Sterile Insect Technique (SIT) applications against major insect pests and disease vectors rely on the cost-effective production of high-quality sterile males. This largely depends on the optimal management of target ...Sterile Insect Technique (SIT) applications against major insect pests and disease vectors rely on the cost-effective production of high-quality sterile males. This largely depends on the optimal management of target pest colonies by maximizing the benefits provided by a genetically rich and pathogen-free mother colony, the presence of symbiotic microorganisms, and efficient domestication, mass-rearing, irradiation, and release processes. At the same time microbial (bacteria, fungi, microsporidia, and viruses) pathogen outbreaks should be minimized or eliminated, and the use of hazardous chemicals restricted. The optimization of the colony management strategies for different SIT target insects will ensure a standardized high-quality mass-rearing process and the cost-effective production of sterile males with enhanced field performance and male mating competitiveness. The aims of the Coordinated Research Project (CRP) were to develop best practices for insect colony management for the cost-effective production of high-quality sterile males for SIT applications against major insect pests and disease vectors through a multidisciplinary approach involving entomologists, geneticists, ecologists, microbiologists, pathologists, virologists, and mass-rearing experts.展开更多
Sterile Insect Technique(SIT)has proven effective to reduce tsetse population density in large infected areas where animal African trypanosomosis(AAT)and human African trypanosomiasis(HAT)elimination was difficult to ...Sterile Insect Technique(SIT)has proven effective to reduce tsetse population density in large infected areas where animal African trypanosomosis(AAT)and human African trypanosomiasis(HAT)elimination was difficult to achieve.However,the decrease in mass production of insectary-reared tsetse and the limited but incomplete knowledge on symbiont–trypanosome interaction over time,impede large-scale use of SIT.We investigated the spatiotemporal changes in symbiont prevalence and symbiont–trypanosome interactions in wild tsetse of Sora-Mboum AAT focus in northern Cameroon,collected in 2019 and 2020,to provide insights into the mass production of refractory tsetse.Spiroplasma spp.,Sodalis glossinidius and trypanosomes were screened with PCR.G.tachinoides was the most abundant Glossina species found in Sora-Mboum focus.Symbiont prevalences in G.tachinoides were higher in 2019 compared to 2020,from 67.6%to 53.5%for Spiroplasma spp.and from 28.8%to 8.1%for S.glossinidius.These symbionts were also found at higher prevalence in flies from Mouhoun HAT focus in Burkina Faso.Four trypanosome taxa(Trypanosoma congolense forest type,T.congolense savannah type,T.brucei s.l.,and T.vivax)were found in Sora-Mboum focus and Mouhoun focus,though at lower prevalence in Mouhoun.The presence of Spiroplasma spp.in adult tsetse was negatively associated with that of trypanosomes.Our study highlights the potential of Spiroplasma spp.as a good paratransgenesis candidate to enhance SIT application.This symbiont is naturally found in high proportions of tsetse and could prevent factory flies from acquiring and transmitting trypanosomes during their lifespan when released for population density control.展开更多
Trypanosomiasis,transmitted by tsetse flies(Glossina spp.),poses a significant health threat in 36 sub-Saharan African countries.Current control methods targeting tsetse flies,while effective,allow reinfestation.This ...Trypanosomiasis,transmitted by tsetse flies(Glossina spp.),poses a significant health threat in 36 sub-Saharan African countries.Current control methods targeting tsetse flies,while effective,allow reinfestation.This study investigates paratransgenesis,a novel strategy to engineer symbiotic bacteria in tsetse flies,Sodalis glossinidius,to deliver anti-trypanosome compounds.Disrupting the trypanosome life cycle within the fly and reducing parasite transmission could offer a sustainable solution for trypanosomiasis control.In this context,we tested the effect of cecropin,reported to be lethal for Trypanosoma cruzi(Chagas disease)and TbgTCTP(Translationally Controlled Tumor Protein from Trypanosoma brucei gambiense),previously reported to modulate the growth of bacteria isolated from the fly microbiome,to delay the first peak of parasitemia and the death of trypanosome-infected mice.We have successfully cloned and transfected the genes encoding the two proteins into Sodalis strains.These Sodalis recombinant strains(recSodalisTbgTCTP and recSodaliscecropin)have been then microinjected into the L3 larval stage of Glossina palpalis gambiensis flies.The stability of the cloned genes was checked up to the 20th day after microinjection of recSodalis.The rate of fly emergence from untreated pupae was 95%;it was reduced by nearly 50%due to the mechanical injury caused by microinjection.It decreased to nearly 7%when larvae were injected with recSodalisTbgTCTP,which suggests TCTP could have a lethal impact to larvae development.When challenged with T.brucei gambiense,a slightly lower,but statistically non-significant,infection rate was recorded in flies harboring recSodaliscecropin compared to control flies.The effect of recSodalisTbgTCTP could not be measured due to the very low rate of fly emergence after corresponding treatment of the larvae.The results do not allow to conclude on the effect of cecropin or TCTP,delivered by para-transgenesis into the fly's gut,on the fly infection by the trypanosome.Nevertheless,the results are encouraging insofar as the technical approach works on the couple G.p.gambiensis/T.brucei gambiense.The next step will be to optimize the system and test other targets chosen among the ESPs(Excreted-Secreted Proteins)of the trypanosome secretum,or the differentially expressed genes associated with the sensitivity/resistance of the fly to trypanosome infection.展开更多
文摘Sterile Insect Technique (SIT) applications against major insect pests and disease vectors rely on the cost-effective production of high-quality sterile males. This largely depends on the optimal management of target pest colonies by maximizing the benefits provided by a genetically rich and pathogen-free mother colony, the presence of symbiotic microorganisms, and efficient domestication, mass-rearing, irradiation, and release processes. At the same time microbial (bacteria, fungi, microsporidia, and viruses) pathogen outbreaks should be minimized or eliminated, and the use of hazardous chemicals restricted. The optimization of the colony management strategies for different SIT target insects will ensure a standardized high-quality mass-rearing process and the cost-effective production of sterile males with enhanced field performance and male mating competitiveness. The aims of the Coordinated Research Project (CRP) were to develop best practices for insect colony management for the cost-effective production of high-quality sterile males for SIT applications against major insect pests and disease vectors through a multidisciplinary approach involving entomologists, geneticists, ecologists, microbiologists, pathologists, virologists, and mass-rearing experts.
