IMNV (Infectious Mionecrosis Virus) on white shrimp (Penaeus Vannamei) and how to prevent it.

IMNV (Infectious Mionecrosis Virus) is a disease found in the white shrimp. The disease was first discovered in Brazil and the coast of South America in 2003. When first attacked, productivity white shrimp in Brazil declined very sharply. Over time IMNV disease a scourge that was greatly feared by the white shrimp farmers worldwide.

IMNV on White Shrimp. Source: http://gis.bkipm.kkp.go.id/edis/upload/20150225114758imnv.jpg

Dispersal and Disease Transmission
IMNV disease primarily spread by the host who had previously been carrying the virus IMNV. Recent research states that the IMNV is a type of virus R-NA. The nature of the R-NA is much simpler than the D-NA makes this virus can survive without a host for 60 days; compared with Whitespot (WSSV) which can only live for 3 hours if without a host. Diameter size of this virus is 40 nm, 1 / 8 times smaller than the Whitespot.

IMNV infected shrimp that have been marked with white as cotton in the third or fourth segment, will now grow up to the sixth segment. If you have severe then most of the affected segment of the shrimp will look red and cause death.

Trigger factors of IMNV
Based on experience, IMNV vicious attack in the pond if the water quality is not stable. Highly fluctuating temperature changes was allegedly a major cause of the spread and transmission of the IMNV. Ponds with stable quality will be more resistant to attack IMNV than ponds with an unstable water quality.

Disease prevention and handling of IMNV
Shrimp that have been stricken with the disease will usually be pulled over to the edge of the pond and is characterized by the onset of the color white as cotton in the 3rd segment. The most effective way to prevent the occurrence of disease IMNV is to implement a good Biosecurity. The selection and fries stocking of disease-free is one way to minimize the incidence of IMNV.

 Disinfection of water going into the pond should always be done in order to kill the host which may spread IMNV, due to its extremely small size, then the double filtering with a filter having a size smaller than 40 nm are also required to be done. Given this IMNV free living virus could reach 60 days it is expected that the already disinfected water is collected in ponds reservoirs as long as possible before it is released into the pond.

Increased endurance shrimp with extra vitamins and immunostimulants application can be done to reduce stress factor. Good water quality management and water quality carefully in order to remain stable is a key factor in order to prevent attacks IMNV disease. The last way is to reduce the stocking density. By reducing the stocking density of solid means give more space to live on the shrimp so that it will reduce stress factors. Conversely, when densely stocking the higher the risk of stress on the larger shrimp will thus be more susceptible to disease attack.