Tsetse flies occur in much of sub-Saharan Africa as vectors of trypanosomes that cause human and animal African trypanosomosis. For its control, the Sterile Insect Technique based on mass rearing is currently used. Bu...Tsetse flies occur in much of sub-Saharan Africa as vectors of trypanosomes that cause human and animal African trypanosomosis. For its control, the Sterile Insect Technique based on mass rearing is currently used. But the improvement of tsetse productivity in mass rearing requires a better environment condition but also the control of productivity parameters. One of these important parameters is the choice of the ratio of females and males according to the targeted species. The aim of this study was to perform tests for getting the best female to male adults ratios in mass-rearing colonies of Glossina palpalis gambiensis for the purpose of optimizing the yield of sterile males. To achieve this, the mortality and fecundity for various male to female ratios (1:2, 1:3, 1:4, 1:8 and 1:10) on adult tsetse fly in routine rearing over 60 days after emergence was monitored and each experimental batch was replicated five times. Pupae production and fly mortalities were monitored daily except on Sunday. Females of the 1:4 ratio survived longer than those from 1:2 and 1:3 but similar to those from 1:8 and 1:10. The best survival was observed with flies from the ratio 1:10. The highest pupae per initial female per 10 days was observed with the ratio 1:4. The best Glossina palpalis gambiensis male to female sex ratio should be 1:4, due to the higher significant fecundity combined with lower mortality of females, in order to maximize the productivity of the colonies and the yield of male flies that can then devoted to sterile insect technique projects.展开更多
Trypanosomosis remains the number one killer of livestock in spite of efforts made to eradicate tsetse flies in the Adamawa plateau of Cameroon. Acetone-baited Laveissière type biconical traps were pitched at 100...Trypanosomosis remains the number one killer of livestock in spite of efforts made to eradicate tsetse flies in the Adamawa plateau of Cameroon. Acetone-baited Laveissière type biconical traps were pitched at 100 meter intervals in strategic geo-referenced positions in various ecological niches of the landscape for 5 consecutive days in selected villages in Mayo Rey, Mbere, Vina and Faro et Deo divisions. All 493 tsetse flies captured in sites other than Mboula wereG. morsitans submositans.Measurement of different morphometric characters on the wings of each individual fly was undertaken using the Du Jardin package. The data was processed and analysed by “Permutaciones, Analisis Discriminante (PAD)” and “Bootstraps, Analisis en Componentes principales”. The three major sampling sites on the plateau yielded similar results as demonstrated by the neighbour joining tree of Mahalanobis distances but tests using PAD showed the differences between group means to be significant展开更多
Tsetse(Glossina spp.)are vectors of African trypanosomes that cause devastating human and animal African trypanosomiases.While much of the research to better understand tsetse genetics and physiology relies on colony-...Tsetse(Glossina spp.)are vectors of African trypanosomes that cause devastating human and animal African trypanosomiases.While much of the research to better understand tsetse genetics and physiology relies on colony-reared flies,these flies may not represent the genetic diversity found in natural wild populations due to their long-term captivity.To enhance the translation of colony research into field applications,we utilized Nanopore sequencing to assemble genomes for a wild-caught female Glossina fuscipes fuscipes(Gff)from northwestern Uganda and for a female Gff from a laboratory line originally sourced from the Central African Republic in 1986.The new assemblies,from the wild-caught Gff(405.98 Mb,N50:56.86 Mb)and the laboratory-derived Gff(398.22 Mb,N50:47.811 Mb),demonstrate near-chromosomal level contiguity,high BUSCO scores(>99.5%),high QV scores(>37),and over 12345 genes.Alignments between both new genomes reveal conserved synteny with only minor structural variants in the X,1L,1R,2L,and 2R tsetse chromosomes.While most orthologs(10730)were shared between both new genomes,we identified 381 unique orthologs and a small number of highly diverged shared single-copy homologs(3.84%).These gene-set differences could represent population-level variation due to the distinct geographic origin of these flies or adaptation to colony conditions.Our new high-quality genomes,with improvements in contiguity and completeness compared to the current NCBI RefSeq Gff genome,lay the foundation for advanced tsetse research,enabling robust lab-to-field translational applications to deepen our understanding of vector biology and disease transmission dynamics.展开更多
