Vibriosis

Vibriosis is the most common fish disease in the marine wild and the cultivated marine fish, everseen. This disease has also observed in freswater habitats and especially seen on the salty and brackish water forms in the shallow coasts together with the sudden changes of water temperatures.

Vibriosis occurs an important threat reason for the nurtured sea bream and sea bass in our country. Commonly in spring; water quality changes and stress sources like vaccination, harvesting, sizing and transfering are the major alerts of the disease. Vibrio’s are naturally located in the digestive system flora of the fish and therefore the fish are always have to be close contact with them.

Disease Agent

There are several Vibrio species which causes Vibriosis in general. The most well-known disease agent is determined as V.anguillarum.This disease agent is the eldest marine fish pathogen as known. It was caused enormous outbreaks on cultured marine fish in the 18^th and 19^th ages. V. alginolyticus, V. vulnificus, V. ordalii, V. salmonicida, V. carchariae and V. damsela  are the other effective disease agents. The first external symptoms of the diseased fish with these bacteria are lethargie (slowing down of the movements), anorexia (having no appetite) and darkening of the body surface.

Agent Features

Vibrio’s are Gram-negative, motile, non-spore forming, bacil shaped, straight or slightly curved and single polar flagellated bacteria. They can easily be produced on the %1-1,5 NaCl included media’s. TCBS (tiosulphate Citrate Bile Salts sucrose) Agar is the selective media for vibrio’s. While doing a bacterial classification the most critical distinctive point of vibrio’s from Aeromonas species is their sensitivity of O/129 test. Vibrio’s can always be seen if fish are under stress conditions.

Clinical Symptoms

The first symptoms of Vibriosis are anorexia, lethargie and the darkening of the skin. There can be red necrotic lesions on abdominal muscles, red spots on fin bases, anal region and mouth. There can also be swelling of spleen, petechial haemorrhagies on abdominal walls in the internal organs. Digestive system can be widen and full of stinky fluid. Exopthalmia can be the another disease symptom on the eyes.

Diagnosis

Diagnosis of the disease can realize with planting the samples taken from kidneys, spleen and liver on the media’s. Detection of the colonies can make with TSA, TCBS and MA. After the production of these colonies on these media’s, there are different helpful biochemical tests, antibiogram tests for the detection of the possible antibiotic usage against vibriosis.

Control