Submitted to: Journal of American Society for Tropical Medicine and Hygiene
Publication Type: Abstract Only
Publication Acceptance Date: 7/1/2001
Publication Date: 9/1/2001
Citation: SULAIMAN, I.M., BERN, C., FAYER, R., DAS, P., GILMAN, R.H., SCHANTZ, P.M., LAL, A.A., XIAO, L. GENETIC VARIATION IN GIARDIA DUODENALIS FROM HUMAN, CATTLE, DOGS, AND AQUATIC WILDLIFE AT THE TRIOSE PHOSPHATE ISOMERASE (TPI) GENE LOCUS. JOURNAL OF AMERICAN SOCIETY FOR TROPICAL MEDICINE AND HYGIENE. 2001.
Technical Abstract: Giardia duodenalis (syn. G. intestinalis) is a common protozoan parasite in humans and other mammals, causing endemic and epidemic diarrhea worldwide. Therefore, the epidemiology of this parasite is of considerable interest. To address the source of infection in humans and public health importance of parasites of animal origins, we sequence-characterized the G. duodenalis striosephosphate isomerase gene (TPI). A two-step nested PCR protocol was developed to amplify a fragment (~525 bp) of the TPI gene from various G. intestinalis isolates, using the primers complementary to the conserved regions of published Giardia species nucleotide sequences. The secondary PCR products were sequenced on an ABI3100 Automated Sequencer using Big DyeTM. Nucleotide sequences of the TPI gene was generated for 45 human isolates, 15 dog isolates, 8 muskrat isolates, 6 isolates each from calves and beavers, and 1 isolate from a rat. The accuracy of nucleotide sequence was confirmed by two-directional sequencing and by sequencing of a new PCR product if necessary. Sequence alignments were done using the ABI Autoassembler and GCG programs. Multiple alignment of G. intestinalis TPI nucleotide sequences analyzed so far has revealed distinct sequences for the human, bovine, beaver, dog, muskrat, and rat isolates. No polymorphism was observed within the bovine and beaver isolates. However, genetic variations were evident within the human, dog and muskrat isolates. Efforts are underway to generate more Giardia TPI sequences to develop a molecular diagnostic tool that can be utilized in the detection and differentiation of various G. intestinalis parasites in future.