Leishmaniasis: The prevalence in the Netherlands and the relation between height of DAT titre and different staging systems.

Abstract

Aim 1: Objective: To determine the (sero)prevalence of Canine Leishmania, Ehrlichia and Dirofilaria immitis, non-endemic vector borne diseases, in dogs imported from endemic areas to the Netherlands. Study Design: This is a prospective study. Animal: Dogs. Methods: Seven dogs imported from Mediterranean endemic areas by several animal welfare organisations were clinically examined within six weeks after import. Blood samples were taken to determine the prevalence of Canine Leishmaniasis, Ehrlichiosis and Dirofilariasis. DAT titres for CanL antibodies and Knott’s tests were performed, blood samples for Ehrlichiosis were stored for tests in the future. Results: Of the seven dogs, only one dog had a positive DAT titre (1:5120). The prevalence at this point of the study was determined and set on 14,3%. Also, one of the seven dogs was tested positive on heartworm antigen, giving a prevalence of 14,3% as well. Conclusion: The prevalence of both Canine Leishmania and Dirofilaria immitis in the Netherlands in this point of the study was set on 14,3%. Key words: Dog, Canine, Leishmaniasis, Leishmania infantum, seroprevalence, DAT antibody titre, Dirofilaria immitis, Ehrlichiosis, vector borne disease. Abbreviations: Canine Leishmaniasis (CanL); Leishmania infantum (L. infantum); immunofluorescence antibodies test (IFAT); direct agglutination test (DAT); enzyme linked immunosorbent assay (ELISA); Utrecht University Clinic of Companion Animals (UUCCA); Stray Animal Foundation Platform (SAFP); capillary refill time (CRT); haematocrit (Ht); content of hemoglobin in reticulocytes (CHr); ethylenediaminetetraacetic acid (EDTA); University Veterinary Diagnostic Laboratory (UVDL).

Aim 2: Objective: To determine the relation between the level of the DAT antibody titre and several different staging systems used to classify a patient based on severity of clinical signs and haematological and biochemical results of Canine Leishmaniasis. Study Design: This is a retrospective study. Animal: Dogs. Methods: Positive and negative titres (n = 109) as well as height of the DAT titre (n = 39) were compared to clinical signs and haematological and biochemical parameters. All dogs were born or had travelled to endemic areas and had clinical signs suggesting infection with CanL and were clinically examined and blood samples were taken. Also, all of these dogs had a DAT titre performed. Retrospectively, all dogs were assigned to fitting stages in five different clinical staging systems, according to severity of clinical signs, and haematological and biochemical alterations. Results: For the first part of the aim, most common alterations in dogs with a negative DAT titre (n =26) were decreased endurance (61,5%), lymphadenopathy (57,5%) and anaemia (69,2%). In dogs with a positive titre (n = 83), most common clinical signs were lymphadenopathy (66,3%), decreased endurance (61,4%), alopecia (43,4%) and hypergammaglobulinemia (73,5%). For the second part of the aim, of the 39 dogs 15 dogs had a positive DAT titre (>1:40). Most common clinical signs and haematological and biochemical alterations found in dogs with a positive DAT titre were lymphadenopathy (66,3%), hypergammaglobulinemia (73,5%) and anaemia (67,5%). This study shows that in all used clinical staging systems no correlations were found between the height of the DAT titre and clinical signs, except for the system of CLWG (1). Besides, height of the DAT titre was not related to any of the haematological or biochemical parameters used in this study. Conclusion: The DAT titre is not significantly related to clinical signs, haematological and biochemical parameters used in this study. However, a positive correlation was found between DAT titre and severity of clinical signs according to the staging system of CLWG. Key words: Dog, Canine, Leishmaniasis, Leishmania infantum, DAT antibody titre, clinical staging system. Abbreviations: Canine Leishmaniasis (CanL); Leishmania infantum (L. infantum); immunofluorescence antibodies test (IFAT); direct agglutination test (DAT); enzyme linked immunosorbent assay (ELISA); polymerase chain reaction (PCR); University Veterinary Diagnostic Laboratory (UVDL); Utrecht University Clinic of Companion Animals (UUCCA); capillary refill time (CRT); haematocrit (Ht); urea- protein-creatinine ratio (UPC ratio); Canine Leishmaniosis Working Group (CLWG); ethylenediaminetetraacetic acid (EDTA).