The chimerical multi-component Q protein from Leishmania in the absence of adjuvant protects dogs against an experimental Leishmania infantum infection.

The protective potential against Leishmania infection of the Leishmania chimerical Q protein administered as a single (Q) or double dose (Q+Q) without adjuvant was analyzed in a double-blind placebo controlled experiment in dogs. During vaccination the protein induced an intense early anti-Q response but no reactivity against total Leishmania infantum proteins was detected. Several end-points were taken into consideration. In the vaccinated animals the amount and intensity of clinical symptoms was lower than in the control group. Pathological signs of disease were observed in liver, kidney and spleen of all dogs from the control group in contrast to the normal appearance of the organs of the vaccinated animals. Vaccination was able to induce parasite clearance in most dogs. Only 1/7 dog was parasite DNA positive in skin in the Q group in contrast to 6/7 dogs in control and 4/7 in Q+Q. Significant anti-SLA clearance was observed in the vaccinated animals at the end of the study. Differences between control and vaccinated animals were also observed at the biochemical level, DTH and nitrite oxide production.

Meningeal leishmaniosis induced by Leishmania infantum in naturally infected dogs.

We report two cases of meningitis caused by Leishmania infantum in naturally infected dogs. In both of these dogs the typical phenotypic features of granulomatous meningitis were observed with important lympho-plasma-cellular infiltrates and the presence of large numbers of parasites inside and outside macrophages. The immunological study of the cerebrospinal fluid of both animals showed that a large number of protein bands were recognized by those fluids and that they were similar to the ones recognized by the sera from the same animals. To our knowledge, this is the first description of meningitis associated to leishmaniosis.