the lowest sero-prevalence (24.7%) and the lowest levels of
E. canis antibodies. In contrast, Nanuque, in which the
optimal temperature for the development of the tick was
observed throughout most of the year, showed the highest
percentage of infested animals (75.0%), the highest sero-
prevalence (65.6%) and the highest titers of a ntibodies
against E. canis. Thus, dogs living in the Nanuque region
had 4.6 times (P 6 0.01) higher risk of being seropositive
to E. canis, when compared to dogs living in the other
two regions.
Future epidemiological studies should incorporate
molecular techniques to determine other infecting Ehrlichia
species by DNA analysis at the time of sample collection.
Acknowledgement
The authors thank CAPES (Brazil) and the DAAD
(Germany) for the partial financial support given for this
project.
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ARTICLE IN PRESS
Please cite this article in press as: Costa, L.M. et al., Sero-prevalence and risk indicators for canine ehrlichiosis in three ..., The Ve-
terinary Journal (2006), doi:10.1016/j.tvjl.2006.11.002