INDICATIONS: WHITE GUT DISEASE
Surveys undertaken on diseases caused by Vibrio spp. in Penaeus monodon from culture ponds of coastal Andhra Pradesh recorded the occurrence of five types of diseases:
Tail necrosis, shell disease, red disease, loose shell syndrome (LSS), and white gut disease (WGD).
Among these, LSS, WGD, and red disease caused mass mortalities in shrimp culture ponds.
Six species of Vibrio—V. harveyi, V. parahaemolyticus, V. alginolyticus, V. anguillarum, V. vulnificus, and V. splendidus—are associated with the diseased shrimp.
The number of Vibrio spp. associated with each disease ranged from two to five. Additionally, shrimp with red disease had concurrent infections with white spot syndrome virus.
Vibrio harveyi in the case of LSS and WGD, V. parahaemolyticus in the case of red disease, and V. alginolyticus in the case of shell disease are the major etiologcal agents.
Differences occur in the degree of virulence of different species of Vibrio and also different isolates of the same species.
Vibrio harveyi isolated from LSS shrimp is the most virulent. In general, all the Vibrio isolates from LSS shrimp tend to be more virulent as compared to their counterparts from other diseased shrimp.
It is apparent that the degree of virulence of various Vibrio isolates depends on its source and the pond environmental conditions.
The luminous V. harveyi exhibited resistance to many antibiotics and susceptibility to only three drugs.
Considering the emergence of antimicrobial resistant strains of Vibrio, the need for using probiotics in place of antibiotics for disease control is evident and promising
Studes reports that
Bacillus subtilis showed greater inhibitory effects against the growth of Vibrio harveyi isolated by agar antagonism assay from Penaeus monodon with black gill disease.
Pathogenic vibrios were controlled by Bacillus under in vitro and in vivo conditions.
(Excerpts from B. Vaseeharan, P. Ramasamy (2003) ; Control of pathogenic Vibrio spp. by Bacillus subtilis BT23, a possible probiotic treatment for black tiger shrimp Penaeus monodon; Letters in Applied Microbiology 36 (2), 83–87; doi:10.1046/j.1472-765X.2003.01255. )