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Smidler AL, Marrogi E, Kauffman J, Paton DG, Westervelt KA, Church GM, Esvelt KM, Shaw WR, Catteruccia F. CRISPR-mediated germline mutagenesis for genetic sterilization of Anopheles gambiae males. Sci Rep 2024; 14:4057. [PMID: 38374393 PMCID: PMC10876656 DOI: 10.1038/s41598-024-54498-8] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2023] [Accepted: 02/13/2024] [Indexed: 02/21/2024] Open
Abstract
Rapid spread of insecticide resistance among anopheline mosquitoes threatens malaria elimination efforts, necessitating development of alternative vector control technologies. Sterile insect technique (SIT) has been successfully implemented in multiple insect pests to suppress field populations by the release of large numbers of sterile males, yet it has proven difficult to adapt to Anopheles vectors. Here we outline adaptation of a CRISPR-based genetic sterilization system to selectively ablate male sperm cells in the malaria mosquito Anopheles gambiae. We achieve robust mosaic biallelic mutagenesis of zero population growth (zpg, a gene essential for differentiation of germ cells) in F1 individuals after intercrossing a germline-expressing Cas9 transgenic line to a line expressing zpg-targeting gRNAs. Approximately 95% of mutagenized males display complete genetic sterilization, and cause similarly high levels of infertility in their female mates. Using a fluorescence reporter that allows detection of the germline leads to a 100% accurate selection of spermless males, improving the system. These males cause a striking reduction in mosquito population size when released at field-like frequencies in competition cages against wild type males. These findings demonstrate that such a genetic system could be adopted for SIT against important malaria vectors.
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Affiliation(s)
- Andrea L Smidler
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
- Department of Biology, University of California - San Diego, San Diego, CA, 92093, USA
| | - Eryney Marrogi
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Jamie Kauffman
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - Douglas G Paton
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
- Department of Infectious Diseases, University of Georgia, Athens, GA, 30602, USA
| | - Kathleen A Westervelt
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA
| | - George M Church
- Department of Genetics, Harvard Medical School, Boston, MA, 02115, USA
| | - Kevin M Esvelt
- Media Lab, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - W Robert Shaw
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA.
- Howard Hughes Medical Institute, Chevy Chase, MD, 20815, USA.
| | - Flaminia Catteruccia
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA, 02115, USA.
- Howard Hughes Medical Institute, Chevy Chase, MD, 20815, USA.
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Ali Y, Siddig EE, Mohamed N, Ahmed A. Rift Valley fever and malaria co-infection: A case report. Clin Case Rep 2023; 11:e7926. [PMID: 37731970 PMCID: PMC10507219 DOI: 10.1002/ccr3.7926] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2023] [Revised: 08/29/2023] [Accepted: 09/04/2023] [Indexed: 09/22/2023] Open
Abstract
Key Clinical Message We report a case of febrile illness that was presented with mild symptoms. However, laboratory investigation confirmed a malaria and Rift Valley fever co-infection. Healthcare providers in settings endemic with several infectious diseases should seek rolling out possibilities of other infections prior to starting treatment for achieving effective case management with less resources and better safety of patients. Abstract Here we report a case of febrile illness that confirmed to be a co-infection of malaria and Rift Valley fever. The patient was initially diagnosed with malaria and started on treatment immediately. However, due to the lack of response to the treatment further laboratory investigations were pursued.
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Affiliation(s)
- Yousif Ali
- Sudan Field Epidemiology Training, Health Emergencies and Epidemics Control General DirectorateSudan Federal Ministry of HealthKhartoumSudan
| | - Emmanuel Edwar Siddig
- Faculty of Medical Laboratory SciencesUniversity of KhartoumKhartoumSudan
- Department of Medical Microbiology and Infectious DiseasesErasmus University Medical Center RotterdamRotterdamThe Netherlands
| | - Nouh Mohamed
- Molecular Biology UnitSirius Training and Research CentreKhartoumSudan
| | - Ayman Ahmed
- Swiss Tropical and Public Health Institute (Swiss TPH)AllschwilSwitzerland
- Faculty of ScienceUniversity of BaselBaselSwitzerland
- Institute of Endemic DiseasesUniversity of KhartoumKhartoumSudan
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Smidler AL, Apte RA, Pai JJ, Chow ML, Chen S, Mondal A, Sánchez C. HM, Antoshechkin I, Marshall JM, Akbari OS. Eliminating Malaria Vectors with Precision Guided Sterile Males. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.07.20.549947. [PMID: 37503146 PMCID: PMC10370176 DOI: 10.1101/2023.07.20.549947] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/29/2023]
Abstract
Controlling the principal African malaria vector, the mosquito Anopheles gambiae, is considered essential to curtail malaria transmission. However existing vector control technologies rely on insecticides, which are becoming increasingly ineffective. Sterile insect technique (SIT) is a powerful suppression approach that has successfully eradicated a number of insect pests, yet the A. gambiae toolkit lacks the requisite technologies for its implementation. SIT relies on iterative mass-releases of non-biting, non-driving, sterile males which seek out and mate with monandrous wild females. Once mated, females are permanently sterilized due to mating-induced refractoriness, which results in population suppression of the subsequent generation. However, sterilization by traditional methods renders males unfit, making the creation of precise genetic sterilization methods imperative. Here we develop precision guided Sterile Insect Technique (pgSIT) in the mosquito A. gambiae for inducible, programmed male-sterilization and female-elimination for wide scale use in SIT campaigns. Using a binary CRISPR strategy, we cross separate engineered Cas9 and gRNA strains to disrupt male-fertility and female-essential genes, yielding >99.5% male-sterility and >99.9% female-lethality in hybrid progeny. We demonstrate that these genetically sterilized males have good longevity, are able to induce population suppression in cage trials, and are predicted to eliminate wild A. gambiae populations using mathematical models, making them ideal candidates for release. This work provides a valuable addition to the malaria genetic biocontrol toolkit, for the first time enabling scalable SIT-like confinable suppression in the species.
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Affiliation(s)
- Andrea L. Smidler
- School of Biological Sciences, Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093
| | - Reema A. Apte
- School of Biological Sciences, Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093
| | - James J. Pai
- School of Biological Sciences, Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093
| | - Martha L. Chow
- School of Biological Sciences, Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093
| | - Sanle Chen
- School of Biological Sciences, Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093
| | - Agastya Mondal
- Divisions of Epidemiology & Biostatistics, School of Public Health, University of California, Berkeley, CA 94720, USA
| | - Héctor M. Sánchez C.
- Divisions of Epidemiology & Biostatistics, School of Public Health, University of California, Berkeley, CA 94720, USA
| | - Igor Antoshechkin
- Division of Biology and Biological Engineering (BBE), California Institute of Technology, Pasadena, CA91125, USA
| | - John M. Marshall
- Divisions of Epidemiology & Biostatistics, School of Public Health, University of California, Berkeley, CA 94720, USA
- Innovative Genomics Institute, University of California, Berkeley, CA 94720, USA
| | - Omar S. Akbari
- School of Biological Sciences, Department of Cell and Developmental Biology, University of California, San Diego, La Jolla, CA 92093
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4
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Smidler AL, Paton DG, Church GM, Esvelt KM, Shaw WR, Catteruccia F. CRISPR-mediated germline mutagenesis for genetic sterilization of Anopheles gambiae males. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.06.13.544841. [PMID: 37398131 PMCID: PMC10312776 DOI: 10.1101/2023.06.13.544841] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Rapid spread of insecticide resistance among anopheline mosquitoes threatens malaria elimination efforts, necessitating development of alternative vector control technologies. Sterile Insect Technique (SIT) has been successfully implemented in multiple insect pests to suppress field populations by the release of large numbers of sterile males, yet it has proven difficult to adapt to Anopheles vectors. Here we outline adaptation of a CRISPR-based genetic sterilization system to selectively ablate male sperm cells in the malaria mosquito Anopheles gambiae. We achieve robust mosaic biallelic mutagenesis of zero population growth (zpg, a gene essential for differentiation of germ cells) in F1 individuals after intercrossing a germline-expressing Cas9 transgenic line to a line expressing zpg-targeting gRNAs. Approximately 95% of mutagenized males display complete genetic sterilization, and cause similarly high levels of infertility in their female mates. Using a fluorescence reporter that allows detection of the germline leads to a 100% accurate selection of spermless males, improving the system. These males cause a striking reduction in mosquito population size when released at field-like frequencies in competition cages against wild type males. These findings demonstrate that such a genetic system could be adopted for SIT against important malaria vectors.
