Heterosporis saurida is an intracellular microsporidian that infects lizardfish Saurida undosquamis. Although some attempts have been introduced to clarify microsporidian host−pathogen interactions, development of novel strategies to combat fish diseases is still needed. Here we present an in vitro cultivation model for fish microsporidia based on an eel kidney cell line (EK-1), which is susceptible to infection by H. saurida. Spores were isolated from infected lizardfish and used to inoculate EK-1 cells. H. saurida were propagated in the eel kidney EK-1 cell line and detected by immunofluorescence. Developmental stages of H. saurida were seen in EK-1 cells by transmission electron microscopy. Identity of the parasite was confirmed by partial se quencing of the 16S rDNA gene. Our cell culture model provides a valuable means to explore molecular and immunological events and will facilitate development of effective treatment strategies.KEY WORDS: Fish · Microsporidia · Heterosporis saurida · Disease · Cell culture · EK-1 cell line
Resale or republication not permitted without written consent of the publisherDis Aquat Org 108: [37][38][39][40][41][42][43][44] 2014 tured eels in Japan (Hoshina 1951), H. schuberti in cultured ornamental cichlids and loricarid catfish from Germany (Lom et al. 1989), and H. finki in cultured angelfish Pterophyllum scalare from France (Michel et al. 1989). An undetermined species of Heterosporis was reported from cultured bettas Betta splendens in Thailand (Lom et al. 1993). Since 2000, Heterosporis has been confirmed in yellow perch Perca flavescens in the USA (Miller 2009). Most recently, H. saurida has been described from lizardfish Saurida undosquamis in the Arabian Gulf, Saudi Arabia (Al-Quraishy et al. 2012). These Hetero sporis species, in particular, cause significant pathogenic effects on the host and hence have negative economic consequences in the fish trade (AlQuraishy et al. 2012).Interest in in vitro propagation of certain microsporidia has intensified recently because several microsporidia are found to have low host specificity (Rinder et al. 2000, Sutherland et al. 2000, Lores et al. 2003, Coyle et al. 2004, Kumar et al. 2013, and some genera have been identified as opportunistic pathogens of humans, especially patients with ac quired immune deficiency syndrome (AIDS; Didier 2005). Microsporidia that parasitize humans have also been reported in domestic animals, which may represent reservoir hosts , Rinder et al. 2000. The fact that microsporidia have been observed in fishes and can be cultured in mammalian cell lines, e.g. Hetero spo rosis sp. in the rabbit kidney epithelial cell line RK-13, supports the hypothesis that mammals may be natural reservoir hosts of fish microsporidia (Lores et al. 2003, Kumar et al. 2013.Although cell and tissue cultures are essential tools for the propagation and study of obligate intracellular pathogens such as microsporidia, research is hinde red by a lack of suitable cell cultures for propagation and study of fish microspor...