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Olbamo T, Tesfaye T, Jorga B. Entomological study on vectorial density, temporal variation of tsetse fly and other biting flies in intervention and non-intervention areas of South Omo Zone, Ethiopia. Vet Parasitol Reg Stud Reports 2024; 49:100996. [PMID: 38462301 DOI: 10.1016/j.vprsr.2024.100996] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2023] [Revised: 01/24/2024] [Accepted: 01/31/2024] [Indexed: 03/12/2024]
Abstract
A repeated cross-sectional entomological survey was conducted to estimate Glossina (tsetse) and other biting flies density, their seasonal variation and associated risk factors in intervention and non- intervention areas of South Omo Zone, Southwest Ethiopia from January 2019-November 2019. In both dry and wet seasons, a total of 96 NGU traps (64 traps in tsetse intervention districts and 32 traps in tsetse non- intervention districts) were deployed at an interval of about 100-200 m in purposively selected and suspected tsetse habitats. Thus, Glossina pallidipes was found to be the only cyclical vector along with mechanical vectors of Tabanus, Stomoxys and Haematopota. In tsetse intervention areas, G. pallidipes apparent density of 2.64 F/T/D and 0.42 F/T/D was recorded in dry and wet season respectively. Mechanical vectors (dry; wet) of Tabanus (205; 155), Stomoxys (34; 54) and Haematopota (50; 33) were also recorded in tsetse intervened areas. Whereas, in non- intervention areas, apparent density of G. pallidipes was 2.03 F/T/D and 0.56 F/T/D, respectively in dry and wet season. Similarly, Tabanus (22; 56), Stomoxys (10; 8) and Haematopota (5; 7) respectively in dry and wet (dry; wet) season were recorded in tsetse non- intervention areas. According to Negative Binomial Regression (NBR), season was the only variable significantly affecting (P < 0.05) the Glossina count in the current study area. Accordingly, the incidence G. pallidipes during wet season was decreased by the factor of 0.21 (CI; 0.097-0.47) when compared to its incidence in dry season by holding other variables constant. In conclusion, cyclical vectors were playing vital role in transmission of trypanosomosis in South Omo Zone along with numerous mechanical vectors even though there have been vector intervention activities in the areas. Therefore, strong, sustainable, environmentally friend and community participating vector control strategies should be followed to tackle the vector distribution in the area.
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Affiliation(s)
- Tekle Olbamo
- Jinka University, College of Agriculture and Natural Resources, Department of Animal Science, Jinka, Ethiopia
| | - Tegegn Tesfaye
- Southern Agricultural Research Institute, Jinka Agricultural Research Centre, Jinka, Ethiopia.
| | - Belete Jorga
- Jinka University, College of Agriculture and Natural Resources, Department of Animal Science, Jinka, Ethiopia
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Janse van Rensburg HD, N'Da DD, Suganuma K. In vitro trypanocidal potency and in vivo treatment efficacy of oligomeric ethylene glycol-tethered nitrofurantoin derivatives. Eur J Pharm Sci 2024; 192:106668. [PMID: 38065268 DOI: 10.1016/j.ejps.2023.106668] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/24/2023] [Revised: 12/05/2023] [Accepted: 12/06/2023] [Indexed: 12/22/2023]
Abstract
African trypanosomiasis is a significant vector-borne disease of humans and animals in the tsetse fly belt of Africa, particularly affecting production animals such as cattle, and thus, hindering food security. Trypanosoma congolense (T. congolense), the causative agent of nagana, is livestock's most virulent trypanosome species. There is currently no vaccine against trypanosomiasis; its treatment relies solely on chemotherapy. However, pathogenic resistance has been established against trypanocidal agents in clinical use. This underscores the need to develop new therapeutics to curb trypanosomiasis. Many nitroheterocyclic drugs or compounds, including nitrofurantoin, possess antiparasitic activities in addition to their clinical use as antibiotics. The current study evaluated the in vitro trypanocidal potency and in vivo treatment efficacy of previously synthesized antileishmanial active oligomeric ethylene glycol derivatives of nitrofurantoin. The trypanocidal potency of analogues 2a-o varied among the trypanosome species; however, T. congolense strain IL3000 was more susceptible to these drug candidates than the other human and animal trypanosomes. The arylated analogues 2k (IC50 0.04 µM; SI >6365) and 2l (IC50 0.06 µM; SI 4133) featuring 4-chlorophenoxy and 4-nitrophenoxy moieties, respectively, were revealed as the most promising antitrypanosomal agents of all analogues against T. congolense strain IL3000 trypomastigotes with nanomolar activities. In a preliminary in vivo study involving T. congolense strain IL3000 infected BALB/c mice, the oral administration of 100 mg/kg/day of 2k caused prolonged survival up to 18 days post-infection relative to the infected but untreated control mice which survived 9 days post-infection. However, no cure was achieved due to its poor solubility in the in vivo testing medium, assumably leading to low oral bioavailability. These results confirm the importance of the physicochemical properties lipophilicity and water solubility in attaining not only in vitro trypanocidal potency but also in vivo treatment efficacy. Future work will focus on the chemical optimization of 2k through the investigation of analogues containing solubilizing groups at certain positions on the core structure to improve solubility in the in vivo testing medium which, in the current investigation, is the biggest stumbling block in successfully treating either animal or human Trypanosoma infections.
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Affiliation(s)
| | - David D N'Da
- Centre of Excellence for Pharmaceutical Sciences, North-West University, Potchefstroom 2520, South Africa
| | - Keisuke Suganuma
- National Research Center for Protozoan Diseases, Obihiro University of Agriculture and Veterinary Medicine, Inada, Obihiro, Hokkaido 080-8555, Japan
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Morrison LJ, Steketee PC, Tettey MD, Matthews KR. Pathogenicity and virulence of African trypanosomes: From laboratory models to clinically relevant hosts. Virulence 2023; 14:2150445. [PMID: 36419235 DOI: 10.1080/21505594.2022.2150445] [Citation(s) in RCA: 9] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2022] [Accepted: 11/17/2022] [Indexed: 11/25/2022] Open
Abstract
African trypanosomes are vector-borne protozoa, which cause significant human and animal disease across sub-Saharan Africa, and animal disease across Asia and South America. In humans, infection is caused by variants of Trypanosoma brucei, and is characterized by varying rate of progression to neurological disease, caused by parasites exiting the vasculature and entering the brain. Animal disease is caused by multiple species of trypanosome, primarily T. congolense, T. vivax, and T. brucei. These trypanosomes also infect multiple species of mammalian host, and this complexity of trypanosome and host diversity is reflected in the spectrum of severity of disease in animal trypanosomiasis, ranging from hyperacute infections associated with mortality to long-term chronic infections, and is also a main reason why designing interventions for animal trypanosomiasis is so challenging. In this review, we will provide an overview of the current understanding of trypanosome determinants of infection progression and severity, covering laboratory models of disease, as well as human and livestock disease. We will also highlight gaps in knowledge and capabilities, which represent opportunities to both further our fundamental understanding of how trypanosomes cause disease, as well as facilitating the development of the novel interventions that are so badly needed to reduce the burden of disease caused by these important pathogens.
