symptoms of light liver and pancreas, stealing death, jejunum, and high mortality.
1. Shrimp rainbow virus symptoms:
The color of the liver and pancreas becomes lighter, the jejunum and jejunum, the overall color of the body segment becomes lighter, the body node is slightly red, the body segment is obvious, some black feet appear, and the mortality rate under stress conditions can reach 60%.
2. Incidence time of shrimp rainbow virus:
After a large number of tests were done by relevant research institutes, it was found that the iridescent virus was mainly detected in April-August, the highest in May-June, all sizes of shrimp were detected, and 4-7 cm shrimp had the highest detection rate. The positive rate decreases significantly when the temperature is higher than 30 °C; The positive rate at pH 8.0-8.4 was high, but it needed to be observed; different salinities were detected and there was no selectivity.
3. Shrimp rainbow virus infection object:
Susceptible reservoirs include Penaeus vannamei, Penaeus chinensis, Macrobrachium rosenbergii, Red Crawfish, Protocephalus crawfish, and Green Shrimp. Positive tests have even been reported in pike crabs, frozen Antarctic krill and sand silkworms.
Giant shrimp roche also has a special symptom: there is a white spot under the carapace at the base of the frontal sword, which is also called "white head disease" by the industry.
4. Shrimp rainbow virus prevention and control:
(1) Before releasing seedlings, the pond should be strictly disinfected and cleared, and all kinds of pests in the pond should be killed;
(2) When the disease occurs, the pond should be strictly isolated, and the feeding tools and water sources should not be shared to prevent cross-infection;
(3) When buying seedlings, virus testing should be carried out, and shrimp fry that do not carry shrimp rainbow virus should be used;
(4) Some demersal fish can be properly raised, and feces and dead shrimp can be ingested to reduce the occurrence of diseases;
(5) It is forbidden to feed chilled fish, which is often not strictly disinfected, which is not only easy to pollute the water, but also may carry pathogenic bacteria;
(6) Timely collection of sewage discharge, reduce the deterioration of the environment at the bottom of the pond and the destruction of water quality;
(7) Enhance immunity and improve the ability of farmed species to resist harsh environments and pathogens. Internal use of Traditional Chinese medicine complex formula Package: gill rot Kang + silver rocker blue root dispersion + liver and gallbladder worry-free Rich in more than 30 kinds of Chinese herbal medicine, antiviral at the same time, promote liver cell development, enhance the body's immune function, repair damaged liver tissue, improve the activity of liver cells, strengthen and improve liver and pancreatic function; Repair intestinal mucosa, enhance intestinal elasticity and toughness, improve the digestion and absorption function of the intestine; Promote enzyme metabolism and nutrient absorption, restore and regulate liver and intestine function, and enhance the body's immunity. Effectively prevents symptoms such as pooping, broken joints, enteritis and white stool.