hrernationol Journal/or Prinred in Grear Britain


Vol. 2 I, No. I, pp. 123-l 24, I99

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w?&7519/91 $3.00 f 0.00 Pergamon Press plc I99 I Ausrralian Sociery for Parasitology


Hospital, West Smithfield, London EClA 7BE, U.K. Terrace, Herston, Brisbane, Queensland 4006, Australia

(Received 1 October 1990; accepted 22 October 1990) Abstract-AncmeALo S. C., MITCHELLR. W., UFCROFTJ. A., BOREHAM P. F. L. and UPCROFT P. 1991. Variation between human and animal isolates of Giurdiu as demonstrated by DNA fingerprinting. International Journalfor Parasitology 21: 123-124. Five Giardia stocks collected from animals and man in Alberta, Canada, were compared by DNA fingerprinting. Although many DNA bands were common to all stocks, differences in the DNA banding patterns were seen. These same stocks had previously been shown to be identical by restriction enzyme cleavage of genomic DNA. INDEX


Giordia; DNA fingerprinting;


SEVERAL enigmas

exist in our understanding of the epidemiology of giardiasis. A variety of vertebrates, including mammals, reptiles and birds, harbour Giurdiu which are morphologically identical to human Giardia and there is much debate as to the zoonotic aspects of this infection (Bemrick & Erlandsen, 1988; Faubert, 1988). Accordingly strain variation has been extensively examined over the last few years employing a variety of techniques, which include analysis of antigens, isoenzymes, sensitivity to drugs, restriction enzyme analysis, virulence and infectivity studies, growth characteristics, karyotyping and DNA fingerprinting (Boreham, Upcroft & Upcroft, 1990). In general, these methods although showing some grouping of strains are not specific enough to allow identification of individual strains. The recently described DNA fingerprinting technique (Upcroft, Mitchell & Boreham, 1990) now allows individual strain identification and hence the possibility of exploring the question of zoonosis in detail. In this paper we have compared five strains isolated from humans and other animals in Alberta which restriction enzyme analysis suggested are closely related (Uji, Wallis & Wenman, 1988). Five stocks of Giurdiu duodenalis, H8, PBl, OASl (described by Uji et cd., 1988 as Sl), DOGD3 (described by Uji et al., 1988 as D3) and MR4, derived from human, beaver, sheep, dog and muskrat hosts, respectively in Alberta, Canada, were used in this

work. The cultures were established and grown as described previously (Capon, Upcroft, Boreham, Cottis & Bundesen, 1989). Genomic DNA was extracted from cultured trophozoites of each stock, cleaved with the restriction enzyme Hinf I (New England Biolabs) and fingerprinted with singlestranded bacteriophage Ml3 DNA as probe as described by Upcroft et al. (1990). The DNA fingerprints of the five stocks are shown in Fig. 1. The smaller hypervariable bands are similar in all stocks but the hypervariable bands in the range of l4 Kb in size show differences. In particular, strain OASl has an extra band at approximately 2 Kb. Variation in the positions of major bands at approximately 1.5 and 3 Kb are evident. Each of the five isolates has a unique DNA fingerprint pattern. DNA fingerprinting of Giardia using Ml 3 DNA as a probe shows distinct differences between each of the five stocks examined here, although most of the bands hybridizing to Ml3 are similar in each stock. The stocks were derived from different hosts but from the same geographic area, Alberta, in Canada. Previously Wenman, Meuser & Wallis (1986) and Uji et al. (1988) showed that these stocks were related antigenically and their genomic DNA had very similar DNA restriction patterns. These workers concluded that the strains were closely related genetically and that the strains had broad host specificity with transmission likely between hosts. The Ml3 probe which detects polymorphic minisatellites in Giurdia demonstrated differences between isolates indicating that the strains are not in fact genetically identical. This probe is thus a more specific method of strain identification and provides a way of investigating potential zoonotic transmission. If identical strains from animals and man in

t Present address: Scottish Parasite Diagnostic Laboratories, Department of Bacteriology, Stobhill General Hospital, Glasgow G21 3UW, Scotland. Q To whom all correspondence should be addressed. 123



the same location can be found it would be suggestive of cross transmission. We have found that DNA fingerprints of Giardia are remarkably stable in long term cultures (unpublished observation). The fingerprints shown here are much more similar than those seen with isolates collected from disparate geographic locations (Boreham et al., 1990; Upcroft et al., 1990) where considerably more change in the number of bands showing size differences is observed. This DNA fingerprinting technique has shown that genetic differences occur between strains which is not evident by simple restriction enzyme analysis.


Acknowledgements-S.C.A. is grateful to the Sir Robert Men&s Centre for Australian Studies, Institute of Commonwealth Studies, London, for the award of a Northcote Scholarship to visit Australia. We would like to thank the National Health and Medical Research Council of Australia for financial support. We also thank Associate Professor W. Wenman, Dr P. Wallis and Dr H. Stibbs for providing us with the strains used in this study. REFERENCES BEMRICK W. J. & ERLANDSENS. L. 1988. Giardiasis-is

12345 FIG. 1. DNA fingerprinting of five stocks of Giardia duodenafis collected from five different hosts. Lane 1, OASl from a sheep; lane 2, MR4 from a muskrat; lane 3, DOGD3 from a dog; lane 4, H8 from a human; lane 5, PBl from a beaver. The size of DNA is shown in Kb.

it really a zoonosis? Parasitology Today 4: 69-l 1. BOREHAM P. F. L., UPCROFT J. A. & UPCROFT P. 1990. Changing approaches to the study of Giardia epidemiology: 1681-2000. International Journal for Parasitology 20: 479487. CAFQN A. G., UPCROFT J. A., BOREHAMP. F. L., Corns L. E. & BUNDESENP. G. 1989. Similarities of Giardia antigens derived from human and animal sources. International Journalfor Parasitology 19:91-98. FAUBERTG. M. 1988. Evidence that giardiasis is a zoonosis. Parasitology Today 4: 66-68. UJI A., WALLIS P. M. & WENMAN W. M. 1988. Comparison of Giardia isolates by DNA-DNA hybridization. In: Advances in Giardia Research (Edited by WALLISP. M. & HAMMOND B. R.), pp. 165-167. University of Calgary Press, Calgary. UPCROFT P., MITCHELL R. W. & BOREHAM P. F. L. 1990. Fingerprinting of the human intestinal parasite Giardia intestinalis with the Ml3 phage genome. International Journal for Parasitology 20: 3 1F&323. WENMAN W. M., MEUSER R. U. & WALLIS P. M. 1986. Antigenic analysis of Giardia duodenalis strains isolated in Alberta. Canadian Journal of Microbiology 32: 926929.

Variation between human and animal isolates of Giardia as demonstrated by DNA fingerprinting.

Five Giardia stocks collected from animals and man in Alberta, Canada, were compared by DNA fingerprinting. Although many DNA bands were common to all...
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