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Affiliation(s)
- Liam J Morrison
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK
| | - Pieter C Steketee
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, UK
| | - Mabel D Tettey
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
| | - Keith R Matthews
- Institute for Immunology and Infection Research, School of Biological Sciences, University of Edinburgh, Edinburgh, UK
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Bessell PR, Salmon G, Schnier C, Tjasink K, Al-Riyami L, Peters A. A high level estimation of the net economic benefits to small-scale livestock producers arising from animal health product distribution initiatives. Front Vet Sci 2023; 10:1171989. [PMID: 37346278 PMCID: PMC10279859 DOI: 10.3389/fvets.2023.1171989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2023] [Accepted: 05/11/2023] [Indexed: 06/23/2023] Open
Abstract
Introduction A fundamental challenge for charities that facilitate distribution of animal health products to small-scale livestock producers (SSPs) in low and middle income countries (LMICs) is identifying the products and market mechanisms that provide the greatest positive impact for SSPs and estimating their associated impact. This paper describes a pragmatic approach to modeling the impact of market-led product distribution initiatives based on estimating the net economic benefit of administration of animal health products. Methods The model estimates the economic impact of diseases at the individual animal level for poultry, small ruminants, and cattle. The economic impact of mortality and growth inhibition associated with disease are then estimated in conjunction with the losses averted or recovered by preventing or treating the disease. Economic benefit is estimated in 2014-2017 values and also adjusted to 2023 values. The flexible model structure allows for addition of new geographies, new products, and increased granularity of modeled production systems. Results Applied to the Global Alliance for Livestock Veterinary Medicines (GALVmed) product distribution initiatives conducted in Africa and South Asia (SA) between 2014 and 2017, the model estimates an adjusted total net economic benefit of 139.9 million USD from sales of vaccines and poultry anthelminthics in these initiatives. Within SSA, the greatest net economic benefit was realized from East Coast fever and Newcastle disease vaccines, while in SA, peste des petits ruminants and Newcastle disease vaccines had the greatest net economic benefits. This translated to an adjusted $37.97 of net economic benefit on average per SSP customer, many of whom were small poultry producers. Discussion While the model currently estimates impacts from mortality and growth inhibition in livestock, there is the potential to extend it to cover impacts of further initiatives, including interventions targeted at diseases that impact production of milk, eggs, and reproduction.
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Affiliation(s)
| | - Gareth Salmon
- SEBI-L Supporting Evidence Based Interventions in Livestock, University of Edinburgh, Edinburgh, United Kingdom
| | - Christian Schnier
- SEBI-L Supporting Evidence Based Interventions in Livestock, University of Edinburgh, Edinburgh, United Kingdom
| | - Katharine Tjasink
- Global Alliance for Livestock Veterinary Medicines (GALVmed), Edinburgh, United Kingdom
| | - Lamyaa Al-Riyami
- Global Alliance for Livestock Veterinary Medicines (GALVmed), Edinburgh, United Kingdom
| | - Andrew Peters
- SEBI-L Supporting Evidence Based Interventions in Livestock, University of Edinburgh, Edinburgh, United Kingdom
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Gebre T, Kapitano B, Beyene D, Alemu D, Beshir A, Worku Z, Kifle T, Selamu A, Debas E, Kalsa A, Asfaw N, Zhao W, Paone M, Cecchi G. The national atlas of tsetse flies and African animal trypanosomosis in Ethiopia. Parasit Vectors 2022; 15:491. [PMID: 36578020 PMCID: PMC9798648 DOI: 10.1186/s13071-022-05617-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2022] [Accepted: 12/13/2022] [Indexed: 12/29/2022] Open
Abstract
BACKGROUND With the largest cattle population in Africa and vast swathes of fertile lands infested by tsetse flies, trypanosomosis is a major challenge for Ethiopian farmers. Managing the problem strategically and rationally requires comprehensive and detailed information on disease and vector distribution at the national level. To this end, the National Institute for Control and Eradication of Tsetse and Trypanosomosis (NICETT) developed a national atlas of tsetse and African animal trypanosomosis (AAT) for Ethiopia. METHODS This first edition of the atlas focused on the tsetse-infested areas in western Ethiopia. Data were collected between 2010 and 2019 in the framework of national surveillance and control activities. Over 88,000 animals, mostly cattle, were tested with the buffy-coat technique (BCT). Odour-enhanced traps were deployed in approximately 14,500 locations for the entomological surveys. Animal- and trap-level data were geo-referenced, harmonized and centralized in a single database. RESULTS AAT occurrence was confirmed in 86% of the districts surveyed (107/124). An overall prevalence of 4.8% was detected by BCT in cattle. The mean packed cell volume (PCV) of positive animals was 22.4, compared to 26.1 of the negative. Trypanosoma congolense was responsible for 61.9% of infections, T. vivax for 35.9% and T. brucei for 1.7%. Four tsetse species were found to have a wide geographic distribution. The highest apparent density (AD) was reported for Glossina pallidipes in the Southern Nations, Nationalities and People's Region (SNNPR) (3.57 flies/trap/day). Glossina tachinoides was the most abundant in Amhara (AD 2.39), Benishangul-Gumuz (2.38), Gambela (1.16) and Oromia (0.94) regions. Glossina fuscipes fuscipes and G. morsitans submorsitans were detected at lower densities (0.19 and 0.42 respectively). Only one specimen of G. longipennis was captured. CONCLUSIONS The atlas establishes a reference for the distribution of tsetse and AAT in Ethiopia. It also provides crucial evidence to plan surveillance and monitor control activities at the national level. Future work on the atlas will focus on the inclusion of data collected by other stakeholders, the broadening of the coverage to tsetse-free areas and continuous updates. The extension of the atlas to data on control activities is also envisaged.
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Affiliation(s)
| | - Berisha Kapitano
- Food and Agriculture Organization of the United Nations, Ethiopia Country Office, Addis Ababa, Ethiopia
| | | | - Dereje Alemu
- Animal Health Institute, Bedelle Animal Health Centre, Bedelle, Ethiopia
| | - Ahimedin Beshir
- Animal Health Institute, Bedelle Animal Health Centre, Bedelle, Ethiopia
| | - Zelalem Worku
- Animal Health Institute, Asossa Animal Health Centre, Asossa, Ethiopia
| | - Teshome Kifle
- Animal Health Institute, Asossa Animal Health Centre, Asossa, Ethiopia
| | - Ayana Selamu
- Animal Health Institute, Finote Selam Animal Health Centre, Finote Selam, Ethiopia
| | - Endalew Debas
- Animal Health Institute, Finote Selam Animal Health Centre, Finote Selam, Ethiopia
| | - Aschenaki Kalsa
- Animal Health Institute, Arba Minch Animal Health Centre, Arba Minch, Ethiopia
| | - Netsanet Asfaw
- Animal Health Institute, Arba Minch Animal Health Centre, Arba Minch, Ethiopia
| | - Weining Zhao
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Massimo Paone
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Giuliano Cecchi
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
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Kizza D, Ocaido M, Mugisha A, Azuba R, Nalubwama S, Nalule S, Onyuth H, Musinguzi SP, Waiswa C. The economic cost of bovine trypanosomosis in pastoral and ago pastoral communities surrounding Murchision Falls National park, Buliisa district, Uganda. BMC Vet Res 2022; 18:372. [PMID: 36253776 PMCID: PMC9578198 DOI: 10.1186/s12917-022-03468-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2022] [Revised: 09/27/2022] [Accepted: 10/05/2022] [Indexed: 11/14/2022] Open
Abstract
Background: Animal diseases that are endemic like tsetse transmitted trypanosomosis cause the continuous expenditure of financial resources of livestock farmers and loss of productivity of livestock. Estimating the cost of controlling animal trypanosomosis can provide evidence for priority setting and targeting cost-effective control strategies. Methodology: A cross-sectional survey to estimate the economic cost of bovine trypanosomosis was conducted in cattle-keeping communities living around Murchision falls National Park, in Buliisa district Uganda. Data was collected on herd structure, the cost of treatment and control, prevalence of morbidity and mortality rates due to trypanosomosis, and salvage sales losses in cattle herds in the last year. Results: In this study, 55.4% (n = 87) of the households reported their cattle had been affected by trypanosomosis during the previous last year. There was a high economic cost of trypanosomosis (USD 653) per household in cattle-keeping communities in Buliisa district of which 83% and 9% were due to mortality and milk loss respectively/ High mortality loss was due to low investment in treatment. The study showed that prophylactic treatment 3 times a year of the whole herd of cattle using Samorin ® (Isometamidium chloride) at a cost of USD 110 could drastically reduce cattle mortality loss due to trypanosomosis due to trypanosomosis with a return on investment of USD 540 annually per herd. This could be coupled with strategic restricted insecticide spraying of cattle with deltamethrin products. Conclusion: The results show a high economic cost of trypanosomosis in cattle-keeping communities in Buliisa district, with cattle mortality contributing the largest proportion of the economic cost. The high mortality loss was due to low investment in treatment of sick cattle.
