Muscle necrosis in shrimp – Causes, treatment methods, and disease control

White spot disease in shrimp (Infectious Myonecrosis Virus – IMNV) was first detected in Brazil in 2002 and quickly spread throughout Asia, becoming a major concern for shrimp farmers today. When the disease breaks out, many ponds suffer mass mortality, causing significant economic losses for farmers. Vemedim will share the causative agent, symptoms, and especially how to treat and control the disease in time to help farmers protect their shrimp stocks and stabilize production below.

What is white muscle disease in shrimp and what are its symptoms?

White muscle disease in shrimp is caused by Infectious Myonecrosis Virus (IMNV), a dangerous infectious disease that can spread rapidly in shrimp farming environments. IMNV belongs to the double-stranded RNA virus group, grows strongly in water, directly attacks the shrimp’s muscle tissues, causing severe damage and a high mortality rate.

The disease was first detected in ponds in northeastern Brazil and later spread to many Asian countries such as Thailand, Indonesia, China, and Vietnam. Due to its rapid development and difficulty to control, white muscle disease in shrimp causes many difficulties for shrimp farmers if it is not detected and handled in time.

*White muscle disease in shrimp is caused by Infectious Myonecrosis Virus (IMNV), which spreads easily and causes mass mortality*

Therefore, pond sanitation, water quality management, and regular shrimp checks are key preventive measures. Signs of white muscle disease in shrimp include:

Faint white spots appear on the abdominal segments, and the tail muscle begins to change color from white to orange.
When the disease becomes severe, shrimp may molt en masse or the body may show clear necrotic areas, white in color, on the abdominal and tail muscles.
Affected shrimp often swim slowly, sink to the bottom of the pond, accompanied by congestion, connective tissue inflammation, and characteristic changes in muscle cells when observed under a microscope.
High mortality rate, especially when environmental conditions are poor, oxygen is low, or stress occurs during farming.

By monitoring these symptoms early, farmers can intervene promptly, minimize losses, and protect their shrimp stocks.

*The most noticeable sign of white muscle disease in shrimp is the appearance of many white necrotic areas on the abdominal and tail muscles*

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How to treat white muscle disease in shrimp

White muscle disease caused by IMNV is a viral disease, and there is currently no specific treatment. Therefore, disease prevention from the seed source is the most effective method. Sterilizing eggs and larvae, selecting healthy shrimp seed free of IMNV before stocking the pond will minimize the risk of an outbreak.

In cases where the shrimp seed is already infected and is about 2–3 cm long, there is no feasible treatment method. At that point, the entire stock must be destroyed and disinfected to prevent spread to other shrimp.

If the disease has only just appeared in the pond, with a few dead shrimp showing signs of muscle necrosis, farmers should take the following measures:

Stabilize the pond environment, especially temperature, salinity, and pH.
Increase aeration to ensure sufficient oxygen for the shrimp.
Reduce or stop feeding to limit stress and reduce waste.
If the mortality rate is high, disinfect the pond for several days to prevent the virus from spreading.

*If white muscle disease appears in a few shrimp, increase aeration and closely control pond temperature, salinity, and pH*

Controlling the spread of white muscle disease in shrimp

To limit IMNV in shrimp farming, comprehensive control measures must be applied:

Preventing infection from diseased facilities

Do not transport live or unprocessed shrimp from infected ponds/areas to IMNV-free areas.
Restrict or prohibit stocking shrimp and discharging water from infected ponds into the environment.
Dispose of dead shrimp and disinfect the farm to prevent the virus from spreading outside.
Limit access by birds, animals, and equipment from other farms.
Regularly clean ponds with Vemedim Anti Parasite - an environmental treatment product specialized in eliminating disease-causing agents in pond water such as fungi, bacteria, viruses, parasites...

Using safe shrimp seed

Select and stock postlarvae free of IMNV, and test periodically by PCR to ensure disease-free shrimp seed.

Using probiotics

Probiotics such as Enter Lactyl plus help improve the pond environment, stabilize pH and dissolved oxygen, reduce organic load, and lower stress factors.
When shrimp are infected with the virus, a good environment will help minimize mortality and increase natural resistance.

General principle

Prevention is always more important than treatment. Isolating the source of white muscle disease in shrimp, maintaining a stable pond environment, and regularly monitoring shrimp will help farmers protect their stocks and reduce economic losses.

*White muscle disease in shrimp* *is caused by a virus, and there is currently no specific treatment, so early prevention is essential*

Although white muscle disease in shrimp is a tough opponent due to its viral cause and rapid spread, if farmers proactively detect it early and handle it properly, it can be effectively controlled. Vemedim is always ready to accompany farmers with optimal solutions, helping protect healthy shrimp stocks and bringing a successful, stable crop. Please contact Vemedim for advice if you need support.