This paper embodies a case study

of mycotic infection, in a fresh water

fish, Tilapia , moss.bica, resulting in

mass mortality, which occurred at the

Taraporevala Aquarium, Bombay

Pillai, C Thankappan

Yvonne, M Freitas

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Fungal Infection Causing Mass Mortality of Fresh Water Fish Tilapia Mossambica C. Thankappan Pillai' and Yvonne M. Freitas (Department of Microbiology, St. Xavier's College, Bombay - I .) ABSTRACT In the year 1977, a case of mass mortality of Tilapia mossambica was diagnosed as caused by a pathogenic furigus of the Fusarium genus. The in vitro and in vivo effect of anti-septics: acriflavine, brilliant green, methylene blue. silver nitrate, and and antibiotics: erythromycin, genta-mycin, kanamycin, mycostatin, against the fungal strain were investigated. The antiseptics, brilliant green and silver nitrate, found effective in vitro, were equally useful in controlling the infection in' vivo, The antibiotics had no effect on this strain even in vitro. INTRODUCTION This paper embodies a case study of mycotic infection, in a fresh water fish, Tilapia , moss.bica, resulting in mass mortality, which occurred at the Taraporevala Aquarium, Bombay, Fungal diseases are widely pre-valent among fish and fish eggs in natural and artiticial environments. Species of Saprolegnia usually affect fish and fish eggs and the infections caused by Achlya, Aphanomyces, Lap-tomitus and Pithium have also been reported (Khan, 1922; Chidambaram. 1942; Scot and O'Bier, 1962; Gopala-· krishnan, 1963 and 1964), Branchio-mycosis times in Rehulka has been reported several carps (Hora and PiliaL 1962:' and Tesareik, 1972). In general, information on various species of fungi which attack finfishes is. available (Conroy and Herman, 1970; Van Duijn, 1973; Roberts, 1978; Ahne, 1980), but cases of Fusarium attacks have rarely been reported (Horter. 1960: Ribelin and Migaki. 1975; Ahne 1980) , MATERIALS AND METHODS The infected fishes from the Aqua-rium were found to be covered with cottony outgrowths (Fig. 1) over almost the entire body, and the gills. and eye tissue were seriously damaged. The moribund fishes collected in sterile containers under aseptic con-ditions were immediately transported to the laboratory, The pathological ' samples-gills, skin and kidney-were removed and diluted according to the method described by Pillai (1978) . The suitably diluted sample was cul-tured in Sabouraud's agar, incubated 'Present address: CMFR Institute, p, B, 1912, Cochin - 18, Kerala, January 1983 .at room temperature (28 + 2CO) for 2-7 days, after microscopic exami-nation of the wet wounts of the . pathological samples. The fungal colonies which deve-loped were picked up and maintained on Sabouraud's agar slants for furthclr . investigation. The gross morphological characters uf the pure strain were studied and the isolate was . identified according to Bessey (1961). To satisfy Koch's postulates. the isolate was tested in healthy fishes. .£trop/us suutensis maintained ' under suitable ecological conditions (Pillai, 1978). To evolve suitable remedies, in vitro and in vivo studies were carried ·out using four antiseptics: acriflavine, brilliant green, methylene blue and silver nitrate, and four antibiotics: -erythromycin, gentamycin, kanamycin. and mycostatin strain according cribed by Pillai against the fungal to the method des-(1978) . RESULTS AND DISCUSSION The gross morphological of the fungal strain are in table 1 . characters presented In India, Khan (1922) has recorded Sapro/egnia disease resulting in mor-tality of fry 01 the murrel, Ophiocepha/u6 maTU/ius. Chidambaran (1942) observed Saprolegniasis in the gourami, Osphro-nemus goramy at Madras and sugg~sted that over crowding, pollution' due to decaying matter and injuries on the fish are the contributing factors for the spread of the disease. The inci-dence