Int. J. Med. Microbiol. 293, Suppl. 37, 117 (2004) © Urban & FischerVerlag http://www.urbanfischer.de/journals/ijmm IJ M Abstract Biodiversity in canine babesiae: molecular and epidemiological investigations M. Zahler-Rinder, W. Beck, F. Krux, S. Geiger Institut fiir Vergleichende Tropenmedizin und Parasitologie, Tierfirztliche Fakult~it, LMU Mtinchen, Germany Abstract Currently, canine babesiae are considered to belong to 2 species, Babesia gibsoni and B. canis. This view is mainly based on the morphological features of the parasites in stained blood smears. "Small" piroplasms are diagnosed as B. gibsoni while larger parasites are considered to be B. canis. We have investigated canine blood samples containing small piroplasms from Japan, Malaysia, Sri Lanka, California and Spain by DNA sequencing and phylogenetic comparisons of the 18S rDNA. An unexpectedly high genetic heterogeneity was found suggesting separate species status for the pathogens from Asia, America and Europe. Phylogenetic analyses using distance matrix, maximum parsimony and maximum likelihood methods revealed that the parasites from Asia genotypically clustered with the classical Babesia spp., while the pathogens from California were most closely related to the genus TheiIeria. The piroplasms from Spain were attributed to a new species most closely related to B. microti. Based on this genotypic characterization, distinct phenotypic features of these 3 species have to be anticipated, especially biological and epidemiological features. In large canine babesiae, 3 subspecies of B. canis are currently recognized based on differences in vector specificity and pathogenicity: B. canis canis, B. canis vogeli and B. canis rossi. To determine whether genotypic features exist to confirm this taxonomic separation, rDNA Internal Transcribed Spacers (ITS1, 5.8S, ITS2) were analyzed in isolates with known or suspected vector specificity. Three genotypic groups were detected correlating with vector specificities and supporting the separation of the large canine babesiae into 3 subspecies, possibly even 3 species. The distinction between the 3 subspecies is not only of clinical interest because of differences in pathogenicity between the 3 B. canis subspecies; it is also of epidemiological importance because of differences in the potential of the parasites to become established in Germany. To rapidly differentiate between the 3 subspecies, a diagnostic Real Time PCR was developed. This test is currently used in an epidemiological investigation and first results are presented. Key words: Babesia gibsoni - B. canis - biodiversity Corresponding author: Monika Zahler-Rinder, Institut fiir Vergleichende Tropenmedizin und Parasito- logie, Leopoldstr. 5, 80802.M~inchen, Germany. Phone: 00498921803619, Fax: 00498921803623, E-maih [email protected] 1433-1128/04/293/Suppl.37-117 $15.00/0

Biodiversity in canine babesiae: molecular and epidemiological investigations

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Int. J. Med. Microbiol. 293, Suppl. 37, 117 (2004) © Urban & Fischer Verlag http://www.urbanfischer.de/journals/ijmm IJ M Abstract

Biodiversity in canine babesiae: molecular and epidemiological investigations

M. Zahler-Rinder, W. Beck, F. Krux, S. Geiger

Institut fiir Vergleichende Tropenmedizin und Parasitologie, Tierfirztliche Fakult~it, LMU Mtinchen, Germany

Abstract Currently, canine babesiae are considered to belong to 2 species, Babesia gibsoni and B. canis. This view is mainly based on the morphological features of the parasites in stained blood smears. "Small" piroplasms are diagnosed as B. gibsoni while larger parasites are considered to be B. canis. We have investigated canine blood samples containing small piroplasms from Japan, Malaysia, Sri Lanka, California and Spain by DNA sequencing and phylogenetic comparisons of the 18S rDNA. An unexpectedly high genetic heterogeneity was found suggesting separate species status for the pathogens from Asia, America and Europe. Phylogenetic analyses using distance matrix, maximum parsimony and maximum likelihood methods revealed that the parasites from Asia genotypically clustered with the classical Babesia spp., while the pathogens from California were most closely related to the genus TheiIeria. The piroplasms from Spain were attributed to a new species most closely related to B. microti. Based on this genotypic characterization, distinct phenotypic features of these 3 species have to be anticipated, especially biological and epidemiological features. In large canine babesiae, 3 subspecies of B. canis are currently recognized based on differences in vector specificity and pathogenicity: B. canis canis, B. canis vogeli and B. canis rossi. To determine whether genotypic features exist to confirm this taxonomic separation, rDNA Internal Transcribed Spacers (ITS1, 5.8S, ITS2) were analyzed in isolates with known or suspected vector specificity. Three genotypic groups were detected correlating with vector specificities and supporting the separation of the large canine babesiae into 3 subspecies, possibly even 3 species. The distinction between the 3 subspecies is not only of clinical interest because of differences in pathogenicity between the 3 B. canis subspecies; it is also of epidemiological importance because of differences in the potential of the parasites to become established in Germany. To rapidly differentiate between the 3 subspecies, a diagnostic Real Time PCR was developed. This test is currently used in an epidemiological investigation and first results are presented.

Key words: Babesia gibsoni - B. canis - biodiversity

Corresponding author: Monika Zahler-Rinder, Institut fiir Vergleichende Tropenmedizin und Parasito- logie, Leopoldstr. 5, 80802.M~inchen, Germany. Phone: 00498921803619, Fax: 00498921803623, E-maih [email protected]

1433-1128/04/293/Suppl.37-117 $15.00/0