Glossina austeni Newstead(Diptera:Glossinidae)is a competent vector of the trypanosomes causing human African trypanosomiasis and the African animal trypanosomosis.Management of this pest has primarily involved trappi...Glossina austeni Newstead(Diptera:Glossinidae)is a competent vector of the trypanosomes causing human African trypanosomiasis and the African animal trypanosomosis.Management of this pest has primarily involved trapping methods,Sterile Insect Technique,and research into vector competence–symbiotic interactions.Nevertheless,the use of entomopathogenic fungi(EPF)in integrated pest management programs for G.austeni control remains limited.Moreover,different tsetse fly species exhibit varying susceptibility to different EPF strains,indicating that no single strain is universally effective.Therefore,our study aimed to identify candidate EPF isolates for G.austeni management,evaluate the effects of temperature on the radial growth of these potent isolates,and assess the impact of the candidate EPF on the gut microbiome of G.austeni.Consequently,16 Metarhizium anisopliae(Metschn.)Sorokin isolates were screened against G.austeni using dry conidia in an infection chamber,with the most virulent isolates having LT50 values of 3.95−9.37 d.Temperature significantly influenced the radial growth,conidia germination,and yield of these strains.There were also significant differences in conidia acquisition,retention and transmission between male and female G.austeni flies.Furthermore,all conidia receivers carried sufficient conidia,5 d post-interaction with EPF-challenged conidia donors.Microbiome analysis revealed Wigglesworthia,Serratia,Klebsiella,and Escherichia as the most abundant taxa.Among the M.anisopliae isolates,ICIPE 82 exhibited the fastest radial growth and highest thermostability,hence selected as a potential biopesticide candidate for managing G.austeni.This study demonstrates the efficacy and potential of M.anisopliae ICIPE 82 as a biopesticide for controlling G.austeni.展开更多
The diurnal activity patterns, trypanosome infection rates and movement of Glossinafuscipesfuscipes （Diptera： Glossinidae） were investigated in Buvuma Island, Lake Victoria, Uganda. Hourly trapping of tsetse flies ...The diurnal activity patterns, trypanosome infection rates and movement of Glossinafuscipesfuscipes （Diptera： Glossinidae） were investigated in Buvuma Island, Lake Victoria, Uganda. Hourly trapping of tsetse flies was undertaken to determine their activity rhythm while a capture-mark-release-recapture method was conducted to assess the movement and dispersal of tsetse flies between lakeshore, hinterland and further inland sites along a transected area. Dissection of tsetse flies was also undertaken to determine the trypanosome infection rates in salivary glands, proboscis and mid-gut. Results indicated a bimodal diurnal activity profile for G. f fuscipes on the Island, both on the lakeshore and in the hinterland. Movement and dispersal of G. f fuscipes tsetse flies occurred between lakeshore, hinterland and further inland sites with a greater tendency of flies to move to the lakeshore. Trypanosome infection rates of 4.32% for Trypasoma vivax and 1.15% for 7. congolense were found in G. f. fuscipes.展开更多
The flies of genus Glossina (Diptera: Glossinidae) are an important vector of African trypanosomiases which cause diseases in humans and animals. The ribosomal DNA Internal Transcribed Spacer-2 (ITS-2) region sequence...The flies of genus Glossina (Diptera: Glossinidae) are an important vector of African trypanosomiases which cause diseases in humans and animals. The ribosomal DNA Internal Transcribed Spacer-2 (ITS-2) region sequences from different Glossina species were PCR-amplified and analyzed in order to construct a molecular phylogeny for genus Glossina. Trees generated by parsimony confirmed the monophyletic taxonomic placement of genus Glossina where fusca group species formed the deepest branch followed by morsitans and palpalis groups, respectively. The placement of Glossina austeni by both the traditional morphological and biochemical criteria has been controversial. Results presented here, based on ITS-2 locus sequence analysis, suggest that Glossina austeni can be placed into a separate subgenerus which forms a sister-group relationship with the morsitans group species.展开更多