of the disease has also been observed in major carps (Gopala-krishnan, 1963 and 1964). Branchio-mycosis has been reported to be common in cultivated fishes in ponds with abundant decaying matter (Hora and Pillai, 1962). Srivastava and Srivastava (1975) could isolate the TABLE ' 1 GROSS CHARACTERS OF THE FUNGAL STRAIN Species -of fish Disease Tilapia Dermato-. mO$sam- mycosis hiea :16 Isolate no (s) Cultural characters cters in Sabouraud's agar Microscopic chara-cters of the wet mount observed under high power and stained with Lactophenol cotton blue Rapid growth Both microconidia producing cottony and macroconidia colonies. Abundant produced. Terminal Identity DM 1 aerial myceliam chlamydospores present. Colour also produced . at first white Unicellular Fusarium sp. turning to pink later . microconidia and multicellular mecrocondia Were noted. Seafood Export Journal fungal strains, Aphanomyces laevis and Achlya flagel/ata from Channa s"iatus The fungal suspension injected intramuscularly and intraperitoneally did not successfully affect the host. But the infections done through arti-ficial surface injuries were quite success-ful. Visible growth appeared within 16-24 hours, rate of infection was very slow and death occurred within 20-25 days, causing severe damage especially to the gills and eye tissue. The antibiotics were totally in-effeciive, but the antiseptics, brilliant S,Jreen and silver nitrate were quite helpful in controlling the pathogen both in vitro and in vivo, the results . agreeing with the findings of van :Duijn (1973) that the above antiseptics are useful in the control of mycotic infections. Although Fusarium infection in carp fishes has been recorded by Horter (1960), the present case of a similar infection in Tilapia mossambica seems to be recorded for the first time in our country (Davis and Graham, 1979; Jhingran, 1982). ACKNOWLEDG EM ENT One of the authors (CTP) is very much indebted to Dr. E. G. Silas, Director, Central Marine Fisheries Research Institute, Cochin for arousing his interest in ichthyopathology and for all the valuable encouragement and guidance he has had, REFERENCES Ahne, W(ed) 1980 FIsh diseases Springer - Verlag New York, 252 pp. Bessy, E. A. 1961. Morphology and taxonomy of fungi Hafner Publishing Co., New York, 791 pp. January 1983 Chidambaram, K. 1942 Curro Sci. 11 (7): 289 Conroy, D. A. and R. L. Herman 1970_ Textbook of fish diseases T. F. H. Publications Inc. Jerssy City, 302pp. Davis, Band M. Graham (eds.) 1979. Diseases of fish cultured for food in South east Asia. R' pr. Worksh op held in Ci ;aru. B oqor Indonesil1 28 No veml er - 1 December (1978) Ottawa, Om, IDRC 32 pp. Gopalakrishnan, V. 1963. Indian Livestk., 1 (1): 51 Gopalakrishnan, V. 1964. Proc. Zool. Soc. Calcutta.,' 17: 95-Hora, S. L. and T. V. R. Pillai 1962. FAD. Fish BioI. Tech. Pap. 14: 203 pp. Jhingran, V. G. 1982. Fish and Fisheries of India Hin-dustan Publishing Corporation India. 666 pp. Khan, H. 1922. Proc. Indian sci. Con gr., 9: 94 Piliai, C. Thankappan 1978. M. Sc .. Thesis, University of Bombay Rehulka, J. and J. Tesareik 1972. Act. vet. Borono .. 41 (1): 101 Ribelin, W. E. and G. Migaki (eds.) 1975-The Pathology of fishes The Uni-versity of Wisconsin Press Publi-cation, 1004 pp. Roberts, R. J. (ed.) 1978. Fish Pathology, A Bailliere- Tindall Publication, 318 pp. Scali. W. W. and A. H. O' Bier 1962_ Proq. Fish Cult.. 24 (1): 3 Snvastava, G. C. and R. C. Srivastava 1975. Curro Sci., 44 (22): 817 Van Duijn, C. Jr. 1973 Diseases of fi;heries 3rd edn. Butter--worth and Co., (Publishers) Ltd. ,. London 372 pp. Von Horter, R. 1960. Z. Parasilkde., 20: 355 17 

Fungal infection causing mass mortality of fresh water fish Tilapia Mossambica

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Fungal infection causing mass mortality of fresh water fish Tilapia Mossambica

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