COMPARATIVE MORPHOMETRY OF GIARDIA TROPHOZOITES FROM MAN AND ANIMALS

Thirty axenic Giardia isolates of the G. duodenalis morphological-type were investigated: 22 were isolated in Poland from humans with sympto matic or asymptomatic giardiasis, 5 from animals in Poland (primates a nd rodents), and three from human, cat and guinea-pig in the USA. G. m uris trophozoites were obtained directly from the intestine of a spont aneously infected mouse. The overall length (L) and the maximum width (B) of the cells and the length of adhesive disk (SL) were measured bo th in live as well as in fixed and stained trophozoites. The major mea surements and ratios were analyzed statistically by using Duncan test and by clustering of average measurements by single linkage or nearest neighbor method and group average strategy in two- or three-dimension al space. Our study proved the existence of statistically significant differences of the three measurements in the trophozoites of different Giardia isolates. The most reliable seems to be the analysis done by clustering of all dimensions in three-dimensional space; the nearest n eighbor method groupped all the Giardia isolates into six groups and t he group average strategy into eight groups. G. muris trophozoites con stituted a separate morphological group in every statistical analysis. The differences made possible the dividing of separate Giardia groups partially correlating with molecular patterns of the isolates. Howeve r, the results of our study also made us aware that morphometrics cann ot constistute a sole reliable criterion for Giardia speciation.