Prevention and Treatment of Spring Viraemia of Carp

Spring Viraemia is a common disease in carp when the weather is cold. Water temperature below 20oC has a high level of infection and can cause serious death rate of up to 70%.

Reason

The disease is caused by Rhabdovirus carpio virus, which is a rod-shaped virus with a round head like a bullet, length of 90 – 180 nm, width of 60 – 90 nm. The virus causes disease in white fish, bighead carp, and crucian carp but mainly in carp. The disease arises due to fluctuations of temperature, especially at the time of season change, when water temperature is lower than 20ºC. When the water temperature is below 18ºC, the mortality rate is higher. In addition, due to poor water quality, poor nutrition, high stocking density, fish resistance is reduced, fish will be susceptible to disease.

Pathological signs

When fish is infected, it often suffocates, separates, swims at the surface. The fish lose balance and disoriented, with hemorrhagic eyes and skin. The body has a dark color, inflamed spots have a lot of mucus, with slightly protruding eyes, pale gills, sticky gill filaments, distended abdomen, and thin blood flowing from the anus. Fish suffering from severe disease die in the surface or drowned in the bottom. Internal surgery shows internal bleeding, hemorrhagic swimming bladder and atrophying in one compartment. The abdomen contains oily fluid, bloated intestine, and swollen pancreas. When the fish is seriously ill, the internal organs often get rotten.

Technical regulations on products used for treatment of aquaculture environment

These regulations are issued by the Ministry of Agriculture and Rural Development in Circular No. 03/2020 products used for treatment of aquaculture environment. Symbol: QCVN 02-32-2 : 2020/BNNPTNT, effective from July 1, 2020.

Specifically, these Regulations specify safety criteria and permissible limits for mineral premixes, vitamin premixes and mineral-vitamin premixes used for aquaculture environment treatment. (HS Code 28422.90.90).

 

In particular, the maximum allowable limit for mineral premixes includes the following criteria: Arsenic (As), lead (Pb), Cadimi (Cd), mercury (Hg); Maximum limits for vitamin premixes include: Samonella, E.coli.

Regarding the method of announcement of conformity to domestically manufactured products, individuals and organizations shall base on certification results of the certification organizations registered or recognized in accordance with law provisions. As for imported products, it should be base on the results of certification and accreditation of certification organizations and accreditation organizations registered or recognized in accordance with law.