ABSTRACT
BACKGROUND Knowledge on synanthropic phlebotomines and their natural infection by Leishmania is necessary for the identification of potential areas for leishmaniasis occurrence. OBJECTIVE To analyse the occurrence of Phlebotominae in gallery forests and household units (HUs) in the city of Palmas and to determine the rate of natural infection by trypanosomatids. METHODS Gallery forests and adjacent household areas were sampled on July (dry season) and November (rainy season) in 2014. The total sampling effort was 960 HP light traps and eight Shannon traps. Trypanosomatids were detected in Phlebotominae females through the amplification of the SSU rDNA region, and the positive samples were used in ITS1-PCR. Trypanosomatid species were identified using sequencing. FINDINGS A total of 1,527 sand flies representing 30 species were captured in which 949 (28 spp.) and 578 (22 spp.) were registered in July and November, respectively. In July, more specimens were captured in the gallery forests than in the HUs, and Nyssomyia whitmani was particularly frequent. In November, most of the specimens were found in the HUs, and again, Ny. whitmani was the predominant species. Lutzomyia longipalpis was commonly found in domestic areas, while Bichromomyia flaviscutellata was most frequent in gallery forests. Molecular analysis of 154 pools of females (752 specimens) identified Leishmania amazonensis, L. infantum, and Crithidia fasciculata in Ny. whitmani, as well as L. amazonensis in Lu. longipalpis, Trypanosoma sp. and L. amazonensis in Pintomyia christenseni, and L. amazonensis in both Psathyromyia hermanlenti and Evandromyia walkeri. MAIN CONCLUSIONS These results show the importance of gallery forests in maintaining Phlebotominae populations in the dry month, as well as their frequent occurrence in household units in the rainy month. This is the first study to identify Leishmania, Trypanosoma, and Crithidia species in Phlebotominae collected in Palmas, Tocantins, Brazil.
Subject(s)
Animals , Female , Psychodidae/classification , Psychodidae/parasitology , Leishmania/isolation & purification , Forests , Grassland , Insect VectorsABSTRACT
We analyzed the effect of the combination of citral, eugenol and thymol, respectively the main constituents of essential oils of Cympobogon citratus (DC) Stapf, Poaceae (lemon grass), Syzygium aromaticum (L.) Merr. & L.M. Perry, Myrtaceae (clove) and Thymus vulgaris L., Lamiaceae (thyme), on the proliferation of the trypanosomatids Crithidia fasciculata and Trypanosoma cruzi. The constituents were initially added individually at different concentrations to C. fasciculata cultures to estimate the IC50/24h. Concentrations in a triple combination were about 2 times and 16.5 times lower against C. fasciculata and T. cruzi, respectively, as compared to isolated compounds. Incubation of C. fasciculata with the trypanocydal agent benznidazole did not affect parasite growth at concentrations up to 500 µg/ml, but the IC50 of this drug against T. cruzi was 15.8 µg/ml, a value about 2-5 times higher than that of constituents in the triple combination. Analysis of treated C. fasciculata by scanning electron microscopy showed rounding of the cell body. Our data show that combination of essential oil constituents resulted in increased inhibitory activity on growth of both non-pathogenic and pathogenic trypanosomatid species and indicate that the non-patogenic C. fasciculata may represent a resistant model for drug screening in trypanosomatids.