Current methods for diagnosis of visceral leishmaniasis (VL) require invasive sampling procedures such as visceral aspiration and/or blood drawing. The use of diagnostic tests using oral fluid, which is easier to collect, would be more simple and practical for VL diagnosis, especially under field conditions. Oral fluids from 37 VL patients and 40 healthy controls were collected using Oracol devices. Blood samples and oral fluid specimens from both groups were analyzed by recombinant protein K39 (rK39) enzyme-linked immunosorbent assay and quantitative real-time PCR. Detection of antibodies in the oral fluid had a sensitivity of 100% and a specificity of 97.5%. Antibody levels measured in serum and oral fluid showed a significant positive correlation ( ‫؍‬ 0.655 and P ‫؍‬ 0.01). Detection of Leishmania DNA in oral fluid had a sensitivity of 94.6% and a specificity of 90%. The median parasite load estimated in blood was 133 parasites/ml (interquartile range [IR], 10 to 1,048), whereas that in oral fluid specimens was 3 parasites/ml (IR, 0.41 to 92). However, there was no significant linear relationship between parasite loads assessed in the two biological samples ( ‫؍‬ 0.31 and P ‫؍‬ 0.06). VL diagnosis based on specific antibody detection and Leishmania DNA identification using oral fluid samples was equivalent in accuracy to that using blood and therefore is promising for clinical use.

No abstract

Phlebotomus perniciosus is one of the major vectors of Leishmania infantum in the Mediterranean basin. The aim of this work was (i) to provide information about abundance and temporal dynamics of this Larroussius species in a hot spot area of visceral leishmaniasis in Tunisia, (ii) to detect L. infantum DNA in wild caught female sandflies and (iii) to measure Phlebotomus perniciosus infection rate throughout the active season. Sandflies were collected monthly during one year using CDC miniature light-traps in house and in animal shelters. Male specimens were identified at species level according to morphological characters. Female specimens were conserved individually for molecular study. Leishmania infection was tested by kinetoplast DNA real-time PCR and ITS-1 PCR-sequencing. Subsequent sandfly species identification of infected specimens was done by mitochondrial cytochrome b sequencing. In one year period, overall 4,441 specimens (2230 males and 2211 females) were collected. Sandfly activity started in end-April and ended in early-November. Mean sandfly density in house was significantly lower than in animal shelters (51 ± 50 versus 504 ± 460 sandflies /CDC night, p<0.05). However, a higher proportion of females was found in house (58.4% versus 49.2%, p<0.001). Based on species identification of male specimens, Phlebotomus perniciosus was the dominant species (56% of the whole male sandfly fauna, p<0.0001). It showed two peaks of density in the active season, a sharp one in early May and a higher long lasting one from end-July to end-September. DNA was extracted from 190 female specimens randomly sampled and corresponding to 96 specimens from house and 94 from animal shelters. Twenty four female sandfly were infected by Leishmania infantum. All infected specimens were recognized as Phlebotomus perniciosus. Leishmania infantum infection rate in female sandflies was 2.3 fold higher in house than in animal shelters (17.7% versus 7.4%, p<0.05). In house, estimated number of infected specimens was the highest at the end of the active season. Abundance, dynamics of density and Leishmania infantum infection prevalence of Phlebotomus perniciosus in Tunisian hot spot of visceral leishmaniasis highlight the major role of this Phlebotominae species in L. infantum transmission.

Visceral leishmaniasis has been associated with hyper-gammaglobulinemia and antinuclear antibodies and may simulate systemic lupus erythematosus. Sera from patients with visceral leishmaniasis have been shown to strongly react against conserved proteins from the parasite, such as ribosomal and histones. Some of these proteins have also been described as immunogenic in several auto-immune syndromes, and the detection of antibodies against them is considered to be indicative of disorder in the immune system. This study aimed to assess by enzyme-linked immunosorbent assay, test routinely employed in visceral leishmaniasis diagnosis, the recognition of Crude Leishmania histone and Soluble Leishmania antigens proteins from Leishmania infantum by adult patients with suggestive signs of autoimmune diseases. Our results show that the humoral response generated during autoimmune diseases cross-reacts with the parasitic Crude Leishmania histone and Soluble Leishmania antigens. In these cases, higher precautions must be taken to confirm the presence of visceral leishmaniasis in front of positive serology in antinuclear antibodies positive sera, in order to avoid wrong diagnosis.

No abstract

No abstract

No abstract

No abstract