Characteristics and pathogenicity of a Vibrio campbellii-like bacterium affecting hatchery-reared Penaeus indicus (Milne Edwards, 1837) larvae |
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| Authors: | A S Sahul Hameed P V Rao J J Farmer F W Hickman-Brenner G R Fanning |
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| Institution: | Central Marine Fisheries Research Institute. P. Box No. 1603. Cochin, 682 014. India;Enteric Bacteriology Section, Center for Infectious Diseases, Centers for Disease Control. Atlanta. GA, 30333, USA;Department of Biochemistry. Walter Reed Army Institute of Research. Washington, DC, 20012, USA |
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| Abstract: | In the summer months, epizootics occurred regularly among larvae of Penaeus indicus (Milne Edwards) in a hatchery located at Narakkal near Cochin, India. The clinical signs of infected larvae were expansion of chromatophores. opaqueness of body with twisting and degeneration of appendages. Bacteria were isolated from the infected larvae. These bacteria had morphological, physiological and biochemical characteristics of the genus Vibrio, but these properties did not correspond with those of known Vibrio species. The Vibrio was most related to Vibrio campbellii according to DNA-hybridization experiments. By pathogenicity experiments, the present Vibrio isolate was proved to be pathogenic to larvae, postlarvae and adult shrimp. Shrimp larvae challenged by immersion showed significant mortalities. The bacterial isolate failed to produce the infection in adult shrimp after oral inoculation but it caused significant mortality in adults after intramuscular injection. LC50 and LD50 values of the Vibrio isolate were determined for larvae and adult shrimps, respectively, at different time intervals. |
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