Case Report: A Case of Haplorchis pumilio Infection in Golden Severum, Heros severus var., in Taiwan

Abstract

Outbreak of Haplorchis pumilio infestation occurred in a cichlid breeding farm in Taiwan in April, 2009. The farm held about 7,000 golden severum (Heros severus var.), weighing 50-60 g, in freshwater culture ponds. The average temperature of weekly changed culture water was 25-28℃. The fish were fed with a commercial pulverized eel diet. Approximately 300 golden severum showed signs of poor appetite, rotten fins, abnormal pigmentation and rapid respiration rate as well as numerous whitish cysts, 0.5-1 mm in diameter, on the surface of the caudal fin. There were an average number of 40-60 cysts per infected fish. A significant pathogenic parasite, metacercariae of, Haplorchis pumilio was identified. However, microbiological studies revealed no significant findings. The pond owner was advised to treat the water with 1 ppm benzalkonium chloride (BKC) and 25 ppm formalin to kill other ectoparasites and bacteria twice a week for a month. We also recommended that snails as the host of this parasite should be eradicated artificially and disinfected the cultural bonds using 10 ppm BKC before re-feeding fish. In addition, we suggested that wild birds, cats and dogs should be prevented from eating diseased or dead fish. The parasite was eventually brought under control. [Hung SW, Liu PC, Lin SL, Tung KC, Chang CH, Chan CY, Wang WS. Case Report: A Case of Haplorchis pumilio Infection in Golden Severum, Heros severus var., in Taiwan. Taiwan Vet J 37 (4): 246-252, 2011. Corresponding author Tel: 886-4-22840894 ext 508, Fax: 886-4-22862073, E-mail: wswang@dragon.nchu.edu.tw]