Abstract: Objective To cultivate a Giardia canis isolate with G.canis virus（GCV）. Methods Five-day-old Meriones unguiculatus was infected with the cysts of G. canis isolated from dogs in Changchun and purified by sucrose density gradient centrifugation-G1 acid funnel filtration method. Trophozoites were isolated aseptically from the duodenum of the infected rodent after 8 days，then transferred to modified TYI-S-33 medium and cultivated at 37 ℃. The trophozoites were centrifuged with 3 000 × g，15 min after liquid nitrogen freeze-thawing three times and the supernatant stained negatively by phosphotungstic acid was observed with transmission electron microscope. Results G. canis trophozoites which adapted gradually to the environment and grew a cellular monolayer after 14 days were examined by freezing and thawing experiment，purity quotient，stability，biology characteristics and microbial contamination detection. The results demonstrated that a stable G.canis trophozoite cell isolate was established. G. canis virus with icosahedron spherical shape and 36 nm in diameter was observed by electron microscope. Conclusion In vitro cultivation of G.canis trophozoites with GCV is established.

Key words: Giardia canis, Virus, In vitro culture, Modified TYI-S-33 medium