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Vale GA, Hargrove JW, Hope A, Torr SJ. Modelled impact of Tiny Targets on the distribution and abundance of riverine tsetse. PLoS Negl Trop Dis 2024; 18:e0011578. [PMID: 38626189 PMCID: PMC11051647 DOI: 10.1371/journal.pntd.0011578] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2023] [Revised: 04/26/2024] [Accepted: 04/01/2024] [Indexed: 04/18/2024] Open
Abstract
BACKGROUND The insecticide-treated baits known as Tiny Targets are one of the cheapest means of controlling riverine species of tsetse flies, the vectors of the trypanosomes that cause sleeping sickness in humans. Models of the efficacy of these targets deployed near rivers are potentially useful in planning control campaigns and highlighting the principles involved. METHODS AND PRINCIPAL FINDINGS To evaluate the potential of models, we produced a simple non-seasonal model of the births, deaths, mobility and aging of tsetse, and we programmed it to simulate the impact of seven years of target use against the tsetse, Glossina fuscipes fuscipes, in the riverine habitats of NW Uganda. Particular attention was given to demonstrating that the model could explain three matters of interest: (i) good control can be achieved despite the degradation of targets, (ii) local elimination of tsetse is impossible if invasion sources are not tackled, and (iii) with invasion and target degradation it is difficult to detect any effect of control on the age structure of the tsetse population. CONCLUSIONS Despite its simplifications, the model can assist planning and teaching, but allowance should be made for any complications due to seasonality and management challenges associated with greater scale.
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Affiliation(s)
- Glyn A. Vale
- South African Centre for Epidemiological Modelling and Analysis, University of Stellenbosch, Stellenbosch, South Africa
- Natural Resources Institute, University of Greenwich, Chatham, United Kingdom
| | - John W. Hargrove
- South African Centre for Epidemiological Modelling and Analysis, University of Stellenbosch, Stellenbosch, South Africa
| | - Andrew Hope
- Liverpool School of Tropical Medicine, Liverpool, Merseyside, United Kingdom
| | - Steve J. Torr
- Liverpool School of Tropical Medicine, Liverpool, Merseyside, United Kingdom
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2
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Mugenyi A, Muhanguzi D, Hendrickx G, Nicolas G, Waiswa C, Torr S, Welburn SC, Atkinson PM. Spatial analysis of G.f.fuscipes abundance in Uganda using Poisson and Zero-Inflated Poisson regression models. PLoS Negl Trop Dis 2021; 15:e0009820. [PMID: 34871296 PMCID: PMC8648107 DOI: 10.1371/journal.pntd.0009820] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 09/17/2021] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Tsetse flies are the major vectors of human trypanosomiasis of the form Trypanosoma brucei rhodesiense and T.b.gambiense. They are widely spread across the sub-Saharan Africa and rendering a lot of challenges to both human and animal health. This stresses effective agricultural production and productivity in Africa. Delimiting the extent and magnitude of tsetse coverage has been a challenge over decades due to limited resources and unsatisfactory technology. In a bid to overcome these limitations, this study attempted to explore modelling skills that can be applied to spatially estimate tsetse abundance in the country using limited tsetse data and a set of remote-sensed environmental variables. METHODOLOGY Entomological data for the period 2008-2018 as used in the model were obtained from various sources and systematically assembled using a structured protocol. Data harmonisation for the purposes of responsiveness and matching was carried out. The key tool for tsetse trapping was itemized as pyramidal trap in many instances and biconical trap in others. Based on the spatially explicit assembled data, we ran two regression models; standard Poisson and Zero-Inflated Poisson (ZIP), to explore the associations between tsetse abundance in Uganda and several environmental and climatic covariates. The covariate data were constituted largely by satellite sensor data in form of meteorological and vegetation surrogates in association with elevation and land cover data. We finally used the Zero-Inflated Poisson (ZIP) regression model to predict tsetse abundance due to its superiority over the standard Poisson after model fitting and testing using the Vuong Non-Nested statistic. RESULTS A total of 1,187 tsetse sampling points were identified and considered as representative for the country. The model results indicated the significance and level of responsiveness of each covariate in influencing tsetse abundance across the study area. Woodland vegetation, elevation, temperature, rainfall, and dry season normalised difference vegetation index (NDVI) were important in determining tsetse abundance and spatial distribution at varied scales. The resultant prediction map shows scaled tsetse abundance with estimated fitted numbers ranging from 0 to 59 flies per trap per day (FTD). Tsetse abundance was found to be largest at low elevations, in areas of high vegetative activity, in game parks, forests and shrubs during the dry season. There was very limited responsiveness of selected predictors to tsetse abundance during the wet season, matching the known fact that tsetse disperse most significantly during wet season. CONCLUSIONS A methodology was advanced to enable compilation of entomological data for 10 years, which supported the generation of tsetse abundance maps for Uganda through modelling. Our findings indicate the spatial distribution of the G. f. fuscipes as; low 0-5 FTD (48%), medium 5.1-35 FTD (18%) and high 35.1-60 FTD (34%) grounded on seasonality. This approach, amidst entomological data shortages due to limited resources and absence of expertise, can be adopted to enable mapping of the vector to provide better decision support towards designing and implementing targeted tsetse and tsetse-transmitted African trypanosomiasis control strategies.
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Affiliation(s)
- Albert Mugenyi
- Coordinating Office for Control of Trypanosomiasis in Uganda, Ministry of Agriculture, Animal Industry and Fisheries, Kampala, Uganda
- School of Biomedical Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, United Kingdom
- * E-mail:
| | - Dennis Muhanguzi
- College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | | | | | - Charles Waiswa
- Coordinating Office for Control of Trypanosomiasis in Uganda, Ministry of Agriculture, Animal Industry and Fisheries, Kampala, Uganda
- College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Steve Torr
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Susan Christina Welburn
- School of Biomedical Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, United Kingdom
- International Campus, ZJU-UoE Institute, Zhejiang University School of Medicine, Zhejiang University, Zhejiang, China
| | - Peter M. Atkinson
- Faculty of Science and Technology, Lancaster University, Lancaster, United Kingdom
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3
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Kizza D, Ocaido M, Mugisha A, Azuba R, Nalule S, Onyuth H, Musinguzi SP, Okwasiimire R, Waiswa C. Prevalence and risk factors for trypanosome infection in cattle from communities surrounding the Murchison Falls National Park, Uganda. Parasit Vectors 2021; 14:513. [PMID: 34620230 PMCID: PMC8499574 DOI: 10.1186/s13071-021-04987-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: 02/18/2021] [Accepted: 08/31/2021] [Indexed: 11/10/2022] Open
Abstract
Background Bovine trypanosomosis transmitted by tsetse flies is a major constraint to cattle health and productivity in all sub-Saharan countries, including Uganda. The objectives of this study were to determine the prevalence of bovine trypanosomosis and identify its associated risk factors and the species of trypanosomes associated with the disease. Methodology A cross-sectional study was conducted around Murchison Falls National Park, Uganda from January 2020 to April 2020. Trypanosomes were detected in blood samples by PCR analysis targeting the internal transcribed spacer 1 (ITS-PCR assays), and trypanosomes in positive blood samples were sequenced. Results Of 460 blood samples collected and tested, 136 (29.6%) were positive for trypanosome infections and 324 (70.4%) were negative. The overall trypanosome prevalence was 29.6% (95% confidence interval 25.4–33.8%), attributed to three trypanosome species. Of these three species, Trypanosoma vivax was the most prevalent (n = 130, 28.3%) while the others were detected as mixed infections: T. vivax + Trypanosomacongolense (n = 2, 0.4%) and T. vivax + Trypanosomaevansi (n = 1, 0.2%). There were significant differences in trypanosome prevalence according to sex (χ2 = 62, df = 1, P < 0.05), age (χ2 = 6.28, df = 2, P = 0.0043) and cattle breed (χ2 = 10.61, df = 1, P = 0.001). Conclusions Trypanosomosis remains a major limitation to cattle production around Murchison Falls National Park and interventions are urgently needed. In our study, the prevalence of trypanosome infections was high, with T. vivax identified as the most prevalent species. Age, sex and breed of cattle were risk factors for trypanosome infection. Graphical Abstract ![]()
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Affiliation(s)
- Daniel Kizza
- Department of Livestock and Industrial Resources, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda.
