Experimental infections and co-infections with Leishmania braziliensis and Leishmania infantum in two sand fly species, Lutzomyia migonei and Lutzomyia longipalpis

Some epidemiological aspects of leishmaniasis in the municipality of Formiga, Brazil, an important touristic site, were evaluated. Those included phlebotomine sand fly vectors, canine infection, and geoprocessing analysis for determining critical transmission areas. Sand flies (224 insects) belonging to ten different species were captured. The most captured species includedLutzomyia longipalpis(35.3%),Lutzomyia cortelezzii(33.5%), andLutzomyia whitmani(18.3%). A significant correlation between sand fly densities and climatic conditions was detected. Serological diagnosis (DPP and ELISA) was performed in 570 dogs indicating a prevalence of 5.8%. After sequencing the main species circulating in the area wereLeishmania infantumandLeishmania braziliensis. Spatial analysis demonstrated that vegetation and hydrography may be related to sand fly distribution and infected dogs. The municipality of Formiga has proven leishmaniasis vectors and infected dogs indicating the circulation of the parasite in the city. Correlation of those data with environmental and human cases has identified the critical areas for control interventions (south, northeast, and northwest). In conclusion, there is current transmission of visceral and canine human cases and the city is on the risk for the appearance of cutaneous cases.

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Ecology of Lutzomyia longipalpis and Lutzomyia migonei in an endemic area for visceral leishmaniasis

Revista Brasileira de Parasitologia Veterinária ◽

10.1590/s1984-29612014068 ◽

2014 ◽

Vol 23 (3) ◽

pp. 320-327 ◽

Cited By ~ 11

Author(s):

Rafaella Albuquerque Silva ◽

Fabricio Kassio Moura Santos ◽

Lindemberg Caranha de Sousa ◽

Elizabeth Ferreira Rangel ◽

Claudia Maria Leal Bevilaqua

Keyword(s):

Visceral Leishmaniasis ◽

Leishmania Infantum ◽

Indoor Environment ◽

Endemic Area ◽

Natural Infection ◽

Sampling Site ◽

Lutzomyia Longipalpis ◽

Sand Flies ◽

Sampling Points ◽

Lutzomyia Migonei

The main vector for visceral leishmaniasis (VL) in Brazil is Lutzomyia longipalpis. However, the absence of L. longipalpis in a region of autochthonous VL demonstrates the participation of other species in the transmission of the parasite. Studies conducted in La Banda, Argentina, and São Vicente Férrer, Pernambuco State, Brazil, have correlated the absence of L. longipalpisand the presence of L. migonei with autochthonous cases of VL. In São Vicente Férrer, Pernambuco, there was evidence for the natural infection of L. migonei with Leishmania infantum chagasi. Thus, the objective of this work was to assess the ecology of the sand flies L. longipalpis and L. migonei in Fortaleza, an endemic area for VL. Insect capture was conducted at 22 sampling points distributed across four regions of Fortaleza. In total, 32,403 sand flies were captured; of these, 18,166 (56%) were identified as L. longipalpis and 14,237 (44%) as L. migonei. There were significant density differences found between the vectors at each sampling site (indoors and outdoors) (p <0.0001). These findings confirm that L. migonei and L. longipalpis are distributed throughout Fortaleza, where they have adapted to an indoor environment, and suggest that L. migonei may share the role as a vector with L. longipalpis in the transmission of VL in Fortaleza.

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Odour of domestic dogs infected with Leishmania infantum is attractive to female but not male sand flies: Evidence for parasite manipulation

PLoS Pathogens ◽

10.1371/journal.ppat.1009354 ◽

2021 ◽

Vol 17 (3) ◽

pp. e1009354

Author(s):

Monica E. Staniek ◽

James G. C. Hamilton

Keyword(s):

Leishmania Infantum ◽

Etiologic Agent ◽

Human Infection ◽

T Test ◽

Sand Fly ◽

Lutzomyia Longipalpis ◽

Sand Flies ◽

Control Female ◽

Behavioural Experiments ◽

Paired T Test

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.

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Leishmania infantum Infection Modulates the Jak-STAT Pathway in Lutzomyia longipalpis LL5 Embryonic Cells and Adult Females, and Affects Parasite Growth in the Sand Fly

Frontiers in Tropical Diseases ◽

10.3389/fitd.2021.747820 ◽

2021 ◽

Vol 2 ◽

Author(s):

Erich Loza Telleria ◽

Daisy Aline Azevedo-Brito ◽

Barbora Kykalová ◽

Bruno Tinoco-Nunes ◽

André Nóbrega Pitaluga ◽

...

Keyword(s):

Post Infection ◽

Leishmania Infantum ◽

Janus Kinase ◽

Sand Fly ◽

Lutzomyia Longipalpis ◽

Sand Flies ◽

Embryonic Cells ◽

Adult Females ◽

Parasite Survival ◽

Stat Pathway

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.

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Distinct gene expression patterns in vector-residing Leishmania infantum identify parasite stage-enriched markers

10.1101/679712 ◽

2019 ◽

Cited By ~ 1

Author(s):

Iliano V. Coutinho-Abreu ◽

Tiago D. Serafim ◽

Claudio Meneses ◽

Shaden Kamhawi ◽

Fabiano Oliveira ◽

...