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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
| | - Sylvia Nalubwama
- 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
- Faculty of Agriculture Department of Agricultural Production, Kyambogo 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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Ofori JA, Bakari SM, Bah S, Kolugu MK, Aning GK, Awandare GA, Carrington M, Gwira TM. A longitudinal two-year survey of the prevalence of trypanosomes in domestic cattle in Ghana by massively parallel sequencing of barcoded amplicons. PLoS Negl Trop Dis 2022; 16:e0010300. [PMID: 35442960 PMCID: PMC9060370 DOI: 10.1371/journal.pntd.0010300] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 05/02/2022] [Accepted: 03/03/2022] [Indexed: 12/01/2022] Open
Abstract
Background Animal African Trypanosomiasis (AAT) is one of the most economically important diseases affecting livestock productivity in sub-Saharan Africa. The disease is caused by a broad range of Trypanosoma spp., infecting both wild and domesticated animals through cyclical and mechanical transmission. This study aimed to characterize trypanosomes present in cattle at regular intervals over two years in an AAT endemic and a non-endemic region of Ghana. Methodology/Principal findings Groups of cattle at Accra and Adidome were selected based on their geographical location, tsetse fly density, prevalence of trypanosomiasis and the breed of cattle available. Blood for DNA extraction was collected at approximately four to five-week intervals over a two-year period. Trypanosome DNA were detected by a sensitive nested PCR targeting the tubulin gene array and massively parallel sequencing of barcoded amplicons. Analysis of the data was a semi-quantitative estimation of infection levels using read counts obtained from the sequencing as a proxy for infection levels. Majority of the cattle were infected with multiple species most of the time [190/259 (73%) at Adidome and 191/324 (59%) at Accra], with T. vivax being the most abundant. The level of infection and in particular T. vivax, was higher in Adidome, the location with a high density of tsetse flies. The infection level varied over the time course, the timings of this variation were not consistent and in Adidome it appeared to be independent of prophylactic treatment for trypanosome infection. Effect of gender or breed on infection levels was insignificant. Conclusions/Significance Most cattle were infected with low levels of several trypanosome species at both study sites, with T. vivax being the most abundant. The measurements of infection over time provided insight to the importance of the approach in identifying cattle that could suppress trypanosome infection over an extended time and may serve as reservoir. Cattle are of economic importance in sub-Saharan Africa as they fulfil multiple roles, ranging from draught power, to providing manure, milk, and meat. However, Animal African Trypanosomiasis (AAT) diseases in cattle affect productivity and food security in most African countries. In Ghana, bovine trypanosomiasis has been detected in few cross-sectional studies by molecular methods. To get a better understanding of the disease, a longitudinal study showing natural trypanosome infection over the life of cattle will be applicable. To explore this issue, the study determined the nature of trypanosome infection in cattle in farm settings in Ghana over two years, a period similar to that used in beef production, by massively parallel amplicon sequencing. The study provided a description of the prevalence over two years and showed that the cattle were infected with multiply species most of the time and the level of infection varied but was low most of the time. The longitudinal study allowed the identification of one individual able to supress infection far more effectively than other members of the herd and this is crucial in implementing control measures in the infected area.
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Affiliation(s)
- Jennifer Afua Ofori
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Soale Majeed Bakari
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Saikou Bah
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Michael Kojo Kolugu
- Department of Computer Science, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - George Kwame Aning
- School of Veterinary Medicine, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Gordon Akanzuwine Awandare
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
| | - Mark Carrington
- Department of Biochemistry, University of Cambridge, Cambridge, United Kingdom
| | - Theresa Manful Gwira
- West African Centre for Cell Biology of Infectious Pathogens, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
- Department of Biochemistry, Cell and Molecular Biology, College of Basic and Applied Sciences, University of Ghana, Accra, Ghana
- * E-mail:
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Richards S, Morrison LJ, Torr SJ, Barrett MP, Manangwa O, Mramba F, Auty H. Pharma to farmer: field challenges of optimizing trypanocide use in African animal trypanosomiasis. Trends Parasitol 2021; 37:831-843. [PMID: 33962879 DOI: 10.1016/j.pt.2021.04.007] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2021] [Revised: 04/05/2021] [Accepted: 04/08/2021] [Indexed: 01/07/2023]
Abstract
Trypanocides are a key control component of African animal trypanosomiasis (AAT) in tsetse-infested areas of sub-Saharan Africa. While farmers are dependent upon trypanocides, recent research highlights their inappropriate and ineffective use, problems with drug quality, and treatment failure. There are currently gaps in knowledge and investment in inexpensive AAT diagnostics, understanding of drug resistance, and the effective use of trypanocides in the field. Without this important knowledge it is difficult to develop best practice and policy for existing drugs or to inform development and use of new drugs. There needs to be better understanding of the drivers and behavioural practices around trypanocide use so that they can be incorporated into sustainable solutions needed for the development of effective control of AAT.
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Affiliation(s)
- Shauna Richards
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK.
| | - Liam J Morrison
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Edinburgh, UK
| | - Steve J Torr
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, UK
| | - Michael P Barrett
- Wellcome Centre for Integrative Parasitology, Institute of Infection, Inflammation & Immunity, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
| | | | - Furaha Mramba
- Tanzania Veterinary Laboratory Agency, Dar Es Salaam, Tanzania
| | - Harriet Auty
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, Glasgow, UK
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Okello WO, MacLeod ET, Muhanguzi D, Waiswa C, Welburn SC. Controlling Tsetse Flies and Ticks Using Insecticide Treatment of Cattle in Tororo District Uganda: Cost Benefit Analysis. Front Vet Sci 2021; 8:616865. [PMID: 33829051 PMCID: PMC8019991 DOI: 10.3389/fvets.2021.616865] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2020] [Accepted: 02/08/2021] [Indexed: 01/09/2023] Open
Abstract
Background: The endemic vector-borne diseases transmitted by tsetse and ticks impose heavy burdens on the livestock keepers in Africa. Applying deltamethrin to the belly, legs, and ears of cattle offers a possibility of mitigating these losses at a cost affordable to livestock keepers. Although studies have quantified the impacts of individual diseases on livestock productivity, little is known about the dual economic benefits of controlling both tsetse and ticks, nor about the number of cattle that need to be treated to confer these benefits. Alongside an epidemiological study in south-east Uganda, a farm level assessment was done to investigate the benefits and costs of spraying different proportions of the village cattle population using this restricted application protocol. Methods: A study comprising 1,902 semi-structured interviews was undertaken over a period of 18 months. Financial data on household income and expenditure on cattle was collected, and cost-benefit analysis was done pre- and post-intervention and for different spraying regimes. The total cost of the intervention was obtained from the implementation costs of the epidemiological study and from expenses incurred by participating farmers enabling examination of benefit-cost ratios and incremental benefit-cost ratios for each treatment regime. Results: The benefit-cost analysis of spraying 25%, 50%, and 75% of the cattle population yielded average benefit-cost ratios of 3.85, 4.51, and 4.46. The incremental benefit-cost ratios from spraying each additional 25% of the cattle population were 11.38, 3.89, and 0.79, showing a very high return on investment for spraying 50% of the population, with returns reducing thereafter. Conclusion: Comparing the gross margins per bovine, the study found that increasing the proportion of cattle sprayed yielded increasing benefits to the farmers, but that these benefits were subject to diminishing returns. From a practical viewpoint, this study recommends spraying only draft cattle to control trypanosomiasis and tick-borne diseases in this area as they make 38.62% of the cattle population, approaching the 50% threshold. In areas with a lower proportion of draft males, farmers could be advised to also include cows.
