Bacterial hepatopancreatic necrosis disease (NHPB) or black spot disease

Necrotizing hepatopancreatitis bacterium NHPB (Necrotizing hepatopancreatitis bacterium) is caused by bacterial infection of shrimp. Bacterial hepatopancreatic necrosis disease is completely different from the acute hepatopancreatic necrosis disease EMSAHPND that we know. PCR test of shrimp with black spots gave completely negative results for EMS/AHPND.

The disease occurs due to poor pond environmental conditions, especially dirty pond bottoms, ponds with “black spot” disease often have very high concentrations of toxic gases such as NH3, NO2. Mortality rate can be up to 95% within 15 – 30 days from the time of disease detection if no treatment measures are applied immediately for the case of heavily polluted ponds and microbiological content. bacteria in the pond water exceeded the threshold many times. Diseased shrimp have symptoms such as lethargy, reduced appetite or anorexia, slow growth rate, many tiny black spots or large black plaques on the body, dark or black gills, thin tail, there may be accessory lesions such as worn tail and antennae scales, antennae amputated, etc. In severe cases, the intestines are empty, the hepatopancreas is pale, the surface of the shrimp body with black spots may have a foul odor (Nguyen Thanh Quang Thuan et al., 2014).

“Black spot” disease is caused by bacteria, so general preventive measures should be applied to bacterial diseases. The recommended preventive measures are as follows: The pond improvement process needs to be thoroughly disinfected. Before and after disinfection, it is necessary to check and evaluate the number of pathogenic bacteria by the simplest method. TCBS agar plate (MP – BIOTEST), through which it is possible to evaluate whether the removal of most pathogens in the pond is satisfactory or not. Check the quality of shrimp seed by PCR technique not only with EMS, white spot, IHHNV, IMNV but also NHP.Stocking density is suitable for infrastructure design, water fan system to provide oxygen, desired squid depth, crop season as well as experience, technical level, knowledge level of vannamei shrimp. the owner himself