Comparative assessment of growth of Trypanosoma danilewskyi (Laveran & Mesnil) in medium containing fish or mammalian serum

The objective of this study was to determine the growth of Trypanosoma danilewskyi (Laveran & Mesnil, 1904) from goldfish, Carassius auratus (L.), in medium containing no serum, or in medium supplemented with either 10% fish serum (goldfish, carp, or tin foil barb) or 10% mammalian serum (horse or foetal bovine). After 10 days, the number of trypanosomes in flasks containing tin foil barb serum increased by nearly 700% over the initial inoculum. Similarly, a substantial increase in the number of parasites was seen after 10 days in the cultures containing carp and goldfish serum. After 6 weeks, there was more than a 15-fold increase of T. danilewskyi in cultures containing goldfish serum. Medium containing no serum or mammalian serum failed to support the growth of parasites. Therefore, serum-related factors within fish blood are required for the propagation of T. danilewskyi isolated from infected goldfish. Since T. danilewskyi can be propagated in vivo and in vitro in the presence of homologous proteins, cultured and wild-type forms can be compared to determine if cultured parasites can be used as analogues of natural life-cycle stages.