PCR evaluation of selected vector-borne pathogens in dogs with pericardial effusion.

OBJECTIVES: To investigate evidence for selected vector-borne pathogen infections in dogs with pericardial effusion living in a Mediterranean area in which several canine vector-borne diseases are endemic. MATERIALS AND METHODS: Archived EDTA blood (n=68) and pericardial fluid samples (n=58) from dogs with pericardial effusion (n=68) were included. Dogs without pericardial effusion examined for other reasons were included as controls (n=60). Pericardial effusion was classified as neoplastic in 40 dogs, idiopathic in 23 dogs and of unknown aetiology in 5 dogs. Real-time PCR was performed for Leishmania infantum, Ehrlichia/Anaplasma species, Hepatozoon canis, Babesia species, Rickettsia species and Bartonella species, and sequencing of PCR products from positive samples was used to confirm species specificity. RESULTS: Vector-borne pathogens were found in 18 dogs: 16 of 68 dogs with pericardial effusion (23·5%) and two of 60 control dogs (3·3%). Positive dogs demonstrated DNA of Leishmania infantum (n=7), Anaplasma platys (n=2, one dog coinfected with Leishmania infantum), Babesia canis (n=5), Babesia gibsoni (n=3) and Hepatozoon canis (n=2). Vector-borne pathogens were more commonly detected among dogs with pericardial effusion than controls (P=0·001). There was no relationship between aetiology of the pericardial effusion and evidence of vector-borne pathogens (P=0·932). CLINICAL SIGNIFICANCE: Vector-borne pathogens are often detected in dogs with pericardial effusion and require further investigation, especially in dogs with idiopathic pericardial effusion. PCR can provide additional information about the potential role of vector-borne pathogens in dogs with pericardial effusion living in endemic areas.

Gammopathy in a Spanish dog infected with Bartonella henselae.

Generalised pyogranulomatous disease and hyperviscosity syndrome associated with a presumed monoclonal gammopathy was diagnosed in a three-year-old intact female Pomeranian. The Bartonella henselae antibody titer was 1:64 and Bartonella species DNA was amplified from the splenic tissue. Monoclonal gammopathies in dogs are typically associated with plasma cell and lymphoid dyscrasias and other inflammatory or infectious diseases such as ehrlichiosis and leishmaniosis. Based on this case report, infection with Bartonella species should also be added to the differential diagnoses for gammopathy in dogs. To the authors' knowledge, this is the first report of molecular evidence of Bartonella species infection in a sick dog in Spain.

Advantages of real-time PCR assay for diagnosis and monitoring of canine leishmaniosis.

The aim of the present study is to highlight the advantages of real-time quantitative PCR intended to aid in the diagnosis and monitoring of canine leishmaniosis. Diagnosis of canine leishmaniosis is extremely challenging, especially in endemic areas, due to the diverse and non-specific clinical manifestations, and due to the high seroprevalence rate in sub-clinical dogs. Veterinarian clinicians are usually confronted with cases that are compatible with the disease, and with several diagnostic tests, sometimes with contradictory results. We have developed a new TaqMan assay, targeting the kinetoplast, applied to 44 samples of bone marrow aspirate or peripheral blood. The dynamic range of detection of Leishmania DNA was established in 7 logs and the limit of detection is 0.001 parasites in the PCR reaction. At the time of diagnosis parasitemia ranges from less than 1 to 10(7)parasites/ml. The ability to quantify the parasite burden allowed: (i) to elucidate the status of positive dogs by conventional PCR, although larger studies are necessary to clarify the dividing line between infection and disease, (ii) to estimate the kinetics of the parasite load and the different response to the treatment in a follow-up and (iii) to validate blood as less invasive sample for qPCR. The continuous data provided by real-time qPCR could solve the dilemma for the clinician managing cases of canine leishmaniosis by differentiating between Leishmania-infected dogs or dogs with active disease of leishmaniosis.