| | - Michael Ocaido
- Department of Wildlife, Aquatic and Animal Resources College of Veterinary Medicine Animal Resources, Biosecurity Makerere University, Kampala, Uganda
| | - Anthony Mugisha
- Department of Livestock and Industrial Resources, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Rose Azuba
- Department of Livestock and Industrial Resources, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Sarah Nalule
- Department of Wildlife, Aquatic and Animal Resources College of Veterinary Medicine Animal Resources, Biosecurity Makerere University, Kampala, Uganda
| | - Howard Onyuth
- Department of Wildlife, Aquatic and Animal Resources College of Veterinary Medicine Animal Resources, Biosecurity Makerere University, Kampala, Uganda
| | - Simon Peter Musinguzi
- Department of Agriculture, Faculty of Vocational studies, Kyambogo University, P.0 Box 1 Kyambogo, Kampala, Uganda
| | - Rodney Okwasiimire
- Central Diagnostic Laboratory, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Charles Waiswa
- Department of Veterinary Pharmacy, Clinical and Comparative Medicine, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
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Okello WO, MacLeod ET, Muhanguzi D, Waiswa C, Shaw AP, Welburn SC. Critical Linkages Between Livestock Production, Livestock Trade and Potential Spread of Human African Trypanosomiasis in Uganda: Bioeconomic Herd Modeling and Livestock Trade Analysis. Front Vet Sci 2021; 8:611141. [PMID: 34381829 PMCID: PMC8350160 DOI: 10.3389/fvets.2021.611141] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2020] [Accepted: 06/28/2021] [Indexed: 11/13/2022] Open
Abstract
Background: Tsetse-transmitted human African trypanosomiasis (HAT) remains endemic in Uganda. The chronic form caused by Trypanosoma brucei gambiense (gHAT) is found in north-western Uganda, whereas the acute zoonotic form of the disease, caused by T. b. brucei rhodesiense (rHAT), occurs in the eastern region. Cattle is the major reservoir of rHAT in Uganda. These two forms of HAT are likely to converge resulting in a public health disaster. This study examines the intricate and intrinsic links between cattle herd dynamics, livestock trade and potential risk of spread of rHAT northwards. Methods: A bio-economic cattle herd model was developed to simulate herd dynamics at the farm level. Semi-structured interviews (n = 310), focus group discussions (n = 9) and key informant interviews (n = 9) were used to evaluate livestock markets (n = 9) as part of the cattle supply chain analysis. The cattle market data was used for stochastic risk analysis. Results: Cattle trade in eastern and northern Uganda is dominated by sale of draft and adult male cattle as well as exportation of young male cattle. The study found that the need to import draft cattle at the farm level was to cover deficits because of the herd structure, which is mostly geared towards animal traction. The importation and exportation of draft cattle and disposal of old adult male cattle formed the major basis of livestock movement and could result in the spread of rHAT northwards. The risk of rHAT infected cattle being introduced to northern Uganda from the eastern region via cattle trade was found to be high (i.e. probability of 1). Conclusion: Through deterministic and stochastic modelling of cattle herd and cattle trade dynamics, this study identifies critical links between livestock production and trade as well as potential risk of rHAT spread in eastern and northern Uganda. The findings highlight the need for targeted and routine surveillance and control of zoonotic diseases such as rHAT.
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Affiliation(s)
- Walter O Okello
- Infection Medicine, Biomedical Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom.,Land & Water Business Unit, Commonwealth Scientific and Industrial Research Organisation (CSIRO), Canberra, ACT, Australia
| | - Ewan T MacLeod
- Infection Medicine, Biomedical Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom
| | - Dennis Muhanguzi
- Department of Biomolecular and Biolaboratory Sciences, School of Biosecurity, Biotechnical and Laboratory Sciences, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Charles Waiswa
- Infection Medicine, Biomedical Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom.,The Coordinating Office for Control of Trypanosomiasis in Uganda (COCTU), Kampala, Uganda
| | - Alexandra P Shaw
- Infection Medicine, Biomedical Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom.,Avia-GIS, Zoersel, Belgium
| | - Susan C Welburn
- Infection Medicine, Biomedical Sciences, Edinburgh Medical School, College of Medicine and Veterinary Medicine, University of Edinburgh, Edinburgh, United Kingdom.,Zhejiang University-University of Edinburgh Institute, Zhejiang University School of Medicine, Zhejiang University, Haining, China
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5
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Kizza D, Ocaido M, Mugisha A, Azuba R, Nalule S, Onyuth H, Musinguzi SP, Nalubwama S, Waiswa C. Knowledge, attitudes and practices on bovine trypanosomosis control in pastoral and agro pastoral communities surrounding Murchison Falls National Park, Uganda. Trop Anim Health Prod 2021; 53:309. [PMID: 33963468 DOI: 10.1007/s11250-021-02752-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Accepted: 05/02/2021] [Indexed: 10/21/2022]
Abstract
A mixed method survey was conducted among pastoral and agro pastoral communities surrounding Murchison Falls National Park, Uganda to assess knowledge, attitudes and practices about control of bovine trypanosomosis. A total of 96.8% (n = 152) of the participants had seen tsetse flies, and close to 91.7% (n = 116) of the participants had heard about bovine trypanosomosis. Bovine trypanosomosis was reported as a major disease in their area by about 73.9% (n = 116). There was a significant difference (P < 0.05) in the level of awareness and perception about tsetse and bovine trypanosomosis across the study sub counties. The majority of the farmers (60.5%) stated that grazing near national parks was the main cause of bovine trypanosomosis. A small proportion of farmers associated sharing grazing land and watering points with wildlife (19.1%) and grazing cattle in tsetse fly-infested areas (8.3%) as the causes of trypanosomosis. The communities in the study sub counties were aware of at least one or two clinical signs of bovine trypanosomosis. Spraying cattle with insecticide and avoiding grazing animals in tsetse-infested areas were the control practices. Curative trypanocides were mainly used to treat their cattle against trypanosomosis. Bush clearing, targets and traps as tsetse fly control measures were less practiced by the farmers. Treatment of cattle was based on observation of clinical signs due to absence of blood diagnostic facilities. Implementing regular tsetse fly population monitoring surveys and promotion of disease rapid diagnostic tools at farm level as long-term strategies are key for effective control of the disease.
