Table 6 Laboratory methods for diagnosis of Leishmania infection in cats

Serology

Detection of specific antibodies by IFAT and ELISA (more frequently used), DAT and WB

Different sensitivities and specificities, partially dependent on the cut-off values; clinical cases may have from low to high positive antibody levels, but the latter are usually diagnostic

Antibodies should be evaluated using techniques validated in cats; parasitological methods should be employed in clinically suspect but seronegative or low positive cats

[23–25, 82–84]

Cytology

Detection of amastigotes in stained tissue smears (ex: lymph node, bone marrow, skin and cornea)

Specific, but time-consuming and requiring expertise

For compatible skin or mucosal lesions, enlarged lymph nodes and other lesions, and for clinically suspected cases if serology is negative or low positive

[50, 61, 63, 65]

Histology with IHC

Detection of amastigotes in histopathology tissue specimens

Specific, but time-consuming and requiring expertise

[59, 68, 69, 72]

IHC is not widely available

Culture

Multiplication of promastigotes from tissues

Not suitable for rapid diagnosis and not widely available

For research and species and/or strain identification

[26, 37]

PCR

Amplification of parasite DNA from tissues and biological fluids, including blood, buffy coat, bone marrow, lymph nodes and conjunctival swabs

More sensitive than cytology or histology with IHC; may allow molecular characterization and quantification of the parasitic load

Preferable to sample more than one tissue, in order to increase sensitivity of detection especially in subclinical infections

[24, 66, 69, 97, 98]