scholarly journals Measuring spatial co-occurrences of species potentially involved in Leishmania transmission cycles through a predictive and fieldwork approach

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Marla López ◽  
Diana Erazo ◽  
Juliana Hoyos ◽  
Cielo León ◽  
Patricia Fuya ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Neglected Tropical Diseases ◽  
Control Strategies ◽  
Mammalian Species ◽  
First Record ◽  
Sand Fly ◽  
Sand Flies ◽  
Mammal Species ◽  
Current Transmission ◽  
Transmission Cycles

AbstractThe Leishmaniases are a group of neglected tropical diseases caused by different species of the protozoan parasite Leishmania, transmitted to its mammalian hosts by the bites of several species of female Phlebotominae sand flies. Many factors have contributed to shifts in the disease distribution and eco epidemiological outcomes, resulting in the emergence of Cutaneous Leishmaniasis outbreaks and the incrimination of vectors in unreported regions. New research development is vital for establishing the new paradigms of the present transmission cycles, hoping to facilitate new control strategies to reduce parasite transmission. Hereafter, this work aims to model and infer the current transmission cycles of Cutaneous Leishmaniasis in Colombia defined by vector and mammal species distributed and interacting in the different regions and validate them by performing sand fly and mammal collections. Vector-host co-occurrences were computed considering five ecoregions of the Colombian territory defined by the World Wide Fund for Nature (WWF) and downloaded from The Nature Conservancy TNC Maps website. Four validation sites were selected based on Cutaneous Leishmaniasis prevalence reports. Sand flies and mammals captured in the field were processed, and species were defined using conventional taxonomic guidelines. Detection of infection by Leishmania was performed to identify transmission cycles in the selected areas. This study uses predictive models based on available information from international gazetteers and fieldwork to confirm sand fly and mammalian species' sustaining Leishmania transmission cycles. Our results show an uneven distribution of mammal samples in Colombia, possibly due to sampling bias, since only two departments contributed 50% of the available samples. Bats were the vertebrates with the highest score values, suggesting substantial spatial overlap with sand flies than the rest of the vertebrates evaluated. Fieldwork allowed identifying three circulating Leishmania species, isolated from three sand fly species. In the Montane Forest ecosystem, one small marsupial, Gracilinanus marica, was found infected with Leishmania panamensis, constituting the first record of this species infected with Leishmania. In the same locality, an infected sand fly, Pintomyia pia, was found. The overall results could support the understanding of the current transmission cycles of Leishmaniasis in Colombia.

scholarly journals Detection of Leishmania infantum DNA in Pintomyia evansi and Lutzomyia longipalpis in Honduras

2020 ◽  
Vol 13 (1) ◽  
Author(s):  
Wilfredo Sosa-Ochoa ◽  
Javier Varela Amador ◽  
Yokomi Lozano-Sardaneta ◽  
Gabriela Rodriguez Segura ◽  
Concepcion Zúniga Valeriano ◽  
...  
Keyword(s):  
Pacific Coast ◽  
First Record ◽  
Abundant Species ◽  
Central American ◽  
Sand Fly ◽  
Lutzomyia Longipalpis ◽  
Sand Flies ◽  
Endemic Region ◽  
Transmission Cycle ◽  
The Pacific

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.

scholarly journals NaturalLeishmania(Viannia) spp. infections in phlebotomine sand flies (Diptera: Psychodidae) from the Brazilian Amazon region reveal new putative transmission cycles of American cutaneous leishmaniasis

Parasite ◽  
2016 ◽  
Vol 23 ◽  
pp. 22 ◽  
Author(s):  
Adelson Alcimar Almeida de Souza ◽  
Thiago Vasconcelos dos Santos ◽  
Yara Lúcia Lins Jennings ◽  
Edna Aoba Yassui Ishikawa ◽  
Iorlando da Rocha Barata ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Brazilian Amazon ◽  
Amazon Region ◽  
Sand Flies ◽  
Phlebotomine Sand Flies ◽  
American Cutaneous Leishmaniasis ◽  
Brazilian Amazon Region ◽  
Transmission Cycles

scholarly journals Evaluation of molecular assays to detect Leishmania donovani in Phlebotomus argentipes fed on post-kala-azar dermal leishmaniasis patients

