Natural Concurrent Infection of Vibrio harveyi and V. alginolyticus in Cultured Hybrid Groupers in Malaysia

Abstract

In September 2016, a marine fish farm operator in Selangor, Malaysia, reported a disease outbreak affecting juvenile hybrid groupers (Camouflage Grouper Epinephelus polyphekadion × Tiger Grouper E. fuscoguttatus). The average daily mortality was 120 fish, resulting in a cumulative mortality rate of 29% within 10 d. The affected hybrid groupers displayed lethargy, excessive mucus production, rotten fins, congestion of livers and kidneys, and enlargement of spleens. Microscopically, general congestion of the brains and internal organs was evident. Vibrio harveyi and V. alginolyticus were successfully isolated from the diseased fish. The isolated pathogens were found to be sensitive to oxytetracycline and tetracycline, but resistant towards ampicillin and vancomycin. Experimental infections using the isolated V. harveyi (10 8 CFU/mL), V. alginolyticus (10 8 CFU/mL), and concurrent infection by V. harveyi (10 8 CFU/mL) and V. alginolyticus (10 8 CFU/mL) in juvenile Asian Seabass Lates calcarifer resulted in 60, 100, and 100% mortality, respectively, within 240 h postinfection. The experimentally infected Asian Seabass demonstrated similar clinical signs and histopathological changes as the naturally infected hybrid groupers. However, concurrently infected

Effect of Dietary Canarium indicum L. on the Growth, Health, and Resistance of Asian Seabass Challenged with Vibrio alginolyticus

“…Further observation using the scoring method (Table 3) revealed that after the challenge test, the treatment injected with V. alginolyticus showed a mild damage to the liver, while the negative control treatment showed a normal damage. The mild damage found in this study is the same as Mohamad et al (2019b) reported on grouper hybrid Epinephelus polyphekadion x E. Fuscoguttatus injected with V. alginolyticus.…”

First Report and Pathogenicity Analysis of Photobacterium damselae subsp. piscicida in Cage-Cultured Black Rockfish (Sebastes schlegelii) Associated with Skin Ulcers

“…Cytolytic necrosis was observed in the liver, spleen, kidney, and gills during pathological examination, which might be caused by the release of bacterial toxins such as hemolysin or other extracellular enzymes. Comparable histological changes have also been reported in other fish species infected with PDP, Aeromonas hydrophila , or V. harveyi [ 48 , 49 , 50 ]. Herein, the cytotoxicity test demonstrated that the ECPs of PDP exhibited high virulence to RAW cells in a time-dependent manner.…”

Coinfection with two strains of Photobacterium damselae subsp. damselae and Vibrio harveyi in cage farmed cobia, Rachycentron canadum (Linnaeus, 1766)

“…Natural coinfection caused by V . harveyi and V. alginolyticus , with a cumulative mortality of 29% was reported in cultured juvenile hybrid groupers (Mohamad et al., 2019).…”

“…Lesions in the digestive tract were also reported in Arabian Surgeonfish ( Acanthurus sohal ) naturally infected with V. harveyi (Hashem & El‐Barbary, 2013). Earlier studies on experimental infections in Asian seabass with V. harveyi and V. alginolyticus unveiled focal necrosis of the liver and tubular damage in kidneys which were more severe in concurrent infections when compared to the infection caused by an individual pathogen (Mohamad et al., 2019). Since adult fish were infected in natural infections, the lesions were chronic in nature compared to congestion of internal organs observed in the juveniles in experimental infections.…”