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Affiliation(s)
- Andrea L Smidler
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Douglas G Paton
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
| | - George M Church
- Department of Genetics, Harvard Medical School, Boston, MA 02115, USA
| | - Kevin M Esvelt
- Media Lab, Massachusetts Institute of Technology, Cambridge, MA 02139, USA
| | - W Robert Shaw
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- Howard Hughes Medical Institute, Chevy Chase MD 20815, USA
| | - Flaminia Catteruccia
- Department of Immunology and Infectious Diseases, Harvard T.H. Chan School of Public Health, Boston, MA 02115, USA
- Howard Hughes Medical Institute, Chevy Chase MD 20815, USA
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Abubakr M, Sami H, Mahdi I, Altahir O, Abdelbagi H, Mohamed NS, Ahmed A. The Phylodynamic and Spread of the Invasive Asian Malaria Vectors, Anopheles stephensi, in Sudan. BIOLOGY 2022; 11:biology11030409. [PMID: 35336783 PMCID: PMC8945054 DOI: 10.3390/biology11030409] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 01/22/2022] [Revised: 02/14/2022] [Accepted: 02/17/2022] [Indexed: 11/28/2022]
Abstract
Simple Summary Climate change increases the suitability of some environments for the establishment of newly introduced insects and is a major driver for the spread of mosquitoes that transmit diseases. Anopheles stephensi is a disease vector mosquito that transmits malaria and is naturally endemic in Asia. This vector newly emerged in Africa (first report from Djibouti in 2012), where annual malaria infections and deaths are the highest worldwide. This mosquito has different ecology and behavior from previously known malaria vectors in Africa, which makes control difficult for local under-resourced health systems. Considering the capacity of this vector to transmit at least two malaria-causing parasites (Plasmodium falciparum and Plasmodium vivax), we investigated its distribution and population structure in Sudan and assessed the potential risk of its further spread into neighboring countries. Using morphological and genomic sequencing techniques, we confirmed the presence of Anopheles stephensi along the borders of six countries previously assumed as free, including Chad, Egypt, Eritrea, Libya, Republic of Central Africa, and South Sudan. African countries need to enhance vector surveillance and control services and utilize genomics tools for tracking the dynamics of invasive disease vectors. Abstract Anopheles stephensi is an invasive Asian malaria vector that initially emerged in Africa in 2012 and was reported in Sudan in 2019. We investigated the distribution and population structure of An. stephensi throughout Sudan by using sequencing and molecular tools. We confirmed the presence of An. stephensi in eight border-states, identifying both natural and human-made breeding sites. Our analysis revealed the presence of 20 haplotypes with different distributions per state. This study revealed a countrywide spread of An. stephensi in Sudan, with confirmed presence in borders states with Chad, Egypt, Eritrea, Ethiopia, Libya, Republic of Central Africa, and South Sudan. Detection of An. stephensi at points of entry with these countries, particularly Chad, Libya, and South Sudan, indicates the rapid previously undetected spread of this invasive vector. Our phylogenetic and haplotype analysis suggested local establishment and evolutionary adaptation of the vector to different ecological and environmental conditions in Sudan. Urgent engagement of the global community is essential to control and prevent further spread into Africa.
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Affiliation(s)
- Mustafa Abubakr
- Directorate of the Integrated Vector Management (IVM), Federal Ministry of Health, Khartoum 11111, Sudan; (M.A.); (H.S.); (I.M.)
| | - Hamza Sami
- Directorate of the Integrated Vector Management (IVM), Federal Ministry of Health, Khartoum 11111, Sudan; (M.A.); (H.S.); (I.M.)
| | - Isam Mahdi
- Directorate of the Integrated Vector Management (IVM), Federal Ministry of Health, Khartoum 11111, Sudan; (M.A.); (H.S.); (I.M.)
| | - Omnia Altahir
- Molecular Biology Unit, Sirius Training and Research Centre, Khartoum 11111, Sudan; (O.A.); (H.A.); (N.S.M.)
| | - Hanadi Abdelbagi
- Molecular Biology Unit, Sirius Training and Research Centre, Khartoum 11111, Sudan; (O.A.); (H.A.); (N.S.M.)
| | - Nouh Saad Mohamed
- Molecular Biology Unit, Sirius Training and Research Centre, Khartoum 11111, Sudan; (O.A.); (H.A.); (N.S.M.)
| | - Ayman Ahmed
- Directorate of the Integrated Vector Management (IVM), Federal Ministry of Health, Khartoum 11111, Sudan; (M.A.); (H.S.); (I.M.)
- Molecular Biology Unit, Sirius Training and Research Centre, Khartoum 11111, Sudan; (O.A.); (H.A.); (N.S.M.)
- Institute of Endemic Diseases, University of Khartoum, Khartoum 11111, Sudan
- Swiss Tropical and Public Health Institute (Swiss TPH), 4123 Allschwil, Switzerland
- Faculty of Science, University of Basel, Petersplatz 1, 4001 Basel, Switzerland
- Correspondence: or ; Tel.: +249-123997091
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Mark-release-recapture experiment in Burkina Faso demonstrates reduced fitness and dispersal of genetically-modified sterile malaria mosquitoes. Nat Commun 2022; 13:796. [PMID: 35145082 PMCID: PMC8831579 DOI: 10.1038/s41467-022-28419-0] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2021] [Accepted: 01/12/2022] [Indexed: 11/15/2022] Open
Abstract
Every year, malaria kills approximately 405,000 people in Sub-Saharan Africa, most of them children under the age of five years. In many countries, progress in malaria control has been threatened by the rapid spread of resistance to antimalarial drugs and insecticides. Novel genetic mosquito control approaches could play an important role in future integrated malaria control strategies. In July 2019, the Target Malaria consortium proceeded with the first release of hemizygous genetically-modified (GM) sterile and non-transgenic sibling males of the malaria mosquito Anopheles coluzzii in Burkina Faso. This study aimed to determine the potential fitness cost associated to the transgene and gather important information related to the dynamic of transgene-carrying mosquitoes, crucial for next development steps. Bayesian estimations confirmed that GM males had lower survival and were less mobile than their wild type (WT) siblings. The estimated male population size in Bana village, at the time of the release was 28,000 - 37,000. These results provide unique information about the fitness and behaviour of released GM males that will inform future releases of more effective strains of the A. gambiae complex. Release of genetically-modified sterile mosquitoes is a potential method of malaria control but has yet to be tested in the field. Here, the authors perform a mark-release-recapture experiment and show that genetically-modified mosquitoes have reduced survival and dispersal compared to wild-types.
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Mohamed NS, AbdElbagi H, Elsadig AR, Ahmed AE, Mohammed YO, Elssir LT, Elnour MAB, Ali Y, Ali MS, Altahir O, Abubakr M, Siddig EE, Ahmed A, Omer RA. Assessment of genetic diversity of Plasmodium falciparum circumsporozoite protein in Sudan: the RTS,S leading malaria vaccine candidate. Malar J 2021; 20:436. [PMID: 34758827 PMCID: PMC8579544 DOI: 10.1186/s12936-021-03971-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/13/2021] [Accepted: 11/01/2021] [Indexed: 11/20/2022] Open
Abstract
Background The currently used malaria vaccine, RTS,S, is designed based on the Plasmodium falciparum circumsporozoite protein (PfCSP). The pfcsp gene, besides having different polymorphic patterns, can vary between P. falciparum isolates due to geographical origin and host immune response. Such aspects are essential when considering the deployment of the RTS,S vaccine in a certain region. Therefore, this study assessed the genetic diversity of P. falciparum in Sudan based on the pfcsp gene by investigating the diversity at the N-terminal, central repeat, and the C-terminal regions. Methods A cross-sectional molecular study was conducted; P. falciparum isolates were collected from different health centres in Khartoum State between January and December 2019. During the study period, a total of 261 febrile patients were recruited. Malaria diagnosis was made by expert microscopists using Giemsa-stained thick and thin blood films. DNA samples were examined by the semi-nested polymerase chain reaction (PCR). Single clonal infection of the confirmed P. falciparum cases, were used to amplify the pfcsp gene. The amplified amplicons of pfcsp have been sequenced using the Sanger dideoxy method. The obtained sequences of pfcsp nucleotide diversity parameters including the numbers of haplotypes (Hap), haplotypes diversity (Hapd), the average number of nucleotide differences between two sequences (p), and the numbers of segregating sites (S) were obtained. The haplotype networks were constructed using the online tcsBU software. Natural selection theory was also tested on pfcsp using Fuand Li’s D, Fuand Li’s F statistics, and Tajima’s D test using DnaSP. Results In comparison with the different pfcsp reference strains, the Sudanese isolates showed high similarity with other African isolates. The results of the N-terminal region showed the presence of 2 different haplotypes with a Hapd of 0.425 ± 0.00727. The presence of the unique insertion of NNNGDNGREGKDEDKRDGNN was reported. The KLKQP motif was conserved in all the studied isolates. At the central repeat region, 11 haplotypes were seen with a Hapd of 0.779 ± 0.00097. The analysis of the genetic diversity in the C-terminal region showed the presence of 10 haplotypes with a Hapd of 0.457 ± 0.073. Several non-synonymous amino acids changes were also seen at the Th2R and the Th3R T-cell epitope regions including T317K, E317K, Q318E, K321N, I322K, T322K, R322K, K324Q, I327L, G352N, S354P, R355K, N356D, Q357E, and E361A. Conclusions In this study, the results indicated a high conservation at the pfcsp gene. This may further contribute in understanding the genetic polymorphisms of P. falciparum prior to the deployment of the RTS,S vaccine in Sudan.