2021 ◽  
Vol 14 (1) ◽  
Author(s):  
Md Anik Ashfaq Khan ◽  
Khaledul Faisal ◽  
Rajashree Chowdhury ◽  
Rupen Nath ◽  
Prakash Ghosh ◽  
...  
Keyword(s):  
Leishmania Donovani ◽  
Control Strategies ◽  
Reference Method ◽  
Critical Factor ◽  
Sand Fly ◽  
Accurate Estimation ◽  
Limiting Factor ◽  
Sand Flies ◽  
Real Time Quantitative Pcr ◽  
Kala Azar

Abstract Background Post-kala-azar dermal leishmaniasis (PKDL) caused by Leishmania donovani (LD) is a skin disorder that often appears after treatment of visceral leishmaniasis (VL) patients. PKDL patients are potential reservoirs of LD parasites, which can initiate a new epidemic of anthroponotic VL. Therefore, host infectiousness to its sand fly vector is a critical factor for transmission, and its accurate estimation can facilitate control strategies. At present, conventional microscopy serves as the reference method to detect parasites in its vector. However, low sensitivity of microscopy can be a limiting factor. Methods In this study, real-time quantitative PCR (LD-qPCR) and recombinase polymerase amplification (LD-RPA) assays were evaluated against microscopy for the detection of LD DNA extracted from live sand flies five days after controlled feeding on PKDL cases. Results The sensitivity of LD-qPCR and LD-RPA assays were found to be 96.43 and 100%, respectively, against microscopy for the selected fed sand flies (n = 28), and an absolute specificity of both molecular tools for apparently unfed sand flies (n = 30). While the proportion of infectious cases among 47 PKDL patients was estimated as 46.81% as defined by microscopic detection of LD in at least one fed sand fly per case, LD-RPA assay evaluation of only the microscopy negative sand flies fed to those 47 PKDL cases estimated an even greater proportion of infectious cases (51.06%). In overall estimation of the infectious cases in retrospective manner, discordance in positivity rate was observed (p < 0.05) between LD-RPA (59.57%) assay and microscopy (46.81%), while LD-RPA had slightly better positivity rate than LD-qPCR (55.32%) as well. Conclusions Considering the sensitivity, cost, detection time, and field applicability, RPA assay can be considered as a promising single molecular detection tool for investigations pertaining to LD infections in sand flies and/or host infectiousness in PKDL, while it can also be useful in confirmation of microscopy negative sand fly samples. Graphical abstract

Trypanosomatids in Phlebotomine Sand Flies (Diptera: Phlebotominae) From Anthropic and Sinantropic Landscapes in a Rural Settlement in the Brazilian Amazon

2022 ◽  
Author(s):  
R C S Guimarães ◽  
E F Marialva ◽  
J A Feijó ◽  
J W Pereira-Silva ◽  
K M Martins-Campos ◽  
...  
Keyword(s):  
Natural Infection ◽  
Species Abundance ◽  
First Record ◽  
Rural Settlement ◽  
Sand Fly ◽  
Sand Flies ◽  
Forest Environment ◽  
Genetic Sequencing ◽  
Transmission Cycle ◽  
Pcr Rflp

