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Orubuloye OY, Mbewe NJ, Tchouassi DP, Yusuf AA, Pirk CWW, Torto B. An Overview of Tsetse Fly Repellents: Identification and Applications. J Chem Ecol 2024; 50:581-592. [PMID: 38976099 PMCID: PMC11543710 DOI: 10.1007/s10886-024-01527-5] [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: 02/29/2024] [Revised: 06/22/2024] [Accepted: 06/28/2024] [Indexed: 07/09/2024]
Abstract
Tsetse flies are vectors of the parasite trypanosoma that cause the neglected tropical diseases human and animal African trypanosomosis. Semiochemicals play important roles in the biology and ecology of tsetse flies. Previous reviews have focused on olfactory-based attractants of tsetse flies. Here, we present an overview of the identification of repellents and their development into control tools for tsetse flies. Both natural and synthetic repellents have been successfully tested in laboratory and field assays against specific tsetse fly species. Thus, these repellents presented as innovative mobile tools offer opportunities for their use in integrated disease management strategies.
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Affiliation(s)
- Olabimpe Y Orubuloye
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, Pretoria, South Africa.
| | - Njelembo J Mbewe
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, Pretoria, South Africa
- Faculty of Infectious and Tropical Diseases, London School of Hygiene and Tropical Medicine, London, United Kingdom
| | - David P Tchouassi
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Abdullahi A Yusuf
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, Pretoria, South Africa
| | - Christian W W Pirk
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, Pretoria, South Africa
| | - Baldwyn Torto
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Hatfield, 0028, Pretoria, South Africa
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
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Ogolla KO, Onyango T, Bwana BK, Otiende MY, Mang’era CM, Ochieng B, Omolo MO, Mugambi JM, Hassanali A, Omondi P, Mireji PO. Bloodmeal host identities among sympatric Glossina austeni and Glossina pallidipes tsetse flies in Shimba Hills National Reserve, Kwale, Kenya. FRONTIERS IN TROPICAL DISEASES 2023; 4:1145993. [PMID: 38455667 PMCID: PMC10919243 DOI: 10.3389/fitd.2023.1145993] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 03/09/2024] Open
Abstract
Odor from preferred/non-preferred tsetse fly vertebrate hosts have been exploited in R&D of attractants/repellents of the fly for human and livestock protection. Odors from vertebrate hosts of Glossina austeni and Glossina pallidipes tsetse flies can facilitate formulation of novel attractants effective against G. austeni or improvement of existing attractant blends for G. pallidipes. We compared vertebrate blood meal sources of both fly species at Shimba Hills National Reserve, Kenya, to establish putative preferred host of either species, hence potential source of G. austeni or G. pallidipes specific odors. We trapped sympatric adult flies in 2021 and 2022 using NGU traps/sticky panels baited with POCA, collected their blood meals and characterize the meals using HRM vertebrate 16S rRNA- PCR (for host identification), and compared host profiles using GLM and Fisher's exact tests. We collected 168 and 62 sympatric G. pallidipes and G. austeni with bloodmeal, respectively in 2021 and, 230 and 142 respectively in 2022. In 2021, we identified putative hosts of 65.48 and 69.35 % of the G. pallidipes and G. austeni respectively and 82.61 and 80.28%, respectively in 2022. In 2021, we detected harnessed bushbuck, buffalo, common warthog and cattle putative host bloodmeals, and additionally bushpig and suni antelope bloodmeals in 2022. Putative vertebrate bloodmeal sources were significantly different by tsetse fly species (χ2(1, N=457) = 43.215, p < 0.001) and sampling year (χ2(1, N=457) = 8.044, p = 0.005). Frequency of common warthog bloodmeals was higher in G. pallidipes (65.79 %) than G. austeni (38.60%), and that of suni antelope and harnessed bushbuck putative bloodmeals higher in G. austeni (21.05-28.07%) than in G. pallidipes (6.84 - 17.37%) in 2022. There was an apparent change in putative feeding preference/host choices in both fly species between 2021 and 2022. Host bloodmeals in G. pallidipes or G. austeni predominantly from putative harnessed bushbuck, suni antelope or common warthog reveal these vertebrates with potential odors that can be harnessed and formulated into appropriate attractants for respective species and integrated into routine control regiment for G. pallidipes and/or G. austeni.