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Affiliation(s)
- Nouh Saad Mohamed
- Department of Parasitology and Medical Entomology, Tropical Medicine Research Institute, National Centre for Research, Khartoum, Sudan. .,Molecular Biology Unit, Sirius Training and Research Centre, Khartoum, Sudan.
| | - Hanadi AbdElbagi
- Molecular Biology Unit, Sirius Training and Research Centre, Khartoum, Sudan
| | | | | | - Yassir Osman Mohammed
- Department of Parasitology and Medical Entomology, Tropical Medicine Research Institute, National Centre for Research, Khartoum, Sudan
| | - Lubna Taj Elssir
- Department of Parasitology and Medical Entomology, Tropical Medicine Research Institute, National Centre for Research, Khartoum, Sudan
| | - Mohammed-Ahmed B Elnour
- Department of Parasitology and Medical Entomology, Tropical Medicine Research Institute, National Centre for Research, Khartoum, Sudan
| | - Yousif Ali
- Health Emergencies and Epidemics Control General Directorate, Sudan Federal Ministry of Health, Khartoum, Sudan
| | - Mohamed S Ali
- Faculty of Medicine, EL-Neelain University, Khartoum, Sudan
| | - Omnia Altahir
- Department of Parasitology and Medical Entomology, Tropical Medicine Research Institute, National Centre for Research, Khartoum, Sudan
| | - Mustafa Abubakr
- Department of the Integrated Vector Management (IVM), Federal Ministry of Health, Khartoum, Sudan
| | | | - Ayman Ahmed
- Molecular Biology Unit, Sirius Training and Research Centre, Khartoum, Sudan
| | - Rihab Ali Omer
- Pediatric Epidemiology, Clinic and Polyclinic for Child and Adolescent Medicine, Medical Faculty, University of Leipzig, Leipzig, Germany
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8
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Ahmed A, Khogali R, Elnour MAB, Nakao R, Salim B. Emergence of the invasive malaria vector Anopheles stephensi in Khartoum State, Central Sudan. Parasit Vectors 2021; 14:511. [PMID: 34600584 PMCID: PMC8487507 DOI: 10.1186/s13071-021-05026-4] [Citation(s) in RCA: 24] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2021] [Accepted: 09/16/2021] [Indexed: 11/10/2022] Open
Abstract
The emergence of the Asian invasive malaria vector, Anopheles stephensi, has been identified in Khartoum, the capital city of Sudan. This is the first report that confirms the geographical expansion of this urban mosquito into Central Sudan. We urgently recommend the launch of a national entomological survey to determine the distribution of this invasive disease vector and to generate essential information about its bionomics and susceptibility to available malaria control measures.
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Affiliation(s)
- Ayman Ahmed
- Institute of Endemic Diseases, University of Khartoum, 11111, Khartoum, Sudan
| | - Rua Khogali
- Department of Parasitology, Faculty of Veterinary Medicine, University of Khartoum, P.O. Box 32, Khartoum North, Sudan
| | - Mohammed-Ahmed B Elnour
- Department of Parasitology & Medical Entomology, Tropical Medicine Research Institute, National Center for Research, P.O. Box 1304, 11111, Khartoum, Sudan
| | - Ryo Nakao
- Laboratory of Parasitology, Faculty of Veterinary Medicine, Graduate School of Infectious Diseases, Hokkaido University, Sapporo, Japan
| | - Bashir Salim
- Department of Parasitology, Faculty of Veterinary Medicine, University of Khartoum, P.O. Box 32, Khartoum North, Sudan.
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Kaiser ML, Wood OR, Damiens D, Brooke BD, Koekemoer LL, Munhenga G. Estimates of the population size and dispersal range of Anopheles arabiensis in Northern KwaZulu-Natal, South Africa: implications for a planned pilot programme to release sterile male mosquitoes. Parasit Vectors 2021; 14:205. [PMID: 33874984 PMCID: PMC8056555 DOI: 10.1186/s13071-021-04674-w] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2020] [Accepted: 03/07/2021] [Indexed: 11/20/2022] Open
Abstract
Background Anopheles arabiensis is a major malaria vector, recently implicated as contributing to ongoing residual malaria transmission in South Africa, which feeds and rests both indoors and outdoors. This species is, therefore, not effectively targeted using core malaria vector control interventions alone. Additionally, increasing resistance to available insecticides necessitates investigations into complementary non-insecticide-based vector control methods for outdoor-resting mosquitoes. The feasibility of the sterile insect technique (SIT) as a complementary vector control intervention is being investigated in South Africa. Successful implementation of an SIT programme largely depends on inundating a target insect population with sterilized laboratory-bred males. Therefore, knowledge of the native population size and dispersal ability of released sterile laboratory-reared males is critical. In this study, we estimated the male An. arabiensis population size and the dispersal of released males in an area targeted for a pilot sterile male release programme. Methods Three separate releases were performed within a 2-year period. Approximately 5000–15,000 laboratory-reared male An. arabiensis (KWAG) were produced and marked for mark–release–recapture experiments. To recapture released mosquitoes, cloth tubes were deployed in widening concentric circles. The average dispersal distance of released males was calculated and the wild male An. arabiensis population size was estimated using two Lincoln index formulae. The natural population was sampled concurrently and Anopheles species diversity examined. Results The Anopheles gambiae complex and An. funestus group species made up the majority of wild collections along with other anophelines. The An. arabiensis population size was estimated to be between 550 and 9500 males per hectare depending on time of year, weather conditions and method used. Average dispersal distance of marked males ranged from 58 to 86 m. Marked males were found in swarms with wild males, indicating that laboratory-reared males are able to locate and participate in mating swarms. Conclusions It was logistically feasible to conduct mark–release–recapture studies at the current scale. The population size estimates obtained may provide a guideline for the initial number of males to use for a pending SIT pilot trial. It is promising for future SIT trials that laboratory-reared marked males participated in natural swarms, appearing at the right place at the right time. ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s13071-021-04674-w.