Abstract Trypanosomatids (Kinetoplastida:Trypanosomatidae) protozoa are a diverse group of obligate parasites. The genera Trypanosoma and Leishmania are the most studied because of their medical importance. This work aims to evaluate the effects of anthropization processes on the composition of the phlebotomine sand fly fauna and the natural infection by Trypanosomatids, with emphasis on Leishmania. At all 3,186 sand flies were collected, distributed in 13 genera and 52 species, being Ny. umbratilis the most abundant species. There was no difference in the diversity between canopy and soil environments. The species abundance and richness were higher in the forest environment while species diversity and evenness were highest in the forest edge. The ITS1 region was used by PCR-RFLP to identify the fragment profiles of Leishmania species, followed by genetic sequencing. Here were analyzed 100 pools of female sand flies, being six positive for DNA parasite. PCR-RFLP fragment patterns similar to Endotrypanum sp. were observed in Nyssomyia anduzei, Psychodopygus amazonensis and Lutzomyia gomezi, and those fragments similar to Leishmania (Leishmania) amazonensis were observed in Bichromomyia flaviscutellata. ITS1 sequencing confirmed the presence of Leishmania sp. in Bi. flaviscutellata, and Leishmania (Viannia) naiffi in Ny. anduzei, Psychodopygus amazonensis, and Lu. gomezi. This is the first record of Lu. gomezi and Ps. amazonensis infection by L. naiffi in the State of Amazonas. These results show the trypanosomatid infection in sandflies from different landscapes in a rural settlement, and the finding of species infected with L.(V.) naiffi suggest that they can develop a role in the transmission cycle of leishmaniasis.

scholarly journals Data on sand fly fauna (Diptera, Psychodidae, Phlebotominae) in Itatiaia National Park, Rio de Janeiro State, Brazil

2007 ◽  
Vol 23 (3) ◽  
pp. 725-730 ◽  
Author(s):  
Margarete M. S. Afonso ◽  
Wagner A. Costa ◽  
Alfredo C. R. Azevedo ◽  
Simone M. da Costa ◽  
Maurício L. Vilela ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Human Activity ◽  
Rio De Janeiro ◽  
National Park ◽  
Sand Fly ◽  
Sand Flies ◽  
Light Traps ◽  
Janeiro State

The sand fly fauna in Itatiaia National Park, Rio de Janeiro, Brazil, was investigated in different habitats ranging from sylvatic areas to those altered by human activity related to ecotourism, specifically identifying species that have been suggested as potential leishmaniasis vectors. Sand flies were captured from June 2002 to March 2004, using CDC light traps and Shannon traps. A total of 1,256 sand fly specimens were captured, from species belonging to genera Lutzomyia and Brumptomyia: Brumptomyia guimaraesi, B. troglodytes, Lutzomyia (Lutzomyia) amarali, L. lanei, L. migonei, L. sallesi, L. edwardsi, L. tupynambai, L. (Pintomyia) pessoai, L. (P.) bianchigalatie, L. rupicola, L. (Psathyromyia) shannoni, L. pascalei, L. (Psychodopygus) matosi, L. (P.) davisi, L. (P.) hirsuta hirsuta, L. (P.) ayrozai, L. peresi, L. monticola, and L. misionensis. Worthy of special attention were four species that are considered potential vectors for cutaneous leishmaniasis in Brazil: L. ayrozai, L. hirsuta hirsuta, L. migonei, and L. davisi, representing 19.19% of the specimens captured in this study.

scholarly journals Assessing public perception of a sand fly biting study on the pathway to a controlled human infection model for cutaneous leishmaniasis

2021 ◽  
Vol 7 (1) ◽  
Author(s):  
Vivak Parkash ◽  
Georgina Jones ◽  
Nina Martin ◽  
Morgan Steigmann ◽  
Elizabeth Greensted ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Study Design ◽  
Public Involvement ◽  
Human Infection ◽  
Sand Fly ◽  
Infection Model ◽  
Sand Flies ◽  
Link Type ◽  
Stage Of Development ◽  
Facing Material

