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Parasites & Vectors May 2024Volatile organic compounds (VOCs) are chemicals emitted as products of cell metabolism, which reflects the physiological and pathological conditions of any living... (Review)
Review
Volatile organic compounds (VOCs) are chemicals emitted as products of cell metabolism, which reflects the physiological and pathological conditions of any living organisms. These compounds play a key role as olfactory cues for arthropod vectors such as mosquitoes, sand flies, and ticks, which act in the transmission of pathogens to many animal species, including humans. Some VOCs may influence arthropod behaviour, e.g., host preference and oviposition site selection for gravid females. Furthermore, deadly vector-borne pathogens such as Plasmodium falciparum and Leishmania infantum are suggested to manipulate the VOCs profile of the host to make them more attractive to mosquitoes and sand fly vectors, respectively. Under the above circumstances, studies on these compounds have demonstrated their potential usefulness for investigating the behavioural response of mosquitoes, sand flies, and ticks toward their vertebrate hosts, as well as potential tools for diagnosis of vector-borne diseases (VBDs). Herein, we provide an account for scientific data available on VOCs to study the host seeking behaviour of arthropod vectors, and their usefulness as attractants, repellents, or tools for an early diagnosis of VBDs.
Topics: Animals; Volatile Organic Compounds; Psychodidae; Ticks; Humans; Culicidae; Behavior, Animal; Vector Borne Diseases; Female; Mosquito Vectors; Plasmodium falciparum
PubMed: 38755646
DOI: 10.1186/s13071-024-06299-1 -
Parasites & Vectors Feb 2016Cutaneous Leishmaniasis (CL) is one of the most neglected tropical diseases in Morocco. Leishmania major and L. tropica are the main culprits identified in all endemic...
BACKGROUND
Cutaneous Leishmaniasis (CL) is one of the most neglected tropical diseases in Morocco. Leishmania major and L. tropica are the main culprits identified in all endemic foci across the country. These two etiological agents are transmitted by Phlebotomus papatasi and P. sergenti, the two most prevalent sand fly species in Morocco. Previous studies reflected gaps of knowledge regarding the environmental fingerprints that affect the distribution of these two potential vectors across Morocco.
METHODS
The sand flies were collected from 48 districts across Morocco using sticky paper traps. Collected specimens were preserved in 70% ethanol for further processing and identification. Male and female densities were calculated in each site to examine their relations to the environmental conditions across these sites. The study used 19 environmental variables including precipitation, aridity, elevation, soil variables and a composite representing maximum, minimum and mean of day- and night-time Land Surface Temperature (LST), and Normalized Difference Vegetation Index (NDVI).
RESULTS
A total of 11,717 specimens were collected during this entomological survey. These specimens represented 11 species of two genera; Phlebotomus and Sergentomyia. Correlations of the sand fly densities with the environmental variables were estimated to identify the variables which influence the distribution of the two potential vectors, Phlebotomus papatasi and P. sergenti, associated with all CL endemic foci across the country. The density of P. papatasi was most affected by temperature changes. The study showed a significant positive correlation between the densities of both sexes of P. papatasi and night-time temperatures. Both P. papatasi and P. sergenti showed a negative correlation with aridity, but, such correlation was only significant in case of P. papatasi. NDVI showed a positive correlation only with densities of P. sergenti, while, soil PH and soil water stress were negatively correlated with the densities of both males and females of only P. papatasi.
CONCLUSIONS
Our results identified the sand fly species across all CL endemic sites and underlined the influences of night-time temperature, soil water stress and NDVI as the most important variables affecting the sand fly distribution in all sampled sites. This preliminary study considered the importance of these covariates to anticipate the potential distribution of P. papatasi and P. sergenti in Morocco.