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Affiliation(s)
- Daniel Kizza
- Department of Livestock and Industrial Resources, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda.
| | - Michael Ocaido
- Department of Wildlife, Aquatic and Animal Resources, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Anthony Mugisha
- Department of Livestock and Industrial Resources, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Rose Azuba
- Department of Livestock and Industrial Resources, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Sarah Nalule
- Department of Wildlife, Aquatic and Animal Resources, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Howard Onyuth
- Department of Wildlife, Aquatic and Animal Resources, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Simon Peter Musinguzi
- Department of Animal Sciences, Faculty of Agriculture and Environmental Sciences, Kabale University, Kabale, Uganda
| | - Sylvia Nalubwama
- Department of Livestock and Industrial Resources, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Charles Waiswa
- Department of Veterinary Pharmacy, Clinical and Comparative Medicine, College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
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Nnko HJ, Gwakisa PS, Ngonyoka A, Sindato C, Estes AB. Potential impacts of climate change on geographical distribution of three primary vectors of African Trypanosomiasis in Tanzania's Maasai Steppe: G. m. morsitans, G. pallidipes and G. swynnertoni. PLoS Negl Trop Dis 2021; 15:e0009081. [PMID: 33571190 PMCID: PMC7904224 DOI: 10.1371/journal.pntd.0009081] [Citation(s) in RCA: 9] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/01/2020] [Revised: 02/24/2021] [Accepted: 12/16/2020] [Indexed: 12/03/2022] Open
Abstract
In the Maasai Steppe, public health and economy are threatened by African Trypanosomiasis, a debilitating and fatal disease to livestock (African Animal Trypanosomiasis -AAT) and humans (Human African Trypanosomiasis—HAT), if not treated. The tsetse fly is the primary vector for both HAT and AAT and climate is an important predictor of their occurrence and the parasites they carry. While understanding tsetse fly distribution is essential for informing vector and disease control strategies, existing distribution maps are old and were based on coarse spatial resolution data, consequently, inaccurately representing vector and disease dynamics necessary to design and implement fit-for-purpose mitigation strategies. Also, the assertion that climate change is altering tsetse fly distribution in Tanzania lacks empirical evidence. Despite tsetse flies posing public health risks and economic hardship, no study has modelled their distributions at a scale needed for local planning. This study used MaxEnt species distribution modelling (SDM) and ecological niche modeling tools to predict potential distribution of three tsetse fly species in Tanzania’s Maasai Steppe from current climate information, and project their distributions to midcentury climatic conditions under representative concentration pathways (RCP) 4.5 scenarios. Current climate results predicted that G. m. morsitans, G. pallidipes and G swynnertoni cover 19,225 km2, 7,113 km2 and 32,335 km2 and future prediction indicated that by the year 2050, the habitable area may decrease by up to 23.13%, 12.9% and 22.8% of current habitable area, respectively. This information can serve as a useful predictor of potential HAT and AAT hotspots and inform surveillance strategies. Distribution maps generated by this study can be useful in guiding tsetse fly control managers, and health, livestock and wildlife officers when setting surveys and surveillance programs. The maps can also inform protected area managers of potential encroachment into the protected areas (PAs) due to shrinkage of tsetse fly habitats outside PAs. Spatial variation of African Trypanosomiasis burden depends on distribution of biotopes necessary for tsetse flies to thrive. Therefore, mapping the occurrence of the tsetse fly species is a useful predictor of African Trypanosomiasis transmission risk areas. Climate is a major determining factor for occurrence and survival of tsetse flies, the vector responsible for both HAT and AAT. Since resources for prevention and control of tsetse fly species and the disease they transmit are generally scarce in endemic settings, understanding potential impacts of climate change on tsetse fly species distribution in space and time is essential for informing coherent strategies for vector and disease control at a local scale.
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Affiliation(s)
| | | | | | - Calvin Sindato
- National Institute for Medical Research, Tabora, Tanzania
- Southern African Centre for Infectious Disease Surveillance, Morogoro Tanzania
| | - Anna Bond Estes
- Carleton College, Northfield, Minnesota, USA
- The Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
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Odeniran PO, Onifade AA, MacLeod ET, Ademola IO, Alderton S, Welburn SC. Mathematical modelling and control of African animal trypanosomosis with interacting populations in West Africa-Could biting flies be important in main taining the disease endemicity? PLoS One 2020; 15:e0242435. [PMID: 33216770 PMCID: PMC7679153 DOI: 10.1371/journal.pone.0242435] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2020] [Accepted: 11/02/2020] [Indexed: 12/03/2022] Open
Abstract
African animal trypanosomosis (AAT) is transmitted cyclically by tsetse flies and mechanically by biting flies (tabanids and stomoxyines) in West Africa. AAT caused by Trypanosoma congolense, T. vivax and T. brucei brucei is a major threat to the cattle industry. A mathematical model involving three vertebrate hosts (cattle, small ruminants and wildlife) and three vector flies (Tsetse flies, tabanids and stomoxyines) was described to identify elimination strategies. The basic reproduction number (R0) was obtained with respect to the growth rate of infected wildlife (reservoir hosts) present around the susceptible population using a next generation matrix technique. With the aid of suitable Lyapunov functions, stability analyses of disease-free and endemic equilibria were established. Simulation of the predictive model was presented by solving the system of ordinary differential equations to explore the behaviour of the model. An operational area in southwest Nigeria was simulated using generated pertinent data. The R0 < 1 in the formulated model indicates the elimination of AAT. The comprehensive use of insecticide treated targets and insecticide treated cattle (ITT/ITC) affected the feeding tsetse and other biting flies resulting in R0 < 1. The insecticide type, application timing and method, expertise and environmental conditions could affect the model stability. In areas with abundant biting flies and no tsetse flies, T. vivax showed R0 > 1 when infected wildlife hosts were present. High tsetse populations revealed R0 <1 for T. vivax when ITT and ITC were administered, either individually or together. Elimination of the transmitting vectors of AAT could cost a total of US$ 1,056,990 in southwest Nigeria. Hence, AAT in West Africa can only be controlled by strategically applying insecticides targeting all transmitting vectors, appropriate use of trypanocides, and institutionalising an appropriate barrier between the domestic and sylvatic areas.
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Affiliation(s)
- Paul Olalekan Odeniran
- Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria
- Infection Medicine, Biomedical Sciences, University of Edinburgh, Scotland, United Kingdom
- * E-mail:
| | | | - Ewan Thomas MacLeod
- Infection Medicine, Biomedical Sciences, University of Edinburgh, Scotland, United Kingdom
| | - Isaiah Oluwafemi Ademola
- Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria
| | - Simon Alderton
- Centre for Health Informatics, Computing and Statistics (CHICAS), Lancaster Medical School, Lancaster University, Lancaster, United Kingdom
| | - Susan Christina Welburn
- Infection Medicine, Biomedical Sciences, University of Edinburgh, Scotland, United Kingdom
- Zhejiang University - University of Edinburgh Joint Institute, Zhejiang University, Haining, China
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Waiswa C, Azuba R, Makeba J, Waiswa IC, Wangoola RM. Experiences of the one-health approach by the Uganda Trypanosomiasis Control Council and its secretariat in the control of zoonotic sleeping sickness in Uganda. Parasite Epidemiol Control 2020; 11:e00185. [PMID: 33015381 PMCID: PMC7518742 DOI: 10.1016/j.parepi.2020.e00185] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/08/2019] [Revised: 08/28/2020] [Accepted: 09/20/2020] [Indexed: 11/30/2022] Open
Abstract
Elimination of sleeping sickness from endemic countries like Uganda is key if the affected communities are to exploit the potential of the available human and livestock resources (production and productivity). Trypanosoma brucei rhodesiense, the parasite that causes acute sleeping sickness in humans, is transmitted by tsetse flies and co-exists in non-human animal reservoirs. Uganda by Act of Parliament in 1992 decided to handle the complex approach to control of sleeping sickness and animal trypanosomiasis by establishing the Uganda Trypanosomiasis Control Council (UTCC) and its secretariat the Coordinating Office for the Control of Trypanosomiasis in Uganda (COCTU). The Institutional arrangement aimed to promote engagement with key stakeholders across nine key ministries and the community, all vital for control of zoonotic sleeping sickness, creating a One Health platform, long before such practice was common. From 2006, approaches by the Public Private Partnership, Stamp Out Sleeping Sickness (SOS) have required involvement of stakeholders in the promotion of insecticide treated cattle as live tsetse baits, targeting elimination of zoonotic sleeping sickness. Experiences in promoting sustainability of these interventions have been captured in this study as part of the Tackling Infections to Benefit Africa (TIBA) partnership. Meeting transcripts, focus group discussions and questionnaires were used to collect data from the different stakeholders involved in a rapid impact live bait study over 12 months from Dec 2017. The study provides unprecedented insights into the stakeholders involved in the application of a One health approach for control of zoonotic sleeping sickness across the most important active human African trypanosomiasis focus in East Africa. This unique study is fundamental in guiding multi-stakeholder engagement if the goal to eliminate zoonotic sleeping sickness is to be realised. A major challenge is timely feedback to the community as regards human and animal disease status; rapid diagnostic services that can be delivered from facilities established in close proximity to the affected communities and well equipped in-country reference laboratories are key to delivering effective control and best One Health Approach.
