Abstract
Although Trypanosoma (Megatrypanum) theileri, a blood parasite of Bovidae species, is spread widely throughout the world, it has never been reported in Taiwan. An anti-coagulated blood sample from febrile dairy cattle was directly smeared and no parasite was observed. However, a highly distinctive morphological feature of trypanosome appeared in baby hamster kidney (BHK) cell culture inoculated with non-thrown blood buffy coat. The different stages and typical ultrastructures of trypanosome were observed in our isolate. The isolate was subsequently identified as T. theileri by species-specific PCR assay (Tth625), 18S RNA sequencing alignment and internal transcribed spacer of ribosomal genes (ITS) as a marker for molecular phylogenetic analysis. Intriguingly, the first T. theileri isolate in Taiwan (TWTth1) can be periodicaly passaged in BHK cell culture for more than one year and retain good re-cryopreservation viability. The BHK culture method would excellent for diagnostic isolation, sustaining long-term development, life cycle or further studies.