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Affiliation(s)
- Walter O. Okello
- Infection Medicine, Deanery of Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, United Kingdom
- Commonwealth Scientific and Industrial Research Organisation, Black Mountain Science and Innovation Park, Canberra, ACT, Australia
| | - Ewan T. MacLeod
- Infection Medicine, Deanery of Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, United Kingdom
| | - Dennis Muhanguzi
- Infection Medicine, Deanery of Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, United Kingdom
- 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, Deanery of Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, United Kingdom
- 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
- The Coordinating Office for Control of Trypanosomiasis in Uganda, Kampala, Uganda
| | - Susan C. Welburn
- Infection Medicine, Deanery of Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, United Kingdom
- Zhejiang University–University of Edinburgh Institute, Zhejiang University, International Campus, Haining, China
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Financial losses estimation of African animal trypanosomosis in Nigeria: field reality-based model. Trop Anim Health Prod 2021; 53:159. [PMID: 33569637 DOI: 10.1007/s11250-021-02603-8] [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: 11/01/2020] [Accepted: 02/08/2021] [Indexed: 10/22/2022]
Abstract
INTRODUCTION Theoretical and modelling approaches were undertaken on Nigerian livestock industry to estimate financial losses due to African animal trypanosomosis. METHODS Surveys were conducted between March 2018 and February 2019 to include focus group interactions, in-depth household engagements concerning livestock practices in relation to AAT. Financial losses estimation on livestock were targeted to provide ways to regain cost and maximize household livelihoods. Mathematical equation was developed to project the effects of intervention strategies. Important variables such as mean AAT prevalence, incidence rate, birth rate, morbidity and mortality were estimated and inserted in the model. RESULTS Mean total income per capita was US$ 1.31 / person / day among livestock producers in Nigeria. A total of US$ 518. 9 million were estimated from direct losses, while US$ 58.8 million as indirect losses. Annual estimated losses to AAT from cattle, sheep, goat and pigs in Nigeria is US$ 577.7 million. This is equivalent to 207.98 billion Nigerian naira and represents 6.93% of annual livestock GDP in the country. This could increase to 85% in the next 50 years if there are no proper control interventions. Control efforts could reduce the losses to US$ 16.7 million at the rate of 0.2% during the same period. DISCUSSIONS AAT has severe socioeconomic impact on producer's livelihood and urgent improved control intervention strategies should be instituted to reduce the losses attributed to the disease.
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Özkan Gülzari Ş, Owade JO, Ndambi OA. A review of interventions and parameters used to address milk quality in eastern and southern Africa. Food Control 2020. [DOI: 10.1016/j.foodcont.2020.107300] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
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12
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Rayaisse JB, Courtin F, Mahamat MH, Chérif M, Yoni W, Gadjibet NMO, Peka M, Solano P, Torr SJ, Shaw APM. Delivering 'tiny targets' in a remote region of southern Chad: a cost analysis of tsetse control in the Mandoul sleeping sickness focus. Parasit Vectors 2020; 13:419. [PMID: 32795375 PMCID: PMC7427721 DOI: 10.1186/s13071-020-04286-w] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/24/2020] [Accepted: 08/03/2020] [Indexed: 11/16/2022] Open
Abstract
Background Since 2012, the World Health Organisation and the countries affected by the Gambian form of human African trypanosomiasis (HAT) have been committed to eliminating the disease, primarily through active case-finding and treatment. To interrupt transmission of Trypanosoma brucei gambiense and move more rapidly towards elimination, it was decided to add vector control using ‘tiny targets’. Chad’s Mandoul HAT focus extends over 840 km2, with a human population of 39,000 as well as 14,000 cattle and 3000 pigs. Some 2700 tiny targets were deployed annually from 2014 onwards. Methods A protocol was developed for the routine collection of tsetse control costs during all field missions. This was implemented throughout 2015 and 2016, and combined with the recorded costs of the preliminary survey and sensitisation activities. The objective was to calculate the full costs at local prices in Chad. Costs were adjusted to remove research components and to ensure that items outside the project budget lines were included, such as administrative overheads and a share of staff salaries. Results Targets were deployed at about 60 per linear km of riverine tsetse habitat. The average annual cost of the operation was USD 56,113, working out at USD 66.8 per km2 protected and USD 1.4 per person protected. Of this, 12.8% was an annual share of the initial tsetse survey, 40.6% for regular tsetse monitoring undertaken three times a year, 36.8% for target deployment and checking and 9.8% for sensitisation of local populations. Targets accounted for 8.3% of the cost, and the cost of delivering a target was USD 19.0 per target deployed. Conclusions This study has confirmed that tiny targets provide a consistently low cost option for controlling tsetse in gambiense HAT foci. Although the study area is remote with a tsetse habitat characterised by wide river marshes, the costs were similar to those of tiny target work in Uganda, with some differences, in particular a higher cost per target delivered. As was the case in Uganda, the cost was between a quarter and a third that of historical target operations using full size targets or traps. ![]()
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Affiliation(s)
- Jean-Baptiste Rayaisse
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso
| | - Fabrice Courtin
- Institut Pierre Richet (IPR), Bouaké, Côte d'Ivoire.,Institut de Recherche pour le Développement (IRD), Unité mixte de recherche, (UMR) 177 Intertryp IRD-Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), Université Montpellier, Montpellier, France
| | | | - Mahamat Chérif
- Institut de Recherche en Elevage pour le Développement (IRED), N'Djaména, Chad
| | - Wilfrid Yoni
- Centre International de Recherche-Développement sur l'Elevage en zone Subhumide (CIRDES), Bobo-Dioulasso, Burkina Faso
| | - Nadmba M O Gadjibet
- Institut de Recherche en Elevage pour le Développement (IRED), N'Djaména, Chad
| | - Mallaye Peka
- Programme National de Lutte contre la Trypanosomiase Humaine Africaine (PNLTHA), N'Djaména, Chad
| | - Philippe Solano
- Institut de Recherche pour le Développement (IRD), Unité mixte de recherche, (UMR) 177 Intertryp IRD-Centre de coopération internationale en recherche agronomique pour le développement (CIRAD), Université Montpellier, Montpellier, France
| | - Steve J Torr
- Liverpool School of Tropical Medicine (LSTM), Liverpool, Merseyside, UK
| | - Alexandra P M Shaw
- Infection Medicine, Deanery of Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Edinburgh, UK. .,AP Consultants, Walworth Enterprise Centre, Andover, UK.
