scholarly journals Molecular signatures of sexual communication in the phlebotomine sand flies

2020 ◽  
Vol 14 (12) ◽  
pp. e0008967
Author(s):  
Paul V. Hickner ◽  
Nataliya Timoshevskaya ◽  
Ronald J. Nowling ◽  
Frédéric Labbé ◽  
Andrew D. Nguyen ◽  
...  

Phlebotomine sand flies employ an elaborate system of pheromone communication wherein males produce pheromones that attract other males to leks (thus acting as an aggregation pheromone) and females to the lekking males (sex pheromone). In addition, the type of pheromone produced varies among populations. Despite the numerous studies on sand fly chemical communication, little is known of their chemosensory genome. Chemoreceptors interact with chemicals in an organism’s environment to elicit essential behaviors such as the identification of suitable mates and food sources. Thus, they play important roles during adaptation and speciation. Major chemoreceptor gene families, odorant receptors (ORs), gustatory receptors (GRs) and ionotropic receptors (IRs) together detect and discriminate the chemical landscape. Here, we annotated the chemoreceptor repertoire in the genomes of Lutzomyia longipalpis and Phlebotomus papatasi, major phlebotomine vectors in the New World and Old World, respectively. Comparison with other sequenced Diptera revealed a large and unique expansion where over 80% of the ~140 ORs belong to a single, taxonomically restricted clade. We next conducted a comprehensive analysis of the chemoreceptors in 63 L. longipalpis individuals from four different locations in Brazil representing allopatric and sympatric populations and three sex-aggregation pheromone types (chemotypes). Population structure based on single nucleotide polymorphisms (SNPs) and gene copy number in the chemoreceptors corresponded with their putative chemotypes, and corroborate previous studies that identified multiple populations. Our work provides genomic insights into the underlying behavioral evolution of sexual communication in the L. longipalpis species complex in Brazil, and highlights the importance of accounting for the ongoing speciation in central and South American Lutzomyia that could have important implications for vectorial capacity.

2020 ◽  
Author(s):  
Paul V. Hickner ◽  
Nataliya Timoshevskaya ◽  
RJ Nowling ◽  
Frédéric Labbé ◽  
Andrew D. Nguyen ◽  
...  

AbstractPhlebotomine sand flies employ an elaborate system of pheromone communication wherein males produce pheromones that attracts other males to leks (thus acting as aggregation pheromone) and females to the lekking males (sex pheromone). In addition, the type of pheromone produced varies among populations. Despite the numerous studies on sand fly chemical communication, little is known of their chemosensory genome. Chemoreceptors interact with chemicals in an organism’s environment to elicit essential behaviors such as the identification of suitable mates and food sources, thus, they play important roles during adaptation and speciation. Major chemoreceptor gene families, odorant receptors (ORs), gustatory receptors (GRs) and ionotropic receptors (IRs) together detect and discriminate the chemical landscape. Here, we annotated the chemoreceptor repertoire in the genomes of Lutzomyia longipalpis and Phlebotomus papatasi, major phlebotomine vectors in the New World and Old World, respectively. Comparison with other sequenced Diptera revealed a large and unique expansion where over 80% of the ~140 ORs belong to a single, taxonomically restricted clade. We next conducted comprehensive analysis of the chemoreceptors in 63 Lu. longipalpis individuals from four different locations in Brazil representing allopatric and sympatric populations and three aggregation-sex pheromone types (chemotypes). Population structure based on single nucleotide polymorphisms (SNPs) and gene copy number in the chemoreceptors corresponded with their putative chemotypes, and corroborate previous studies that identified multiple populations. Our work provides genomic insights into the underlying behavioral evolution of sexual communication in the L. longipalpis species complex in Brazil, and highlights the importance of accounting for the ongoing speciation in central and South American Lutzomyia that could have important implications for vectorial capacity.


