Sand fly behavior: much more than weak-flying

Nocturnal activity and forestry-urban dispersal of phlebotomine sand flies (Diptera: Psychodidae) from an ecotourism park in Amazonian Brazil

Phlebotomine sand flies are insects of notorious importance in public health, mainly due to their involvement in the transmission of Leishmania protozoa. Their flight activity occurs predominantly in the twilight/night period, being stimulated mainly by the need to search for food and reproduction. Despite being naturally wild, some species are able to invade anthropized environments. Present work aimed to assess the nocturnal activity and forestry-urban dispersal of phlebotomine sand flies from an ecotourism park in Belém, Amazonian Brazil. The study area comprised a horizontal transect, extending from a forest park to the neighboring urban environment, in Belém. Sampling was conducted with night-operating light traps. Nocturnal activity was assessed through time-set captures with a collection bottle rotator in the forest environment. Dispersal was assessed through captures carried out along the transect, starting from the forest edge (0 m), extending to the urban environment (50-200 m), phlebotomine sand flies were identified. Abundance, richness, diversity, and sampling sufficiency were estimated. Fourteen species were recorded in the surveyed environments, with Nyssomyia antunesi, Trichophoromyia brachipyga, and Trichophoromyia ubiquitalis being the most abundant. Nocturnal activity behavior of Ny. antunesi occurred between 8 PM and 4 AM while that of Th. brachipyga and Th. ubiquitalis occurred between 2 AM and 6 AM. In the urban environment, the 150 m site presented the highest abundance. Bichromomyia flaviscutellata was sampled in all sites. Gravid females of Pressatia choti and Bi. flaviscutellata were sampled in the urban environment. Putative differential activity between the species herein assessed and their urban dispersal observed are worthy of note, adding data for supporting vector surveillance at a local scale.

Ecological setting of phlebotomine sand flies in the Republic of Kosovo

Sand flies (Diptera, Psychodidae) are the principal vectors of Leishmania spp., the causative agents of leishmaniasis, as well as phleboviruses. In the Balkans, the endemicity and spreading of sand fly-borne diseases are evident, particularly in the Republic of Kosovo, a country with a predominantly humid continental climate. To date, understanding the drivers behind the spatial structure and diversity patterns of sand fly communities in humid continental regions remains limited. Therefore, elucidating the geographical and ecological factors contributing to the presence of potential vector species in the country is crucial. We aimed to enhance our understanding of factors influencing sand fly occurrence in cool and wet wintering humid continental areas, which could serve as a model for other countries with similar climatic conditions. Therefore, we assessed the currently known sand fly fauna through detailed environmental analyses, including Voronoi tessellation patterns, entropy calculations, Principal Coordinate and Component Analyses, Hierarchical Clustering, Random Trees, and climatic suitability patterns. Notable differences in the ecological tolerance of the species were detected, and the most important climatic features limiting sand fly presence were wind speed and temperature seasonality. Sand flies were observed to prefer topographical environments with little roughness, and the modelled climatic suitability values indicated that, dominantly, the western plain regions of Kosovo harbour the most diverse sand fly fauna; and are the most threatened by sand fly-borne diseases. Phlebotomus neglectus and P. perfiliewi, both confirmed vectors for L. infantum and phleboviruses, were identified as two main species with vast distribution in Kosovo. Contrary to this, most other present species are relatively sparse and restricted to temperate rather than humid continental regions. Our findings reveal a diverse potential sand fly fauna in Kosovo, indicating the need for tailored strategies to address varying risks across the country's western and eastern regions in relation to leishmaniasis control amidst changing environmental conditions.

Overview and Approaches for Handling of Animal Models of Leishmaniasis

Leishmaniasis, a disease of global relevance, results from infection with the protozoan parasite, Leishmania, which is transmitted to susceptible hosts through the bite of sand flies. Multiple forms of leishmaniasis may occur, including cutaneous, mucocutaneous, and visceral. Research with animal models remains an important approach to help define basic pathophysi- ologic processes associated with infection and disease. In this regard, mice and hamsters represent the most commonly used models. The severity of leishmaniasis in animal models depends on several factors, including genotype of the host and parasite and the dose and route of administration of the parasite to the host, and severity of outcome may range from subclinical to severe illness. This review provides basic background on leishmaniasis, relevant animal models, the pathophysiology and clinical signs in animals used as models of leishmaniasis, and general approaches to mitigate risk to personnel.

An optical system to detect, surveil, and kill flying insect vectors of human and crop pathogens

Sustainable and effective means to control flying insect vectors are critically needed, especially with widespread insecticide resistance and global climate change. Understanding and controlling vectors requires accurate information about their movement and activity, which is often lacking. The Photonic Fence (PF) is an optical system that uses machine vision, infrared light, and lasers to identify, track, and interdict vectors in flight. The PF examines an insect's outline, flight speed, and other flight parameters and if these match those of a targeted vector species, then a low-power, retina-safe laser kills it. We report on proof-of-concept tests of a large, field-sized PF (30 mL × 3 mH) conducted with Aedes aegypti, a mosquito that transmits dangerous arboviruses, and Diaphorina citri, a psyllid which transmits the fatal huanglongbing disease of citrus. In tests with the laser engaged, < 1% and 3% of A. aegypti and D. citri, respectfully, were recovered versus a 38% and 19% recovery when the lacer was silenced. The PF tracked, but did not intercept the orchid bee, Euglossa dilemma. The system effectively intercepted flying vectors, but not bees, at a distance of 30 m, heralding the use of photonic energy, rather than chemicals, to control flying vectors.

Reconstructing the post-glacial spread of the sand fly Phlebotomus mascittii Grassi, 1908 (Diptera: Psychodidae) in Europe

Phlebotomine sand flies (Diptera: Phlebotominae) are the principal vectors of Leishmania spp. (Kinetoplastida: Trypanosomatidae). In Central Europe, Phlebotomus mascittii is the predominant species, but largely understudied. To better understand factors driving its current distribution, we infer patterns of genetic diversity by testing for signals of population expansion based on two mitochondrial genes and model current and past climate and habitat suitability for seven post-glacial maximum periods, taking 19 climatic variables into account. Consequently, we elucidate their connections by environmental-geographical network analysis. Most analyzed populations share a main haplotype tracing back to a single glacial maximum refuge area on the Mediterranean coasts of South France, which is supported by network analysis. The rapid range expansion of Ph. mascittii likely started in the early mid-Holocene epoch until today and its spread possibly followed two routes. The first one was through northern France to Germany and then Belgium, and the second across the Ligurian coast through present-day Slovenia to Austria, toward the northern Balkans. Here we present a combined approach to reveal glacial refugia and post-glacial spread of Ph. mascittii and observed discrepancies between the modelled and the current known distribution might reveal yet overlooked populations and potential further spread.