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Ngari NN, Gamba DO, Olet PA, Zhao W, Paone M, Cecchi G. Developing a national atlas to support the progressive control of tsetse-transmitted animal trypanosomosis in Kenya. Parasit Vectors 2020; 13:286. [PMID: 32503681 PMCID: PMC7275614 DOI: 10.1186/s13071-020-04156-5] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 05/28/2020] [Indexed: 11/30/2022] Open
Abstract
Background African animal trypanosomosis (AAT) is a major livestock disease in Kenya. Even though, over the years various organizations have collected a vast amount of field data on tsetse and AAT in different parts of the country, recent national-level maps are lacking. To address this gap, a national atlas of tsetse and AAT distribution is being developed by the Kenya Tsetse and Trypanosomosis Eradication Council (KENTTEC) and partners. Methods All data collected by KENTTEC from 2006 to 2019 were systematically assembled, georeferenced and harmonized. A comprehensive data repository and a spatially-explicit database were created. Input data were collected mainly in the context of control activities, and include both baseline surveys (i.e. pre-intervention) and the subsequent monitoring during and after interventions. Surveys were carried out in four regions (i.e. Western, Rift Valley, Central and Coast), and in 21 of the 47 counties in Kenya. Various devices were used for entomological data collection (i.e. biconical, NGU and H traps, and sticky panels), while the buffy-coat technique was the method used to detect AAT. Results Tsetse trapping was carried out in approximately 5000 locations, and flies (> 71,000) were caught in all four investigated regions. Six species of Glossina were detected: G. pallidipes (87% of the catches); G. brevipalpis (8%); G. fuscipes fuscipes (4%); G. longipennis (< 1%); G. austeni (< 1%); and G. swynnertoni (< 1%). A total of 49,785 animals (98% of which cattle) were tested for AAT in approximately 500 locations. Of these, 914 animals were found to be infected. AAT was confirmed in all study regions, in particular caused by Trypanosoma vivax (48% of infections) and T. congolense (42%). Fewer cases of T. brucei were found. Conclusions The development and regular update of a comprehensive national database of tsetse and AAT is crucial to guide decision making for the progressive control of the disease. This first version of the atlas based on KENTTEC data has achieved a remarkable level of geographical coverage, but temporal and spatial gaps still exist. Other stakeholders at the national and international level will contribute to the initiative, thus improving the completeness of the atlas. ![]()
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Affiliation(s)
- Nancy N Ngari
- Kenya Tsetse and Trypanosomosis Eradication Council (KENTTEC), Nairobi, Kenya
| | - Daniel O Gamba
- Kenya Tsetse and Trypanosomosis Eradication Council (KENTTEC), Nairobi, Kenya
| | - Pamela A Olet
- Kenya Tsetse and Trypanosomosis Eradication Council (KENTTEC), Nairobi, Kenya
| | - Weining Zhao
- Food and Agriculture Organization of the United Nations (FAO), Animal Production and Health Division, Rome, Italy
| | - Massimo Paone
- Food and Agriculture Organization of the United Nations (FAO), Animal Production and Health Division, Rome, Italy
| | - Giuliano Cecchi
- Food and Agriculture Organization of the United Nations (FAO), Animal Production and Health Division, Rome, Italy.
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Integrated Health Interventions for Improved Livelihoods: A Case Study in Ethiopia. SUSTAINABILITY 2020. [DOI: 10.3390/su12062284] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Smallholder farmers in sub-Saharan Africa (SSA) face multifaceted and co-existing risks, such as human and animal diseases and pests. Even though smallholder farmers often experience these challenges simultaneously, interventions to address these challenges are often implemented in a piecemeal fashion. However, managing agricultural production constraints without alleviating human and livestock health burdens might not generate significant and sustained benefits to achieve the desired development outcome (e.g., reducing hunger, malnutrition, and poverty). As such, building farmers’ resilience and adaptive capacity to co-existing production constraints and health burdens may require an integrated and holistic approach. Understanding the potential benefits of an integrated approach would provide critical information, for example, for revisiting the extension systems and for designing pro-poor holistically integrated interventions to tackle interrelated challenges facing smallholder farmers. In this paper, we examined the economic benefits of integrated human–plant–animal health interventions aimed at controlling malaria, stemborer infestations of crops, and trypanosomiasis, along with beekeeping as a livelihood diversification option in rural Ethiopia. We developed a whole-farm multiperiod mathematical linear programming model to examine the economic consequences of the interventions. Our results suggest that relaxing livelihoods and the human–plant–animal health constraints that farmers face has the potential to at least double income. The results further show that exploiting the potential synergies among interventions can generate higher economic benefits. The annual income from the combined interventions is 35% higher than the sum of the income gains from each intervention alone. Our results support an integrated approach to achieve holistic outcomes in areas where these development constraints co-exist.
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A systematic review on modelling approaches for economic losses studies caused by parasites and their associated diseases in cattle. Parasitology 2018; 146:129-141. [PMID: 30068403 DOI: 10.1017/s0031182018001282] [Citation(s) in RCA: 55] [Impact Index Per Article: 9.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
Abstract
Parasites reside inside or outside their hosts and get host nutrition and blood. Here, we have emphasized economic losses in cattle caused by parasitic diseases due to ecto- and endo- parasites (flies, ticks, mites and helminths). We have outlined different methods/models including economic evaluation techniques and dynamic analysis as a major class, used for the calculation of economic losses caused by parasites in cattle. According to already conducted studies, a decrease in production is mentioned in quantity and percentage while financial losses are expressed in the form of account with respect to per head, herd or for the specific study area. The parasites cause the reduced production and financial losses due to control, treatment and mortality costs. We calculated the average decrease in milk production and organ condemnation as 1.16 L animal-1 day-1 and 12.95%, respectively, from overall cattle parasitic infections. Moreover, the average calculated financial and percentage losses were US$ 50.67 animal-1 year-1 and 17.94%, respectively. Economically important parasitic diseases mentioned here are caused by specific spp. of protozoans and helminths according to data collected from the literature. Protozoan diseases include tick-borne diseases, coccidiosis, neosporosis, trypanosomiasis and cryptosporidiosis. Losses due to tick-borne infections were encountered for decreased milk production, mortality, treatment and control. Losses from coccidiosis were due to decreased weight gain, treatment costs and mortality. While abortion losses were encountered in neosporosis. Trypanosomiasis caused losses due to a decrease in milk yield. Moreover, only diagnostic (conventional or molecular techniques) cost was taken into account for cryptosporidiosis. Economically important nematode parasites are Oesophagostomum spp., Cooperia spp., Trichostrongylus spp., Strongyloides spp., Ostertagia spp. and Haemonchus placei. Due to the zoonotic importance of echinococcosis, Echinococcus granulosus is the most economically important cestode parasite. Losses caused by echinococcosis were due to organ condemnation, carcass weight loss and decreases hide value, milk production and fecundity. While, fascioliasis is one of the most economically important trematodal disease, which causes cirrhosis of the liver due to parasite migration, and thus, the organ becomes inedible. So, it would be helpful for farmers and researchers to approach these methods/models for calculation of parasitic losses and should adopt suitable measures to avoid long-term economic losses.
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Eyssen LEA, Vather P, Jackson L, Ximba P, Biteau N, Baltz T, Boulangé A, Büscher P, Coetzer THT. Recombinant and native TviCATL from Trypanosoma vivax: Enzymatic characterisation and evaluation as a diagnostic target for animal African trypanosomosis. Mol Biochem Parasitol 2018; 223:50-54. [PMID: 29990512 DOI: 10.1016/j.molbiopara.2018.07.001] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/10/2018] [Revised: 06/29/2018] [Accepted: 07/04/2018] [Indexed: 10/28/2022]
Abstract
African animal trypanosomosis (nagana) is caused by tsetse-transmitted protozoan parasites. Their cysteine proteases are potential chemotherapeutic and diagnostic targets. The N-glycosylated catalytic domain of Trypanosoma vivax cathepsin L-like cysteine protease, rTviCATLcat, was recombinantly expressed and purified from culture supernatants while native TviCATL was purified from T. vivax Y486 parasite lysates. Typical of Clan CA, family C1 proteases, TviCATL activity is sensitive to E-64 and cystatin and substrate specificity is defined by the S2 pocket. Leucine was preferred in P2 and basic and non-bulky, hydrophobic residues accepted in P1 and P3 respectively. Reversible aldehyde inhibitors, antipain, chymostatin and leupeptin, with Arg in P1 and irreversible peptidyl chloromethylketone inhibitors with hydrophobic residues in P2 inhibited TviCATL activity. TviCATL digested host proteins: bovine haemoglobin, serum albumin, fibrinogen and denatured collagen (gelatine) over a wide pH range, including neutral to slightly acidic pH. The recombinant catalytic domain of TviCATL showed promise as a diagnostic target for detecting T. vivax infection in cattle in an indirect antibody detection ELISA.
