Vertical stratification of sand fly diversity in relation to natural infections of Leishmania sp. and blood-meal sources in Jamari National Forest, Rondonia State, Brazil

Background: Almost 1000 cases of American cutaneous leishmaniasis have been registered yearly in Rondonia State, Brazil. Little is known about theLeishmaniatransmission cycle (vectors and reservoirs) in the state. This study aimed to evaluate sand fly fauna from two vertical stratification layers in order to identify potential vectors and their blood-meal sources. Methods: The study was conducted in Jamari National Forest. Sand flies were collected in the canopy (15 m) and at ground level (1 m) using HP light traps during four months, February, April, August and October, 2018. Insects were identified to the species level, and females were subjected to DNA extraction and PCR targeting minicirclekDNA andhsp70 (forLeishmaniadetection and species identification), andcytb(to identify blood-meal sources). Exploratory data analysis was used to determine mean of abundance and species richness between stratifications. Thehsp70 andcytbsequences were analyzed and compared with sequences from GenBank. Results: Overall, 68 species were identified from 15,457 individuals. On the Potosi trail, 7531 individuals of 49 species were collected; canopy captures totaled 6463 individuals of 46 species, while ground captures totaled 1068 individuals of 38 species. On the Santa Maria trail, 7926 individuals of 61 species were collected; canopy captures totaled 6136 individuals of 51 species, while ground captures totaled 1790 individuals of 53 species. A total of 23 pools were positive forkDNA (canopyn = 21, groundn = 2). Only two samples were sequenced forhsp70 (both in canopy); one sequence exhibited similarity withLeishmania braziliensis(Lutzomyia davisipool) and another withL. naiffi(Lu. antunesipool). Thecytbfragment was amplified in 11 of 86 samples. Sample sequencing identifiedcytbDNA from 5 blood-meal sources:Micrastur gilvicollis,Psophia viridis,Tamandua tetradactyla,Homo sapiensandCholoepus didactylus. Conclusions: Sand fly fauna is more diverse in the canopy than at ground level. Factors such as blood-meal sources, resting sites, and abiotic components probably contribute to high abundance in the canopy. Our results reinforce the possibility thatLu. antunesiandLu.davisiparticipate inLeishmaniatransmission in forest environments and may play an important role in transmission from sylvatic to human hosts.