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Affiliation(s)
- C Waiswa
- Coordinating Office for the Control of Trypanosomiasis in Uganda (COCTU), P.O Box 16345, Wandegeya, Kampala, Uganda.,School of Veterinary Medicine, Makerere University, P.O Box 7062, Kampala, Uganda
| | - R Azuba
- School of Veterinary Medicine, Makerere University, P.O Box 7062, Kampala, Uganda
| | - J Makeba
- High Heights Services Limited, P.O Box 21828, Kampala, Uganda
| | - I C Waiswa
- Student Support and Philanthropy Program, P.O. Box 21828, Kampala, Uganda
| | - R M Wangoola
- Coordinating Office for the Control of Trypanosomiasis in Uganda (COCTU), P.O Box 16345, Wandegeya, Kampala, Uganda
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9
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Adungo F, Mokaya T, Makwaga O, Mwau M. Tsetse distribution, trypanosome infection rates, and small-holder livestock producers' capacity enhancement for sustainable tsetse and trypanosomiasis control in Busia, Kenya. Trop Med Health 2020; 48:62. [PMID: 32760194 PMCID: PMC7393918 DOI: 10.1186/s41182-020-00249-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/14/2020] [Accepted: 07/21/2020] [Indexed: 11/20/2022] Open
Abstract
BACKGROUND Tsetse flies are the cyclical vectors of both human and animal diseases. Kenya's commitment to eradicate tsetse and trypanosomiasis dates to the 1980s through various control approaches which were spearheaded by the African Union. The aggressive control programmes together with climatic, land-use, and socio-economic changes immensely contributed to the reduction of African trypanosomiasis. Since 2012, Kenya has not recorded a case of human trypanosomiasis. However, African animal trypanosomiasis remains a major challenge to livestock production in 38 out of 47 counties. We aimed to determine the prevalence of tsetse flies and trypanosome infection rate and to build the capacity of small-holder livestock producers in vector control activities in Busia county. METHODS This cross-sectional study was conducted between May 2018 and December 2018 in Busia county, a beneficiary of the previous African Union-led trypanosomiasis and tsetse control initiatives. Odour-baited biconical traps were deployed for 48 h in five sampling areas. Captured tsetse flies were analysed by microscopy for trypanosome infections. Additionally, training and field demonstrations were conducted as part of capacity building to enhance participation of small-holder livestock producers in tsetse control activities. RESULTS A total of 94 tsetse flies mainly Glossina fuscipes fuscipes were captured from the five sampling areas. The apparent fly densities range from 0.08 to 1.55 tsetse per trap per day. Additionally, 75 biting flies mainly Stomoxys spp. were also trapped. An overall tsetse infection rate of 1.39% and 4.17% was observed for Trypanosoma congolense and Trypanosoma vivax, respectively. Regarding capacity building, a total of 26 small-holder livestock producers were trained on tsetse and trypanosomiasis control activities. Out of which, five were selected as focal persons and were further trained on integrated vector management techniques and tsetse survey methods. CONCLUSIONS Our findings revealed the existence of trypanosome-infected tsetse flies which could potentially spread to other parts of the county. Training of small-holder livestock producers in tsetse and trypanosomiasis control activities should be supported and integrated in the county animal health and veterinary services. Given the observed low tsetse densities and trypanosome infection rates, the elimination of trypanosomiasis in Busia county is feasible.
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Affiliation(s)
- Ferdinard Adungo
- Kenya Medical Research Institute, P.O. Box 54840-00200, Nairobi, Kenya
| | - Tom Mokaya
- Kenya Medical Research Institute, P.O. Box 54840-00200, Nairobi, Kenya
| | - Olipher Makwaga
- Kenya Medical Research Institute, P.O. Box 54840-00200, Nairobi, Kenya
| | - Matilu Mwau
- Kenya Medical Research Institute, P.O. Box 54840-00200, Nairobi, Kenya
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Odeniran PO, Macleod ET, Ademola IO, Welburn SC. Molecular identification of bloodmeal sources and trypanosomes in Glossina spp., Tabanus spp. and Stomoxys spp. trapped on cattle farm settlements in southwest Nigeria. MEDICAL AND VETERINARY ENTOMOLOGY 2019; 33:269-281. [PMID: 30730048 DOI: 10.1111/mve.12358] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/31/2018] [Revised: 12/03/2018] [Accepted: 12/18/2018] [Indexed: 06/09/2023]
Abstract
The interactions of host, vector and parasite in bovine trypanosomiasis transmission cycles in southwest Nigeria are not yet well understood. Trypanosoma (Trypanosomatida: Trypanosomatidae) species infection prevalences and bloodmeal sources were determined in transmitting vectors of the genera Glossina (Diptera: Glossinidae), Tabanus (Diptera: Tabanidae) and Stomoxys (Diptera: Muscidae) collected using Nzi traps in cattle settlements in southwest Nigeria. Sequenced cytochrome B mitochondrial DNA segments obtained from vector digestive tracts identified bloodmeal sources from eight host species, namely human, cattle, hippopotamus, giraffe, gazelle, spotted hyena, long-tailed rat and one unidentified species. Overall, 71.1% [95% confidence interval (CI) 63.0-78.1], 33.3% (95% CI 21.9-47.0) and 22.2% (95% CI 16.2-29.9), respectively, of Glossina, Tabanus and Stomoxys flies were positive for trypanosomes. The observed trypanosome species were Trypanosoma vivax, Trypanosoma congolense, Trypanosoma brucei, Trypanosoma evansi, Trypanosoma simiae and Trypanosoma godfreyi. Trypanosome DNA was more prevalent in tsetse (34.8% Tr. vivax, 51.1% Tr. b. brucei, 5.2% Tr. congolense, 4.4% Tr. simiae and 24.4% mixed infections) than in other flies and the main determinants in all flies were seasonal factors and host availability. To the best of the present group's knowledge, this is the first report of Trypanosoma species in Tabanus and Stomoxys flies in Nigeria. It indicates that vector control programmes should always consider biting flies along with tsetse flies in the control of human and animal trypanosomiasis.