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Affiliation(s)
- Maria L Kaiser
- Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa. .,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - Oliver R Wood
- Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa.,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - David Damiens
- UMR IRD 224, Maladies Infectieuses et Vecteurs-Ecologie-Génétique, Evolution et Contrôle (MIVEGEC), Institut de Recherche Pour Le Développement (IRD) CNRS 5290-Université de Montpellier, Montpellier, France.,IRD Réunion/GIP CYROI (Recherche Santé Bio-innovation), Sainte Clotilde, Reunion Island, France
| | - Basil D Brooke
- Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa.,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Lizette L Koekemoer
- Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa.,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Givemore Munhenga
- Centre for Emerging Zoonotic & Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa.,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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10
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Vreysen MJB, Abd-Alla AMM, Bourtzis K, Bouyer J, Caceres C, de Beer C, Oliveira Carvalho D, Maiga H, Mamai W, Nikolouli K, Yamada H, Pereira R. The Insect Pest Control Laboratory of the Joint FAO/IAEA Programme: Ten Years (2010-2020) of Research and Development, Achievements and Challenges in Support of the Sterile Insect Technique. INSECTS 2021; 12:346. [PMID: 33924539 PMCID: PMC8070182 DOI: 10.3390/insects12040346] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 03/01/2021] [Revised: 03/30/2021] [Accepted: 04/01/2021] [Indexed: 02/06/2023]
Abstract
The Joint FAO/IAEA Centre (formerly called Division) of Nuclear Techniques in Food and Agriculture was established in 1964 and its accompanying laboratories in 1961. One of its subprograms deals with insect pest control, and has the mandate to develop and implement the sterile insect technique (SIT) for selected key insect pests, with the goal of reducing the use of insecticides, reducing animal and crop losses, protecting the environment, facilitating international trade in agricultural commodities and improving human health. Since its inception, the Insect Pest Control Laboratory (IPCL) (formerly named Entomology Unit) has been implementing research in relation to the development of the SIT package for insect pests of crops, livestock and human health. This paper provides a review of research carried out between 2010 and 2020 at the IPCL. Research on plant pests has focused on the development of genetic sexing strains, characterizing and assessing the performance of these strains (e.g., Ceratitis capitata), elucidation of the taxonomic status of several members of the Bactrocera dorsalis and Anastrepha fraterculus complexes, the use of microbiota as probiotics, genomics, supplements to improve the performance of the reared insects, and the development of the SIT package for fruit fly species such as Bactrocera oleae and Drosophila suzukii. Research on livestock pests has focused on colony maintenance and establishment, tsetse symbionts and pathogens, sex separation, morphology, sterile male quality, radiation biology, mating behavior and transportation and release systems. Research with human disease vectors has focused on the development of genetic sexing strains (Anopheles arabiensis, Aedes aegypti and Aedes albopictus), the development of a more cost-effective larvae and adult rearing system, assessing various aspects of radiation biology, characterizing symbionts and pathogens, studying mating behavior and the development of quality control procedures, and handling and release methods. During the review period, 13 coordinated research projects (CRPs) were completed and six are still being implemented. At the end of each CRP, the results were published in a special issue of a peer-reviewed journal. The review concludes with an overview of future challenges, such as the need to adhere to a phased conditional approach for the implementation of operational SIT programs, the need to make the SIT more cost effective, to respond with demand driven research to solve the problems faced by the operational SIT programs and the use of the SIT to address a multitude of exotic species that are being introduced, due to globalization, and established in areas where they could not survive before, due to climate change.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Hanano Yamada
- Insect Pest Control Subprogramme, Joint FAO/IAEA Centre of Nuclear Techniques in Food and Agriculture, Department of Nuclear Sciences and Applications, International Atomic Energy Agency, A-1400 Vienna, Austria; (M.J.B.V.); (A.M.M.A.-A.); (K.B.); (J.B.); (C.C.); (C.d.B.); (D.O.C.); (H.M.); (W.M.); (K.N.); (R.P.)
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11
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Abdelwhab OF, Elaagip A, Albsheer MM, Ahmed A, Paganotti GM, Abdel Hamid MM. Molecular and morphological identification of suspected Plasmodium vivax vectors in Central and Eastern Sudan. Malar J 2021; 20:132. [PMID: 33663534 PMCID: PMC7934255 DOI: 10.1186/s12936-021-03671-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/04/2020] [Accepted: 02/25/2021] [Indexed: 11/24/2022] Open
Abstract
Background In spite of the global effort to eliminate malaria, it remains the most significant vector-borne disease of humans. Plasmodium falciparum is the dominant malaria parasite in sub-Saharan Africa. However, Plasmodium vivax is becoming widely spread throughout Africa. The overuse of vector control methods has resulted in a remarkable change in the behaviour of mosquito that feeds on human as well as on vector composition. The aim of this study was to identify Anopheles mosquito species in vivax malaria endemic regions and to investigate their role in P. vivax circumsporozoite protein (Pvcsp) allele diversity. Methods Mosquito samples were collected from Central Sudan (Rural Khartoum and Sennar) and Eastern Sudan (New Halfa, Kassala state) using pyrethrum spray catch (PSC) and CDC light traps. Mosquitoes were identified using appropriate morphological identification keys and Anopheles gambiae complex were confirmed to species level using molecular analysis. A subset of blood-fed anopheline mosquitoes were dissected to determine the presence of natural infection of malaria parasites. In addition, the rest of the samples were investigated for the presence of Pvcsp gene using nested-PCR. Results A total of 1037 adult anopheline mosquitoes were collected from New Halfa (N = 467), Rural Khartoum (N = 132), and Sennar (N = 438). Morphological and molecular identification of the collected mosquitoes revealed the presence of Anopheles arabiensis (94.2%), Anopheles funestus (0.5%), and Anopheles pharoensis (5.4%). None of the dissected mosquitoes (N = 108) showed to be infected with malaria parasite. Overall P. vivax infectivity rate was 6.1% (63/1037) by Pvcsp nested PCR. Co-dominance of An. arabiensis and An. pharoensis is reported in Sennar state both being infected with P. vivax. Conclusion This study reported P. vivax infection among wild-caught anopheline mosquitoes in Central and Eastern Sudan. While An. arabiensis is the most abundant vector observed in all study areas, An. funestus was recorded for the first time in New Halfa, Eastern Sudan. The documented Anopheles species are implicated in Pvcsp allele diversity. Large-scale surveys are needed to identify the incriminated vectors of P. vivax malaria and determine their contribution in disease transmission dynamics.
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Affiliation(s)
- Omnia Fathelrhman Abdelwhab
- Department of Epidemiology, Tropical Medicine Research Institute, National Center for Research, Khartoum, Sudan
| | - Arwa Elaagip
- Department of Parasitology and Medical Entomology, Faculty of Medical Laboratory Sciences, University of Khartoum, Khartoum, Sudan.,Department of Parasitology and Medical Entomology, Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan
| | - Musab M Albsheer
- Department of Parasitology and Medical Entomology, Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan
| | - Ayman Ahmed
- Department of Parasitology and Medical Entomology, Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan
| | - Giacomo Maria Paganotti
- Botswana-University of Pennsylvania Partnership, Gaborone, Botswana.,Division of Infectious Diseases, Perelman School of Medicine, University of Pennsylvania, Philadelphia, PA, USA.,Department of Biomedical Sciences, University of Botswana, Gaborone, Botswana
| | - Muzamil Mahdi Abdel Hamid
- Department of Parasitology and Medical Entomology, Institute of Endemic Diseases, University of Khartoum, Khartoum, Sudan.
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12
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Aviles EI, Rotenberry RD, Collins CM, Dotson EM, Benedict MQ. Fluorescent markers rhodamine B and uranine for Anopheles gambiae adults and matings. Malar J 2020; 19:236. [PMID: 32631340 PMCID: PMC7336461 DOI: 10.1186/s12936-020-03306-5] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/26/2019] [Accepted: 06/20/2020] [Indexed: 11/10/2022] Open
Abstract
Background Marking mosquitoes is vital for mark-release-recapture and many laboratory studies, but their small size precludes the use of methods that are available for larger animals such as unique identifier tags and radio devices. Fluorescent dust is the most commonly used method to distinguish released individuals from the wild population. Numerous colours and combinations can be used, however, dust sometimes affects longevity and behaviour so alternatives that do not have these effects would contribute substantially. Rhodamine B has previously been demonstrated to be useful for marking adult Aedes aegypti males when added to the sugar meal. Unlike dust, this also marked the seminal fluid making it possible to detect matings by marked males in the spermatheca of females. Here, marking of Anopheles gambiae sensu stricto with rhodamine B and uranine was performed to estimate their potential contribution. Methods Two fluorescent markers, rhodamine B and uranine, were dissolved in sugar water and fed to adult An. gambiae. Concentrations that are useful for marking individuals and seminal fluid were determined. The effects on adult longevity, the durability of the marking and detection of the marker in mated females was determined. Male mating competitiveness was also evaluated. Results Rhodamine B marking in adults is detectable for at least 3 weeks, however uranine marking declines with time and at low doses can be confused with auto-fluorescence. Both can be used for marking seminal fluid which can be detected in females mated by marked males, but, again, at low concentrations uranine-marking is more easily confused with the natural fluorescence of seminal fluid. Neither dye affected mating competitiveness. Conclusions Both markers tested could be useful for field and laboratory studies. Their use has substantial potential to contribute to a greater understanding of the bio-ecology of this important malaria vector. Rhodamine B has the advantage that it appears to be permanent and is less easily confused with auto-fluorescence. The primary limitation of both methods is that sugar feeding is necessary for marking and adults must be held for at least 2 nights to ensure all individuals are marked whereas dusts provide immediate and thorough marking.
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Affiliation(s)
- Erica I Aviles
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Rachel D Rotenberry
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - C Mathilda Collins
- Centre for Environmental Policy, Imperial College London, 16-18 Princes Gardens, London, SW7 1NE, UK
| | - Ellen M Dotson
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA
| | - Mark Q Benedict
- Centers for Disease Control and Prevention, 1600 Clifton Road, Atlanta, GA, 30329, USA.
