Diagnosis is based on clinical signs and/or clinicopathological abnormalities compatible with disease combined with confirmation of L. infantum infection, predominantly using serological and/or molecular techniques. However, cytology and histology combined with immunohistochemistry can be used or are adequate.
Main purposes for the diagnosis of L. infantum infection:
A. Confirm etiology of disease in a dog with clinical signs and/or clinicopathological abnormalities consistent with leishmaniosis.
B. Screening of apparently healthy dogs living in or travelling to or from endemic areas:
- blood donors
- breeding dogs
- dogs prior to Leishmania vaccination
- imported dogs
- dogs admitted for the annual Leishmania health check
Flow chart for the diagnostic approach to dogs not vaccinated against leishmaniosis with suspected clinical signs and/or clinicopathological abnormalities consistent with leishmaniosis
- Dogs with clinical leishmaniosis are those presenting compatible clinical signs and/or clinicopathological abnormalities, and having a confirmed L. infantum infection.
- Dogs with subclinical infection (infected but clinically health y) are those that present neither clinical signs on physical examination nor clinicopathological abnormalities on routine laboratory tests (CBC, biochemical profile and urinalysi s) but have a confirmed L. infantum infection.
- Parasitological: cytology/histology, immunohistochemistry and culture.
- Molecular: conventional, nested and real-time polymerase chain reaction (PCR).
- Serological: quantitative (IFAT and ELISA) and qualitative (rap id test) assays.
- First choice: bone marrow, lymph node, spleen, skin or conjunctival swabs.
The sensitivity of the PCR assay is lower when performed on the se samples: blood, buffy coat and urine.
- Most sensitive technique: real-time/quantitative PCR.