Four isolates of Giardia lamblia cultivated axenically in China and the restriction endonuclease analysis of their DNA.

Axenic culture of 4 Giardia lamblia isolates, 3 from humans and 1 from a rabbit, have been established in China for the first time. The trophozoites of Giardia used for the initial cultivation were obtained from the purified cysts excysted in suckling gerbil (Meriones unguiculatus) and BALB/c mice. Modified TYI-S-33 medium was used in establishment of the culture. DNA banding patterns were compared using restriction-endonuclease analysis and then followed by Southern blot analysis with genomic DNA as a probe. The 4 isolates showed identical banding patterns after being digested with Hind III, Bgl II, Pts I, Hae III, and Hinf. Two different banding patterns were observed after further digestion with Alu I and southern blot analysis. This indicated that isolates of human and rabbit origins do not have strict host specificity and that cross transmission may occur between humans and rabbits.