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13
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Sougoufara S, Ottih EC, Tripet F. The need for new vector control approaches targeting outdoor biting Anopheline malaria vector communities. Parasit Vectors 2020; 13:295. [PMID: 32522290 PMCID: PMC7285743 DOI: 10.1186/s13071-020-04170-7] [Citation(s) in RCA: 59] [Impact Index Per Article: 14.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/05/2020] [Accepted: 06/04/2020] [Indexed: 12/13/2022] Open
Abstract
Since the implementation of Roll Back Malaria, the widespread use of insecticide-treated nets (ITNs) and indoor residual spraying (IRS) is thought to have played a major part in the decrease in mortality and morbidity achieved in malaria-endemic regions. In the past decade, resistance to major classes of insecticides recommended for public health has spread across many malaria vector populations. Increasingly, malaria vectors are also showing changes in vector behaviour in response to current indoor chemical vector control interventions. Changes in the time of biting and proportion of indoor biting of major vectors, as well as changes in the species composition of mosquito communities threaten the progress made to control malaria transmission. Outdoor biting mosquito populations contribute to malaria transmission in many parts of sub-Saharan Africa and pose new challenges as they cannot be reliably monitored or controlled using conventional tools. Here, we review existing and novel approaches that may be used to target outdoor communities of malaria vectors. We conclude that scalable tools designed specifically for the control and monitoring of outdoor biting and resting malaria vectors with increasingly complex and dynamic responses to intensifying malaria control interventions are urgently needed. These are crucial for integrated vector management programmes designed to challenge current and future vector populations.
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Affiliation(s)
- Seynabou Sougoufara
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Emmanuel Chinweuba Ottih
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
| | - Frederic Tripet
- Centre of Applied Entomology and Parasitology, School of Life Sciences, Keele University, Staffordshire, UK
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14
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Culbert NJ, Kaiser M, Venter N, Vreysen MJB, Gilles JRL, Bouyer J. A standardised method of marking male mosquitoes with fluorescent dust. Parasit Vectors 2020; 13:192. [PMID: 32293537 PMCID: PMC7158013 DOI: 10.1186/s13071-020-04066-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2019] [Accepted: 04/09/2020] [Indexed: 11/06/2022] Open
Abstract
Background Prior to a major release campaign of sterile insects, including the sterile insect technique, male mosquitoes must be marked and released (small scale) to determine key parameters including wild population abundance, dispersal and survival. Marking insects has been routinely carried out for over 100 years; however, there is no gold standard regarding the marking of specific disease-transmitting mosquitoes including Anopheles arabiensis, Aedes aegypti and Aedes albopictus. The research presented offers a novel dusting technique and optimal dust colour and quantities, suitable for small-scale releases, such as mark-release-recapture studies. Methods We sought to establish a suitable dust colour and quantity for batches of 100 male An. arabiensis, that was visible both by eye and under UV light, long-lasting and did not negatively impact longevity. A set of lower dust weights were selected to conduct longevity experiments with both Ae. aegypti and Ae. albopictus to underpin the optimal dust weight. A further study assessed the potential of marked male An. arabiensis to transfer their mark to undusted males and females. Results The longevity of male An. arabiensis marked with various dust colours was not significantly reduced when compared to unmarked controls. Furthermore, the chosen dust quantity (5 mg) did not negatively impact longevity (P = 0.717) and provided a long-lasting mark. Dust transfer was found to occur from marked An. arabiensis males to unmarked males and females when left in close proximity. However, this was only noticeable when examining individuals under a stereomicroscope and thus deemed negligible. Overall, male Ae. aegypti and Ae. albopictus displayed a greater sensitivity to dusting. Only the lowest dust weight (0.5 mg) did not significantly reduce longevity (P = 0.888) in Ae. aegypti, whilst the lowest two dust weights (0.5 and 0.75 mg) had no significant impact on longevity (P = 0.951 and 0.166, respectively) in Ae. albopictus. Conclusion We have devised a fast, inexpensive and simple marking method and provided recommended dust quantities for several major species of disease-causing mosquitoes. The novel technique provides an evenly distributed, long-lasting mark which is non-detrimental. Our results will be useful for future MRR studies, prior to a major release campaign.![]()
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Affiliation(s)
- Nicole J Culbert
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, Seibersdorf, Vienna, Austria. .,Institute of Integrative Biology & The Centre for Genomic Research, University of Liverpool, Liverpool, Merseyside, UK.
| | - Maria Kaiser
- Vector Control Reference Unit, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg, South Africa
| | - Nelius Venter
- Vector Control Reference Unit, National Institute for Communicable Diseases of the National Health Laboratory Service, Sandringham, Johannesburg, South Africa
| | - Marc J B Vreysen
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, Seibersdorf, Vienna, Austria
| | - Jeremie R L Gilles
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, Seibersdorf, Vienna, Austria
| | - Jérémy Bouyer
- Insect Pest Control Laboratory, Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, Seibersdorf, Vienna, Austria.,CIRAD, UMR ASTRE CIRAD-INRA, Animals, Health, Territories, Risks and Ecosystems, Campus International de Baillarguet, 34398, Montpellier, France
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15
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Li X, Zhang K, Deng Y, He R, Zhang X, Zhong G, Hu Q, Weng Q. Effects of 60Co-γ radiation on testis physiological aspects of Plutella xylostella (Linnaeus). ECOTOXICOLOGY AND ENVIRONMENTAL SAFETY 2019; 169:937-943. [PMID: 30597794 DOI: 10.1016/j.ecoenv.2018.11.028] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/06/2018] [Revised: 11/05/2018] [Accepted: 11/08/2018] [Indexed: 06/09/2023]
Abstract
The diamondback moth, Plutella xylostella (Linnaeus), is one of the notorious pests causing substantial loses to many cruciferous vegetables across the nations. Sterile insect technique (SIT) is considered as an effective bio-control agent for controlling numerous lepidopteran pests. We searched the deformity spermatozoon and sperm bundles of diamondback moth. In our research, 200 Gy and 400 Gy 60Co-γ radiation doesn't alter the number of apyrene and eupyrene sperm bundles in testis. However, the ratio of abnormal eupyrene sperm bundles was increasing with radiation dosage. The malformation of mitochondrial derivatives is characterized by "V" shape with 400 Gy. Also, the results showed that the expression of caspase-3 with 200 Gy was down-regulated, but was obviously up-regulated after 400 Gy radiation. Thus the present research investigation highlights that the 60Co-γ radiation treatments alters the physiological development of diamondback moth testis.
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Affiliation(s)
- Xiaoxue Li
- Key Laboratory of Natural Pesticide & Chemical Biology, Ministry of Education, China.
| | - Ke Zhang
- Key Laboratory of Natural Pesticide & Chemical Biology, Ministry of Education, China.
| | - Yukun Deng
- Key Laboratory of Natural Pesticide & Chemical Biology, Ministry of Education, China.
| | - Renkun He
- Key Laboratory of Natural Pesticide & Chemical Biology, Ministry of Education, China.
| | - Xiaofeng Zhang
- Key Laboratory of Natural Pesticide & Chemical Biology, Ministry of Education, China.
| | - Guohua Zhong
- Key Laboratory of Natural Pesticide & Chemical Biology, Ministry of Education, China; Key Laboratory of Integrated Pest Management on Crops in South China, Ministry of Agriculture, College of Agriculture, South China Agricultural University, Guangzhou 510642, China.
| | - Qiongbo Hu
- Key Laboratory of Natural Pesticide & Chemical Biology, Ministry of Education, China; Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, China.
| | - Qunfang Weng
- Key Laboratory of Natural Pesticide & Chemical Biology, Ministry of Education, China; Key Laboratory of Bio-Pesticide Innovation and Application of Guangdong Province, China.