Topics: Animals; Ecology; Endemic Diseases; Female; Leishmaniasis, Cutaneous; Male; Morocco; Phlebotomus; Phylogeography; Psychodidae
PubMed: 26830689
DOI: 10.1186/s13071-016-1343-6 -
Parasites & Vectors Jan 2019The leishmaniases are important neglected diseases caused by Leishmania spp. which are transmitted by sand flies, Lutzomyia longipalpis being the main vector of visceral...
Wolbachia introduction into Lutzomyia longipalpis (Diptera: Psychodidae) cell lines and its effects on immune-related gene expression and interaction with Leishmania infantum.
BACKGROUND
The leishmaniases are important neglected diseases caused by Leishmania spp. which are transmitted by sand flies, Lutzomyia longipalpis being the main vector of visceral leishmaniasis in the Americas. The methodologies for leishmaniasis control are not efficient, causing 1.5 million reported cases annually worldwide, therefore showing the need for development of novel strategies and interventions to control transmission of the disease. The bacterium Wolbachia pipientis is being used to control viruses transmitted by mosquitoes, such as dengue and Zika, and its introduction in disease vectors has been effective against parasites such as Plasmodium. Here we show the first successful establishment of Wolbachia into two different embryonic cell lines from L. longipalpis, LL-5 and Lulo, and analysed its effects on the sand fly innate immune system, followed by in vitro Leishmania infantum interaction.
RESULTS
Our results show that LL-5 cells respond to wMel and wMelPop-CLA strains within the first 72 h post-infection, through the expression of antimicrobial peptides and inducible nitric oxide synthase resulting in a decrease of Wolbachia detection in the early stages of infection. In subsequent passages, the wMel strain was not able to infect any of the sand fly cell lines while the wMelPop-CLA strain was able to stably infect Lulo cells and LL-5 at lower levels. In Wolbachia stably infected cells, the expression of immune-related genes involved with downregulation of the IMD, Toll and Jak-Stat innate immune pathways was significantly decreased, in comparison with the uninfected control, suggesting immune activation upon Wolbachia transinfection. Furthermore, Wolbachia transinfection did not promote a negative effect on parasite load in those cells.
CONCLUSIONS
Initial strong immune responses of LL5 cells might explain the inefficiency of stable infections in these cells while we found that Lulo cells are more permissive to infection with Wolbachia causing an effect on the cell immune system, but not against in vitro L. infantum interaction. This establishes Lulo cells as a good system for the adaptation of Wolbachia in L. longipalpis.
Topics: Animals; Cell Line; Gene Expression; Immunity, Innate; Immunologic Factors; Leishmania infantum; Microbial Interactions; Parasite Load; Psychodidae; Wolbachia
PubMed: 30646951
DOI: 10.1186/s13071-018-3227-4 -
Medecine Tropicale Et Sante... Sep 2021Professor Jean-Antoine Rioux (1925-2017) has spent much of his long and fruitful scientific career exploring and understanding the functioning of leishmaniasis foci in...
BACKGROUND
Professor Jean-Antoine Rioux (1925-2017) has spent much of his long and fruitful scientific career exploring and understanding the functioning of leishmaniasis foci in several regions of the Mediterranean, the Near and Middle East and Africa. Phlebotomine sand flies study was an important part of his work in the foci studied and a large number of specimens have been collected by himself and stored in his collection, detailed in this note.
MATERIALS AND METHODS
His collection has been completely inventoried. Phlebotomine sand flies have been classified here by species and by country. Each specimen is mounted individually between slide and cover-slip in Canada balsam.
RESULTS
The collection includes 130 840 specimens coming from 10 countries: France (mainland and Corsica), Italy, Spain, Algeria, Tunisia, Morocco, Yemen, Syria, Sudan, and Republic of Congo. These specimens belong to 26 species: () () () () () () () () () () () () () () () () () () () () () () () () () and
DISCUSSION
The collection was transferred to the Platform of Reims Biological Resource Centers (PF CRBs Reims) located at the Biology Department of the Reims University Hospital in order to be curated and stored physically and electronically in a secure manner. In a near future, it will be made available to scientists wishing to access it for all purposes.In addition to and topotypes, the collection includes many specimens from North Africa, mainly from Morocco (53% of the collection is originated from this country where Professor Rioux worked during 30 years) but also specimens from Syria or Yemen, the interest of which is obvious given the current geopolitical context.
