Fish Disease: Edwarsiellosis

Fish Disease: Edwarsiellosis

Cause: Edwarsiella tarda

Bio-Ecology Pathogens:
• curved rod-shaped bacteria, gram-negative character moves with the aid of flagella, do not form spores or capsules, are facultative anaerobes, and able to produce H2S.
• Found in freshwater environments and sea water, infecting several species of fish include: salmon, catfish, carp, tilapia. etc..
• Transmission of horizontally ie contact between host one with another host or through water.
• Generally occurs at a relatively high water temperature (± 30 degrees Celsius) and high organic matter content.
• The death rate depends on environmental conditions, in very poor conditions can lead to death by 50%.

Clinical Symptoms:
• In mild infections, revealing only minor injuries.
• As the development of more advanced disease, purulent wound developed in the ribs and stomach muscles.

• Pale, bloated stomach containing a yellowish liquid or redness, bleeding of the rectum and / or depressed into the anus, and eyes faded.
• Further development, injuries (cavities) experience swelling and if scratched will smell of H2S gas.

Diagnosis:
• Isolation and identification of bacteria through bio-chemical tests.
• Detection of bacterial genes by polymerase chain reaction (PCR)


Control:
• Avoiding the occurrence of stress (physical, chemical, biological)
• Improve overall water quality, particularly reducing the levels of dissolved organic material and / or increase the frequency of replacement of new water
• Management of fish health in an integrated (fish, environment and pathogens)
• Limit and / or regulate feeding and mixing of feed with drugs (medicated feed and feed restriction)
• Conducting anti-Edwardsiella tarda vaccination.

source: Ministry of Maritime Affairs and Fisheries of Indonesia, Directorate General of Aquaculture, Fish and Environmental Health Directorate, 2010