2019 ◽  
Vol 56 (5) ◽  
pp. 1368-1376 ◽  
Author(s):  
Josiane V Lopes ◽  
Erika M Michalsky ◽  
Nathalia C L Pereira ◽  
Adão J V de Paula ◽  
Fabiana O Lara-Silva ◽  
...  

Abstract Among neglected tropical diseases, visceral leishmaniasis (VL) shows great relevance in global terms and is a serious public health concern due to the possibility of severe and lethal forms in humans. In this study, we evaluate entomological factors such as diversity and abundance of phlebotomine sand flies (Diptera:Psychodidae) and the Leishmania species circulating in these species in possible association with VL transmission in the Brazilian town Itaúna. The entomological collections were performed during three consecutive nights, always in the third week of each month, within a period of 12 mo. A total of 1,786 sand fly specimens were collected, from which 20% were collected inside houses. The influence of three local climatic variables (temperature, rainfall, relative humidity) on the population sizes of these insects was evaluated. Temperature was the most influential factor, with a significant positive correlation with the local population size of phlebotomine sand flies collected per month. Lutzomyia longipalpis (Lutz & Neiva, 1912) was the predominant species in the study area. Leishmania DNA was detected in nine out of 133 pools of sand fly females, using nested/PCR, which resulted in a minimal natural infection rate of 2.91%. DNA from Leishmania infantum Nicolle, 1908 (Kinetoplastida: Trypanosomatida), was detected in Evandromyia cortelezzii (Bréthes, 1923), Ev. evandroi (Costa, Lima & Antunes, 1936), Ev. lenti (Mangabeira, 1938), and Ev. termitophila (Martins, Falcão & Silva, 1964), besides Lu. longipalpis. Our study indicates favorable conditions for VL spreading in Itaúna due to the presence of Lu. longipalpis and Le. infantum-infected phlebotomine sand flies.


2020 ◽  
Author(s):  
Vanessa Barbosa ◽  
Cristian F Souza ◽  
Derek Gatherer ◽  
Reginaldo P Brazil ◽  
James Gordon Campbell Hamilton

Abstract Background: The sand fly, Lutzomyia longipalpis, is the main vector of Leishmania infantum in Brazil. A previous laboratory study showed that covering surfaces with insecticide-impregnated netting may provide an alternative method for killing sand flies. Synthetic male Lu. longipalpis sex/aggregation pheromone co-located with micro-encapsulated l-cyhalothrin demonstrated the potential of “lure-and-kill” to significantly reduce canine infection and sand fly densities. In this study we were interested to determine if insecticide impregnated netting could replace sprayed insecticide for Lu. longipalpis control.Methods: We placed synthetic pheromone in experimental and real chicken sheds treated with a 1m2 surface of either sprayed insecticide or insecticide-impregnated netting. Two experiments in experimental chicken sheds were carried out to determine the effect of the insecticide treatments on Lu. longipalpis over 1-week and 16-week periods. We counted the number of Lu. longipalpis collected overnight and dead at 24 hours. Two longitudinal intervention studies were carried in real chicken sheds and compared the numbers of Lu. longipalpis (collected and dead at 24h) before adding the intervention (either the netting or sprayed insecticide treatments) with the numbers collected 24h after the intervention. Results: In the first experiment all flies caught in the spray treated experimental chicken sheds were dead at 24 hours and in netting treated sheds 97% of females and 88% of males were dead at 24 hours (257 vs 225, Wilcoxon Signed Ranks Test P=0.043). The netting and spray treated traps were equally effective at killing both female and male Lu. longipalpis over the first 8-weeks however after 16-weeks both treatments killed a significantly lower proportion of females (64%vs 96%; P=0.000) and males 89%vs 100%; P=0.000) compared to the beginning. In the first of the longitudinal studies in real chicken sheds only the netting intervention significantly increased the proportion of females dead after 24h (60%vs81%; P=0.042). The subsequent study showed that both netting and spraying treatments had similarly significant impacts on the proportion of females dead after 24h (netting: 60%vs80%: P=0.0194 and spraying: 43%vs72%: P=0.0004).Conclusions: The netting and spray insecticide interventions (with synthetic sex/aggregation pheromone) have similar impacts on the Lu. longipalpis population.


