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Are vector-borne pathogen co-infections complicating the clinical presentation in dogs?

Anna Sara De Tommasi1, Domenico Otranto1*, Filipe Dantas-Torres12, Gioia Capelli3, Edward B Breitschwerdt4 and Donato de Caprariis1

Author Affiliations

1 Department of Veterinary Public Health, Faculty of Veterinary Medicine, University of Bari, Str. prov. per Casamassima km 3, Valenzano, Bari, 70010, Italy

2 Departamento de Imunologia, Centro de Pesquisas Aggeu Magalhães, Fundação Oswaldo Cruz – Pernambuco, Av. Prof. Moraes Rego s/n, Recife, PE, 50670-420, Brazil

3 Istituto Zooprofilattico Sperimentale delle Venezie, Viale dell’Università, Legnaro, Padova, 10, 35020, Italy

4 Intracellular Pathogens Research Laboratory, Center for Comparative Medicine and Translational Research, College of Veterinary Medicine, North Carolina State University, Raleigh, North Carolina, USA

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Parasites & Vectors 2013, 6:97  doi:10.1186/1756-3305-6-97

Published: 15 April 2013



Infection by two or more canine vector-borne disease (CVBD)-causing pathogens is common in subtropical and tropical regions where vectors are plentiful. Co-infections may potentiate disease pathogenesis, thereby altering clinical manifestations typically associated with singular infections. These factors complicate diagnosis, treatment and can adversely influence prognosis if the practitioner fails to suspect, document, and treat each concurrent infection. The spectrum of pathogens co-infecting dogs may change over time in a given practice location due to the rapid expansion of arthropods and their associated vectored agents, and international transit among pets and wild animals. This applies, for example, to Dirofilaria immitis and Leishmania infantum, the distributions of which have expanded from northern to southern Italy, and vice versa, respectively. Indeed, mixed infections by D. immitis and L. infantum have only been reported once in Italy, probably due to the fact that competent vectors for these infections do not usually occur in the same geographical areas. Thus, information that would help practitioners to identify clinical presentations in dogs co-infected by D. immitis and L. infantum and other CVBD-causing pathogens is scant.


This manuscript describes the clinical history and physical examination of findings for 7 CVBD co-infected dogs that were examined because of a spectrum of clinical signs. Five dogs were co-infected with L. infantum and Ehrlichia canis, one dog with L. infantum, E. canis and D. immitis and the remaining dog with L. infantum and D. immitis.


The clinical signs and haematological abnormalities associated with the diagnostic evaluation and treatment of these dogs is discussed. Also, the usefulness of bone marrow specimens for the molecular diagnosis of CVBDs and for the enhanced monitoring of treatment response is emphasized.

Co-infection; Dirofilaria immitis; Ehrlichia canis; Leishmania infantum; Bone marrow