title: Diagnosis and incidence risk of clinical canine monocytic ehrlichiosis under field conditions in Southern Europe.
abstract: BACKGROUND
  Canine Monocytic Ehrlichiosis (CME), due to the bacterium Ehrlichia canis and transmitted by the brown dog tick Rhipicephalus sanguineus, is a major tick-borne disease in southern Europe. In this area, infections with other vector-borne pathogens (VBP) are also described and result in similar clinical expression. The aim of the present study was to evaluate the incidence risk of clinical CME in those endemic areas and to assess the potential involvement of other VBP in the occurrence of clinical and/or biological signs evocative of the disease.
  
  
  METHODS
  The study was conducted from April to November 2011 in veterinary clinics across Italy, Spain and Portugal. Sick animals were included when fitting at least three clinical and/or biological criteria compatible with ehrlichiosis. Serological tests (SNAP®4Dx, SNAP®Leish tests, Idexx, USA) and diagnostic PCR for E. canis, Anaplasma platys, Anaplasma phagocytophilum, Babesia spp, Hepatozoon canis and Leishmania infantum detection were performed to identify the etiological agents. Ehrlichiosis was considered when three clinical and/or biological suggestive signs were associated with at least one positive paraclinical test (serology or PCR). The annual incidence risk was calculated and data were geo-referenced for map construction. The probabilities of CME and other vector-borne diseases when facing clinical and/or biological signs suggestive of CME were then evaluated.
  
  
  RESULTS
  A total of 366 dogs from 78 veterinary clinics were enrolled in the survey. Among them, 99 (27%) were confirmed CME cases, which allowed an estimation of the average annual incidence risk of CME amongst the investigated dog population to be 0.08%. Maps showed an increasing gradient of CME incidence risk from northern towards southern areas, in particular in Italy. It also suggested the existence of hot-spots of infections by VBP in Portugal. In addition, the detection of other VBP in the samples was common and the study demonstrated that a dog with clinical signs evocative of CME is as likely to be positive to Ehrlichia canis as to another VBP.
  
  
  CONCLUSIONS
  The study confirms the endemicity of CME in southern Europe and highlights the difficulties encountered by veterinarians to differentiate CME from other vector-borne diseases under field conditions.
authors.affiliation: Université de Lyon, VetAgro Sup Campus vétérinaire de Lyon, Jeune équipe Hémopathogènes vectorisés, 1 avenue Bourgelat, 69280, Marcy L'Etoile, France. magalie.renemartellet@vetagro-sup.fr.|INRA, UR 346 Epidémiologie Animale, 63122, Saint-Genès-Champanelle, France. magalie.renemartellet@vetagro-sup.fr.
authors.forename: Magalie
authors.initials: M
authors.lastname: René-Martellet
authors.affiliation: INRA, UR 346 Epidémiologie Animale, 63122, Saint-Genès-Champanelle, France. isabelle.lebert@clermont.inra.fr.
authors.forename: Isabelle
authors.initials: I
authors.lastname: Lebert
authors.affiliation: Université de Lyon, VetAgro Sup Campus vétérinaire de Lyon, Jeune équipe Hémopathogènes vectorisés, 1 avenue Bourgelat, 69280, Marcy L'Etoile, France. jeanne.chene@vetagro-sup.fr.
authors.forename: Jeanne
authors.initials: J
authors.lastname: Chêne
authors.affiliation: Université de Lyon, VetAgro Sup Campus vétérinaire de Lyon, Jeune équipe Hémopathogènes vectorisés, 1 avenue Bourgelat, 69280, Marcy L'Etoile, France. raphael.massot@vetagro-sup.fr.
authors.forename: Raphaël
authors.initials: R
authors.lastname: Massot
authors.affiliation: Merial S.A.S, 29 avenue Tony Garnier, 69007, Lyon, France. Marta.LEON@Merial.com.
authors.forename: Marta
authors.initials: M
authors.lastname: Leon
authors.affiliation: Merial S.A.S, 29 avenue Tony Garnier, 69007, Lyon, France. Ana.LEAL@merial.com.
authors.forename: Ana
authors.initials: A
authors.lastname: Leal
authors.affiliation: Merial S.A.S, 29 avenue Tony Garnier, 69007, Lyon, France. Stefania.BADAVELLI@Merial.com.
authors.forename: Stefania
authors.initials: S
authors.lastname: Badavelli
authors.affiliation: INRA, UR 346 Epidémiologie Animale, 63122, Saint-Genès-Champanelle, France. karine.chalvet-monfray@vetagro-sup.fr.|VetAgro Sup campus vétérinaire de Lyon, 1 avenue Bourgelat, 69280, Marcy l'Etoile, France. karine.chalvet-monfray@vetagro-sup.fr.
authors.forename: Karine
authors.initials: K
authors.lastname: Chalvet-Monfray
authors.affiliation: INRA, UR 346 Epidémiologie Animale, 63122, Saint-Genès-Champanelle, France. christian.ducrot@clermont.inra.fr.
authors.forename: Christian
authors.initials: C
authors.lastname: Ducrot
authors.affiliation: INRA, UR 346 Epidémiologie Animale, 63122, Saint-Genès-Champanelle, France. david.abrial@clermont.inra.fr.
authors.forename: David
authors.initials: D
authors.lastname: Abrial
authors.affiliation: Université de Lyon, VetAgro Sup Campus vétérinaire de Lyon, Jeune équipe Hémopathogènes vectorisés, 1 avenue Bourgelat, 69280, Marcy L'Etoile, France. luc.chabanne@vetagro-sup.fr.
authors.forename: Luc
authors.initials: L
authors.lastname: Chabanne
authors.affiliation: Merial S.A.S, 29 avenue Tony Garnier, 69007, Lyon, France. Lenaig.HALOS@Merial.com.
authors.forename: Lénaïg
authors.initials: L
authors.lastname: Halos
mesh_terms: D000709:Anaplasma / Q000302:isolation & purification; D000712:Anaplasmosis / Q000453:epidemiology / Q000382:microbiology; D000818:Animals; D016782:Apicomplexa / Q000302:isolation & purification; D001403:Babesia / Q000145:classification / Q000302:isolation & purification; D001404:Babesiosis / Q000453:epidemiology / Q000469:parasitology; D004283:Dog Diseases / Q000175:diagnosis* / Q000453:epidemiology; D004285:Dogs; D041061:Ehrlichia canis / Q000302:isolation & purification*; D016873:Ehrlichiosis / Q000175:diagnosis / Q000453:epidemiology / Q000662:veterinary*; D015994:Incidence; D007558:Italy / Q000453:epidemiology; D011174:Portugal / Q000453:epidemiology; D012307:Risk Factors; D013030:Spain / Q000453:epidemiology