Epizootics of epizootic ulcerative syndrome among estuarine fishes of Kerala, India, under post-flood conditions

Sumithra, T G and Arun Kumar, T V and Swaminathan, T R and Nair, V Anusree and Amala, P V and Reshma, K J and Kishore, T G and Ratheesh Kumar, R and Sharma, S R Krupesha and Kripa, V and Prema, D and Sanil, N K (2020) Epizootics of epizootic ulcerative syndrome among estuarine fishes of Kerala, India, under post-flood conditions. Diseases of Aquatic Organisms (DAO), 139. pp. 1-13.

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Abstract

Epizootic ulcerative syndrome (EUS), primarily caused by the water mold Aphano - myces invadans, is an OIE-notifiable disease, having potential impacts on fisheries. We report EUS epizootics among estuarine fishes of Kerala, India, during 2018, under post-flood conditions 3 decades after its primary outbreak. Six fish species (Mugil cephalus, Platycephalus sp., Scato - phagus argus, Arius sp., Planiliza macrolepis and Epinephelus malabaricus) were infected, in - cluding the first confirmed natural case in E. malabaricus and P. macrolepis. Salinity, surface temperature, dissolved oxygen and pH of water during the epizootics were <2 ppt, 25°C, 4.1 ppm and 7.0. The presence of zoonotic bacterial pathogens (Aeromonas veronii, Shewanella putrefaciens, Vibrio vulnificus and V. parahaemolyticus) in tissues of affected fish indicates that EUSinfected fish may pose a public health hazard if not handled properly. Lack of clinical evidence in the region during the last 3 decades, a high number of affected fishes, including 2 new fish species, the severity of skin lesions and very low water salinity (<2 ppt) during the outbreak in contrast to historical water salinity records suggest relatively recent invasion by A. invadans. Phylo genetic analysis based on the internal transcribed spacer region of the rRNA gene showed that the same clone of pathogen has spread across different continents regardless of fish species and ecotypes (fresh/estuarine environments). Altogether, the present study provides baseline data which can be applied in EUS management strategies within brackish-water ecosystems. We recommend strict surveillance and development of sound bio security measures against the disease.

Item Type:	Article
Uncontrolled Keywords:	Aphanomyces invadans; Epinephelus malabaricus; Planiliza macrolepis; Salinity
Subjects:	Fish and Fisheries > Fish Disease Fish Biotechnology
Divisions:	CMFRI-Kochi > Marine Biotechnology, Fish Nutrition and Health Division Subject Area > CMFRI > CMFRI-Kochi > Marine Biotechnology, Fish Nutrition and Health Division CMFRI-Kochi > Marine Biotechnology, Fish Nutrition and Health Division Subject Area > CMFRI-Kochi > Marine Biotechnology, Fish Nutrition and Health Division
Depositing User:	Arun Surendran
Date Deposited:	19 May 2020 06:05
Last Modified:	02 Sep 2020 05:13
URI:	http://eprints.cmfri.org.in/id/eprint/14254

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