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Affiliation(s)
- Lauren E-A Eyssen
- Biochemistry, School of Life Sciences, University of KwaZulu-Natal (Pietermaritzburg campus), Private Bag X01, Scottsville, 3209, South Africa
| | - Perina Vather
- Biochemistry, School of Life Sciences, University of KwaZulu-Natal (Pietermaritzburg campus), Private Bag X01, Scottsville, 3209, South Africa
| | - Laurelle Jackson
- Biochemistry, School of Life Sciences, University of KwaZulu-Natal (Pietermaritzburg campus), Private Bag X01, Scottsville, 3209, South Africa
| | - Phindile Ximba
- Biochemistry, School of Life Sciences, University of KwaZulu-Natal (Pietermaritzburg campus), Private Bag X01, Scottsville, 3209, South Africa
| | - Nicolas Biteau
- Laboratoire de Microbiologie Fondamentale et Pathogénicité, Université Bordeaux. UMR-CNRS 5234, 146, Rue Léo Saignat, 33076, Bordeaux Cedex, France
| | - Théo Baltz
- Laboratoire de Microbiologie Fondamentale et Pathogénicité, Université Bordeaux. UMR-CNRS 5234, 146, Rue Léo Saignat, 33076, Bordeaux Cedex, France
| | - Alain Boulangé
- Biochemistry, School of Life Sciences, University of KwaZulu-Natal (Pietermaritzburg campus), Private Bag X01, Scottsville, 3209, South Africa; CIRAD, UMR INTERTRYP, 01009 Maputo, Mozambique; INTERTRYP, Univ Montpellier, CIRAD, IRD, Montpellier, France; Centro de Biotecnologia, Universidade Eduardo Mondlane, 01009 Maputo, Mozambique
| | - Philippe Büscher
- Department of Biomedical Sciences, Institute of Tropical Medicine, Nationalestraat 155, B-2000, Antwerp, Belgium
| | - Theresa H T Coetzer
- Biochemistry, School of Life Sciences, University of KwaZulu-Natal (Pietermaritzburg campus), Private Bag X01, Scottsville, 3209, South Africa.
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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] [Grants] [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.
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Affiliation(s)
- Jennifer S. Lord
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | - Stephen J. Torr
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
| | | | - Paddy M. Brock
- Institute of Biodiversity, Animal Health and Comparative MedicineCollege of Medical, Veterinary and Life SciencesUniversity of GlasgowGlasgowUK
| | | | | | - Liam J. Morrison
- Roslin InstituteRoyal (Dick) School of Veterinary StudiesUniversity of EdinburghMidlothianUK
| | - Furaha Mramba
- Vector and Vector‐Borne Diseases Research InstituteTangaTanzania
| | - Glyn A. Vale
- SACEMAUniversity of StellenboschStellenboschSouth Africa
- Natural Resources InstituteUniversity of GreenwichChathamUK
| | - Michelle C. Stanton
- Department of Vector BiologyLiverpool School of Tropical MedicineLiverpoolUK
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18
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Assessing the Greenhouse Gas Mitigation Effect of Removing Bovine Trypanosomiasis in Eastern Africa. SUSTAINABILITY 2018. [DOI: 10.3390/su10051633] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
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Meyer A, Holt HR, Oumarou F, Chilongo K, Gilbert W, Fauron A, Mumba C, Guitian J. Integrated cost-benefit analysis of tsetse control and herd productivity to inform control programs for animal African trypanosomiasis. Parasit Vectors 2018. [PMID: 29514668 PMCID: PMC5842553 DOI: 10.1186/s13071-018-2679-x] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/15/2023] Open
Abstract
Background Animal African trypanosomiasis (AAT) and its tsetse vector are responsible for annual losses estimated in billions of US dollars ($). Recent years have seen the implementation of a series of multinational interventions. However, actors of AAT control face complex resource allocation decisions due to the geographical range of AAT, diversity of ecological and livestock systems, and range of control methods available. Methods The study presented here integrates an existing tsetse abundance model with a bio-economic herd model that captures local production characteristics as well as heterogeneities in AAT incidence and breed. These models were used to predict the impact of tsetse elimination on the net value of cattle production in the districts of Mambwe, in Zambia, and Faro et Déo in Cameroon. The net value of cattle production under the current situation was used as a baseline, and compared with alternative publicly funded control programmes. In Zambia, the current baseline is AAT control implemented privately by cattle owners (Scenario Z0). In Cameroon, the baseline (Scenario C0) is a small-scale publicly funded tsetse control programme and privately funded control at farm level. The model was run for 10 years, using a discount rate of 5%. Results Compared to Scenario C0, benefit-cost ratios (BCR) of 4.5 (4.4–4.7) for Scenario C1 (tsetse suppression using insecticide treatment of cattle (ITC) and traps + maintenance with ITC barrier), and 3.8 (3.6–4.0) for Scenario C2 (tsetse suppression using ITC and traps + maintenance with barrier of targets), were estimated in Cameroon. For Zambia, the benefit-cost ratio calculated for Scenarios Z1 (targets, ITC barrier), Z2 (targets, barrier traps), Z3 (aerial spraying, ITC barrier), and Z4 (aerial spraying, barrier traps) were 2.3 (1.8 - 2.7), 2.0 (1.6-2.4), 2.8 (2.3–3.3) and 2.5 (2.0–2.9), respectively. Sensitivity analysis showed that the profitability of the projects is relatively resistant to variations in the costs of the interventions and their technical efficiency. Conclusions It is envisioned that the methodologies presented here will be useful for the evaluation and design of existing and future control programmes, ensuring they have tangible benefits in the communities they are targeting. Electronic supplementary material The online version of this article (10.1186/s13071-018-2679-x) contains supplementary material, which is available to authorized users.
