In recent years, shrimp farming in Vietnam has been facing many challenges due to increasingly complex disease outbreaks, especially White Spot Disease in shrimp (WSSV). The disease is considered a “terrifying obsession” for farmers, especially in whiteleg shrimp ponds.
White spot disease in shrimp often breaks out strongly in cold weather, causing mass mortality in a short time and leading to severe economic losses. Please refer to Vemedim’s sharing below to proactively detect early, prevent, and effectively control white spot disease in shrimp farming.
What is White Spot Disease in shrimp, and what are its signs?
White spot disease in shrimp, also known as White Spot Disease (WSD), is one of the most dangerous diseases in aquaculture. The causative agent is WSSV (White Spot Syndrome Virus) – a virus with extremely rapid spread and the ability to cause mass mortality in farmed shrimp species, commonly black tiger shrimp (Penaeus monodon) and whiteleg shrimp (Penaeus vannamei).
After infection, shrimp often swim weakly, eat less or stop eating completely, and the shell develops many tiny milky-white spots, 0.5–2 mm in diameter, usually concentrated on the cephalothorax or abdominal segments 5–6. Shrimp may die in large numbers within just a few days, with mortality rates reaching 80–100%. Therefore, early detection and timely control of white spot disease are key factors helping farmers minimize losses and effectively protect the crop.
Causes of White Spot Disease in shrimp
White spot disease can originate from many different factors, including the environment, bacteria, and viruses. Each factor plays its own role in promoting disease outbreaks.
1. Environmental influences in the pond
- Unstable water quality (pH, alkalinity, and salinity fluctuating strongly) creates favorable conditions for pathogens to develop.
- Accumulation of organic waste such as algae remains, molted shrimp shells, and leftover feed... causes pond bottoms to become polluted, increasing harmful microorganisms.
- Sudden weather changes, especially when water temperature drops below 32°C, can easily weaken shrimp, reduce resistance, and trigger disease.
- Untreated water sources may carry pathogens from outside into the pond.
2. Causes due to bacteria
Some studies indicate that, in addition to viruses, bacteria belonging to the Bacillaceae and Vibrio families may also contribute to the formation of bacterial white spot syndrome (BWSS – Bacterial White Spot Syndrome). When pond conditions have high alkalinity or pH, these bacteria grow strongly, attack the shrimp shell epithelium, and make it easier for viruses to invade.
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3. Causes due to viruses
The main causative agent of White Spot Disease in shrimp is WSSV, a virus in the family Nimaviridae, genus Whispovirus. This virus can survive under many harsh conditions:
- Salinity from 5–40‰
- pH from 4–10
- Temperature from 0–80°C
WSSV can attack all developmental stages of shrimp, from larvae to adults, and once it enters the pond, it can spread very quickly through water, intermediate animals, or farming equipment.
How to effectively treat White Spot Disease in shrimp
To reduce losses, farmers can handle white spot disease in shrimp farming using the following measures:
When the pond has not yet been infected
- Inspect shrimp regularly to detect unusual signs early.
- Disinfect the farming area with chlorine or 5% formalin, and limit people and strange animals from entering the pond.
- Apply lime around the pond banks and install protective nets to prevent crabs, fish, and birds from carrying pathogens.
- Stabilize pH (7.5–8.3), maintain high dissolved oxygen, and siphon the pond bottom periodically.
- Supplement vitamin C and probiotics to help increase resistance and stabilize the environment.
When the shrimp pond has been infected with white spot disease
- Stop feeding, collect dead shrimp, and dispose of them properly.
- Use Aqualisan to disinfect pond water:
- Mildly affected pond: 4 ppm, use once every 7 days.
- Outbreak pond: 6–8 ppm daily until the outbreak is controlled.
- Do not use chlorine simultaneously with Aqualisan.
- Lower pond pH (7.8–8.0) to support shrimp molting and remove white calcium deposits.
- After the disease crop, drain the water, disinfect, and dry the pond for at least 2–3 weeks before restocking.
- In addition, you can use Vemedim Protectol to disinfect the pond
Measures to prevent White Spot Disease in shrimp
Farmers can proactively prevent White Spot Disease in shrimp with the following measures:
- Prepare the pond thoroughly: remove mud, apply CaO lime, and dry the pond bottom for 10–15 days.
- Disinfect incoming water with chlorine or Aqualisan before stocking shrimp.
- Install protective nets around the banks to prevent crabs, mud crabs, and birds from carrying pathogens.
- Maintain stable pH (7.5–8.3), high dissolved oxygen, and periodic bottom siphoning.
- Supplement vitamin C, probiotics, and minerals to increase resistance.
- Choose healthy shrimp seed and ensure PCR tests are negative for WSSV.
It can be seen that White Spot Disease in shrimp remains a major threat, endangering the sustainable development of the shrimp industry. In the context of disease outbreaks tending to become more complex and unpredictable, farmers need to regularly update information, comply with technical procedures, and apply proactive, biosecure disease prevention measures. Vemedim is always with farmers, bringing effective disease prevention and treatment solutions. Please contact Vemedim for consultation and support!