Keyword(s):

Leishmania Infantum ◽

Developmental Stages ◽

Expression Patterns ◽

Principal Component ◽

Sand Fly ◽

Parasite Development ◽

Lutzomyia Longipalpis ◽

Specific Marker ◽

Limited Information ◽

Natural Sand

AbstractPromastigotes of Leishmania infantum undergo a series of extracellular developmental stages inside the natural sand fly vector Lutzomyia longipalpis to reach the infectious stage, the metacyclic promastigote. There is limited information regarding the expression profile of L. infantum developmental stages inside the sand fly vector, and molecular markers that can distinguish the different parasite stages are lacking. We performed RNAseq on unaltered midguts of the sand fly Lutzomyia longipalpis after infection with L. infantum parasites. RNAseq was carried out at various time points throughout parasite development. Principal component analysis mapped the sequences corresponding to the procyclic, nectomonad, leptomonad or metacyclic promastigote stage into distinct positions, with the procyclic stage being the most divergent population. Transcriptional levels across genes varied on average between 10- to 100-fold. Comparison between procyclic and nectomonad promastigotes resulted in 836 differentially expressed (DE) genes; between nectomonad and leptomonad promastigotes in 113 DE genes; and between leptomonad and metacyclic promastigotes in 302 DE genes. Most of the DE genes do not overlap across stages, highlighting the uniqueness of each stage. Furthermore, the different stages of Leishmania parasites exhibited specific transcriptional enrichment across chromosomes. Using the transcriptional signatures exhibited by distinct Leishmania stages during their development in the sand fly midgut, we determined the genes predominantly enriched in each stage, identifying multiple stage-specific markers for L. Infantum. Leading stage-specific marker candidates include genes encoding a zinc transporter in procyclics, a beta-fructofuranidase in nectomonads, a surface antigen-like protein in leptomonads, and an amastin-like surface protein in metacyclics. Overall, these findings demonstrate the transcriptional plasticity of the Leishmania parasite inside the sand fly vector and provide a repertoire of stage-specific markers for further development as molecular tools for epidemiological studies.

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Leishmania infantum proteophosphoglycans regurgitated by the bite of its natural sand fly vector, Lutzomyia longipalpis, promote parasite establishment in mouse skin and skin-distant tissues

Microbes and Infection ◽

10.1016/j.micinf.2010.05.014 ◽

2010 ◽

Vol 12 (11) ◽

pp. 875-879 ◽

Cited By ~ 30

Author(s):

Matthew Edward Rogers ◽

Karina Corware ◽

Ingrid Müller ◽

Paul Andrew Bates

Keyword(s):

Leishmania Infantum ◽

Mouse Skin ◽

Sand Fly ◽

Lutzomyia Longipalpis ◽

Natural Sand

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Assessment of PCR in the detection of Leishmania spp in experimentally infected individual phlebotomine sandflies (Diptera: Psychodidae: Phlebotominae)

Revista do Instituto de Medicina Tropical de São Paulo ◽

10.1590/s0036-46652002000500004 ◽

2002 ◽

Vol 44 (5) ◽

pp. 255-259 ◽

Cited By ~ 37

Author(s):

Érika M. MICHALSKY ◽

Consuelo L. FORTES-DIAS ◽

Paulo F.P. PIMENTA ◽

Nágila F.C. SECUNDINO ◽

Edelberto S. DIAS

Keyword(s):

Digestive Tract ◽

Infected Individual ◽

Dna Amplification ◽

Leishmania Braziliensis ◽

Lutzomyia Longipalpis ◽

Leishmania Chagasi ◽

Phlebotomine Sandflies ◽

Leishmania Spp ◽

Polymerase Chain ◽

Lutzomyia Migonei

DNA amplification by the polymerase chain reaction (PCR) was applied in the investigation of the presence of Leishmania (Kinetoplastida: Trypanosomatidae) parasites in single phlebotomine sandflies. Three phlebotomine/parasite pairs were used: Lutzomyia longipalpis/Leishmania chagasi, Lutzomyia migonei/Leishmania amazonensis and Lutzomyia migonei/Leishmania braziliensis, all of them incriminated in the transmission of visceral or cutaneous leishmaniasis. DNA extraction was performed with whole insects, with no need of previous digestive tract dissection or pooling specimens. The presence of either mouse blood in the digestive tract of the sandflies or the digestive tract itself did not interfere in the PCR. Infection by as few as 10 Leishmania sp. per individual were sufficient for DNA amplification with genus-specific primers. Using primers for L. braziliensis and L. mexicana complexes, respectively, it was possible to discriminate between L. braziliensis and L. amazonensis in experimentally infected vectors (L. migonei).

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Insecticide-impregnated netting as a potential surface treatment: an alternative to insecticide spraying for control of the leishmaniasis vector Lutzomyia longipalpis (Diptera: Psychodidae)?