Background:In recent years,a programme of vector control,screening and treatment of gambiense human African trypanosomiasis(gHAT)infections led to a rapid decline in cases in the Mandoul focus of Chad.To represent the...Background:In recent years,a programme of vector control,screening and treatment of gambiense human African trypanosomiasis(gHAT)infections led to a rapid decline in cases in the Mandoul focus of Chad.To represent the biology of transmission between humans and tsetse,we previously developed a mechanistic transmission model,fitted to data between 2000 and 2013 which suggested that transmission was interrupted by 2015.The present study outlines refinements to the model to:(1)Assess whether elimination of transmission has already been achieved despite low-level case reporting;(2)quantify the role of intensified interventions in transmission reduction;and(3)predict the trajectory of gHAT in Mandoul for the next decade under different strategies.Method:Our previous gHAT transmission model for Mandoul was updated using human case data(2000-2019)and a series of model refinements.These include how diagnostic specificity is incorporated into the model and improvements to the fitting method(increased variance in observed case reporting and how underreporting and improvements to passive screening are captured).A side-by-side comparison of fitting to case data was performed between the models.Results:We estimated that passive detection rates have increased due to improvements in diagnostic availability in fixed health facilities since 2015,by 2.1-fold for stage 1 detection,and 1.5-fold for stage 2.We find that whilst the diagnostic algorithm for active screening is estimated to be highly specific(95%credible interval(CI):99.9-100%,Specificity=99.9%),the high screening and low infection levels mean that some recently reported cases with no parasitological confirmation might be false positives.We also find that the focus-wide tsetse reduction estimated through model fitting(95%CI:96.1-99.6%,Reduction=99.1%)is comparable to the reduction previously measured by the decline in tsetse catches from monitoring traps.In line with previous results,the model suggests that transmission was interrupted in 2015 due to intensified interventions.Conclusions:We recommend that additional confirmatory testing is performed in Mandoul to ensure the endgame can be carefully monitored.More specific measurement of cases,would better inform when it is safe to stop active screening and vector control,provided there is a strong passive surveillance system in place.展开更多
文摘Tsetse flies occur in much of sub-Saharan Africa as vectors of trypanosomes that cause human and animal African trypanosomosis. For its control, the Sterile Insect Technique based on mass rearing is currently used. But the improvement of tsetse productivity in mass rearing requires a better environment condition but also the control of productivity parameters. One of these important parameters is the choice of the ratio of females and males according to the targeted species. The aim of this study was to perform tests for getting the best female to male adults ratios in mass-rearing colonies of Glossina palpalis gambiensis for the purpose of optimizing the yield of sterile males. To achieve this, the mortality and fecundity for various male to female ratios (1:2, 1:3, 1:4, 1:8 and 1:10) on adult tsetse fly in routine rearing over 60 days after emergence was monitored and each experimental batch was replicated five times. Pupae production and fly mortalities were monitored daily except on Sunday. Females of the 1:4 ratio survived longer than those from 1:2 and 1:3 but similar to those from 1:8 and 1:10. The best survival was observed with flies from the ratio 1:10. The highest pupae per initial female per 10 days was observed with the ratio 1:4. The best Glossina palpalis gambiensis male to female sex ratio should be 1:4, due to the higher significant fecundity combined with lower mortality of females, in order to maximize the productivity of the colonies and the yield of male flies that can then devoted to sterile insect technique projects.
文摘Trypanosomosis remains the number one killer of livestock in spite of efforts made to eradicate tsetse flies in the Adamawa plateau of Cameroon. Acetone-baited Laveissière type biconical traps were pitched at 100 meter intervals in strategic geo-referenced positions in various ecological niches of the landscape for 5 consecutive days in selected villages in Mayo Rey, Mbere, Vina and Faro et Deo divisions. All 493 tsetse flies captured in sites other than Mboula wereG. morsitans submositans.Measurement of different morphometric characters on the wings of each individual fly was undertaken using the Du Jardin package. The data was processed and analysed by “Permutaciones, Analisis Discriminante (PAD)” and “Bootstraps, Analisis en Componentes principales”. The three major sampling sites on the plateau yielded similar results as demonstrated by the neighbour joining tree of Mahalanobis distances but tests using PAD showed the differences between group means to be significant
基金support provided by the Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture,Insect Pest Control Subprograms under the CRP D4201supported with funding from Ambrose Monell Foundation(to SA),and National Institutes of Health(R01AI068932 and R01AI139525 to SA)National Institutes of Health(R21AI163969 to SA and BW).