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Affiliation(s)
- Anne Meyer
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, UK
| | - Hannah R Holt
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, UK.
| | - Farikou Oumarou
- Mission Spéciale d'Eradication des Glossines, Ngaoundéré, Cameroon
| | - Kalinga Chilongo
- Department of Veterinary Services, Tsetse and Trypanosomiasis Control Unit, Ministry of Fisheries and Livestock, Lusaka, Zambia
| | - William Gilbert
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, UK
| | - Albane Fauron
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, UK
| | - Chisoni Mumba
- Department of Disease Control, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka, Zambia
| | - Javier Guitian
- Department of Pathobiology and Population Sciences, Royal Veterinary College, Hatfield, UK
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Falzon LC, Lechner I, Chantziaras I, Collineau L, Courcoul A, Filippitzi ME, Laukkanen-Ninios R, Peroz C, Pinto Ferreira J, Postma M, Prestmo PG, Phythian CJ, Sarno E, Vanantwerpen G, Vergne T, Grindlay DJC, Brennan ML. Quantitative Outcomes of a One Health approach to Study Global Health Challenges. ECOHEALTH 2018; 15:209-227. [PMID: 29330676 PMCID: PMC6003973 DOI: 10.1007/s10393-017-1310-5] [Citation(s) in RCA: 17] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 07/11/2017] [Revised: 11/18/2017] [Accepted: 11/20/2017] [Indexed: 06/07/2023]
Abstract
Having gained momentum in the last decade, the One Health initiative promotes a holistic approach to address complex global health issues. Before recommending its adoption to stakeholders, however, it is paramount to first compile quantitative evidence of the benefit of such an approach. The aim of this scoping review was to identify and summarize primary research that describes monetary and non-monetary outcomes following adoption of a One Health approach. An extensive literature search yielded a total of 42,167 references, of which 85 were included in the final analysis. The top two biotic health issues addressed in these studies were rabies and malaria; the top abiotic health issue was air pollution. Most studies described collaborations between human and animal (n = 42), or human and environmental disciplines (n = 41); commonly reported interventions included vector control and animal vaccination. Monetary outcomes were commonly expressed as cost-benefit or cost-utility ratios; non-monetary outcomes were described using disease frequency or disease burden measurements. The majority of the studies reported positive or partially positive outcomes. This paper illustrates the variety of health challenges that can be addressed using a One Health approach, and provides tangible quantitative measures that can be used to evaluate future implementations of the One Health approach.
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Affiliation(s)
- Laura C Falzon
- Veterinary Public Health Institute, University of Bern, Schwarzenburgstrasse 155, 3097, Liebefeld, Switzerland.
- Institute of Infection and Global Health, University of Liverpool, 8 West Derby Street, Liverpool, L69 7BE, UK.
| | - Isabel Lechner
- Veterinary Public Health Institute, University of Bern, Schwarzenburgstrasse 155, 3097, Liebefeld, Switzerland
| | - Ilias Chantziaras
- Veterinary Epidemiology Unit, Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | | | - Aurélie Courcoul
- Anses, Laboratory of Animal Health, Epidemiology Unit, University Paris Est, 23, Avenue du Général de Gaulle, 94706, Maisons-Alfort Cedex, France
| | - Maria-Eleni Filippitzi
- Veterinary Epidemiology Unit, Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Riikka Laukkanen-Ninios
- Department of Food Hygiene and Environmental Health, Faculty of Veterinary Medicine, University of Helsinki, P.O. Box 66, 00014, Helsinki, Finland
| | | | | | - Merel Postma
- Veterinary Epidemiology Unit, Department of Reproduction, Obstetrics and Herd Health, Faculty of Veterinary Medicine, Ghent University, Salisburylaan 133, 9820, Merelbeke, Belgium
| | - Pia G Prestmo
- School of Veterinary Sciences, University of Bristol, Langford House, Langford, Bristol, BS40 5DU, UK
| | - Clare J Phythian
- Section for Small Ruminant Research, Faculty of Veterinary Medicine, Institute for Production Animal Clinical Science, Norwegian University of Life Sciences, 4325, Sandnes, Norway
| | - Eleonora Sarno
- Institute for Food Safety and Hygiene, University of Zurich, Winterthurerstrasse 272, 8057, Zürich, Switzerland
| | - Gerty Vanantwerpen
- Department of Veterinary Public Health and Food Safety, Faculty of Veterinary Medicine, Ghent University, Merelbeke, Belgium
| | - Timothée Vergne
- Veterinary Epidemiology Economics and Public Health group, Royal Veterinary College, London, UK
- MIVEGEC Group, Institut de Recherche pour le développement, Montpellier, France
- UMR ENVT-INRA IHAP, University of Toulouse, Toulouse, France
| | - Douglas J C Grindlay
- Centre of Evidence-based Dermatology, The University of Nottingham, King's Meadow Campus, Nottingham, NG7 2NR, UK
| | - Marnie L Brennan
- Centre for Evidence-based Veterinary Medicine, School of Veterinary Medicine and Science, The University of Nottingham, Sutton Bonington Campus, Loughborough, LE12 5RD, UK
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Tekle T, Terefe G, Cherenet T, Ashenafi H, Akoda KG, Teko-Agbo A, Van Den Abbeele J, Gari G, Clausen PH, Hoppenheit A, Mattioli RC, Peter R, Marcotty T, Cecchi G, Delespaux V. Aberrant use and poor quality of trypanocides: a risk for drug resistance in south western Ethiopia. BMC Vet Res 2018; 14:4. [PMID: 29304792 PMCID: PMC5755418 DOI: 10.1186/s12917-017-1327-6] [Citation(s) in RCA: 20] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 12/22/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Trypanocidal drugs have been used to control African animal trypanosomosis for several decades. In Ethiopia, these drugs are available from both authorized (legal) and unauthorized (illegal) sources but documentation on utilization practices and quality of circulating products is scanty. This study looked at the practices of trypanocidal drug utilization by farmers and the integrity of active ingredient in trypanocides sold in Gurage zone, south western Ethiopia. The surveys were based on a structured questionnaire and drug quality determination of commonly used brands originating from European and Asian companies and sold at both authorized and unauthorized markets. One hundred farmers were interviewed and 50 drug samples were collected in 2013 (Diminazene aceturate = 33 and Isometamidium chloride = 17; 25 from authorized and 25 from unauthorized sources). Samples were tested at the OIE-certified Veterinary Drug Control Laboratory (LACOMEV) in Dakar, Senegal, by using galenic standards and high performance liquid chromatography. RESULTS Trypanosomosis was found to be a major threat according to all interviewed livestock keepers in the study area. Diminazene aceturate and isometamidium chloride were preferred by 79% and 21% of the respondents respectively, and 85% of them indicated that an animal receives more than six treatments per year. About 60% of these treatments were reported to be administered by untrained farmers. Trypanocidal drug sources included both unauthorized outlets (56%) and authorized government and private sources (44%). A wide availability and usage of substandard quality drugs was revealed. Twenty eight percent of trypanocidal drugs tested failed to comply with quality requirements. There was no significant difference in the frequency of non-compliance between diminazene-based and isometamidium chloride products (P = 0.87) irrespective of the marketing channel (official and unofficial). However, higher rates of non-compliant trypanocides were detected for drugs originating from Asia than from Europe (P = 0.029). CONCLUSION The findings revealed the presence of risk factors for the development of drug resistance, i.e. wide distribution of poor quality drugs as well as substandard administration practices. Therefore, it is strongly recommended to enforce regulatory measures for quality control of veterinary drugs, to expand and strengthen veterinary services and to undertake trypanocidal drug efficacy studies of wider coverage.