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Affiliation(s)
- P O Odeniran
- Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria
- Division of Infection and Pathway Medicine, University of Edinburgh, Edinburgh, U.K
| | - E T Macleod
- Division of Infection and Pathway Medicine, University of Edinburgh, Edinburgh, U.K
| | - I O Ademola
- Department of Veterinary Parasitology and Entomology, Faculty of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria
| | - S C Welburn
- Division of Infection and Pathway Medicine, University of Edinburgh, Edinburgh, U.K
- Zhejiang University-University of Edinburgh Joint Institute, Zhejiang University, Haining, China
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11
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Odeniran PO, Ademola IO. Alighting and Feeding Behavior of Trypanosome-Transmitting Vectors on Cattle in Nigeria. JOURNAL OF MEDICAL ENTOMOLOGY 2018; 55:1594-1601. [PMID: 30137423 DOI: 10.1093/jme/tjy139] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/15/2018] [Indexed: 06/08/2023]
Abstract
Vector control is important to effectively prevent trypanosomiasis. Therefore, alighting and feeding responses of trypanosome-transmitting vectors were conducted in Nigeria. The aim of this study was to assess the landing preference, level of fly annoyance on cattle, and feeding behavior by direct observation of cows, bulls, and calves. The percentage of Glossina species, Tabanus species, and stomoxyine that fed on cattle blood after landing varied according to the age and sex of the cattle host. Although most flies left the cattle host before completing their meal because of host defensive behaviors, an average of 78, 19.6, and 10.2% of Glossina, Tabanus, and stomoxyines, respectively, were fully engorged. The longest mean feeding time was observed in Glossina. Over more than 90% of Glossina spp. landed on the belly and legs. Most Tabanus spp. (85%) also landed on the belly and legs while Tabanus par Walker (Diptera: Tabanidae) often landed on the back (45%). Half of Stomoxys species landed on the head and neck. Vector flies' feeding success varied according to cattle host age and was negatively correlated with defensive host behaviors and apparent fly density. Hence, fly defensive behaviors contribute to trypanosomiasis dynamics in a cattle herd, and expended energy from defensive behaviors could adversely affect productivity.
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Affiliation(s)
- Paul Olalekan Odeniran
- Department of Veterinary Parasitology, Faculty of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria
- Deanery of Biomedical Sciences, Edinburgh Medical School, College of Medicine & Veterinary Medicine, The University of Edinburgh, Edinburgh, UK
| | - Isaiah Oluwafemi Ademola
- Department of Veterinary Parasitology, Faculty of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria
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12
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Krafsur ES, Maudlin I. Tsetse fly evolution, genetics and the trypanosomiases - A review. INFECTION GENETICS AND EVOLUTION 2018; 64:185-206. [PMID: 29885477 DOI: 10.1016/j.meegid.2018.05.033] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/24/2018] [Revised: 05/30/2018] [Accepted: 05/31/2018] [Indexed: 01/27/2023]
Abstract
This reviews work published since 2007. Relative efforts devoted to the agents of African trypanosomiasis and their tsetse fly vectors are given by the numbers of PubMed accessions. In the last 10 years PubMed citations number 3457 for Trypanosoma brucei and 769 for Glossina. The development of simple sequence repeats and single nucleotide polymorphisms afford much higher resolution of Glossina and Trypanosoma population structures than heretofore. Even greater resolution is offered by partial and whole genome sequencing. Reproduction in T. brucei sensu lato is principally clonal although genetic recombination in tsetse salivary glands has been demonstrated in T. b. brucei and T. b. rhodesiense but not in T. b. gambiense. In the past decade most genetic attention was given to the chief human African trypanosomiasis vectors in subgenus Nemorhina e.g., Glossina f. fuscipes, G. p. palpalis, and G. p. gambiense. The chief interest in Nemorhina population genetics seemed to be finding vector populations sufficiently isolated to enable efficient and long-lasting suppression. To this end estimates were made of gene flow, derived from FST and its analogues, and Ne, the size of a hypothetical population equivalent to that under study. Genetic drift was greater, gene flow and Ne typically lesser in savannah inhabiting tsetse (subgenus Glossina) than in riverine forms (Nemorhina). Population stabilities were examined by sequential sampling and genotypic analysis of nuclear and mitochondrial genomes in both groups and found to be stable. Gene frequencies estimated in sequential samplings differed by drift and allowed estimates of effective population numbers that were greater for Nemorhina spp than Glossina spp. Prospects are examined of genetic methods of vector control. The tsetse long generation time (c. 50 d) is a major contraindication to any suggested genetic method of tsetse population manipulation. Ecological and modelling research convincingly show that conventional methods of targeted insecticide applications and traps/targets can achieve cost-effective reduction in tsetse densities.
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Affiliation(s)
- E S Krafsur
- Department of Entomology, Iowa State University, Ames, IA 50011, USA.
| | - Ian Maudlin
- School of Biomedical Sciences, The University of Edinburgh, Scotland, UK
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Ochwo S, VanderWaal K, Munsey A, Ndekezi C, Mwebe R, Okurut ARA, Nantima N, Mwiine FN. Spatial and temporal distribution of lumpy skin disease outbreaks in Uganda (2002-2016). BMC Vet Res 2018; 14:174. [PMID: 29859091 PMCID: PMC5984736 DOI: 10.1186/s12917-018-1503-3] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/22/2018] [Accepted: 05/24/2018] [Indexed: 11/24/2022] Open
Abstract
BACKGROUND Lumpy skin disease (LSD) is a devastating transboundary viral disease of cattle which causes significant loss in production. Although this disease has been reported in Uganda and throughout East Africa, there is almost no information about its epidemiology, spatial or spatio-temporal distribution. We carried out a retrospective study on the epidemiology of LSD in Uganda between the years 2002 and 2016, using data on reported outbreaks collected monthly by the central government veterinary administration. Descriptive statistics were computed on frequency of outbreaks, number of cases, vaccinations and deaths. We evaluated differences in the number of reported outbreaks across different regions (agro-ecological zones), districts, months and years. Spatial, temporal and space-time scan statistics were used to identify possible epidemiological clusters of LSD outbreaks. RESULTS A total of 1161 outbreaks and 319,355 cases of LSD were reported from 55 out of 56 districts of Uganda. There was a significant difference in incidence between years (P = 0.007) and across different regions. However, there was no significant difference in the number of outbreaks per month (P = 0.443). The Central region reported the highest number of outbreaks (n = 418, 36%) followed by Eastern (n = 372, 32%), Southwestern (n = 140, 12%), Northern (n = 131, 11%), Northeastern (n = 37, 3%), Western (n = 41, 4%) and Northwestern (n = 22, 2%) regions. Several endemic hotspots for the circulation of LSD were identified in the Central and Eastern regions using spatial cluster analyses. Outbreaks in endemic hotspots were less seasonal and had strikingly lower mortality and case-fatality rates than the other regions, suggesting an underlying difference in the epidemiology and impact of LSD in these different zones. CONCLUSION Lumpy Skin disease is endemic in Uganda, with outbreaks occurring annually in all regions of the country. We identified potential spatial hotspots for LSD outbreaks, underlining the need for risk-based surveillance to establish the actual disease prevalence and risk factors for disease maintenance. Space-time analysis revealed that sporadic LSD outbreaks tend to occur both within and outside of endemic areas. The findings from this study will be used as a baseline for further epidemiological studies for the development of sustainable programmes towards the control of LSD in Uganda.
