A. Cause: Edwarsiella tarda
B. Characteristics of pathogens:
- Edwardsiella tarda is a bent rod shaped, is a gram-negative bacteria, this bacteria moves with the help of flagella, does not form spores or capsules, is facultative anaerobic, and is capable of producing H2S;
- These bacteria can be found in freshwater and seawater environments, these bacteria infect several types of fish, including: salmon, catfish, mas, tilapia. Some natural hosts can survive as carriers;
- Transmission of the disease can occur horizontally, ie spread through contact between one host and another or through water;
- Edwardsiellosis cases generally occur at relatively high pond water temperatures (± 30 oC) with high content of organic matter dissolved in water;
- The mortality rate of fish depends on environmental conditions, in very bad conditions can lead to death up to 50%.
C. Clinical Symptoms:
- External symptoms of fish attacked by edwardsiellosis in mild infections, only showing minor injuries;
- As further disease progresses, festering wounds develop in the rib muscles and stomach;
- In acute cases there will be a rapidly increasing festering wound of various sizes;
- Pale body color, bloated stomach filled with yellowish or reddish fluid, bleeding in the anus and / or anus is pressed into, and the eyes of the fish fade;
- Isolation and identification of bacteria through bio-chemical tests;
Detection of bacterial genes through polymerase chain reaction (PCR) technique.
- Cultivation facilities need to be disinfected before and during the fish rearing process;
- Immunostimulant elements need to be given (for example adding vitamin C to feed) regularly during maintenance;
- Avoiding stress on fish (physical, chemical, biological);
- Water quality needs to be improved as a whole, especially reducing dissolved organic matter levels and / or increasing the frequency of new water replacements;
- Manage integrated fish health (fish, environment and pathogens);
- Treatment with herbs using meniran leaves (Phyllanthus niruri L., P urinaria L.) in ways such as treatment of diseases caused by Aeromonas hydrophilla.