Diagnostic methods used for FeL.
| IMMUNOLOGICAL* | PARASITOLOGICAL |
| Antibody detection IFAT (cut off: 1:80) ELISA DAT Western blot |
Cytological evaluation of any skin, mucosal or muco-cutaneous lesion, lymph node and bone marrow smears (Fig. 9) Histological evaluation of any skin, mucosal or muco-cutaneous biopsied lesions (± IHC and/or PCR) PCR from any skin, mucosal or muco-cutaneous lesion, lymph node, bone marrow, blood, conjunctival and oral swabs Culture of any skin, mucosal or muco-cutaneous lesion, lymph node, bone marrow, blood samples |
DAT: direct agglutination test; ELISA: enzyme-linked immunosorbent assay; IFAT: indirect fluorescence antibody test; IHC: immunohistochemistry; PCR: polymerase chain reaction.
To confirm diagnosis, a quantitative serological test or Western blot should be performed in sera from cats with risk of exposure to Leishmania infection and clinical signs or clinicopathological abnormalities compatible with leishmaniosis. However, in case of negative or low-positive antibody titers, a parasitological technique should be used to identify infection (cytology, histology, PCR), before discharging diagnosis.
Point-of-care tests validated to detect anti-L. infantum antibodies in cats are currently not available. The screening of clinically healthy cats by means of Leishmania-specific serology and PCR techniques (blood, lymph nodes or conjunctival swabs) is recommended in the following special situations in endemic areas:
- Blood donors
- Cats requiring immunosuppressive therapies
- Before re-homing cats to non-endemic areas
Figure 9: Fine needle aspirate of a reactive lymph node: lymphoid hyperplasia and a macrophage with L. infantum amastigotes (red arrows). May-Grünwald-Giemsa stain, scale bar = 20 μm (© Maria Grazia Pennisi)