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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 2024:10.1007/s10886-024-01527-5. [PMID: 38976099 DOI: 10.1007/s10886-024-01527-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [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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Serem EK, Mburu DM, Abdullahi OA, Bargul JL. A scoping review on tsetse fly blood meal sources and its assay methods since 1956 to 2022. Parasit Vectors 2024; 17:52. [PMID: 38308365 PMCID: PMC10837921 DOI: 10.1186/s13071-023-06114-3] [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: 06/20/2023] [Accepted: 12/27/2023] [Indexed: 02/04/2024] Open
Abstract
BACKGROUND Tsetse flies (Glossina spp.) are the definitive biological vectors of African trypanosomes in humans and animals. Controlling this vector is the most promising method of preventing trypanosome transmission. This requires a comprehensive understanding of tsetse biology and host preference to inform targeted design and management strategies, such as the use of olfaction and visual cues in tsetse traps. No current review exists on host preference and blood meal analyses of tsetse flies. METHODS This review presents a meta-analysis of tsetse fly blood meal sources and the methodologies used to identify animal hosts from 1956 to August 2022. The Preferred Reporting Items for Systematic Reviews and Meta-Analyses extension for Scoping Reviews (PRIMA-ScR) was applied. This focused on tsetse-endemic countries, blood meal analysis methodologies and the blood meal hosts identified. The articles were retrieved and screened from databases using predetermined eligibility criteria. RESULTS Only 49/393 of the articles retrieved matched the inclusion criteria. Glossina's main hosts in the wild included the bushbuck, buffalo, elephant, warthog, bushpig and hippopotamus. Pigs, livestock and humans were key hosts at the domestic interface. The least studied species included Glossina fuscipleuris, G. fusca, G. medicorum, G. tabaniformis and G. austeni. In the absence of preferred hosts, Glossina fed opportunistically on a variety of hosts. Precipitin, haemagglutination, disc diffusion, complement fixation, ELISA and PCR-based assays were used to evaluate blood meals. Cytochrome b (Cyt b) was the main target gene in PCR to identify the vertebrate hosts. CONCLUSIONS Tsetse blood meal sources have likely expanded because of ecological changes that could have rendered preferred hosts unavailable. The major approaches for analysing tsetse fly blood meal hosts targeted Cyt b gene for species identification by Sanger sequencing. However, small-fragment DNAs, such as the mammalian 12S and 16S rRNA genes, along with second- and third-generation sequencing techniques, could increase sensitivity for host identification in multiple host feeders that Sanger sequencing may misidentify as "noise". This review of tsetse fly blood meal sources and approaches to host identification could inform strategies for tsetse control.
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Affiliation(s)
- Erick Kibichiy Serem
- Department of Anatomy and Physiology, School of Health and Human Sciences, Pwani University, P.O. Box 195-80108, Kilifi, Kenya.
- Pwani University Bioscience Research Centre (PUBReC), Pwani University, P.O. Box 195-80108, Kilifi, Kenya.
| | - David Mwangi Mburu
- Pwani University Bioscience Research Centre (PUBReC), Pwani University, P.O. Box 195-80108, Kilifi, Kenya
- Department of Biological Sciences, School of Pure and Applied Sciences, Pwani University, P.O. Box 195-80108, Kilifi, Kenya
| | - Osman Abdikarim Abdullahi
- Pwani University Bioscience Research Centre (PUBReC), Pwani University, P.O. Box 195-80108, Kilifi, Kenya
- Department of Public Health, School of Health and Human Sciences, Pwani University, P.O. Box 195-80108, Kilifi, Kenya
| | - Joel Ltilitan Bargul
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology (JKUAT), P.O. Box 62000-00200, Nairobi, Kenya
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Gashururu RS, Maingi N, Githigia SM, Getange DO, Ntivuguruzwa JB, Habimana R, Cecchi G, Gashumba J, Bargul JL, Masiga DK. Trypanosomes infection, endosymbionts, and host preferences in tsetse flies ( Glossina spp.) collected from Akagera park region, Rwanda: A correlational xenomonitoring study. One Health 2023; 16:100550. [PMID: 37363264 PMCID: PMC10288097 DOI: 10.1016/j.onehlt.2023.100550] [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: 11/16/2022] [Revised: 04/10/2023] [Accepted: 04/21/2023] [Indexed: 06/28/2023] Open
Abstract
Akagera National Park and its surroundings are home to tsetse flies and a number of their mammalian hosts in Rwanda. A One-health approach is being used in the control and surveillance of both animal and human trypanosomosis in Rwanda. Determination of the infection level in tsetse flies, species of trypanosomes circulating in vectors, the source of tsetse blood meal and endosymbionts is crucial in understanding the epidemiology of the disease in animals and humans in the region. Tsetse flies (n = 1101), comprising Glossina pallidipes (n = 771) and Glossina morsitans centralis (n = 330) were collected from Akagera park and surrounding areas between May 2018 and June 2019. The flies were screened for trypanosomes, vertebrate host DNA to identify sources of blood meal, and endosymbionts by PCR - High Resolution Melting analysis and amplicon