基金financial support from IAEA CRP D42017(Improvement of Colony Management in insect Mass-Rearing for SIT Applications)Contract Number:22636,from the Medical Research Council of the UK through the Global Challenges Research Fund(grant number MR/P027873/1)Laboratory facilities from the Centre for Research in Infectious Diseases(CRID),Yaoundé,Cameroon.
文摘Sterile Insect Technique(SIT)has proven effective to reduce tsetse population density in large infected areas where animal African trypanosomosis(AAT)and human African trypanosomiasis(HAT)elimination was difficult to achieve.However,the decrease in mass production of insectary-reared tsetse and the limited but incomplete knowledge on symbiont–trypanosome interaction over time,impede large-scale use of SIT.We investigated the spatiotemporal changes in symbiont prevalence and symbiont–trypanosome interactions in wild tsetse of Sora-Mboum AAT focus in northern Cameroon,collected in 2019 and 2020,to provide insights into the mass production of refractory tsetse.Spiroplasma spp.,Sodalis glossinidius and trypanosomes were screened with PCR.G.tachinoides was the most abundant Glossina species found in Sora-Mboum focus.Symbiont prevalences in G.tachinoides were higher in 2019 compared to 2020,from 67.6%to 53.5%for Spiroplasma spp.and from 28.8%to 8.1%for S.glossinidius.These symbionts were also found at higher prevalence in flies from Mouhoun HAT focus in Burkina Faso.Four trypanosome taxa(Trypanosoma congolense forest type,T.congolense savannah type,T.brucei s.l.,and T.vivax)were found in Sora-Mboum focus and Mouhoun focus,though at lower prevalence in Mouhoun.The presence of Spiroplasma spp.in adult tsetse was negatively associated with that of trypanosomes.Our study highlights the potential of Spiroplasma spp.as a good paratransgenesis candidate to enhance SIT application.This symbiont is naturally found in high proportions of tsetse and could prevent factory flies from acquiring and transmitting trypanosomes during their lifespan when released for population density control.
文摘Trypanosomiasis,transmitted by tsetse flies(Glossina spp.),poses a significant health threat in 36 sub-Saharan African countries.Current control methods targeting tsetse flies,while effective,allow reinfestation.This study investigates paratransgenesis,a novel strategy to engineer symbiotic bacteria in tsetse flies,Sodalis glossinidius,to deliver anti-trypanosome compounds.Disrupting the trypanosome life cycle within the fly and reducing parasite transmission could offer a sustainable solution for trypanosomiasis control.In this context,we tested the effect of cecropin,reported to be lethal for Trypanosoma cruzi(Chagas disease)and TbgTCTP(Translationally Controlled Tumor Protein from Trypanosoma brucei gambiense),previously reported to modulate the growth of bacteria isolated from the fly microbiome,to delay the first peak of parasitemia and the death of trypanosome-infected mice.We have successfully cloned and transfected the genes encoding the two proteins into Sodalis strains.These Sodalis recombinant strains(recSodalisTbgTCTP and recSodaliscecropin)have been then microinjected into the L3 larval stage of Glossina palpalis gambiensis flies.The stability of the cloned genes was checked up to the 20th day after microinjection of recSodalis.The rate of fly emergence from untreated pupae was 95%;it was reduced by nearly 50%due to the mechanical injury caused by microinjection.It decreased to nearly 7%when larvae were injected with recSodalisTbgTCTP,which suggests TCTP could have a lethal impact to larvae development.When challenged with T.brucei gambiense,a slightly lower,but statistically non-significant,infection rate was recorded in flies harboring recSodaliscecropin compared to control flies.The effect of recSodalisTbgTCTP could not be measured due to the very low rate of fly emergence after corresponding treatment of the larvae.The results do not allow to conclude on the effect of cecropin or TCTP,delivered by para-transgenesis into the fly's gut,on the fly infection by the trypanosome.Nevertheless,the results are encouraging insofar as the technical approach works on the couple G.p.gambiensis/T.brucei gambiense.The next step will be to optimize the system and test other targets chosen among the ESPs(Excreted-Secreted Proteins)of the trypanosome secretum,or the differentially expressed genes associated with the sensitivity/resistance of the fly to trypanosome infection.
