Axenic isolation of Giardia strains from primates and rodents

Abstract

During the examination of animals at the Poznan Zoological Gardens, attempts were made to isolate Giardia strains. Using an in vitro excystation procedure, eight samples of cysts from animals with asymptomatic giardiasis were inoculated on BI-S-33 medium. The ease of isolation and axenization of Giardia was surprising; five axenic isolates of Giardia, belonging to the G. duodenalis morphological group, were established from primates (slow loris, lesser slow loris and siamang) and from rodents (Gambian giant pouched rat and cuis). The growth of all isolates was abundant and similar; the peak number of trophozoites on the seventh day (depending on the Giardia isolate) was 2.3×10 6−3.2×10 6 and generation times were 8.2–19.3 h. The easy establishment of these isolates confirmed that they belong to the G. duodenalis morphological group. The recent hypothesis that Giardia may be introduced to a human population from an animal source implies the necessity to isolate and differentiate parasite strains from various hosts. In this respect, the first isolation of Giardia strains from non-human primates and from rodents is of particular importance.