Cross-sectional serosurvey of feline leishmaniasis in ecoregions around the Northwestern Mediterranean.

A cross-sectional serosurvey using Leishmania infantum ELISA was performed on 445 cats living in ecoregions around the Northwestern Mediterranean basin; 58 cats from an area of the US where leishmaniasis is not endemic were used as negative controls. ELISA results were further confirmed in 69 cats by Western blot (WB). Finally, 76 of them were also tested for FeLV and FIV. Seroprevalence by ELISA-prot A was 6.29%, and that by ELISA-IgG was 5.25%. Positive cat sera recognized patterns of polypeptides in WB, including L. infantum-specific antigenic fractions. There was no association with retroviruses. Leishmania-specific antibodies are prevalent in cats living in ecoregions around the Northwestern Mediterranean basin; thus, leishmaniasis must be included in the differential diagnosis of diseases in cats living in these ecoregions. Their role as peridomestic reservoirs for L. infantum needs further characterization, but it could be hypothesized that the cat is a secondary reservoir host, rather than an accidental one.

Dynamics of Leishmania-specific immunoglobulin isotypes in dogs with clinical leishmaniasis before and after treatment.

Concentrations of Leishmania-specific immunoglobulin G (IgG), immunoglobulin M (IgM), and immunoglobulin A (IgA) isotypes were analyzed by enzyme-linked immunosorbent assay (ELISA) in 23 dogs naturally infected with Leishmania infantum before and 1 year after initiating drug therapy. Results showed a high expression and prevalence of Leishmania-specific IgG (176.4 +/- 89 ELISA units [EU]), IgM (105.3 +/- 95.5 EU), and IgA (153.6 +/- 98 EU) in dogs before treatment (median +/- interquartile range EU). One year after treatment was started, dogs were classified as responsive dogs (RDs; n = 13) or unresponsive dogs (UDs; n = 10) based on clinicopathologic findings. Both groups of dogs experienced a statistically significant decrease (P < .05) in Leishmania-specific IgG (RDs = 27%, UDs = 41%), IgM (RDs = 42%, UDs = 29%), and IgA (RDs = 56%, UDs = 46%). Concentrations of specific IgG and IgM were not different at diagnosis or after treatment between the 2 groups. However, the median value for Leishmania-specific IgA 1 year after treatment was significantly lower (P < .05) in RDs (60.8 +/- 67 EU) than in UDs (117 +/- 54 EU). Examination of our data indicates that both the IgA isotype, which is mostly produced by mucosal plasma cells, and the IgM isotype are increased in infected symptomatic dogs, as previously reported for IgG. These 3 isotypes decreased significantly 1 year after initiation of medical treatment.