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16
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Smidler AL, Scott SN, Mameli E, Shaw WR, Catteruccia F. A transgenic tool to assess Anopheles mating competitiveness in the field. Parasit Vectors 2018; 11:651. [PMID: 30583744 PMCID: PMC6304768 DOI: 10.1186/s13071-018-3218-5] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/04/2022] Open
Abstract
Background Malaria parasites, transmitted by the bite of an anopheline mosquito, pose an immense public health burden on many tropical and subtropical regions. The most important malaria vectors in sub-Saharan Africa are mosquitoes of the Anopheles gambiae complex including An. gambiae (sensu stricto). Given the increasing rates of insecticide resistance in these mosquitoes, alternative control strategies based on the release of genetically modified males are being evaluated to stop transmission by these disease vectors. These strategies rely on the mating competitiveness of release males, however currently there is no method to determine male mating success without sacrificing the female. Interestingly, unlike other insects, during mating An. gambiae males transfer their male accessory glands (MAGs) seminal secretions as a coagulated mating plug which is deposited in the female atrium. Results Here we exploit this male reproductive feature and validate the use of a MAG-specific promoter to fluorescently label the mating plug and visualize the occurrence of insemination in vivo. We used the promoter region of the major mating plug protein, Plugin, to control the expression of a Plugin-tdTomato (PluTo) fusion protein, hypothesizing that this fusion protein could be incorporated into the plug for sexual transfer to the female. Anopheles gambiae PluTo transgenic males showed strong red fluorescence specifically in the MAGs and with a pattern closely matching endogenous Plugin expression. Moreover, the fusion protein was integrated into the mating plug and transferred to the female atrium during mating where it could be visualized microscopically in vivo without sacrificing the female. PluTo males were equally as competitive at mating as wild type males, and females mated to these males did not show any reduction in reproductive fitness. Conclusion The validation of the first MAG-specific promoter in transgenic An. gambiae facilitates the live detection of successful insemination hours after copulation has occurred. This provides a valuable tool for the assessment of male mating competitiveness not only in laboratory experiments but also in semi-field and field studies aimed at testing the feasibility of releasing genetically modified mosquitoes for disease control. Electronic supplementary material The online version of this article (10.1186/s13071-018-3218-5) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Andrea L Smidler
- Harvard T.H. Chan School of Public Health, Department of Immunology and Infectious Diseases, Boston, MA, USA
| | - Sean N Scott
- Harvard T.H. Chan School of Public Health, Department of Immunology and Infectious Diseases, Boston, MA, USA
| | - Enzo Mameli
- Harvard T.H. Chan School of Public Health, Department of Immunology and Infectious Diseases, Boston, MA, USA
| | - W Robert Shaw
- Harvard T.H. Chan School of Public Health, Department of Immunology and Infectious Diseases, Boston, MA, USA.
| | - Flaminia Catteruccia
- Harvard T.H. Chan School of Public Health, Department of Immunology and Infectious Diseases, Boston, MA, USA.
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17
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Mashatola T, Ndo C, Koekemoer LL, Dandalo LC, Wood OR, Malakoane L, Poumachu Y, Lobb LN, Kaiser M, Bourtzis K, Munhenga G. A review on the progress of sex-separation techniques for sterile insect technique applications against Anopheles arabiensis. Parasit Vectors 2018; 11:646. [PMID: 30583746 PMCID: PMC6304763 DOI: 10.1186/s13071-018-3219-4] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/14/2022] Open
Abstract
The feasibility of the sterile insect technique (SIT) as a malaria vector control strategy against Anopheles arabiensis has been under investigation over the past decade. One of the critical steps required for the application of this technique to mosquito control is the availability of an efficient and effective sex-separation system. Sex-separation systems eliminate female mosquitoes from the production line prior to irradiation and field release of sterile males. This is necessary because female mosquitoes can transmit pathogens such as malaria and, therefore, their release must be prevented. Sex separation also increases the efficiency of an SIT programme. Various sex-separation strategies have been explored including the exploitation of developmental and behavioural differences between male and female mosquitoes, and genetic approaches. Most of these are however species-specific and are not indicated for the major African malaria vectors such as An. arabiensis. As there is currently no reliable sex-separation method for An. arabiensis, various strategies were explored in an attempt to develop a robust system that can be applied on a mass-rearing scale. The progress and challenges faced during the development of a sexing system for future pilot and/or large-scale SIT release programmes against An. arabiensis are reviewed here. Three methods of sex separation were examined. The first is the use of pupal size for gender prediction. The second is the elimination of blood-feeding adult females through the addition of an endectocide to a blood meal source. The third is the establishment of a genetic sexing strain (GSS) carrying an insecticide resistance selectable marker (dieldrin-resistance rdl gene and/or other GABA receptor antagonists that can be used as alternative insecticides to dieldrin) or a temperature-sensitive lethal marker.
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Affiliation(s)
- Thabo Mashatola
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
| | - Cyrille Ndo
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de recherche de Yaoundé (IRY), Yaoundé, Cameroon
- Department of Biological Sciences, Faculty of Medicine and Pharmaceutical Sciences, University of Douala, Douala, Cameroon
- Centre for Research in Infectious Disease (CRI), Yaoundé, Cameroon
| | - Lizette L. Koekemoer
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Leonard C. Dandalo
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Oliver R. Wood
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Lerato Malakoane
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Yacouba Poumachu
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
- Organisation de Coordination pour la lutte Contre les Endémies en Afrique Centrale (OCEAC), Institut de recherche de Yaoundé (IRY), Yaoundé, Cameroon
- Vector Borne Disease Laboratory of the Applied Biology and Ecology Research Unit (VBDL-URBEA) Department of Animal Biology, Faculty of Sciences of the University of Dschang, Dschang, Cameroon
| | - Leanne N. Lobb
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Maria Kaiser
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
| | - Kostas Bourtzis
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
| | - Givemore Munhenga
- Centre for Emerging Zoonotic and Parasitic Diseases, National Institute for Communicable Diseases of the National Health Laboratory Service, Johannesburg, South Africa
- Wits Research Institute for Malaria, MRC Collaborating Centre for Multi-Disciplinary Research on Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa
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Impact of irradiation on the reproductive traits of field and laboratory An. arabiensis mosquitoes. Parasit Vectors 2018; 11:641. [PMID: 30558681 PMCID: PMC6296153 DOI: 10.1186/s13071-018-3228-3] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2018] [Accepted: 11/23/2018] [Indexed: 11/25/2022] Open
Abstract
Background The sterile insect technique (SIT) aims at suppressing or decreasing insect pest populations by introducing sterile insects into wild populations. SIT requires the mass-production of insects and their sterilization through, for example, radiation. However, both mass-rearing and radiation can affect the life history traits of insects making them less competitive than their wild counterparts. In the malaria mosquito Anopheles arabiensis, some progress has been made to improve the mating competitiveness of mass-reared irradiated males. However, to date, no study has explored the relative effects of colonization and irradiation on important reproductive traits in this species. Such data may help to focus research efforts more precisely to improve current techniques. Methods Two strains of An. arabiensis originating from the same locality were used: one reared in the laboratory for five generations and the second collected as late larval instars in the field prior to experimentation. Pupae were irradiated with 95 Gy and some adult reproductive traits, including insemination rate, fecundity, oviposition behavior, fertility and male survivorship, were assessed in different mating combinations. Results Our study revealed the different effects of mosquito strain and irradiation on reproductive processes. The insemination rate was higher in field (67.3%) than in laboratory (54.9%) females and was negatively affected by both female and male irradiation (un-irradiated vs irradiated: 70.2 vs 51.3% in females; 67.7 vs 53.7% in males). Irradiated females did not produce eggs and egg prevalence was lower in the field strain (75.4%) than in the laboratory strain (83.9%). The hatching rate was higher in the field strain (88.7%) than in the laboratory strain (70.6%) as well as in un-irradiated mosquitoes (96.5%) than in irradiated ones (49%). Larval viability was higher in the field strain (96.2%) than in the laboratory strain (78.5%) and in un-irradiated mosquitoes (97.6%) than irradiated ones (52%). Finally, field males lived longer than laboratory males (25.1 vs 20.5 days, respectively). Conclusions Our results revealed that both irradiation and colonization alter reproductive traits. However, different developmental stages are not equally affected. It is necessary to consider as many fitness traits as possible to evaluate the efficacy of the sterile insect technique. Electronic supplementary material The online version of this article (10.1186/s13071-018-3228-3) contains supplementary material, which is available to authorized users.
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Famakinde DO. Mosquitoes and the Lymphatic Filarial Parasites: Research Trends and Budding Roadmaps to Future Disease Eradication. Trop Med Infect Dis 2018; 3:E4. [PMID: 30274403 PMCID: PMC6136629 DOI: 10.3390/tropicalmed3010004] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2017] [Revised: 12/26/2017] [Accepted: 12/27/2017] [Indexed: 11/17/2022] Open
Abstract
The mosquito-borne lymphatic filariasis (LF) is a parasitic, neglected tropical disease that imposes an unbearable human scourge. Despite the unprecedented efforts in mass drug administration (MDA) and morbidity management, achieving the global LF elimination slated for the year 2020 has been thwarted by limited MDA coverage and ineffectiveness in the chemotherapeutic intervention. Moreover, successful and sustainable elimination of mosquito-vectored diseases is often encumbered by reintroduction and resurgence emanating from human residual or new infections being widely disseminated by the vectors even when chemotherapy proves effective, but especially in the absence of effective vaccines. This created impetus for strengthening the current defective mosquito control approach, and profound research in vector⁻pathogen systems and vector biology has been pushing the boundaries of ideas towards developing refined vector-harnessed control strategies. Eventual implementation of these emerging concepts will offer a synergistic approach that will not only accelerate LF elimination, but also augurs well for its future eradication. This brief review focuses on advances in mosquito⁻filaria research and considers the emerging prospects for future eradication of LF.