Abstract Background A controlled human infection model (CHIM) involves deliberate exposure of volunteers to pathogens to assess their response to new therapies at an early stage of development. We show here how we used public involvement to help shape the design of a CHIM to support future testing of candidate vaccines for the neglected tropical disease cutaneous leishmaniasis, a disease transmitted by the bite of infected sand flies in tropical regions. Methods We undertook a public involvement (PI) consultation exercise to inform development of a study to test the safety and effectiveness of a sand fly biting protocol using uninfected sand flies (FLYBITE: ClinicalTrials.gov ID NCT03999970) and a CHIM using Leishmania major-infected sand flies (LEISH_Challenge: ClinicalTrials.gov ID NCT04512742), both taking place in York, UK. We involved 10 members of the public including a patient research ambassador and a previous CHIM volunteer. The session took place at The University of York, UK and examined draft study volunteer-facing material and included the CHIM study design, potential adverse events and therapeutic interventions at study endpoints. A discussion of the scientific, ethical, humanitarian and economic basis for the project was presented to the participants to provoke discourse. An inductive, thematic analysis was used to identify the participants’ key concerns. Results Themes were identified relating to i) quality of volunteer-facing written information, ii) improving study design, and iii) factors to motivate involvement in the research. Group participants responded positively to the overall study aims. Initial concerns were expressed about potential risks of study involvement, but further explanation of the science and mitigations of risk secured participant support. Participants provided advice and identified improved terminology to inform the volunteer-facing material. Lastly, treatment options were discussed, and excision of any cutaneous lesion was favoured over alternatives as a treatment. Conclusion The consultation exercise provided invaluable information which led to improved study design and enhanced clarity in the volunteer-facing material. The session also reinforced the need to maintain public trust in scientific rigour prior to initiation of any study. The investigators hope that this description strengthens understanding of PI in clinical research, and encourages its use within other studies.

scholarly journals Risk Assessment of the Role of the Ecotones in the Transmission of Zoonotic Cutaneous Leishmaniasis in Central Tunisia

2021 ◽  
Vol 18 (17) ◽  
pp. 9274
Author(s):  
Walid Barhoumi ◽  
Ifhem Chelbi ◽  
Wasfi Fares ◽  
Sami Zhioua ◽  
Mohamed Abbas ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Leishmania Major ◽  
Etiologic Agent ◽  
Control Measures ◽  
Sand Fly ◽  
Main Peak ◽  
Sand Flies ◽  
Central Tunisia ◽  
Zoonotic Cutaneous Leishmaniasis ◽  
Significant Difference

Zoonotic cutaneous leishmaniasis (ZCL), endemic in Central and Southern Tunisia, is caused by Leishmania major (Kinetoplastida: Trypanosomatidae), which is transmitted by the sand fly Phlebotomus papatasi. In Tunisia, the fat sand rat Psammomys obesus and the desert jird Meriones shawi are the principal reservoir hosts of L. major. The presence of the P. papatasi vector of the L. major etiologic agent of ZCL was assessed in the vicinity of villages in endemic areas of Central Tunisia. The study was performed from September through October 2019, a period corresponding to the main peak of activity of P. papatasi. Sand flies were collected from rodent burrows located at the ecotone level, which is the transition zone between the natural environment and human settlement. Sand flies were identified to species level and tested for the presence of L. major by PCR. Our entomological survey showed that P. papatasi is the most abundant sand fly species associated with rodent burrows, and this abundance is even higher in ecotones primarily occupied by P. obesus in comparison to ecotones occupied by M. shawi. Infections with Leishmania major were detected only in P. papatasi, with an overall minimum infection rate (MIR) of 2.64%. No significant difference was observed between the MIRs in ecotones of P. obesus and of M. shawi. Incidence of ZCL in the studied areas ranged from 200 to 700 cases per 100,000 inhabitants, with a mean incidence of 385.41 per 100,000. Higher ZCL incidence was identified in ecotones of M. shawi compared to ecotones of P. obesus. ZCL cases are positively correlated with the MIRs. Considering the short flight range of P. papatasi, increases in its densities associated with burrows of P. obesus or M. shawi at the ecotone level expand the overlap of infected vectors with communities and subsequently increase ZCL incidence. Therefore, control measures should target P. papatasi populations at the ecotones.

scholarly journals Detection of Leishmania infantum DNA in Pintomyia evansi and Lutzomyia longipalpis in an endemic area of Non-ulcerative cutaneous leishmaniasis from Honduras

