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Prevalence of Dirofilaria immitis, Ehrlichia canis, Borrelia burgdorferi sensu lato, Anaplasma spp. and Leishmania infantum in apparently healthy and CVBD-suspect dogs in Portugal - a national serological study

Luís Cardoso12*, Cláudio Mendão3 and Luís Madeira de Carvalho4

Author Affiliations

1 Department of Veterinary Sciences, School of Agrarian and Veterinary Sciences, University of Trás-os-Montes e Alto Douro, Vila Real, Portugal

2 Parasite Disease Group, Instituto de Biologia Molecular e Celular (IBMC), Universidade do Porto, Portugal

3 Bayer Portugal S.A., Animal Health Division, Carnaxide, Portugal

4 Interdisciplinary Centre for Research in Animal Health (CIISA), Faculty of Veterinary Medicine, Technical University of Lisbon, Portugal

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Parasites & Vectors 2012, 5:62  doi:10.1186/1756-3305-5-62

Published: 27 March 2012

Abstract

Background

Canine vector-borne diseases (CVBDs) are caused by a wide range of pathogens transmitted to dogs by arthropods including ticks and insects. Many CVBD-agents are of zoonotic concern, with dogs potentially serving as reservoirs and sentinels for human infections. The present study aimed at assessing the seroprevalence of infection with or exposure to Dirofilaria immitis, Ehrlichia canis, Borrelia burgdorferi sensu lato, Anaplasma spp. and Leishmania infantum in dogs in Portugal.

Methods

Based on 120 veterinary medical centres from all the regions of mainland and insular Portugal, 557 apparently healthy and 628 CVBD-suspect dogs were sampled. Serum, plasma or whole blood was tested for qualitative detection of D. immitis antigen and antibodies to E. canis, B. burgdorferi s. l., Anaplasma spp. and L. infantum with two commercial in-clinic enzyme-linked immunosorbent assay kits. Odds ratios (OR) were calculated by logistic regression analysis to identify independent risk factors of exposure to the vector-borne agents.

Results

Total positivity levels to D. immitis, E. canis, B. burgdorferi, Anaplasma spp., L. infantum, one or more agents and mixed agents were 3.6%, 4.1%, 0.2%, 4.5%, 4.3%, 14.0% and 2.0% in the healthy group, and 8.9%, 16.4%, 0.5%, 9.2%, 25.2%, 46.3% and 11.6% in the clinically suspect group, respectively. Non-use of ectoparasiticides was a risk factor for positivity to one or more agents both in the apparently healthy (OR = 2.1) and CVBD-suspect (OR = 1.5) dogs. Seropositivity to L. infantum (OR = 7.6), E. canis (OR = 4.1) and D. immitis (OR = 2.4) were identified as risk factors for the presence of clinical signs compatible with CVBDs. Positivity to mixed agents was not found to be a risk factor for disease.

Conclusions

Dogs in Portugal are at risk of becoming infected with vector-borne pathogens, some of which are of zoonotic concern. CVBDs should be considered by practitioners and prophylactic measures must be put in place to protect dogs and limit the risk of transmission of vector-borne agents to humans. This study is expected to give veterinary and public health authorities an increased awareness about CVBDs in Portugal and to serve as a reference for future investigations and control actions.

Keywords:
Anaplasma spp.; Borrelia burgdorferi sensu lato; Canine Vector-Borne Diseases; Dogs; Dirofilaria immitis; Ehrlichia canis; Epidemiology; In-Clinic ELISA Tests; Leishmania infantum; Portugal