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Affiliation(s)
- Damilare O Famakinde
- Department of Medical Microbiology and Parasitology, College of Medicine of the University of Lagos, Idi-Araba, Lagos 100254, Nigeria.
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Macias VM, Ohm JR, Rasgon JL. Gene Drive for Mosquito Control: Where Did It Come from and Where Are We Headed? INTERNATIONAL JOURNAL OF ENVIRONMENTAL RESEARCH AND PUBLIC HEALTH 2017; 14:ijerph14091006. [PMID: 28869513 PMCID: PMC5615543 DOI: 10.3390/ijerph14091006] [Citation(s) in RCA: 71] [Impact Index Per Article: 10.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 08/03/2017] [Revised: 08/25/2017] [Accepted: 08/28/2017] [Indexed: 02/08/2023]
Abstract
Mosquito-borne pathogens place an enormous burden on human health. The existing toolkit is insufficient to support ongoing vector-control efforts towards meeting disease elimination and eradication goals. The perspective that genetic approaches can potentially add a significant set of tools toward mosquito control is not new, but the recent improvements in site-specific gene editing with CRISPR/Cas9 systems have enhanced our ability to both study mosquito biology using reverse genetics and produce genetics-based tools. Cas9-mediated gene-editing is an efficient and adaptable platform for gene drive strategies, which have advantages over innundative release strategies for introgressing desirable suppression and pathogen-blocking genotypes into wild mosquito populations; until recently, an effective gene drive has been largely out of reach. Many considerations will inform the effective use of new genetic tools, including gene drives. Here we review the lengthy history of genetic advances in mosquito biology and discuss both the impact of efficient site-specific gene editing on vector biology and the resulting potential to deploy new genetic tools for the abatement of mosquito-borne disease.
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Affiliation(s)
- Vanessa M Macias
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA.
| | - Johanna R Ohm
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA 16802, USA.
| | - Jason L Rasgon
- Department of Entomology, Pennsylvania State University, University Park, PA 16802, USA.
- Center for Infectious Disease Dynamics, Pennsylvania State University, University Park, PA 16802, USA.
- The Huck Institutes of the Life Sciences, Pennsylvania State University, University Park, PA 16802, USA.
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Epopa PS, Millogo AA, Collins CM, North A, Tripet F, Benedict MQ, Diabate A. The use of sequential mark-release-recapture experiments to estimate population size, survival and dispersal of male mosquitoes of the Anopheles gambiae complex in Bana, a west African humid savannah village. Parasit Vectors 2017; 10:376. [PMID: 28784147 PMCID: PMC5547516 DOI: 10.1186/s13071-017-2310-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2016] [Accepted: 07/26/2017] [Indexed: 12/14/2022] Open
Abstract
Background Vector control is a major component of the malaria control strategy. The increasing spread of insecticide resistance has encouraged the development of new tools such as genetic control which use releases of modified male mosquitoes. The use of male mosquitoes as part of a control strategy requires an improved understanding of male mosquito biology, including the factors influencing their survival and dispersal, as well as the ability to accurately estimate the size of a target mosquito population. This study was designed to determine the seasonal variation in population size via repeated mark-release-recapture experiments and to estimate the survival and dispersal of male mosquitoes of the Anopheles gambiae complex in a small west African village. Methods Mark-release-recapture experiments were carried out in Bana Village over two consecutive years, during the wet and the dry seasons. For each experiment, around 5000 (3407–5273) adult male Anopheles coluzzii mosquitoes were marked using three different colour dye powders (red, blue and green) and released in three different locations in the village (centre, edge and outside). Mosquitoes were recaptured at sites spread over the village for seven consecutive days following the releases. Three different capture methods were used: clay pots, pyrethroid spray catches and swarm sampling. Results Swarm sampling was the most productive method for recapturing male mosquitoes in the field. Population size and survival were estimated by Bayesian analyses of the Fisher-Ford model, revealing an about 10-fold increase in population size estimates between the end of dry season (10,000–50,000) to the wet season (100,000–500,000). There were no detectable seasonal effects on mosquito survival, suggesting that factors other than weather may play an important role. Mosquito dispersal ranged from 40 to 549 m over the seven days of each study and was not influenced by the season, but mainly by the release location, which explained more than 44% of the variance in net dispersal distance. Conclusion This study clearly shows that male-based MRR experiments can be used to estimate some parameters of wild male populations such as population size, survival, and dispersal and to estimate the spatial patterns of movement in a given locality.
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Affiliation(s)
- Patric Stephane Epopa
- Institut de Recherche en Sciences de la Santé / Centre Muraz, Bobo-Dioulasso, Burkina Faso.
| | | | | | - Ace North
- Department of Zoology, University of Oxford, Oxford, UK
| | - Frederic Tripet
- Centre for Applied Entomology and Parasitology, School of Life Sciences, Keele University, Keele, Staffordshire, UK
| | | | - Abdoulaye Diabate
- Institut de Recherche en Sciences de la Santé / Centre Muraz, Bobo-Dioulasso, Burkina Faso
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Laboratory rearing of Anopheles arabiensis: impact on genetic variability and implications for Sterile Insect Technique (SIT) based mosquito control in northern Sudan. Malar J 2016; 15:432. [PMID: 27799066 PMCID: PMC5088653 DOI: 10.1186/s12936-016-1484-2] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/24/2016] [Accepted: 08/11/2016] [Indexed: 12/18/2022] Open
Abstract
Background Mosquito colony populations often show significant changes in their population genetic make-up compared to the field populations that were used as founding source. Most of the changes that have been reported are indicators of depletion in the overall genetic diversity of the colony populations. The Sterile Insect Techniques programme of mosquito control that is underway in Northern Sudan uses sterilized males produced from a laboratory-maintained colony population. The genetic diversity of an advanced generation of this colony population was quantitatively assessed and compared to the field population from which the colony was derived. Methods Anopheles arabiensis mosquito samples from the 13th generation of the colony, and from the locality that was the source of the first generation of the colony, were genotyped at 11 microsatellite loci distributed throughout the species’ genome. Standard population genetic analyses were carried out to quantify and compare their population genetic make-up and diversities. Results The colony samples showed significant reduction in the total number of alleles, the numbers of rare and private alleles, and the fractions of heterozygote individuals at all the loci. The pattern of change is consistent with the expected effect of the use of a small number of mosquitoes when the colony was established. Departure from Hardy–Weinberg equilibrium in the direction of homozygote excess was observed at some loci and attributed to the presence of null-alleles. Conclusions This study highlights the need for broad sampling when initiating colony populations and for ongoing assessment of the population genetic make-up of colony populations. Previous assessments of survivorship, dispersive behaviour and swarm formation indicate that the inbreeding and reduced genetic variability reported in this study may not have had direct fitness consequences yet. However, noting the lessons learned in other SIT programmes about the impact of colonization on male sexual behaviour and longevity, as well as other inbreeding related adverse effects, a systematic investigation of these potential effects is recommended because they have direct impact on the ultimate success of the programme.
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Rabaan AA, Bazzi AM, Al-Ahmed SH, Al-Ghaith MH, Al-Tawfiq JA. Overview of Zika infection, epidemiology, transmission and control measures. J Infect Public Health 2016; 10:141-149. [PMID: 27283926 DOI: 10.1016/j.jiph.2016.05.007] [Citation(s) in RCA: 26] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 04/05/2016] [Accepted: 05/03/2016] [Indexed: 11/28/2022] Open
Abstract
The current Zika virus outbreak in the Americas and the proposed link to increases in microcephaly and neurological disorders have prompted the World Health Organization to declare a Public Health Emergency of International Concern on February 1, 2016. The virus is transmitted by Aedes mosquitoes and potentially by transfusion, perinatal and sexual transmission. The potential for spread into countries where Aedes mosquitoes are endemic is high. Previously, cases tended to be sporadic and associated with mild, non-specific symptoms. Prior outbreaks occurred in Yap Island in Micronesia in 2007, the first time Zika arose outside of Africa and Asia, and in French Polynesia in 2013. A birth data review has confirmed that the latter outbreak was followed by an increase in microcephaly cases. A coordinated international response is needed to address mosquito control; expedite development of diagnostic tests, vaccines and specific treatments for Zika; and address the proposed link to microcephaly and neurological diseases.