sequencing. The feeding frequency and the feeding indices (selection index - W) were calculated to identify the preferred hosts. An overall trypanosome infection rate of 13.9% in the fly's Head and Proboscis (HP) and 24.3% in the Thorax and Abdomen (TA) were found. Eight trypanosome species were identified in the tsetse fly HP and TA, namely: Trypanosoma (T.) brucei brucei, T. congolense Kilifi, T. congolense savannah, T. vivax, T. simiae, T. evansi, T. godfreyi, T. grayi and T. theileri. We found no evidence of human-infective T. brucei rhodesiense. We also identified eighteen species of vertebrate hosts that tsetse flies fed on, and the most frequent one was the buffalo (Syncerus caffer) (36.5%). The frequently detected host by selection index was the rhinoceros (Diceros bicornis) (W = 16.2). Most trypanosome infections in tsetse flies were associated with the buffalo blood meal. The prevalence of tsetse endosymbionts Sodalis and Wolbachia was 2.8% and 4.8%, respectively. No Spiroplasma and Salivary Gland Hypertrophy Virus were detected. These findings implicate the buffaloes as the important reservoirs of tsetse-transmitted trypanosomes in the area. This contributes to predicting the main cryptic reservoirs and therefore guiding the effective control of the disease. The study findings provide the key scientific information that supports the current One Health collaboration in the control and surveillance of tsetse-transmitted trypanosomosis in Rwanda.
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Affiliation(s)
- Richard S Gashururu
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
- School of Veterinary Medicine, University of Rwanda, P.O. Box 57, Nyagatare, Rwanda
| | - Ndichu Maingi
- Faculty of Veterinary Medicine, University of Nairobi, P.O. Box 29053, Nairobi, Kenya
| | - Samuel M Githigia
- Faculty of Veterinary Medicine, University of Nairobi, P.O. Box 29053, Nairobi, Kenya
| | - Dennis O Getange
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
| | - Jean B Ntivuguruzwa
- School of Veterinary Medicine, University of Rwanda, P.O. Box 57, Nyagatare, Rwanda
| | - Richard Habimana
- Food and Drugs Assessment and Registration Department, Rwanda Food and Drugs Authority (FDA), P.O Box 1948, Kigali, Rwanda
| | - Giuliano Cecchi
- Food and Agriculture Organization of the United Nations (FAO), Animal Production and Health Division, Rome, Italy
| | | | - Joel L Bargul
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
- Department of Biochemistry, Jomo Kenyatta University of Agriculture and Technology, P.O. Box 62000-00200, Nairobi, Kenya
| | - Daniel K Masiga
- International Centre of Insect Physiology and Ecology (icipe), P.O. Box 30772-00100, Nairobi, Kenya
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Ebhodaghe FI, Bastos ADS, Okal MN, Masiga DK. Entomological assessment of tsetse-borne trypanosome risk in the Shimba Hills human-wildlife-livestock interface, Kenya. Front Vet Sci 2022; 9:931078. [PMID: 36051538 PMCID: PMC9424651 DOI: 10.3389/fvets.2022.931078] [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: 04/28/2022] [Accepted: 07/08/2022] [Indexed: 11/13/2022] Open
Abstract
Shimba Hills is a wildlife area in Kenya and a major focus of tsetse-borne trypanosomes in East Africa. In Shimba Hills, tsetse-borne trypanosomes constrain animal health and smallholder livelihoods. However, epidemiological data to guide hotspot-targeted control of infections are limited. This study assessed the dynamics of tsetse-borne trypanosome risk in Shimba Hills with the objective to describe infection hotspots for targeted control. Tsetse flies (n = 696) collected in field surveys between November 2018 and September 2019 in Shimba Hills were characterized for chronological age and phenotypic sizes and screened for trypanosome and cattle DNA. Entomological inoculation rates for trypanosome risk assessment were derived from the product of fly abundance and molecular rates of vector infection and confirmed cattle bloodmeals in tsetse flies. In addition, cattle health indicators including anemia scores were assessed in contemporaneous parasitological surveys that screened livestock blood samples (n = 1,417) for trypanosome using the buffy-coat technique. Compared with Glossina brevipalpis and G. austeni, G. pallidipes was the most abundant tsetse fly species in Shimba Hills and had a wider spatial distribution and greater likelihood for infectious bites on cattle. The risk of cattle infection was similar along the Shimba Hills human-wildlife-livestock interface and high within one thousand meters of the wildlife reserve boundary. Trypanosomes in tsetse flies were highly diverse and included parasites of wild-suids probably acquired from warthogs in Shimba Hills. Age and phenotypic sizes were similar between tsetse fly populations and did not affect the probability of infection or cattle bloodmeals in the vectors. Anemia was more likely in trypanosome-positive cattle whilst parasitological infection rates in cattle samples maintained a weak relationship with entomological inoculation rates probably because of the limited time scale of sample collection. Trypanosome risk in Shimba Hills is high in locations close to the wildlife reserve and driven by G. pallidipes infectious bites on cattle. Therefore, trypanosome vector control programmes in the area should be designed to reduce G. pallidipes abundance and tailored to target sites close to the wildlife reserve.
