[Successful axenic cultivation of a local human strain of Giardia lamblia in suckling gerbil].

G. lamblia cysts isolated from the fresh feces of a Giardia-infected boy in Beijing rural area were inoculated into suckling gerbils (Meriones unguiculatus). Trophozoites of G. lamblia obtained from the intestines of infected gerbils were cultivated in modified TYI-S-33 medium enriched with dehydrated bovine bile. The parasites grew luxuriantly and formed an intensive monolayer on the surface of the culture tube on day 14 after initial cultivation. The culture has been maintained for more than 12 months and more than 120 subcultures have been made. The growth curve of the organism showed that the peak growth of the trophozoites was attained at the 120th hour after seeding. The generation time was 15 +/- 2.0 hours. Periodic examinations of Giardia cultures for bacteria contamination, with Petri dishes of blood agar and beef broth, proved negative. After being cryopreserved in liquid nitrogen for 1 week or longer, the average viable rate of the organism was 65.7% and the resuscitated parasites grew luxuriantly in subcultures.