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Affiliation(s)
- Ali A Rabaan
- Molecular Diagnostic Laboratory, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia.
| | - Ali M Bazzi
- Microbiology Laboratory, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia
| | - Shamsah H Al-Ahmed
- Specialty Paediatric Medicine, Qatif Central Hospital, Qatif, Saudi Arabia
| | - Mohamed H Al-Ghaith
- Laboratory Department, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia
| | - Jaffar A Al-Tawfiq
- Specialty Internal Medicine, Johns Hopkins Aramco Healthcare, Dhahran, Saudi Arabia; Indiana University School of Medicine, IN, USA
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More than one rabbit out of the hat: Radiation, transgenic and symbiont-based approaches for sustainable management of mosquito and tsetse fly populations. Acta Trop 2016; 157:115-30. [PMID: 26774684 DOI: 10.1016/j.actatropica.2016.01.009] [Citation(s) in RCA: 120] [Impact Index Per Article: 15.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2015] [Revised: 01/07/2016] [Accepted: 01/08/2016] [Indexed: 12/19/2022]
Abstract
Mosquitoes (Diptera: Culicidae) and tsetse flies (Diptera: Glossinidae) are bloodsucking vectors of human and animal pathogens. Mosquito-borne diseases (malaria, filariasis, dengue, zika, and chikungunya) cause severe mortality and morbidity annually, and tsetse fly-borne diseases (African trypanosomes causing sleeping sickness in humans and nagana in livestock) cost Sub-Saharan Africa an estimated US$ 4750 million annually. Current reliance on insecticides for vector control is unsustainable: due to increasing insecticide resistance and growing concerns about health and environmental impacts of chemical control there is a growing need for novel, effective and safe biologically-based methods that are more sustainable. The integration of the sterile insect technique has proven successful to manage crop pests and disease vectors, particularly tsetse flies, and is likely to prove effective against mosquito vectors, particularly once sex-separation methods are improved. Transgenic and symbiont-based approaches are in development, and more advanced in (particularly Aedes) mosquitoes than in tsetse flies; however, issues around stability, sustainability and biosecurity have to be addressed, especially when considering population replacement approaches. Regulatory issues and those relating to intellectual property and economic cost of application must also be overcome. Standardised methods to assess insect quality are required to compare and predict efficacy of the different approaches. Different combinations of these three approaches could be integrated to maximise their benefits, and all have the potential to be used in tsetse and mosquito area-wide integrated pest management programmes.
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Munhenga G, Brooke BD, Gilles JRL, Slabbert K, Kemp A, Dandalo LC, Wood OR, Lobb LN, Govender D, Renke M, Koekemoer LL. Mating competitiveness of sterile genetic sexing strain males (GAMA) under laboratory and semi-field conditions: Steps towards the use of the Sterile Insect Technique to control the major malaria vector Anopheles arabiensis in South Africa. Parasit Vectors 2016; 9:122. [PMID: 26934869 PMCID: PMC4774148 DOI: 10.1186/s13071-016-1385-9] [Citation(s) in RCA: 29] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2015] [Accepted: 02/15/2016] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Anopheles arabiensis Patton is primarily responsible for malaria transmission in South Africa after successful suppression of other major vector species using indoor spraying of residual insecticides. Control of An. arabiensis using current insecticide based approaches is proving difficult owing to the development of insecticide resistance, and variable feeding and resting behaviours. The use of the sterile insect technique as an area-wide integrated pest management system to supplement the control of An. arabiensis was proposed for South Africa and is currently under investigation. The success of this technique is dependent on the ability of laboratory-reared sterile males to compete with wild males for mates. As part of the research and development of the SIT technique for use against An. arabiensis in South Africa, radio-sensitivity and mating competitiveness of a local An. arabiensis sexing strain were assessed. METHODS The optimal irradiation dose inducing male sterility without compromising mating vigour was tested using Cobalt 60 irradiation doses ranging from 70-100 Gy. Relative mating competitiveness of sterile laboratory-reared males (GAMA strain) compared to fertile wild-type males (AMAL strain) for virgin wild-type females (AMAL) was investigated under laboratory and semi-field conditions using large outdoor cages. Three different sterile male to fertile male to wild-type female ratios were evaluated [1:1:1, 5:1:1 and 10:1:1 (sterile males: fertile, wild-type males: fertile, wild-type females)]. RESULTS Irradiation at the doses tested did not affect adult emergence but had a moderate effect on adult survivorship and mating vigour. A dose of 75 Gy was selected for the competitiveness assays. Mating competitiveness experiments showed that irradiated GAMA male mosquitoes are a third as competitive as their fertile AMAL counterparts under semi-field conditions. However, they were not as competitive under laboratory conditions. An inundative ratio of 10:1 induced the highest sterility in the representative wild-type population, with potential to effectively suppress reproduction. CONCLUSION Laboratory-reared and sterilised GAMA male An. arabiensis at a release ratio of 3:1 (3 sterile males to 1 wild, fertile male) can successfully compete for insemination of wild-type females. These results will be used to inform subsequent small-scale pilot field releases in South Africa.
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Affiliation(s)
- Givemore Munhenga
- Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, Private Bag X4, Sandringham, Johannesburg, South Africa. .,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - Basil D Brooke
- Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, Private Bag X4, Sandringham, Johannesburg, South Africa. .,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - Jeremie R L Gilles
- Insect Pest Control Laboratory, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, International Atomic Energy Agency, Vienna, Austria.
| | - Kobus Slabbert
- iThemba LABS (Laboratory for Accelerator Based Sciences), Somerset West, South Africa.
| | - Alan Kemp
- Special Pathogens Unit, Center for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, Private Bag X4, Sandringham, Johannesburg, South Africa.
| | - Leonard C Dandalo
- Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, Private Bag X4, Sandringham, Johannesburg, South Africa. .,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - Oliver R Wood
- Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, Private Bag X4, Sandringham, Johannesburg, South Africa. .,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - Leanne N Lobb
- Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, Private Bag X4, Sandringham, Johannesburg, South Africa. .,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
| | - Danny Govender
- Scientific Services, South African National Parks, Private Bag X402, Skukuza, South Africa. .,Department of Paraclinical Sciences, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort, South Africa.
| | - Marius Renke
- Conservation Management, Kruger National Park, Private Bag X402, Skukuza, South Africa.
| | - Lizette L Koekemoer
- Centre for Opportunistic, Tropical and Hospital Infections, National Institute for Communicable Diseases, Private Bag X4, Sandringham, Johannesburg, South Africa. .,Wits Research Institute for Malaria, School of Pathology, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, South Africa.
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Lees RS, Gilles JR, Hendrichs J, Vreysen MJ, Bourtzis K. Back to the future: the sterile insect technique against mosquito disease vectors. CURRENT OPINION IN INSECT SCIENCE 2015; 10:156-162. [PMID: 29588003 DOI: 10.1016/j.cois.2015.05.011] [Citation(s) in RCA: 147] [Impact Index Per Article: 16.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/31/2015] [Revised: 05/12/2015] [Accepted: 05/21/2015] [Indexed: 05/27/2023]
Abstract
With the global burden of mosquito-borne diseases increasing, and some conventional vector control tools losing effectiveness, the sterile insect technique (SIT) is a potential new tool in the arsenal. Equipment and protocols have been developed and validated for efficient mass-rearing, irradiation and release of Aedines and Anophelines that could be useful for several control approaches. Assessment of male quality is becoming more sophisticated, and several groups are well advanced in pilot site selection and population surveillance. It will not be long before SIT feasibility has been evaluated in various settings. Until perfect sexing mechanisms exist, combination of Wolbachia-induced phenotypes, such as cytoplasmic incompatibility and pathogen interference, and irradiation may prove to be the safest solution for population suppression.
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Affiliation(s)
- Rosemary Susan Lees
- Insect Pest Control Sub-programme, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
| | - Jeremie Rl Gilles
- Insect Pest Control Sub-programme, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
| | - Jorge Hendrichs
- Insect Pest Control Sub-programme, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
| | - Marc Jb Vreysen
- Insect Pest Control Sub-programme, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria
| | - Kostas Bourtzis
- Insect Pest Control Sub-programme, Joint FAO/IAEA Division of Nuclear Techniques in Food and Agriculture, Vienna, Austria.
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