2019 ◽  
Author(s):  
Aldenise Martins Campos ◽  
Rodrigo dos Anjos Maia ◽  
Débora Capucci ◽  
Adriano Pereira Paglia ◽  
José Dilermando Andrade Filho

AbstractCaves, though seemingly inhospitable due to the lack of light in areas furthest from the cave entrance and the low availability and variety of resources, can harbor many species of vertebrates and invertebrates, including phlebotomine sand flies, the vectors of species of parasites of the genus Leishmania that cause leishmaniasis. This study aimed to evaluate the species composition of sand flies in located caves at Moeda Sul (MS) and Parque Estadual Serra do Rola Moça (PESRM), in southeastern Brazil at region of the Quadrilátero Ferrífero, state of Minas Gerais. The collections of sand flies were performed with automatic light traps. Were used the Non-Metric Multidimensional Scaling based on dissimilarity matrix calculated with the Jaccard índex and Multivariate Analysis of Permutation to evaluate similarity of the species composition of sand flies among entrance, interior, and surroundings environments of each sampled cave at MS and PESRM, and thus to infer biological mechanisms from the patterns of distribution of sand flies among these different cave environments. A total of 375 phlebotomine sand flies were collected from six genera and 14 species. The most abundant species were Evandromyia tupynambai (54.7%), Brumptomyia troglodytes (25.6%), Evandromyia edwardsi, (6.1%) Psathyromyia brasiliensis (4.8%) and Lutzomyia longipalpis (4.3%). In place MS, 30 individuals were collected, 16 inside the MS cave and 14 its surroundings. In place PESRM, five individuals were collected in surroundings of RM38 cave; a total of 190 individuals at RM39 cave (48 in the cave and 142 its surroundings) and 150 individuals at RM40 cave, 42 in the cave and 108 its surroundings. Our results showed rich fauna of sand flies with a species composition of sand flies similar among the entrance, interior, and surroundings environments of each sampled cave, suggesting that both caves and their surroundings are important for the maintenance of sand fly communities.


2015 ◽  
Vol 2015 ◽  
pp. 1-9 ◽  
Author(s):  
Rosana Silva Lana ◽  
Érika Monteiro Michalsky ◽  
Consuelo Latorre Fortes-Dias ◽  
João Carlos França-Silva ◽  
Fabiana de Oliveira Lara-Silva ◽  
...  

In the New World, the leishmaniases are primarily transmitted to humans through the bites ofLeishmania-infectedLutzomyia(Diptera: Psychodidae) phlebotomine sand flies. Any or both of two basic clinical forms of these diseases are endemic to several cities in Brazil—the American cutaneous leishmaniasis (ACL) and the American visceral leishmaniasis (AVL). The present study was conducted in the urban area of a small-sized Brazilian municipality (Jaboticatubas), in which three cases of AVL and nine of ACL have been reported in the last five years. Jaboticatubas is an important tourism hub, as it includes a major part of the Serra do Cipó National Park. Currently, no local data is available on the entomological fauna or circulatingLeishmania. During the one-year period of this study, we captured 3,104 phlebotomine sand flies belonging to sixteenLutzomyiaspecies. In addition to identifying incriminated or suspected vectors of ACL with DNA of the etiological agent of AVL and vice versa, we also detectedLeishmaniaDNA in unexpectedLutzomyiaspecies. The expressive presence of vectors and naturalLeishmaniainfection indicates favorable conditions for the spreading of leishmaniases in the vicinity of the Serra do Cipó National Park.