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Affiliation(s)
- Sylvester Ochwo
- College of Veterinary Medicine, Animal resources and Biosecurity, Makerere University, P.O.BOX 7062 Kampala, Uganda
| | - Kimberly VanderWaal
- College of Veterinary Medicine, University of Minnesota, 1365 Gortner Avenue, St. Paul, MN 55108 USA
| | - Anna Munsey
- College of Veterinary Medicine, University of Minnesota, 1365 Gortner Avenue, St. Paul, MN 55108 USA
| | - Christian Ndekezi
- College of Veterinary Medicine, Animal resources and Biosecurity, Makerere University, P.O.BOX 7062 Kampala, Uganda
| | - Robert Mwebe
- Ministry of Agriculture Animal Industry & Fisheries, Berkley Ln, Entebbe, Uganda
| | | | - Noelina Nantima
- Ministry of Agriculture Animal Industry & Fisheries, Berkley Ln, Entebbe, Uganda
| | - Frank Norbert Mwiine
- College of Veterinary Medicine, Animal resources and Biosecurity, Makerere University, P.O.BOX 7062 Kampala, Uganda
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Odeniran PO, Ademola IO. A meta-analysis of the prevalence of African animal trypanosomiasis in Nigeria from 1960 to 2017. Parasit Vectors 2018; 11:280. [PMID: 29720251 PMCID: PMC5930763 DOI: 10.1186/s13071-018-2801-0] [Citation(s) in RCA: 25] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2017] [Accepted: 03/19/2018] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND African animal trypanosomiasis is an economically significant disease that affects the livestock industry in Nigeria. It is caused by several parasites of the genus Trypanosoma. National estimates of the disease prevalence in livestock and tsetse flies are lacking, therefore a systematic review and meta-analysis were performed to understand the trend of the disease prevalence over the years. METHODS Publications were screened in Web of Science, Ovid MEDLINE, Global Health, EMBASE and PubMed databases. Using four-stage (identification, screening, eligibility and inclusion) process in the PRIMSA checklist, only studies that met the inclusion criteria for AAT and tsetse infections were analysed. Point estimates prevalence and subgroup analyses based on diagnostic techniques in livestock were evaluated at 95% confidence interval (CI). RESULTS A total of 74 eligible studies published between 1960 and 2017 were selected for meta-analysis. This covers the six geopolitical zones, involving a total of 53,924 animals. The overall prevalence of AAT was 16.1% (95% CI: 12.3-20.3%). Based on diagnostic techniques, the prevalence of AAT in cattle was highest in PCR followed by serology and microscopy while the highest prevalence in pigs was observed with serology. Out of 12,552 tsetse flies examined from 14 eligible studies, an overall prevalence of 17.3% (95% CI: 4.5-36.0%) and subgroup prevalence of 49.7% (95% CI: 30.7-68.8%), 11.5% (95% CI: 6.1-18.5) and 4.5% (95% CI: 1.8-8.8%) in G. morsitans, G. tachinoides and G. palpalis, respectively, were observed using the random effects-model. CONCLUSIONS The prevalence of trypanosomes in both vectors and animal hosts was high in Nigeria. Therefore, further research on risk factors, seasonal and transhumance effects, vectoral capacity and competence are warranted for an effective control of AAT in Nigeria.
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Affiliation(s)
- Paul Olalekan Odeniran
- Department of Veterinary Parasitology, Faculty of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria.,Division of Infection and Pathway Medicine, Deanery of Biomedical Sciences, University of Edinburgh, Edinburgh, EH8 9JZ, UK
| | - Isaiah Oluwafemi Ademola
- Department of Veterinary Parasitology, Faculty of Veterinary Medicine, University of Ibadan, Ibadan, Nigeria.
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15
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Lord JS, Torr SJ, Auty HK, Brock PM, Byamungu M, Hargrove JW, Morrison LJ, Mramba F, Vale GA, Stanton MC. Geostatistical models using remotely-sensed data predict savanna tsetse decline across the interface between protected and unprotected areas in Serengeti, Tanzania. J Appl Ecol 2018; 55:1997-2007. [PMID: 30008483 PMCID: PMC6032868 DOI: 10.1111/1365-2664.13091] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2017] [Accepted: 12/05/2017] [Indexed: 11/29/2022]
Abstract
Monitoring abundance is essential for vector management, but it is often only possible in a fraction of managed areas. For vector control programmes, sampling to estimate abundance is usually carried out at a local‐scale (10s km2), while interventions often extend across 100s km2. Geostatistical models have been used to interpolate between points where data are available, but this still requires costly sampling across the entire area of interest. Instead, we used geostatistical models to predict local‐scale spatial variation in the abundance of tsetse—vectors of human and animal African trypanosomes—beyond the spatial extent of data to which models were fitted, in Serengeti, Tanzania. We sampled Glossina swynnertoni and Glossina pallidipes >10 km inside the Serengeti National Park (SNP) and along four transects extending into areas where humans and livestock live. We fitted geostatistical models to data >10 km inside the SNP to produce maps of abundance for the entire region, including unprotected areas. Inside the SNP, the mean number of G. pallidipes caught per trap per day in dense woodland was 166 (± 24 SE), compared to 3 (±1) in grassland. Glossina swynnertoni was more homogenous with respective means of 15 (±3) and 15 (±8). In general, models predicted a decline in abundance from protected to unprotected areas, related to anthropogenic changes to vegetation, which was confirmed during field survey. Synthesis and applications. Our approach allows vector control managers to identify sites predicted to have relatively high tsetse abundance, and therefore to design and implement improved surveillance strategies. In East and Southern Africa, trypanosomiasis is associated with wilderness areas. Our study identified pockets of vegetation which could sustain tsetse populations in farming areas outside the Serengeti National Park. Our method will assist countries in identifying, monitoring and, if necessary, controlling tsetse in trypanosomiasis foci. This has specific application to tsetse, but the approach could also be developed for vectors of other pathogens.
Our approach allows vector control managers to identify sites predicted to have relatively high tsetse abundance, and therefore to design and implement improved surveillance strategies. In East and Southern Africa, trypanosomiasis is associated with wilderness areas. Our study identified pockets of vegetation which could sustain tsetse populations in farming areas outside the Serengeti National Park. Our method will assist countries in identifying, monitoring and, if necessary, controlling tsetse in trypanosomiasis foci. This has specific application to tsetse, but the approach could also be developed for vectors of other pathogens.
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Affiliation(s)
- Jennifer S Lord
- Department of Vector Biology Liverpool School of Tropical Medicine Liverpool UK
| | - Stephen J Torr
- Department of Vector Biology Liverpool School of Tropical Medicine Liverpool UK
| | | | - Paddy M Brock
- Institute of Biodiversity, Animal Health and Comparative Medicine College of Medical, Veterinary and Life Sciences University of Glasgow Glasgow UK
| | | | | | - Liam J Morrison
- Roslin Institute Royal (Dick) School of Veterinary Studies University of Edinburgh Midlothian UK
| | - Furaha Mramba
- Vector and Vector-Borne Diseases Research Institute Tanga Tanzania
| | - Glyn A Vale
- SACEMA University of Stellenbosch Stellenbosch South Africa.,Natural Resources Institute University of Greenwich Chatham UK
| | - Michelle C Stanton
- Department of Vector Biology Liverpool School of Tropical Medicine Liverpool UK
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Muhanguzi D, Mugenyi A, Bigirwa G, Kamusiime M, Kitibwa A, Akurut GG, Ochwo S, Amanyire W, Okech SG, Hattendorf J, Tweyongyere R. African animal trypanosomiasis as a constraint to livestock health and production in Karamoja region: a detailed qualitative and quantitative assessment. BMC Vet Res 2017; 13:355. [PMID: 29178951 PMCID: PMC5702144 DOI: 10.1186/s12917-017-1285-z] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2017] [Accepted: 11/17/2017] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Nagana (African Animal Trypanosomiasis-AAT) and tick-borne diseases (TBDs) constrain livestock production in most parts of sub-Saharan Africa. To this realisation, Uganda government set up an African trypanosomiasis (AT) control unit, which among other activities generates national tsetse control priority maps using apparent tsetse density data. Such maps underestimate mechanically transmitted AAT and thus ought to be refined using actual AT prevalence data. We therefore set out to generate up-to-date cattle and donkey trypanosomiasis prevalence data as well as find out the constraints to livestock production in Karamoja region in a bid to re-define AT control priority in this region. RESULTS Livestock keepers and animal health workers indicated that TBDs and AAT were the most important livestock diseases in Karamoja region. The prevalence of Trypanosoma spp. in cattle and donkeys was 16.3% (95% CI: 12.4-21.1%) and 32.4% (95% CI; 20.2-47.6%) respectively. Trypanosoma vivax (12.1%) and Trypanosoma congolense savannah (29.6%) were the most prevalent Trypanosoma spp. in cattle and donkeys respectively. Majority of the cattle (85.7%) and more than half of the donkey (57.1%) herds were positive for Trypanosoma spp. CONCLUSIONS African animal trypanosomiasis and TBDs are the most important constraints to livestock production in Karamoja region. In order to improve livestock production and hence Karamajong livelihoods, government of Uganda and her development partners will need to invest in livestock health programs particularly targeting tsetse and TBD control.