文摘Tsetse(Glossina spp.)are vectors of African trypanosomes that cause devastating human and animal African trypanosomiases.While much of the research to better understand tsetse genetics and physiology relies on colony-reared flies,these flies may not represent the genetic diversity found in natural wild populations due to their long-term captivity.To enhance the translation of colony research into field applications,we utilized Nanopore sequencing to assemble genomes for a wild-caught female Glossina fuscipes fuscipes(Gff)from northwestern Uganda and for a female Gff from a laboratory line originally sourced from the Central African Republic in 1986.The new assemblies,from the wild-caught Gff(405.98 Mb,N50:56.86 Mb)and the laboratory-derived Gff(398.22 Mb,N50:47.811 Mb),demonstrate near-chromosomal level contiguity,high BUSCO scores(>99.5%),high QV scores(>37),and over 12345 genes.Alignments between both new genomes reveal conserved synteny with only minor structural variants in the X,1L,1R,2L,and 2R tsetse chromosomes.While most orthologs(10730)were shared between both new genomes,we identified 381 unique orthologs and a small number of highly diverged shared single-copy homologs(3.84%).These gene-set differences could represent population-level variation due to the distinct geographic origin of these flies or adaptation to colony conditions.Our new high-quality genomes,with improvements in contiguity and completeness compared to the current NCBI RefSeq Gff genome,lay the foundation for advanced tsetse research,enabling robust lab-to-field translational applications to deepen our understanding of vector biology and disease transmission dynamics.
基金the financial support for this research by the following organizations and agencies:International Atomic Energy Agency,under the coordinated research project D42017 and contract number:22666the Swedish International Development Cooperation Agency(Sida)+4 种基金the Swiss Agency for Development and Cooperation(SDC)the Australian Centre for International Agricultural Research(ACIAR)the Government of Norwaythe German Federal Ministry for Economic Cooperation and Development(BMZ)the Government of the Republic of Kenya.
文摘Glossina austeni Newstead(Diptera:Glossinidae)is a competent vector of the trypanosomes causing human African trypanosomiasis and the African animal trypanosomosis.Management of this pest has primarily involved trapping methods,Sterile Insect Technique,and research into vector competence–symbiotic interactions.Nevertheless,the use of entomopathogenic fungi(EPF)in integrated pest management programs for G.austeni control remains limited.Moreover,different tsetse fly species exhibit varying susceptibility to different EPF strains,indicating that no single strain is universally effective.Therefore,our study aimed to identify candidate EPF isolates for G.austeni management,evaluate the effects of temperature on the radial growth of these potent isolates,and assess the impact of the candidate EPF on the gut microbiome of G.austeni.Consequently,16 Metarhizium anisopliae(Metschn.)Sorokin isolates were screened against G.austeni using dry conidia in an infection chamber,with the most virulent isolates having LT50 values of 3.95−9.37 d.Temperature significantly influenced the radial growth,conidia germination,and yield of these strains.There were also significant differences in conidia acquisition,retention and transmission between male and female G.austeni flies.Furthermore,all conidia receivers carried sufficient conidia,5 d post-interaction with EPF-challenged conidia donors.Microbiome analysis revealed Wigglesworthia,Serratia,Klebsiella,and Escherichia as the most abundant taxa.Among the M.anisopliae isolates,ICIPE 82 exhibited the fastest radial growth and highest thermostability,hence selected as a potential biopesticide candidate for managing G.austeni.This study demonstrates the efficacy and potential of M.anisopliae ICIPE 82 as a biopesticide for controlling G.austeni.
