Infectious Myonecrosis, commonly known as Myo, is one of the most severe and deadliest diseases in shrimp. Myo disease in shrimp can cause great loss for farmers if not prevented or overcome properly. What is Myo and how to overcome this disease? Read the full explanation in this article!
What is Myo Disease in Shrimp?
Myo is a shrimp disease caused by the Infectious Myonecrosis Virus (IMNV), which attacks striated muscles in shrimp. The first case of Myo in Indonesia was in a shrimp farm in Situbondo, Jawa Timur, in 2006.
IMNV can infect at any stage of the shrimp life cycle, from post larvae, juvenile, to adult shrimp. However, more mortalities occur at the juvenile and adult shrimp phase.
Read more: Viral Diseases in Shrimp Cultivation
Myo is a chronic disease. In other words, it requires a longer time before mortality occurs in shrimp, which ranges from 9-13 days after infection with a probability of 50-70% of shrimp population in the farm.
Characteristics of Shrimp Infected with Myo
Myo disease in the farm can be identified through the following characteristics in shrimp:
1. Shrimp Turns Pale
Myo causes shrimp to turn pale in color and lose its translucency.
2. White Clots on the Abdomen
Shrimp infected by IMNV will have white clots on the abdomen and other segments of their body. Their muscles also turn white.
Read more: Ways to Overcome Vannamei Shrimp Disease: White Feces Disease (WFD)
3. Turns Red at the Bottom to the Tail
Myo also causes shrimp to turn red at the bottom part to the tail. The color resembles that of boiled shrimp.
4. Muscle Cramps
Muscle cramps in shrimp is another indication of Myo as IMNV attacks shrimp muscles, preventing them from moving normally.
5. Shrunken Hepatopancreas
The hepatopancreas is an important organ in shrimp metabolism, and is the habitat for various bacteria that influences shrimp development. The final characteristic of Myo-infected shrimp is a shrunken hepatopancreas.
How to Overcome Myo
Until now, there is yet to be an effective vaccine against Myo. Therefore, farmers should be constantly aware and conduct disease prevention steps in the farm. If IMNV has infected shrimp, farmers can still lessen the severity through various steps. Here are some ways to prevent Myo in the farm or overcome it if the shrimp have been infected.
Preventing Myo in the Farm
The emergence of Myo in shrimp is triggered by a decrease in water quality in ponds. In addition, accumulated feed residue at the bottom of the pond can also increase ammonia content in ponds, causing shrimp to become stressed and more susceptible to disease.
Thus, prevention of Myo can be done through implementing strict biosecurity systems in ponds. Additionally, always use certified SPF or SPR shrimp fry. Plankton and probiotics can also be applied to prevent disease outbreaks.
Read more: The Application of Biosecurity in Shrimp Farms: Cleaning and Sterilization
Overcoming Myo in the Farm
If shrimp in the pond are already infected with Myo, steps that can be taken during the early stages of infection or when mortality is still low. These include stabilizing water quality by monitoring temperature, salinity, and pH regularly to keep these parameters at ideal levels.
Furthermore, increase aeration and provide additional feed containing vitamin C as well as probiotic treatment in the pond. If necessary, reduce the amount of feed or temporarily stop feeding.
If one pond is already affected with Myo, do not immediately discharge water, but sterilize it with chlorine first to minimize the spread of the disease to other ponds.
Read more: WSSV or White Spot Disease As The Main Cause of Shrimp Productivity Decrease
Conclusion
Myo disease in shrimp is caused by the IMNV virus and attacks shrimp's muscle tissue. This disease is considered chronic and can cause mortality starting from 9-13 days after infection. Shrimp affected by Myo will experience muscle cramps and turn red in the lower part of the body to the tail.
Since there is no vaccination for Myo disease, shrimp farmers are advised to always be aware by implementing biosecurity measures in their ponds. If Myo has already infected in the early stages, stabilize water quality and provide feed with added vitamin C to the shrimp. Additionally, sterilize the pond water that has been affected by Myo with chlorine before disposing of it.
By always monitoring farm conditions and developments, farmers can mitigate the possibility of shrimp diseases and avoid significant loss. That’s why JALA App is #HeretoHelp farmers as a reliable application to record and analyze farm conditions in detail anytime and anywhere.
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