2021 ◽  
Vol 17 (3) ◽  
pp. e1009354
Author(s):  
Monica E. Staniek ◽  
James G. C. Hamilton

Globally visceral leishmaniasis (VL) causes thousands of human deaths every year. In South America, the etiologic agent, Leishmania infantum, is transmitted from an infected canine reservoir to human hosts by the bite of the sand fly vector; predominantly Lutzomyia longipalpis. Previous evidence from model rodent systems have suggested that the odour of infected hosts is altered by the parasite making them more attractive to the vector leading to an increased biting rate and improved transmission prospects for the pathogen. However, there has been no assessment of the effect of Le infantum infection on the attractiveness of dogs, which are the natural reservoirs for human infection. Hair collected from infected and uninfected dogs residing in a VL endemic city in Brazil was entrained to collect the volatile chemical odours present in the headspace. Female and male Lu. longipalpis sand flies were offered a choice of odour entrained from infected and uninfected dogs in a series of behavioural experiments. Odour of uninfected dogs was equally attractive to male or female Lu. longipalpis when compared to a solvent control. Female Lu. longipalpis were significantly more attracted to infected dog odour than uninfected dog odour in all 15 experimental replicates (average 45.7±0.87 females attracted to infected odour; 23.9±0.82 to uninfected odour; paired T-test, P = 0.000). Male Lu. longipalpis did not significantly prefer either infected or uninfected odour (average 36.1±0.4 males to infected odour; 35.7±0.6 to uninfected odour; paired T-test, P = 0.722). A significantly greater proportion of females chose the infected dog odour compared to the males (paired T-test, P = 0.000). The results showed that the odour of dogs infected with Le. infantum was significantly more attractive to blood-seeking female sand flies than it was to male sand flies. This is strong evidence for parasite manipulation of the host odour in a natural transmission system and indicates that infected dogs may have a disproportionate significance in maintaining infection in the canine and human population.


2021 ◽  
Vol 2 ◽  
Author(s):  
Erich Loza Telleria ◽  
Daisy Aline Azevedo-Brito ◽  
Barbora Kykalová ◽  
Bruno Tinoco-Nunes ◽  
André Nóbrega Pitaluga ◽  
...  

Phlebotomine sand flies (Diptera, Psychodidae) belonging to the Lutzomyia genus transmit zoonoses in the New World. Lutzomyia longipalpis is the main vector of Leishmania infantum, which is the causative agent of visceral leishmaniasis in Brazil. To identify key molecular aspects involved in the interaction between vector and pathogens and contribute to developing disease transmission controls, we investigated the sand fly innate immunity mediated by the Janus kinase/signal transducer and activator of transcription (Jak-STAT) pathway in response to L. infantum infection. We used two study models: L. longipalpis LL5 embryonic cells co-cultured with L. infantum and sand fly females artificially infected with the parasite. We used qPCR to follow the L. longipalpis gene expression of molecules involved in the Jak-STAT pathway. Also, we modulated the Jak-STAT mediated immune response to understand its role in Leishmania parasite infection. For that, we used RNAi to silence the pathway regulators, protein inhibitor of activated STATs (PIAS) in LL5 cells, and STAT in adult females. In addition, the pathway suppression effect on parasite development within the vector was assessed by light microscopy in late-phase infection. The silencing of the repressor PIAS in LL5 cells led to a moderate increase in a protein tyrosine phosphatase 61F (PTP61F) expression. It suggests a compensatory regulation between these two repressors. L. infantum co-culture with LL5 cells upregulated repressors PIAS, suppressor of cytokine signaling (SOCS), and PTP61F. It also downmodulated virus-induced RNA-1 (VIR-1), a pathway effector, indicating that the parasite could repress the Jak-STAT pathway in LL5 cells. In Leishmania-infected L. longipalpis females, STAT and the antimicrobial peptide attacin were downregulated on the third day post-infection, suggesting a correlation that favors the parasite survival at the end of blood digestion in the sand fly. The antibiotic treatment of infected females showed that the reduction of gut bacteria had little effect on the Jak-STAT pathway regulation. STAT gene silencing mediated by RNAi reduced the expression of inducible nitric oxide synthase (iNOS) and favored Leishmania growth in sand flies on the first day post-infection. These results indicate that STAT participated in the iNOS regulation with subsequent effect on parasite survival.