文摘The diurnal activity patterns, trypanosome infection rates and movement of Glossinafuscipesfuscipes （Diptera： Glossinidae） were investigated in Buvuma Island, Lake Victoria, Uganda. Hourly trapping of tsetse flies was undertaken to determine their activity rhythm while a capture-mark-release-recapture method was conducted to assess the movement and dispersal of tsetse flies between lakeshore, hinterland and further inland sites along a transected area. Dissection of tsetse flies was also undertaken to determine the trypanosome infection rates in salivary glands, proboscis and mid-gut. Results indicated a bimodal diurnal activity profile for G. f fuscipes on the Island, both on the lakeshore and in the hinterland. Movement and dispersal of G. f fuscipes tsetse flies occurred between lakeshore, hinterland and further inland sites with a greater tendency of flies to move to the lakeshore. Trypanosome infection rates of 4.32% for Trypasoma vivax and 1.15% for 7. congolense were found in G. f. fuscipes.
文摘The flies of genus Glossina (Diptera: Glossinidae) are an important vector of African trypanosomiases which cause diseases in humans and animals. The ribosomal DNA Internal Transcribed Spacer-2 (ITS-2) region sequences from different Glossina species were PCR-amplified and analyzed in order to construct a molecular phylogeny for genus Glossina. Trees generated by parsimony confirmed the monophyletic taxonomic placement of genus Glossina where fusca group species formed the deepest branch followed by morsitans and palpalis groups, respectively. The placement of Glossina austeni by both the traditional morphological and biochemical criteria has been controversial. Results presented here, based on ITS-2 locus sequence analysis, suggest that Glossina austeni can be placed into a separate subgenerus which forms a sister-group relationship with the morsitans group species.
基金This work was supported by the Bill and Melinda Gates Foundation(www.gatesfoundation.org)through the Human African Trypanosomiasis Modelling and Economic Predictions for Policy(HAT MEPP)project[OPP1177824 and INV-005121](CH,REC,PEB,MA,EHC,KSR)through the NTD Modelling Consortium[OPP1184344](KSR),and the Trypa-NO!project[INV-008412 and INV-001785](PRB,AP,SJT,PS and IT)+1 种基金SJT received funding from the Biotechnology and Biological Sciences Research Council(www.bbsrc.ukri.orgGrants BB/S01375X/1,BB/S00243X/1,BB/P005888/1).The funders had no role in study design,data collection and analysis,decision to publish,or preparation of the manuscript.
文摘Background:In recent years,a programme of vector control,screening and treatment of gambiense human African trypanosomiasis(gHAT)infections led to a rapid decline in cases in the Mandoul focus of Chad.To represent the biology of transmission between humans and tsetse,we previously developed a mechanistic transmission model,fitted to data between 2000 and 2013 which suggested that transmission was interrupted by 2015.The present study outlines refinements to the model to:(1)Assess whether elimination of transmission has already been achieved despite low-level case reporting;(2)quantify the role of intensified interventions in transmission reduction;and(3)predict the trajectory of gHAT in Mandoul for the next decade under different strategies.Method:Our previous gHAT transmission model for Mandoul was updated using human case data(2000-2019)and a series of model refinements.These include how diagnostic specificity is incorporated into the model and improvements to the fitting method(increased variance in observed case reporting and how underreporting and improvements to passive screening are captured).A side-by-side comparison of fitting to case data was performed between the models.Results:We estimated that passive detection rates have increased due to improvements in diagnostic availability in fixed health facilities since 2015,by 2.1-fold for stage 1 detection,and 1.5-fold for stage 2.We find that whilst the diagnostic algorithm for active screening is estimated to be highly specific(95%credible interval(CI):99.9-100%,Specificity=99.9%),the high screening and low infection levels mean that some recently reported cases with no parasitological confirmation might be false positives.We also find that the focus-wide tsetse reduction estimated through model fitting(95%CI:96.1-99.6%,Reduction=99.1%)is comparable to the reduction previously measured by the decline in tsetse catches from monitoring traps.In line with previous results,the model suggests that transmission was interrupted in 2015 due to intensified interventions.Conclusions:We recommend that additional confirmatory testing is performed in Mandoul to ensure the endgame can be carefully monitored.More specific measurement of cases,would better inform when it is safe to stop active screening and vector control,provided there is a strong passive surveillance system in place.