Topics: Animals; Humans; Middle East; Phlebotomus; Psychodidae; Tunisia; Yemen
PubMed: 35686165
DOI: 10.48327/mtsibulletin.2021/127 -
Cell Host & Microbe Jan 2018The Leishmania parasite is transmitted via the bite of a sand fly. In this issue of Cell Host & Microbe, Dey et al. (2018) report that sand fly gut microbiota are also...
The Leishmania parasite is transmitted via the bite of a sand fly. In this issue of Cell Host & Microbe, Dey et al. (2018) report that sand fly gut microbiota are also transferred to the bite site, promoting neutrophil recruitment and parasite dissemination to distal organs.
Topics: Animals; Gastrointestinal Microbiome; Humans; Insect Vectors; Leishmania; Psychodidae
PubMed: 29324232
DOI: 10.1016/j.chom.2017.12.016 -
Proceedings of the National Academy of... Nov 2018Blood-sucking phlebotomine sand flies (Diptera: Psychodidae) transmit leishmaniasis as well as arboviral diseases and bartonellosis. Sand fly females become infected...
Blood-sucking phlebotomine sand flies (Diptera: Psychodidae) transmit leishmaniasis as well as arboviral diseases and bartonellosis. Sand fly females become infected with parasites and transmit them while imbibing vertebrates' blood, required as a source of protein for maturation of eggs. In addition, both females and males consume plant-derived sugar meals as a source of energy. Plant meals may comprise sugary solutions such as nectar or honeydew (secreted by plant-sucking homopteran insects), as well as phloem sap that sand flies obtain by piercing leaves and stems with their needle-like mouthparts. Hence, the structure of plant communities can influence the distribution and epidemiology of leishmaniasis. We designed a next-generation sequencing (NGS)-based assay for determining the source of sand fly plant meals, based upon the chloroplast DNA gene ribulose bisphosphate carboxylase large chain (). Here, we report on the predilection of several sand fly species, vectors of leishmaniasis in different parts of the world, for feeding on We infer this preference based on the substantial percentage of sand flies that had fed on plants despite the apparent "absence" of these plants from most of the field sites. We discuss the conceivable implications of the affinity of sand flies for on their vectorial capacity for and the putative exploitation of their attraction to for the control of sand fly-borne diseases.
Topics: Animals; Behavior, Animal; Cannabis; Female; Herbivory; Insect Vectors; Leishmania; Leishmaniasis; Male; Psychodidae; Sex Factors
PubMed: 30373823
DOI: 10.1073/pnas.1810435115 -
PLoS Neglected Tropical Diseases Aug 2021The scarce information about breeding sites of phlebotomines limits our understanding of the epidemiology of tegumentary leishmaniasis. Identifying the breeding sites...
