How to prevent and treat filamentous bacterial disease in prawns? Methods farmers must see

(1) Pathogen The pathogens are Leucothrix mucor, Thiothrix (TAiothrix) and Flexibacter, etc. Leucothrix is filamentous, unbranched, slightly thicker at the base and slightly narrower at the tip, with a length of 5-500 microns or more. It reproduces by conidia and develops into new bacterial cells. 

(2) Symptoms In severely affected diseased prawns, the gill area of the cephalothorax turns dark brown, with poor appetite, slow growth and difficulty molting. In prawn ponds without aerators, just before dawn, because of the low dissolved oxygen content in the pond, severely affected prawns often suffocate and die. 

(3) Diagnosis It mainly infects prawn eggs, larvae and overwintering broodstock prawns. Take the gill tissue of eggs or larvae and broodstock prawns to make a wet mount, observe under a microscope, and a large number of filamentous bacteria can be found to confirm the diagnosis. 

(4) Prevalence Leucothrix mucor and similar organisms are microorganisms commonly found in estuaries and the ocean. It can live independently and can also attach to the surface of marine animals or algae. Therefore, it may appear at all stages of the prawn life cycle, but it will only attach in large numbers under conditions such as high disease prevention and treatment density and fertile pond water. The cumulative mortality rate of affected prawns can reach as high as 60%. Leucothrix mucor is widely distributed in prawn hatcheries and disease prevention and treatment sites along the coast of China, especially in the middle and late stages of disease prevention and treatment or in closed and semi-closed broodstock ponds with poor water exchange conditions. 

(5) Prevention and treatment 1. Thoroughly clear the pond, disinfect and eliminate pests, keep the substrate clean and the water quality clean and good. 2. Feed high-quality feed, reduce leftover bait, and prevent pollution by organic debris. 3. Sprinkle chelated copper throughout the pond at a concentration of 0.5×0.000001-0.8×0.000001. 4. Bathe with potassium permanganate at 2.5×0.000001-5×0.000001 for 4 hours.