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Affiliation(s)
- Kennedy O. Ogolla
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Tevin Onyango
- Wildlife Research and Training Institute, Naivasha, Kenya
| | - Billiah K. Bwana
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | | | - Clarence M. Mang’era
- Department of Biochemistry and Molecular Biology, Egerton University, Nakuru, Kenya
| | - Benard Ochieng
- Wildlife Research and Training Institute, Naivasha, Kenya
| | - Maurice O Omolo
- Center for African Medicinal and Nutritional Flora and Fauna, Masinde Muliro University of Science and Technology, Kakamega, Kenya
| | - John M Mugambi
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Ahmed Hassanali
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
| | - Patrick Omondi
- Wildlife Research and Training Institute, Naivasha, Kenya
| | - Paul O. Mireji
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
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Annotations of novel antennae-expressed genes in male Glossina morsitans morsitans tsetse flies. PLoS One 2022; 17:e0273543. [PMID: 36037171 PMCID: PMC9423656 DOI: 10.1371/journal.pone.0273543] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2021] [Accepted: 08/10/2022] [Indexed: 11/25/2022] Open
Abstract
Tsetse flies use antennal expressed genes to navigate their environment. While most canonical genes associated with chemoreception are annotated, potential gaps with important antennal genes are uncharacterized in Glossina morsitans morsitans. We generated antennae-specific transcriptomes from adult male G. m. morsitans flies fed/unfed on bloodmeal and/or exposed to an attractant (ε-nonalactone), a repellant (δ-nonalactone) or paraffin diluent. Using bioinformatics approach, we mapped raw reads onto G. m. morsitans gene-set from VectorBase and collected un-mapped reads (constituting the gaps in annotation). We de novo assembled these reads (un-mapped) into transcript and identified corresponding genes of the transcripts in G. m. morsitans gene-set and protein homologs in UniProt protein database to further annotate the gaps. We predicted potential protein-coding gene regions associated with these transcripts in G. m. morsitans genome, annotated/curated these genes and identified their putative annotated orthologs/homologs in Drosophila melanogaster, Musca domestica or Anopheles gambiae genomes. We finally evaluated differential expression of the novel genes in relation to odor exposures relative to no-odor control (unfed flies). About 45.21% of the sequenced reads had no corresponding transcripts within G. m. morsitans gene-set, corresponding to the gap in existing annotation of the tsetse fly genome. The total reads assembled into 72,428 unique transcripts, most (74.43%) of which had no corresponding genes in the UniProt database. We annotated/curated 592 genes from these transcripts, among which 202 were novel while 390 were improvements of existing genes in the G. m. morsitans genome. Among the novel genes, 94 had orthologs in D. melanogaster, M. domestica or An. gambiae while 88 had homologs in UniProt. These orthologs were putatively associated with oxidative regulation, protein synthesis, transcriptional and/or translational regulation, detoxification and metal ion binding, thus providing insight into their specific roles in antennal physiological processes in male G. m. morsitans. A novel gene (GMOY014237.R1396) was differentially expressed in response to the attractant. We thus established significant gaps in G. m. morsitans genome annotation and identified novel male antennae-expressed genes in the genome, among which > 53% (108) are potentially G. m. morsitans specific.
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Mireji PO, Mang’era CM, Bwana BK, Hassanali A. Perspectives on Odor-Based Control of Tsetse Flies in Africa. Front Physiol 2022; 13:831618. [PMID: 35250633 PMCID: PMC8896535 DOI: 10.3389/fphys.2022.831618] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2021] [Accepted: 01/06/2022] [Indexed: 11/21/2022] Open
Abstract
Tsetse-transmitted trypanosomiases are among the most neglected tropical diseases in sub-Sahara Africa. Although all tsetse species are susceptible to trypanosome infections, their differential attraction/feeding preferences for different wildlife, domestic animals, and/or humans constitute critical determinants of trypanosomes species they predominantly transmit. Artificial bait technologies, based on long-range tsetse olfactory responses to natural cues emitted by preferred hosts and blends of synthetic versions that mimic these cues, have successfully been applied in attractant-odor-based (“pull” tactic) reduction of field populations of some tsetse species. Olfactory attribute associated with active avoidance of tsetse-refractory non-hosts has similarly been exploited in design of repellent-odor-based (“push” tactic) protection of livestock. These tactics have opened possibility of spatially strategic deployment of the two sets of odor baits in “push-pull” tactics. Possibility of developing blends with enhanced attraction and repellence compared with those associated with savannah tsetse fly hosts and non-hosts, respectively, have been explored, where structure activity and blends of different components generated two novel blends. The studies evaluated structure activity and blends of different components. One based on attractive constituents associated with buffalo (Syncerus caffer) comprised of ε-nonalactone, nonanoic acid, 2-nonanone (in 1:3:2 proportion) delivered together with acetone, which showed significantly better attractancy on savannah tsetse fly than the standard blend comprised of 3-propylphenol, octenol, p-cresol, and acetone (POCA). The other blend comprised of δ-nonalactone, heptanoic acid, 4-methylguaiacol and geranylacetone (in 6:4:2:1 proportion) was significantly more repellent than previously characterized blend based on tsetse fly refractory waterbuck (Kobus defassa) constituents (δ-octalactone, pentanoic acid, guaiacol and geranylacetone). So far, no effective attractants or repellents of riverine tsetse fly species have been characterized. Optimized attractant and repellent blends for savannah tsetse flies lay down useful groundwork for future development of the “push-pull” deployment tactic for area-wide control of tsetse flies. Better understanding of the physiological, cellular, and molecular basis of response in the tsetse fly to odors can potentially augment the current tsetse fly-control interventions.
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Affiliation(s)
- Paul O. Mireji
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
- *Correspondence: Paul O. Mireji,
| | - Clarence M. Mang’era
- Department of Biochemistry and Molecular Biology, Egerton University, Njoro, Kenya
| | - Billiah K. Bwana
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya
- Department of Biological Sciences, University of Embu, Embu, Kenya
- Billiah K. Bwana,
| | - Ahmed Hassanali
- Department of Chemistry, School of Pure and Applied Sciences, Kenyatta University, Nairobi, Kenya
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