The scarce information about breeding sites of phlebotomines limits our understanding of the epidemiology of tegumentary leishmaniasis. Identifying the breeding sites and seasons of immature stages of these vectors is essential to propose prevention and control strategies different from those targeting the adult stage. Here we identified the rural breeding environments of immature stages of Ny. whitmani, vector species of Leishmania braziliensis in the north of Misiones province, Argentina; then we determined and compared the environmental and structural characteristics of those sites. We also identified the season of greatest emergence and its relationship with adult abundance. During a first collection period, between 28 and 48 emergence traps were set continuously for 16 months in six environments of the farm peridomicile and domicile: below house, chicken shed, experimental chicken shed, forest edge, pigsty and under fruit tree. Traps were checked and rotated every 40 nights. A total of 146 newly emerged individuals were collected (93.8% of them were Ny. whitmani), totaling an effort of 23,040 emergence trap-nights. The most productive environments were chicken shed and below house, and the greatest emergence was recorded in spring and summer. During a second collection period, emergence traps and light traps for adult capture were placed in the chicken shed and below house environments of eight farms. Emergence traps were active continuously during spring, summer, and early autumn. Environmental and structural characteristics of each environment were recorded. A total of 84 newly emerged phlebotomines (92.9% Ny. whitmani; 72,144 emergence trap-nights) and 13,993 adult phlebotomines (147 light trap-nights) were recorded in the chicken shed and below house environments. A positive correlation was also observed between trap success of newly emerged phlebotomines and of adults after 120 days. A high spatial variability was observed in the emergence of Ny. whitmani, with the number of newly emerged individuals being highest in soils of chicken sheds with the highest number of chickens and closest to forest edge. Moreover, below house was found to be as important as chicken sheds as breeding sites of Ny. whitmani. Management of the number of chickens in sheds, soil moisture and pH, and the decision of where to localize the chicken sheds in relation to the houses and the forest edge, might contribute to reduce the risk of human vector exposure and transmission of Leishmania.
Topics: Animals; Argentina; Breeding; Chickens; Female; Insect Vectors; Leishmania; Leishmaniasis; Male; Psychodidae; Seasons
PubMed: 34411102
DOI: 10.1371/journal.pntd.0009676 -
Journal of Vector Ecology : Journal of... Jun 2020The richness and abundance of sand fly species were studied in northeastern Brazil in areas of leishmaniasis transmission. The study was carried out in two forest areas...
The richness and abundance of sand fly species were studied in northeastern Brazil in areas of leishmaniasis transmission. The study was carried out in two forest areas with different deforestation times for agricultural and livestock activities: one modified by long-term settlement (more than 50 years of occupation) and another less impacted by short-term settlement (10 years). The sand flies were captured with CDC light traps from 18:00 to 06:00 for three consecutive nights, once a month, from May, 2012 to April, 2014. The study captured 21,708 specimens and also 33 species of Lutzomyia and two of Brumptomyia. Species richness and abundance were higher in the more conserved area of short-term occupation (31 species; 61.7%) than in the more degraded area with long-term occupation (17 species; 38.3%). In the most conserved area, the species richness was higher in the forest fragment than in the rural settlement, whereas in the degraded area the richness was higher in the peri-domicile than in the forest. The diversity was higher in the degraded area forest. There were significant statistical differences when comparing the means of total abundance with the intra-domicile, peri-domicile, and forest environments. The average abundance was statistically higher in the peri-domicile compared to the forest (p = 0.009), but there were no statistically significant differences between intra-domicile-peri-domicile (p = 0.11) and forest-intra-domicile (p = 0.87). In conclusion, a change in vegetation cover negatively affects the richness and abundance of sand flies in the natural environment.
Topics: Animals; Brazil; Ecology; Forests; Psychodidae; Tropical Climate
PubMed: 32492277
DOI: 10.1111/jvec.12376 -
Parasites & Vectors Jan 2015Identification of the microflora of the sand fly gut and the environmental distribution of these bacteria are important components for paratransgenic control of...
BACKGROUND
Identification of the microflora of the sand fly gut and the environmental distribution of these bacteria are important components for paratransgenic control of Leishmania transmission by sand flies.
METHODS
Biotic and abiotic bacterial communities of four compartments of a hyper-endemic focus of Zoonotic Cutaneous Leishmaniasis (ZCL) were investigated using 16S ribosomal DNA sequencing and phylogenetic tree construction. These compartments include Phlebotomus papatasi's gut, skin and intestinal tract of great gerbil Rhombomys opimus, the gerbil nest supplies, and plant food sources of the vectors and reservoirs.