2018 ◽  
Vol 2018 ◽  
pp. 1-7 ◽  
Author(s):  
Gabriella Gaglio ◽  
Ettore Napoli ◽  
Francesca Arfuso ◽  
Jessica Maria Abbate ◽  
Salvatore Giannetto ◽  
...  

Light traps represent the most used attractive system to collect and monitor phlebotomine sand flies. Recent studies have suggested that light traps can be easily upgraded by the use of light-emitting diode (LED) with positive effects on trap design, weight, and battery life. However, scant data on the effect of different LED colours on the attractiveness to phlebotomine sand fly species are available in literature. In this study, the capture performances of light traps equipped with different LED colours on phlebotomine sand fly species indigenous in the Mediterranean area were evaluated. Phlebotomine sand fly collections were performed using a classical light trap (CLT), equipped with a traditional incandescent lamp, and five Laika 4.0 light traps supplied, each with LED of different colours and wavelengths: (i) white; (ii) red; (iii) green; (iv) blue; (v) UV. Light traps were set for three consecutive nights fortnightly from May to October 2017 and climate data recorded using a meteorological station. A total of 411 phlebotomine sand flies (191 males and 220 females), belonging to three different species, namely, Phlebotomus perniciosus (n= 298, 141 males and 157 females), Sergentomyia minuta (n=110, 48 males and 62 females), and Phlebotomus neglectus (n=3, 2 males and 1 females) were collected. Abundance of capture was influenced by colours of LED and time. The highest number of phlebotomine sand flies was captured on June (P<0.01) and by UV LED (P<0.01). As regard to species, P. perniciosus was mainly captured by UV LED on June (P<0.01). No effect of time (P>0.05) or LED colour (P>0.05) was recorded for S. minuta and P. neglectus. According to the results of the present study light trap equipped with UV LED can represent an effective tool for the capture of sand fly species in the Mediterranean area.


2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Wilfredo Sosa-Ochoa ◽  
Javier Varela Amador ◽  
Yokomi Lozano-Sardaneta ◽  
Gabriela Rodriguez Segura ◽  
Concepcion Zúniga Valeriano ◽  
...  

Abstract Background The two most abundant sand fly species on the Honduran Pacific coast are Lutzomyia (Lutzomyia) longipalpis and Pintomyia (Pifanomyia) evansi. Both species are known vectors of Leishmania (Leishmania) infantum, the etiological agent of visceral leishmaniasis (VL) in the Americas. Although VL and non-ulcerative cutaneous leishmaniasis (NUCL) are endemic on the Pacific versant of the Central American Pacific, the latter is the most frequent manifestation of leishmaniasis there. We evaluated the circulation of Leishmania spp. in the sand fly species on El Tigre Island, an endemic area of NUCL. Results We collected 222 specimens of six sand fly species. Lu. longipalpis (180 specimens; 81%) and Pif. (Pi.) evansi (35 specimens; 16%) were the most abundant species. L. (L.) infantum DNA was detected in nine of the 96 specimens analyzed; seven of these specimens were identified as Lu. longipalpis, and the remaining two were Pi.evansi, with an infection rate of 9.4% and 2.7%, respectively. Conclusion We present the first record of L. (L.) infantum DNA in Pi.evansi from a NUCL endemic region of Central America. Our results suggest that Pi. evansi could be a secondary vector of L. (L.) infantum in the transmission cycle of leishmaniasis. The detection of natural infections of L. (L.) infantum in sand flies in this region contributes to an understanding of the epidemiology of leishmaniasis in Honduras.


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