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Affiliation(s)
- Dennis Muhanguzi
- College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Albert Mugenyi
- Coordinating Office for Control of Trypanosomiasis in Uganda, Ministry of Agriculture, Animal Industry and Fisheries, Plot 78, Buganda Road, P. O. Box: 16345 Wandegeya, Kampala, Uganda
| | - Godfrey Bigirwa
- College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, P.O. Box 7062, Kampala, Uganda
| | | | - Ann Kitibwa
- College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Grace Gloria Akurut
- College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Sylvester Ochwo
- College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Wilson Amanyire
- College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Samuel George Okech
- College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Jan Hattendorf
- Swiss Tropical Institute, Socinstrasse 57, -4002 Basel, CH Switzerland
- University of Basel, Petersplatz 1, 4003 Basel, Switzerland
| | - Robert Tweyongyere
- College of Veterinary Medicine Animal Resources and Biosecurity, Makerere University, P.O. Box 7062, Kampala, Uganda
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Manangwa O, Nkwengulila G, Ouma JO, Mramba F, Malele I, Dion K, Sistrom M, Khan F, Aksoy S, Caccone A. Genetic diversity of Glossina fuscipes fuscipes along the shores of Lake Victoria in Tanzania and Kenya: implications for management. Parasit Vectors 2017; 10:268. [PMID: 28558831 PMCID: PMC5450392 DOI: 10.1186/s13071-017-2201-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2016] [Accepted: 05/16/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Tsetse flies (Diptera: Glossinidae) are sole vectors for trypanosomiasis, which affect human health and livestock productivity in Africa. Little is known about the genetic diversity of Glossina fuscipes fuscipes, which is an important species in Tanzania and Kenya. The main objective of the study was to provide baseline data to determine the genetic variability and divergence of G. f. fuscipes in the Lake Victoria basin of Tanzania and Kenya in order to guide future vector control efforts in the region. FINDINGS Two hundred and seventy five G. f. fuscipes from 8 sites along the shores of Lake Victoria were screened for genetic polymorphisms at 19 microsatellite loci. Samples were collected from two sites in Kenya and six sites in Tanzania. Four of the Tanzanian sites were located in the Rorya district, on the eastern shores of Lake Victoria, while the other two sites were from Ukerewe and Bukoba districts from the southern and western Lake Victoria shores, respectively. Four genetically distinct allopatric clusters were revealed by microsatellite analysis, which sorted the sampling sites according to geography, with sites separated by as little as ~65 km belonging to distinct genetic clusters, while samples located within ~35 km from each other group in the same cluster. CONCLUSION Our results suggest that there is ongoing genetic admixture within sampling sites located ~35 km from each other, while sites located ~65 km apart are genetically isolated from each other. Similar patterns emerged from a parallel study on G. f. fuscipes analyzed from the Lake Victoria Uganda shores. From a control perspective these results suggest that for sites within the same genetic cluster, control efforts should be carried out in a coordinated fashion in order to avoid re-invasions. Future work should focus on better quantifying the extent and spatial patterns of the observed genetic discontinuities of the G. f. fuscipes populations along the Tanzanian shores. This will aid in their control by providing guidelines on the geographical extent of the area to be treated at the same time.
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Affiliation(s)
- Oliver Manangwa
- Vector and Vector Borne Disease Institute, P. O. Box 1026, Tanga, Tanzania.
| | - Gamba Nkwengulila
- Department of Zoology, University of Dar es Salaam, P. O. Box 35064, Dar es Salaam, Tanzania
| | - Johnson O Ouma
- Africa Technical Research Centre, Vector Health International, P.O. Box 15500, Arusha, Tanzania.,Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, P.O. Box 362-00902, Kikuyu, Kenya
| | - Furaha Mramba
- Tanzania Veterinary Laboratory Agency (TVLA), P. O. Box 9154, Dar es Salaam, Tanzania
| | - Imna Malele
- Vector and Vector Borne Disease Institute, P. O. Box 1026, Tanga, Tanzania
| | - Kirsten Dion
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, USA
| | - Mark Sistrom
- School of Natural Sciences, University of California, Merced, CA, USA
| | - Farrah Khan
- Department of Molecular, Cellular, and Developmental Biology, Yale University, New Haven, CT, USA
| | - Serap Aksoy
- Yale School of Public Health, Yale University, 60 College Street, New Haven, CT, USA
| | - Adalgisa Caccone
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, Connecticut, USA
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Hamill L, Picozzi K, Fyfe J, von Wissmann B, Wastling S, Wardrop N, Selby R, Acup CA, Bardosh KL, Muhanguzi D, Kabasa JD, Waiswa C, Welburn SC. Evaluating the impact of targeting livestock for the prevention of human and animal trypanosomiasis, at village level, in districts newly affected with T. b. rhodesiense in Uganda. Infect Dis Poverty 2017; 6:16. [PMID: 28162093 PMCID: PMC5292814 DOI: 10.1186/s40249-016-0224-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Accepted: 12/15/2016] [Indexed: 11/24/2022] Open
Abstract
Background Uganda has suffered from a series of epidemics of Human African Trypanosomiasis (HAT), a tsetse transmitted disease, also known as sleeping sickness. The area affected by acute Trypanosoma brucei rhodesiense HAT (rHAT) has been expanding, driven by importation of infected cattle into regions previously free of the disease. These regions are also affected by African Animal Trypanosomiasis (AAT) demanding a strategy for integrated disease control. Methods In 2008, the Public Private Partnership, Stamp Out Sleeping Sickness (SOS) administered a single dose of trypanocide to 31 486 head of cattle in 29 parishes in Dokolo and Kaberamaido districts. This study examines the impact of this intervention on the prevalence of rHAT and AAT trypanosomes in cattle from villages that had (HAT+ve) or had not (HAT-ve) experienced a recent case of rHAT. Cattle herds from 20 villages were sampled and screened by PCR, pre-intervention and 6-months post-intervention, for the presence or absence of: Trypanosoma brucei s.l.; human infective T. b. rhodesiense; Trypanosoma vivax; and Trypanosoma congolense savannah. Results Post-intervention, there was a significant decrease in the prevalence of T. brucei s.l. and the human infective sub-species T. b. rhodesiense in village cattle across all 20 villages. The prevalence of T. b. rhodesiense was reduced from 2.4% to 0.74% (P < 0.0001), with the intervention showing greater impact in HAT-ve villages. The number of villages containing cattle harbouring human infective parasites decreased from 15/20 to 8/20, with T. b. rhodesiense infection mainly persisting within cattle in HAT+ve villages (six/eight). The proportion of T. brucei s.l. infections identified as human infective T. b. rhodesiense decreased after the intervention from 8.3% (95% CI = 11.1–5.9%) to 4.1% (95% CI = 6.8–2.3%). Villages that had experienced a recent human case (HAT+ve villages) showed a significantly higher prevalence for AAT both pre- and post-intervention. For AAT the prevalence of T. vivax was significantly reduced from 5.9% to 0.05% post-intervention while the prevalence of T. congolense increased from 8.0% to 12.2%. Conclusions The intervention resulted in a significant decrease in the prevalence of T. brucei s.l., human infective T. b. rhodesiense and T. vivax infection in village cattle herds. The proportion of T. brucei s.l. that were human infective, decreased from 1:12 T. brucei s.l. infections before the intervention to 1:33 post-intervention. It is clearly more difficult to eliminate T. b. rhodesiense from cattle in villages that have experienced a human case. Evidence of elevated levels of AAT in livestock within village herds is a useful indicator of risk for rHAT in Uganda. Integrated veterinary and medical surveillance is key to successful control of zoonotic rHAT. Electronic supplementary material The online version of this article (doi:10.1186/s40249-016-0224-8) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Louise Hamill
- Edinburgh Infectious Diseases, Division of Infection and Pathway Medicine, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Kim Picozzi
