Preventing microsporidiosis and EHP in shrimp

Enterocytozoon hepatopenaei (EHP) is a microsporidian parasite found in hepatopancreas cells of shrimp. The parasite causes microsporidiosis disease. Although the disease doesn’t cause mass deaths, it makes shrimp grow slowly and even stop growing despite a large consumption of feed. Shrimp with EHP can only reach an average size of 4-5 grams after 100 days of farming.

Currently, using PCR techniques can help detect EHP in commercial shrimp and shrimp post-larvae.

Shrimp infected with EHP grow slowly, have soft shell and pale hepatopancreas. There is currently no cure for this disease.

To prevent the spread of EHP, according to Viet Linh, shrimp farmers should take preventive measures, specifically as follows:

- Handle and improve ponds: For ponds with PVC canvas, farmers must clean ponds. For traditional ponds without canvas, plow and dry pond bottoms. Use lime treatment, rinse ponds, then apply 30 ppm chlorine water.

- Sedimentation ponds must also be renovated. Water must be disinfected before it is pumped to farming ponds.

- Need to check the density of vibrio in water and in pond soil before managing water color.

- To avoid spreading germs between ponds in a farm, keep tools, utensils, checking meters separately for each area or for each pond. In case of a pond is suffering from EHP infection, must avoid spreading the disease to neighboring ponds.

- Choose to buy shrimp post-larvae from reputable and good-quality suppliers. Depending on the scale and farming techniques, adjust stocking density at a moderate level. For black tiger prawn, stock 15-25 prawn/square meter; for whiteleg shrimp, stock 60-70 shrimp/square meter.

- During the farming process, monitor pond indicators such as pH, temperature, alkalinity, and dissolved oxygen. Timely adjust indicators to appropriate levels. Avoid shrimp shock caused by environmental factors, which will create conditions for pathogens to develop.

- Track, care, and manage shrimp’s feed intake. Avoid leftovers. Regularly check shrimp color, hepatopancreas and size.