2020 ◽  
Author(s):  
Wilfredo Humberto Sosa-Ochoa ◽  
Javier Varela Amador ◽  
Yokomi N Lozano-Sardaneta ◽  
Gabriela Rodriguez Segura ◽  
Concepcion Zúniga ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Leishmania Infantum ◽  
Endemic Area ◽  
Natural Infection ◽  
First Record ◽  
Abundant Species ◽  
Lutzomyia Longipalpis ◽  
Sand Flies ◽  
Endemic Region ◽  
Transmission Cycle

Abstract Background The two most abundant sand flies species in Honduran Pacific coast are Lutzomyia (Lutzomyia) longipalpis and Pintomyia (Pintomyia) evansi. Both species are proved vectors of the agent of for visceral leishmaniasis in South America. Although, visceral and cutaneous non-ulcerated leishmaniasis are endemic of the Central American Pacific, being the Non-ulcerative cutaneous leishmaniasis the most frequent manifestation. In this study, we evaluate the circulation of Leishmania spp in sand flies species in the El Tigre Island, an endemic area of Visceral and Non -ulcerative cutaneous leishmaniasis in Honduras. Results Six sand flies species were identified, being Lu. longipalpis (81%) and Pi. evansi (16%) the more abundant species. Leishmania (Leishmania) infantum DNA was found in 9 of the 96 specimens analyzed, 7 of these specimens was identify as Lutzomyia (Lutzomyia) longipalpis and 2 as Pintomyia (Pifanomyia) evansi, with an infection rate of 9.4% and 2.7% respectively. Conclusion Our results present the first record of Leishmania (L.) infantum DNA in Pintomyia (Pintomyia) evansi in a Non-ulcerative cutaneous leishmaniasis endemic region from Central America. Considering the natural infection of Lu. longipalpis our results suggest that Pintomyia (Pifanomyia) evansi might be a secondary vector of Leishmania (L.) infantum and probably involved in the disease’s transmission cycle. Undoubtedly, the detection of natural infections of in this region contributes to the understanding of the L. (L.) infantum infection epidemiology in Honduras

scholarly journals Genomics and transcriptomics to unravel sex determination pathway and its evolution in sand flies

2019 ◽  
Author(s):  
Valeria Petrella ◽  
Serena Aceto ◽  
Vincenza Colonna ◽  
Giuseppe Saccone ◽  
Remo Sanges ◽  
...  
Keyword(s):  
Sex Determination ◽  
Control Strategies ◽  
Fruit Fly ◽  
Sand Fly ◽  
Sand Flies ◽  
Developmental Pathway ◽  
Phlebotomine Sand Flies ◽  
Developmental Gene Expression ◽  
Molecular Bases ◽  
First Time

AbstractBackgroundPhlebotomine sand flies (Diptera, Nematocera) are important vectors of several pathogens, including Leishmania parasites, causing serious diseases of humans and dogs. Despite their importance as disease vectors, most aspects of sand fly biology remain unknown including the molecular bases of their reproduction and sex determination, aspects also relevant for the development of novel vector control strategies.ResultsUsing a comparative genomics/transcriptomics approach, we identified the sex determining genes in phlebotomine sand flies and proposed the first model for the sex determination cascade of these insects. For all the genes identified, we produced manually curated gene models, developmental gene expression profile and performed evolutionary molecular analysis. We identified and characterized, for the first time in a Nematocera species, the transformer (tra) homolog which exhibits both conserved and novel features. The analysis of the tra locus in sand flies and its expression pattern suggest that this gene is able to autoregulate its own splicing, as observed in the fruit fly Ceratitis capitata and several other insect species.ConclusionsOur results permit to fill the gap about sex determination in sand flies, contribute to a better understanding of this developmental pathway in Nematocera and open the way for the identification of sex determining orthologs in other species of this important Diptera sub-order. Furthermore, the sex determination genes identified in our work also provide the opportunity of future biotech applications to control natural population of sand flies, reducing their impact on public health.

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