RESULTS
Sequence homology analysis using nine available 16S rDNA data bases revealed 40, 24, 15 and 14 aerobic bacterial species from the vector guts, the gerbil bodies, the gerbil nests, and the plants, respectively. The isolated bacteria belong to wide ranges including aerobic to facultative anaerobic, pathogen to commensals, sand fly oviposition inducers, land to air and ocean habitats, animal and human probiotics, and plant growth-promoting rhizobacteria. Matching data analysis suggested that the adult P. papatasi gut bacteria could be acquired from three routes, adult sugar feeding on the plant saps, adult blood feeding on the animal host, and larval feeding from nest supplies. However, our laboratory experiment showed that none of the bacteria of the reservoir skin was transmitted to female sand fly guts via blood feeding. The microflora of sand fly guts were associated with the sand fly environment in which the predominant bacteria were Microbacterium, Pseudomonas, and Staphylococcus in human dwellings, cattle farms, and rodent colonies, respectively. Staphylococcus aureus was the most common bacterium in sand fly guts. Presence of some sand fly ovipoisition inducers such Bacillus spp. and Staphylococcus saprophyticus support association between gut flora and oviposition induction.
CONCLUSIONS
Results of this study showed that Bacillus subtilis and Enterobacter cloacae particularly subsp. dissolvens are circulated among the sand fly guts, the plants, and the sand fly larval breeding places and hence are possible candidates for a paratransgenic approach to reduce Leishmania transmission.
Topics: Animals; Bacteria; Cattle; Disease Reservoirs; Female; Gastrointestinal Tract; Gerbillinae; Humans; Iran; Leishmania; Leishmaniasis, Cutaneous; Male; Oviposition; Plants; Psychodidae
PubMed: 25630498
DOI: 10.1186/s13071-014-0517-3 -
Parasites & Vectors Aug 2023The successful use of semiochemicals to attract insects to traps is based on research on the most suitable compounds and their release profiles over time. Based on the...
BACKGROUND
The successful use of semiochemicals to attract insects to traps is based on research on the most suitable compounds and their release profiles over time. Based on the group's promising results, matrices with a more adequate release profile and more eco-friendly properties for the release of 1-hexanol were developed. To use a more suitable prototype in the field, the most promising systems were added to a capsule and evaluated in a wind tunnel. Behavioral experiments were performed using the sand fly species, Lutzomyia longipalpis, to evaluate the efficacy of the proposed system.
METHODS
Different delivery systems were developed by varying the polymer (gellan gum and pectin) ratio, crosslinker (aluminum chloride) concentration, and glutaraldehyde removal.The delivery systems were loaded with 1-hexanol, and their release profiles were evaluated using gravimetric analysis under ambient and high-humidity conditions. When the matrix system was placed inside a plastic container, modulations in the active release profile were observed and the system could be reused. Actid attraction behaviors of the sand fly species, Lu. longipalpis, were evaluated in a wind tunnel when exposed to 1-hexanol-loaded release systems at different times.
RESULTS
Among the four formulations evaluated, System 2 (gellan gum and pectin in a 1:1 ratio with 5% aluminum chloride) exhibited the most promising release profile, with greater uniformity and longer compound release time. The maximum 1-hexanol release uniformity was achieved over a longer time, mainly every 24 h, under both ambient and high-humidity conditions. System 2 can be reused at least once with the same structure. The wind tunnel trials exhibited efficient activation and attraction of Lu. longipalpis to 1-hexanol after 24, 48, and 72 h in System 2 placed inside the capsules.
CONCLUSIONS
The polymeric matrix supplemented with 1-hexanol and introduced in plastic capsules showed promising results in attracting sand flies. This system can be used as a solution for other attractive compounds as well as in other applications where their release needs to be controlled or prolonged.
Topics: Animals; Psychodidae; Aluminum Chloride; Capsules; Polymers; Phlebotomus; Plastics; Pectins
PubMed: 37644584
DOI: 10.1186/s13071-023-05931-w