Infection of mice with oral administration of trophozoites of Giardia muris]

For the last 9 years we have used Giardia muris for chemotherapy research, passing trophozoites scraped from the mouse small intestine into fresh mice, by gavage. More or less every trophozoite administered orally reproduces in the intestine, as shown by quantitative studies in groups of young, specific pathogen-free mice, treated with 1, 3, 10, 30 or 100 Giardia each. After 7-9 days the number of protozoa in the intestine diminished somewhat, in the groups infected with the largest number of trophozoites.