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Affiliation(s)
- Faith I. Ebhodaghe
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
- *Correspondence: Faith I. Ebhodaghe ;
| | - Armanda D. S. Bastos
- Department of Zoology and Entomology, University of Pretoria, Pretoria, South Africa
| | - Michael N. Okal
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
| | - Daniel K. Masiga
- International Centre of Insect Physiology and Ecology, Nairobi, Kenya
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Ebhodaghe FI, Okal MN, Kalayou S, Bastos ADS, Masiga DK. Tsetse Bloodmeal Analyses Incriminate the Common Warthog Phacochoerus africanus as an Important Cryptic Host of Animal Trypanosomes in Smallholder Cattle Farming Communities in Shimba Hills, Kenya. Pathogens 2021; 10:pathogens10111501. [PMID: 34832656 PMCID: PMC8623152 DOI: 10.3390/pathogens10111501] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2021] [Revised: 10/26/2021] [Accepted: 11/02/2021] [Indexed: 11/30/2022] Open
Abstract
Trypanosomes are endemic and retard cattle health in Shimba Hills, Kenya. Wildlife in the area act as reservoirs of the parasites. However, wild animal species that harbor and expose cattle to tsetse-borne trypanosomes are not well known in Shimba Hills. Using xeno-monitoring surveillance to investigate wild animal reservoirs and sources of trypanosomes in Shimba Hills, we screened 696 trypanosome-infected and uninfected tsetse flies for vertebrate DNA using multiple-gene PCR-High Resolution Melting analysis and amplicon sequencing. Results revealed that tsetse flies fed on 13 mammalian species, preferentially Phacochoerus africanus (warthogs) (17.39%, 95% CI: 14.56–20.21) and Bos taurus (cattle) (11.35%, 95% CI: 8.99–13.71). Some tsetse flies showed positive cases of bloodmeals from multiple hosts (3.45%, 95% CI: 2.09–4.81), including warthog and cattle (0.57%, 95% CI: 0.01–1.14). Importantly, tsetse flies that took bloodmeals from warthog had significant risk of infections with Trypanosoma vivax (5.79%, 95% CI: 1.57–10.00), T. congolense (7.44%, 95% CI: 2.70–12.18), and T. brucei sl (2.48%, 95% CI: −0.33–5.29). These findings implicate warthogs as important reservoirs of tsetse-borne trypanosomes affecting cattle in Shimba Hills and provide valuable epidemiological insights to underpin the parasites targeted management in Nagana vector control programs in the area.
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Affiliation(s)
- Faith I. Ebhodaghe
- International Centre of Insect Physiology and Ecology, Nairobi P.O. Box 30772-00100, Kenya; (M.N.O.); (S.K.)
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Pretoria Hatfield 0083, South Africa;
- Correspondence: (F.I.E.); (D.K.M.)
| | - Michael N. Okal
- International Centre of Insect Physiology and Ecology, Nairobi P.O. Box 30772-00100, Kenya; (M.N.O.); (S.K.)
| | - Shewit Kalayou
- International Centre of Insect Physiology and Ecology, Nairobi P.O. Box 30772-00100, Kenya; (M.N.O.); (S.K.)
| | - Armanda D. S. Bastos
- Department of Zoology and Entomology, University of Pretoria, Private Bag X20, Pretoria Hatfield 0083, South Africa;
| | - Daniel K. Masiga
- International Centre of Insect Physiology and Ecology, Nairobi P.O. Box 30772-00100, Kenya; (M.N.O.); (S.K.)
- Correspondence: (F.I.E.); (D.K.M.)
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