10.21203/rs.3.rs-52839/v1 ◽

2020 ◽

Author(s):

Vanessa Barbosa ◽

Cristian F Souza ◽

Derek Gatherer ◽

Reginaldo P Brazil ◽

James Gordon Campbell Hamilton

Keyword(s):

Aggregation Pheromone ◽

Leishmania Infantum ◽

Intervention Studies ◽

Potential Surface ◽

Lower Proportion ◽

Sand Fly ◽

Lutzomyia Longipalpis ◽

Sand Flies ◽

Synthetic Pheromone ◽

Canine Infection

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.

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Leishmania infantum xenodiagnosis from vertically infected dogs reveals significant skin tropism

PLoS Neglected Tropical Diseases ◽

10.1371/journal.pntd.0009366 ◽

2021 ◽

Vol 15 (10) ◽

pp. e0009366

Author(s):

Breanna M. Scorza ◽

Kurayi G. Mahachi ◽

Arin C. Cox ◽

Angela J. Toepp ◽

Adam Leal-Lima ◽

...

Keyword(s):

Leishmania Infantum ◽

Severe Disease ◽

Clinical Status ◽

Parasite Burden ◽

Parasite Load ◽

Sand Fly ◽

Lutzomyia Longipalpis ◽

Sand Flies ◽

Feeding Site ◽

Transmission Potential

Background Dogs are the primary reservoir for human visceral leishmaniasis due to Leishmania infantum. Phlebotomine sand flies maintain zoonotic transmission of parasites between dogs and humans. A subset of dogs is infected transplacentally during gestation, but at what stage of the clinical spectrum vertically infected dogs contribute to the infected sand fly pool is unknown. Methodology/Principal findings We examined infectiousness of dogs vertically infected with L. infantum from multiple clinical states to the vector Lutzomyia longipalpis using xenodiagnosis and found that vertically infected dogs were infectious to sand flies at differing rates. Dogs with mild to moderate disease showed significantly higher transmission to the vector than dogs with subclinical or severe disease. We documented a substantial parasite burden in the skin of vertically infected dogs by RT-qPCR, despite these dogs not having received intradermal parasites via sand flies. There was a highly significant correlation between skin parasite burden at the feeding site and sand fly parasite uptake. This suggests dogs with high skin parasite burden contribute the most to the infected sand fly pool. Although skin parasite load and parasitemia correlated with one another, the average parasite number detected in skin was significantly higher compared to blood in matched subjects. Thus, dermal resident parasites were infectious to sand flies from dogs without detectable parasitemia. Conclusions/Significance Together, our data implicate skin parasite burden and earlier clinical status as stronger indicators of outward transmission potential than blood parasite burden. Our studies of a population of dogs without vector transmission highlights the need to consider canine vertical transmission in surveillance and prevention strategies.

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Transmission potential of paromomycin-resistant Leishmania infantum and Leishmania donovani

Journal of Antimicrobial Chemotherapy ◽

10.1093/jac/dkz517 ◽

2019 ◽

Vol 75 (4) ◽

pp. 951-957 ◽

Cited By ~ 3

Author(s):

S Hendrickx ◽

L Van Bockstal ◽

H Aslan ◽

J Sadlova ◽

L Maes ◽

...

Keyword(s):

Leishmania Infantum ◽

Leishmania Donovani ◽

Leishmania Species ◽

Blood Feeding ◽

Sand Fly ◽

Lutzomyia Longipalpis ◽

Transmission Potential ◽

Laboratory Rodents ◽

The Impact

Abstract Objectives Former studies demonstrated quick selection of paromomycin resistance for Leishmania infantum and Leishmania donovani accompanied by increased fitness. The present study aimed to interpret these findings in an epidemiological context by comparing infection of WT and experimentally derived paromomycin-resistant strains in the sand fly vector. Methods Depending on the Leishmania species, Lutzomyia longipalpis and Phlebotomus perniciosus or Phlebotomus argentipes sand flies were artificially infected with procyclic promastigotes of WT and paromomycin-resistant L. infantum (MHOM/FR/96/LEM3323-cl4) or L. donovani (MHOM/NP/03/BPK275/0-cl18). The infection rate and gut/stomodeal valve colonization were determined to monitor parasite phenotypic behaviour within the vector. The impact of the previously described gain of fitness in the vertebrate host on infectivity for the vector was assessed by feeding L. longipalpis on Syrian golden hamsters heavily infected with either WT or paromomycin-resistant parasites. Results WT and paromomycin-resistant Leishmania of both species behaved similarly in terms of infection and parasite location within the studied sand fly species. Blood feeding on infected hamsters did not reveal differences in acquisition of WT and paromomycin-resistant parasites, despite the higher organ burdens observed for the paromomycin-resistant strain. Strains remained resistant after passage in the vector. Conclusions Although paromomycin-resistant parasites show an increased parasite fitness in vitro and in laboratory rodents, the intrinsic infection potential of paromomycin-resistant parasites remains unaltered in the sand fly. Of importance is the fact that paromomycin-resistant Leishmania are able to complete development in the natural vectors and produce stomodeal infection with metacyclic forms, which clearly suggests their potential to spread and circulate in nature.

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