- Edinburgh Infectious Diseases, Division of Infection and Pathway Medicine, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Jenna Fyfe
- Edinburgh Infectious Diseases, Division of Infection and Pathway Medicine, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Beatrix von Wissmann
- Edinburgh Infectious Diseases, Division of Infection and Pathway Medicine, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Sally Wastling
- Edinburgh Infectious Diseases, Division of Infection and Pathway Medicine, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Nicola Wardrop
- Edinburgh Infectious Diseases, Division of Infection and Pathway Medicine, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Richard Selby
- Edinburgh Infectious Diseases, Division of Infection and Pathway Medicine, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Christine Amongi Acup
- Edinburgh Infectious Diseases, Division of Infection and Pathway Medicine, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Kevin L Bardosh
- Edinburgh Infectious Diseases, Division of Infection and Pathway Medicine, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
| | - Dennis Muhanguzi
- Department of Pharmacy, Clinical and Comparative Medicine, School of Veterinary Medicine and Animal Resources, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - John D Kabasa
- Department of Pharmacy, Clinical and Comparative Medicine, School of Veterinary Medicine and Animal Resources, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - Charles Waiswa
- Department of Pharmacy, Clinical and Comparative Medicine, School of Veterinary Medicine and Animal Resources, Makerere University, P.O. Box 7062, Kampala, Uganda.,The Coordinating Office for Control of Trypanosomiasis in Uganda (COCTU), Wandegeya, Plot 76/78 Buganda Road, P.O. Box 16345, Kampala, Uganda
| | - Susan C Welburn
- Edinburgh Infectious Diseases, Division of Infection and Pathway Medicine, Edinburgh Medical School: Biomedical Sciences, The University of Edinburgh, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
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Abstract
The development and application of interventions for the control of vector-borne zoonoses requires broad understanding of epidemiological linkages between vector, animal infection and human infection. However, there are significant gaps in our understanding of these linkages and a lack of appropriate data poses a considerable barrier to addressing this issue. A move towards strengthened surveillance of vectors and disease in both animal and human hosts, in combination with linked human-animal surveys, could form the backbone for epidemiological integration, enabling explicit assessment of the animal-human (and vector) interface, and subsequent implications for spill-over to human populations. Currently available data on the spatial distribution of human African trypanosomiasis allow an illustrative example.
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Affiliation(s)
- Nicola A Wardrop
- Geography and Environment, University of Southampton, Southampton, SO17 1BJ, UK
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Sakamoto T. Computational Research on Mobile Pastoralism Using Agent-Based Modeling and Satellite Imagery. PLoS One 2016; 11:e0151157. [PMID: 26963526 PMCID: PMC4786315 DOI: 10.1371/journal.pone.0151157] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Accepted: 02/24/2016] [Indexed: 12/03/2022] Open
Abstract
Dryland pastoralism has long attracted considerable attention from researchers in diverse fields. However, rigorous formal study is made difficult by the high level of mobility of pastoralists as well as by the sizable spatio-temporal variability of their environment. This article presents a new computational approach for studying mobile pastoralism that overcomes these issues. Combining multi-temporal satellite images and agent-based modeling allows a comprehensive examination of pastoral resource access over a realistic dryland landscape with unpredictable ecological dynamics. The article demonstrates the analytical potential of this approach through its application to mobile pastoralism in northeast Nigeria. Employing more than 100 satellite images of the area, extensive simulations are conducted under a wide array of circumstances, including different land-use constraints. The simulation results reveal complex dependencies of pastoral resource access on these circumstances along with persistent patterns of seasonal land use observed at the macro level.
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Affiliation(s)
- Takuto Sakamoto
- Institute of Developing Economies, Japan External Trade Organization, Chiba, Japan
- * E-mail:
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Kato AB, Hyseni C, Okedi LM, Ouma JO, Aksoy S, Caccone A, Masembe C. Mitochondrial DNA sequence divergence and diversity of Glossina fuscipes fuscipes in the Lake Victoria basin of Uganda: implications for control. Parasit Vectors 2015; 8:385. [PMID: 26197892 PMCID: PMC4511262 DOI: 10.1186/s13071-015-0984-1] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2015] [Accepted: 07/02/2015] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Glossina fuscipes fuscipes is the main vector of African Trypanosomiasis affecting both humans and livestock in Uganda. The human disease (sleeping sickness) manifests itself in two forms: acute and chronic. The Lake Victoria basin in Uganda has the acute form and a history of tsetse re-emergence despite concerted efforts to control tsetse. The government of Uganda has targeted the basin for tsetse eradication. To provide empirical data for this initiative, we screened tsetse flies from the basin for genetic variation at the mitochondrial DNA cytochrome oxidase II (mtDNA COII) gene with the goal of investigating genetic diversity and gene flow among tsetse, tsetse demographic history; and compare these results with results from a previous study based on microsatellite loci data in the same area. METHODS We collected 429 Gff tsetse fly samples from 14 localities in the entire Ugandan portion of the Lake Victoria coast, covering 40,000 km(2). We performed genetic analyses on them and added data collected for 56 Gff individuals from 4 additional sampling sites in the basin. The 529 pb partial mitochondrial DNA cytochrome oxidase II (mtDNA COII) sequences totaling 485 were analysed for genetic differentiation, structuring and demographic history. The results were compared with findings from a previous study based on microsatellite loci data from the basin. RESULTS The differences within sampling sites explained a significant proportion of the genetic variation. We found three very closely related mtDNA population clusters, which co-occurred in multiple sites. Although Φ ST (0 - 0.592; P < 0.05) and Bayesian analyses suggest some level of weak genetic differentiation, there is no correlation between genetic divergence and geographic distance (r = 0.109, P = 0.185), and demographic tests provide evidence of locality-based demographic history. CONCLUSION The mtDNA data analysed here complement inferences made in a previous study based on microsatellite data. Given the differences in mutation rates, mtDNA afforded a look further back in time than microsatellites and revealed that Gff populations were more connected in the past. Microsatellite data revealed more genetic structuring than mtDNA. The differences in connectedness and structuring over time could be related to vector control efforts. Tsetse re-emergence after control interventions may be due to re-invasions from outside the treated areas, which emphasizes the need for an integrated area-wide tsetse eradication strategy for sustainable removal of the tsetse and trypanosomiasis problem from this area.
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Affiliation(s)
- Agapitus B Kato
- Department of Biological Sciences, College of Natural Sciences, Makerere University, Box 7062, Kampala, Uganda.
| | - Chaz Hyseni
- Department of Biology, University of Mississippi, Oxford, MS, 38677, USA.
| | - Loyce M Okedi
- National Livestock Resources Research Institute, Tororo, Uganda.
| | - Johnson O Ouma
- Biotechnology Research Institute, Kenya Agricultural and Livestock Research Organization, Kikuyu, Kenya.
| | - Serap Aksoy
- Division of Epidemiology of Microbial Diseases, Yale School of Public Health, Yale University, New Haven, CT, 06520, USA.
| | - Adalgisa Caccone
- Department of Ecology and Evolutionary Biology, Yale University, New Haven, CT, 06520, USA.
| | - Charles Masembe
- Department of Biological Sciences, College of Natural Sciences, Makerere University, Box 7062, Kampala, Uganda.
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