Studies on ulcerative disease caused by Aeromonas caviae-like bacterium in Indian catfish, Clarias batrachus (Linn)
Highlights
► Study the prevalence of bacterial ulcerative disease in Clarias batrachus. ► Identification, causative organism for ulcerative syndrome in catfish. ► Confirmation of Aeromonas caviae by PCR.
Introduction
Indian walking catfish, Clarias batrachus (Linn), is an economically important fish species in south and south-east Asian countries, including India, because it is suitable for monoculture or polyculture with other catfish species. It is euryhaline across its native range, inhabiting fresh and brackish water as well as muddy marshes (Sen, 1985). Infectious diseases caused by viruses and bacteria are responsible for substantial financial loss to catfish farmers worldwide. Channel catfish virus (CCV) is an important fish virus causing economic losses in channel catfish Ictalurus punctatus. CCV is a cytopathic herpes virus that can cause an acute, hemorrhagic and lethal disease in the channel catfish (Fijan, 1968). This virus also causes an acute hemorrhagic disease in channel catfish fry and fingerlings (Buck, 1990, Plumb, 1977). Crumlish et al. (2003) challenged hybrid catfish (Clarias gariepinus × C. batrachus) with Aeromonas hydrophila under stressful conditions and reported high mortality of fish in high temperature stress. Chattopadhyay et al. (1992) isolated fifteen strains of A. hydrophila from three species of fish including C. batrachus with typical ulcers on the surface of the body. In the present study, high mortality of young C. batrachus with clinical sign of ulcers on the body surface was observed in a hatchery and grow out ponds. An attempt was made to isolate and identify the causative organism responsible for high mortality of catfish fry. Experimental pathogenicity was conducted to reproduce the infection in normal fish using the bacterial isolate isolated from naturally infected fish. Chauhan (2012) carried out a study on certain fungal diseases in culturable and non-culturable species of fishes of Upper Lake, Bhopal. Achlya and Saprolegnia were found to be the most virulent genera. Out of 2066 fishes examined, the most affected species was C. batrachus (24.6%). Sarkar and Rashid (2012) investigated pathogenicity of the bacterial isolate Aeromonas hydrophilla to catfishes, carps and perch. They reported a mortality of 60–100% in all the six species of catfishes studied at a water temperature of 30 °C.
Section snippets
Collection and maintenance of naturally infected fish
The young ones (fingerlings) of Indian catfish (C. batrachus) weighing approximately 3–5 g with clinical signs of ulcerative lesions having a depth of approximately 2 mm on the body surface and base of the fins were collected from a farm located at Walajapet, Tamil Nadu and transported within half an hour at 28 °C in live condition to the laboratory in a container with continuous aeration. In the laboratory, the infected animals were maintained in 100-l aquarium tanks containing ground spring
Results
The physicochemical characteristics of pond water were determined. Temperature, pH, and dissolved oxygen ranged from 26 to 31 °C, 7.2 to 7.4 and 4.6 to 6.0 mg/l, respectively, during the collection of infected fish. A high temperature of 31 °C was recorded during summer. Mortality of fish due to infection reached 95–97% within 3–5 days after the appearance of ulcer on the surface of infected fish. The clinical signs of infected fish include ulcerative lesions on the body surface, bases of the fins
Discussion
C. batrachus is considered as a potential aquaculture species in the Indian subcontinent. The population of catfish has been affected by many factors including diseases caused by viral and bacterial pathogens, even though it is a hardy species. High mortality of young C. batrachus was observed in nursery and grow-out ponds located in Tamil Nadu and Andhra Pradesh. Among the bacterial pathogens, motile Aeromonas caused high mortality in catfish (Lewis and Plumb, 1979, Meyer, 1975) and induced
Acknowledgments
The authors thank the management of C. Abdul Hakeem College for providing the facilities to carry out this work. This work was funded by the University Grants Commission, Government of India, New Delhi.
References (30)
Clarias culture in Thailand
Aquaculture
(1987)Vibriosis pathogenicity and pathology. A review
Aquaculture
(1987)- et al.
Aeromonas hydrophila associated with ulcerative disease epizootic in Laguna de Bay, Philippines
Aquaculture
(1987) 16S rRNA gene sequencing for bacterial pathogen identification in the clinical laboratory
Molecular Diagnostics
(2001)- et al.
Protective efficacy of Aeromonas hydrophila vaccines in Nile tilapia
Veterinary Immunology and Immunopathology
(1986) - et al.
Blood picture and bacteria isolated from ulcered and crookedback Clarias batrachus
Biotrop Special
(1988) - et al.
Establishment and characterization of a fin cell line from Indian walking catfish, Clarias batrachus (L.)
Journal of Fish Diseases
(2011) - et al.
Bergey's Manual of Determinative Bacteriology
(1984) Channel catfish virus a review
ATCC Quarterly Newsletter
(1990)Identification of fish pathogenic bacteria
Association of fish and environmental strains of Aeromonas hydrophila in the causation of ulcerative disease syndrome in fish
International Journal of Environmental Health Research
Study on certain fungal diseases in culturable and non-culturable species of fishes of Upper Lake, Bhopal
Journal of Chemical, Biological and Physical Sciences, Section B.
Microbiological methods
The effects of stressful conditions on an artificial Aeromonas hydrophila challenge in hybrid catfish (Clarias gariepinus × Clarias batrachus)
Asian Fisheries Science
Experimental pathogenicity of Vibrio parahaemolyticus for the schistosome bearing snail Biomphalaria glabrata
Canadian Journal of Microbiology
Cited by (36)
Pathogenesis of Aeromonas caviae in Clarias magur
2022, Microbial PathogenesisEffect of cassic acid on immunity and immune-reproductive genes transcription in Clarias gariepinus against Edwardsiella tarda
2020, Fish and Shellfish ImmunologyProtective efficacy of microencapsulated seaweed extracts for preventing Aeromonas infections in Oreochromis mossambicus
2019, Comparative Biochemistry and Physiology Part - C: Toxicology and Pharmacology