Nematode worm infections (Camallanus cotti, Camallanidae) in guppies (Poecilia reticulata) imported to Korea

Abstract

Camallanus cotti [Jpn. J. Zool. 1(1927) 169] is a common intestinal nematode parasite of guppies. It was first reported from several kinds of freshwater fishes in Japan in 1927, and is thought to be native to continental Asia, from Japan westwards, perhaps extending as far as the Nile delta. Because of the worldwide trade in aquarium fishes, it is now found in many fishes in several continents. Guppies are one of the most popular tropical pet fishes in Korea. Here we report C. cotti infection of cultured guppies in Korea, originally imported from Indonesia, for the first time. In a tropical fish farm, mortality reached up to 30% and most guppies did not show any clinical signs except in heavily infected fish, in which worms were extruded from the anus. Prevalence of infection was 71% (59/83 fish), and there was no preference for host sex (34 of 45 female fish and 25 of 38 male fish). Although we found C. cotti in dead guppies, we could not conclude that C. cotti infection was the cause of death, because some fish died without C. cotti infection. In addition, we detected high numbers of the histophagous ciliate, Tetrahymena corlissi (Thompson, 1955) in these fish. We suspect that both C. cotti and T. corlissi infections contributed to death, but more detailed studies are required.