Molecular detection of Ehrlichia canisand Anaplasma platys in dogs in Southern Brazil

Camila Serina Lasta,Félix Hilario Diaz González,Andrea Pires dos Santos,Rafael Felipe da Costa Vieira,Alexander Welker Biondo,Magnus Larruscaim Dalmolin,Simone Tostes Oliveira,Joanne Belle Messick

doi:10.1590/s1984-29612013000300007

Abstract

The aims of this study were to determine the occurrence of Anaplasma platys and Ehrlichia canis infection in dogs in Porto Alegre, Southern Brazil; and to investigate their association with hematological abnormalities. Serum samples from 196 dogs were first tested using dot-ELISA for antibodies against Anaplasma spp. and Ehrlichia canis. Peripheral blood samples from 199 dogs were subjected to 16S rRNA nested PCR (nPCR) for A. platys and E. canis, followed by DNA sequencing to ensure pathogen identity. A total of 19/196 samples (9.69%) were positive for Anaplasma spp. using ELISA and 28/199 (14.07%) samples were positive for A. platys by nested PCR. All the dog samples were negative for E. canis, both in anti-E. canis antibody tests and in nested PCR. There were no significant differences in hematological parameters between A. platys-PCR positive and negative dogs and Anaplasma spp. serologically positive dogs, except for basophil counts, which were higher in nPCR-positive dogs. This is the first report showing A. platys presence in dogs in Southern Brazil. In conclusion, hematological parameters may not be sufficient to diagnose A. platys infection in dogs in Southern Brazil, probably due either to low pathogenicity or to chronic infection. On the other hand, E. canis may either have very low occurrence or be absent in dogs in Porto Alegre.

Highlights

Anaplasma platys and Ehrlichia canis are tick-borne bacteria that cause mild to severe disease in dogs (BEALL et al, 2008; GAUNT et al, 2010)
Anaplasma platys - formerly known as Ehrlichia platys (DUMLER et al, 2001) - and E. canis, from the Anaplasmataceae family, cause canine infectious cyclic thrombocytopenia (CICT) and canine monocytic ehrlichiosis (CME), respectively (HARVEY, 2006; DANTAS-TORRES, 2008)
The nested PCR (nPCR) assays were able to amplify the control template diluted to as few as 101 and 103 gene copies per microliters for E. canis and A. platys, respectively, and all the samples were positive for glyceraldehyde-3-phosphate dehydrogenase (GAPDH), thereby confirming the presence of amplifiable DNA in the samples

Summary

Introduction

Anaplasma platys and Ehrlichia canis are tick-borne bacteria that cause mild to severe disease in dogs (BEALL et al, 2008; GAUNT et al, 2010). Both organisms are transmitted by ticks, mainly by Rhipicephalus sanguineus. Reports on experimental and natural infections have mostly indicated that A. platys causes few or no clinical signs in dogs in the United States (HARVEY, 2006; GAUNT et al, 2010). E. canis infects monocytes and has been associated with serious and sometimes fatal disease in dogs (NEER; HARRUS, 2006). It has been suggested to be a zoonotic agent in Venezuela (PEREZ et al, 1996, 2006)

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