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Affiliation(s)
- T Tekle
- National Animal Health Diagnostic and Investigation Center-Protozoology unit, P.O. Box 8615, Addis Ababa, Ethiopia
| | - G Terefe
- Department of Pathology & Parasitology, Addis Ababa University College of Veterinary Medicine and Agriculture, P.O.Box 34, Bishoftu, Ethiopia.
| | - T Cherenet
- Minstry of Livestock and Fisheries, Addis Ababa, Ethiopia
| | - H Ashenafi
- Department of Pathology & Parasitology, Addis Ababa University College of Veterinary Medicine and Agriculture, P.O.Box 34, Bishoftu, Ethiopia
| | - K G Akoda
- Ecole Inter- Etats des Sciences et Médecine vétérinaires de Dakar, P.O.Box 5077, Dakar, Fann, Senegal
| | - A Teko-Agbo
- Ecole Inter- Etats des Sciences et Médecine vétérinaires de Dakar, P.O.Box 5077, Dakar, Fann, Senegal
| | - J Van Den Abbeele
- Department of Biomedical Sciences Veterinary Protozoology, Institute of Tropical Medicine, Unit 155 Nationalestraat, B-2000, Antwerp, Belgium
| | - G Gari
- National Animal Health Diagnostic and Investigation Center-Protozoology unit, P.O. Box 8615, Addis Ababa, Ethiopia
| | - P-H Clausen
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universitaet Berlin, Robert-von-Ostertag Str. 7-13, 14163, Berlin, Germany
| | - A Hoppenheit
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universitaet Berlin, Robert-von-Ostertag Str. 7-13, 14163, Berlin, Germany
| | - R C Mattioli
- Food and Agriculture Organization of the United Nations, Viale delle Terme di Caracalla, 00153, Rome, Italy
| | - R Peter
- Global Alliance for Livestock Veterinary Medicines (GALVmed), Doherty Building, Pentlands Park, Bush Loan, Edinburgh, EH26 0PZ, UK
| | - T Marcotty
- Veterinary Epidemiology and Risk Analysis - Research and Development (VERDI-R&D), Rue du Gravier 7, 4141, Sprimont, Belgium
| | - G Cecchi
- Food and Agriculture Organization of the United Nations, Sub-Regional Office for Eastern Africa, Addis Ababa, Ethiopia
| | - V Delespaux
- Faculty of Sciences and Bio-engineering Sciences, Vrije Universiteit Brussel, Pleinlaan 2, B-1050, Brussels, Belgium
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22
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Büscher P, Cecchi G, Jamonneau V, Priotto G. Human African trypanosomiasis. Lancet 2017; 390:2397-2409. [PMID: 28673422 DOI: 10.1016/s0140-6736(17)31510-6] [Citation(s) in RCA: 430] [Impact Index Per Article: 61.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 02/06/2017] [Revised: 03/20/2017] [Accepted: 04/28/2017] [Indexed: 10/19/2022]
Abstract
Human African trypanosomiasis (sleeping sickness) is a parasitic infection that almost invariably progresses to death unless treated. Human African trypanosomiasis caused devastating epidemics during the 20th century. Thanks to sustained and coordinated efforts over the past 15 years, the number of reported cases has fallen to an historically low level. Fewer than 3000 cases were reported in 2015, and the disease is targeted for elimination by WHO. Despite these recent successes, the disease is still endemic in parts of sub-Saharan Africa, where it is a considerable burden on rural communities, most notably in central Africa. Since patients are also reported from non-endemic countries, human African trypanosomiasis should be considered in differential diagnosis for travellers, tourists, migrants, and expatriates who have visited or lived in endemic areas. In the absence of a vaccine, disease control relies on case detection and treatment, and vector control. Available drugs are suboptimal, but ongoing clinical trials provide hope for safer and simpler treatments.
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Affiliation(s)
- Philippe Büscher
- Department of Biomedical Sciences, Institute of Tropical Medicine, Antwerp, Belgium.
| | - Giuliano Cecchi
- Food and Agriculture Organization of the United Nations, Sub-regional Office for Eastern Africa, Addis Ababa, Ethiopia
| | - Vincent Jamonneau
- UMR INTERTRYP, Institut de Recherche pour le Développement, Montpellier, France
| | - Gerardo Priotto
- World Health Organization, Control of Neglected Tropical Diseases, Innovative and Intensified Disease Management, Geneva, Switzerland
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23
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Wamboga C, Matovu E, Bessell PR, Picado A, Biéler S, Ndung’u JM. Enhanced passive screening and diagnosis for gambiense human African trypanosomiasis in north-western Uganda - Moving towards elimination. PLoS One 2017; 12:e0186429. [PMID: 29023573 PMCID: PMC5638538 DOI: 10.1371/journal.pone.0186429] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/22/2017] [Accepted: 09/29/2017] [Indexed: 11/18/2022] Open
Abstract
Introduction The incidence of gambiense human African trypanosomiasis (gHAT) in Uganda has been declining, from 198 cases in 2008, to only 20 in 2012. Interruption of transmission of the disease by early diagnosis and treatment is core to the control and eventual elimination of gHAT. Until recently, the format of available screening tests had restricted screening and diagnosis to central health facilities (passive screening). We describe a novel strategy that is contributing to elimination of gHAT in Uganda through expansion of passive screening to the entire population at risk. Methodology / Principal findings In this strategy, patients who are clinically suspected of having gHAT at primary health facilities are screened using a rapid diagnostic test (RDT), followed by parasitological confirmation at strategically located microscopy centres. For patients who are positive with the RDT and negative by microscopy, blood samples undergo further testing using loop-mediated isothermal amplification (LAMP), a molecular test that detects parasite DNA. LAMP positive patients are considered strong suspects, and are re-evaluated by microscopy. Location and upgrading of facilities to perform microscopy and LAMP was informed by results of georeferencing and characterization of all public healthcare facilities in the 7 gHAT endemic districts in Uganda. Three facilities were upgraded to perform RDTs, microscopy and LAMP, 9 to perform RDTs and microscopy, and 200 to screen patients with RDTs. This reduced the distance that a sick person must travel to be screened for gHAT to a median distance of 2.5km compared to 23km previously. In this strategy, 9 gHAT cases were diagnosed in 2014, and 4 in 2015. Conclusions This enhanced passive screening strategy for gHAT has enabled full coverage of the population at risk, and is being replicated in other gHAT endemic countries. The improvement in case detection is making elimination of the disease in Uganda an imminent possibility.
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Affiliation(s)
| | - Enock Matovu
- College of Veterinary Medicine, Animal Resources and Biosecurity (COVAB), Makerere University, Kampala, Uganda
| | | | - Albert Picado
- Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
| | - Sylvain Biéler
- Foundation for Innovative New Diagnostics (FIND), Geneva, Switzerland
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Diall O, Cecchi G, Wanda G, Argilés-Herrero R, Vreysen MJB, Cattoli G, Viljoen GJ, Mattioli R, Bouyer J. Developing a Progressive Control Pathway for African Animal Trypanosomosis. Trends Parasitol 2017; 33:499-509. [PMID: 28456474 DOI: 10.1016/j.pt.2017.02.005] [Citation(s) in RCA: 86] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/25/2017] [Revised: 02/21/2017] [Accepted: 02/22/2017] [Indexed: 11/25/2022]
Abstract
Progressive control pathways (PCPs) are stepwise approaches for the reduction, elimination, and eradication of human and animal diseases. They provide systematic frameworks for planning and evaluating interventions. Here we outline a PCP for tsetse-transmitted animal trypanosomosis, the scourge of poor livestock keepers in tropical Africa. Initial PCP stages focus on the establishment of national coordination structures, engagement of stakeholders, development of technical capacities, data collection and management, and pilot field interventions. The intermediate stage aims at a sustainable and economically profitable reduction of disease burden, while higher stages target elimination. The mixed-record of success and failure in past efforts against African animal trypanosomosis (AAT) makes the development of this PCP a high priority.
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Affiliation(s)
- Oumar Diall
- Food and Agriculture Organization of the United Nations (FAO), Sub-Regional Office for Eastern Africa, Addis Ababa, Ethiopia
| | - Giuliano Cecchi
- Food and Agriculture Organization of the United Nations (FAO), Sub-Regional Office for Eastern Africa, Addis Ababa, Ethiopia.
| | - Gift Wanda
- African Union - Pan African Tsetse and Trypanosomosis Eradication Campaign (AU-PATTEC), Addis Ababa, Ethiopia
| | - Rafael Argilés-Herrero
- Joint FAO/International Atomic Energy Agency (IAEA) Programme of Nuclear Techniques in Food and Agriculture, Insect Pest Control Sub-Programme, Vienna, Austria
| | - Marc J B Vreysen
- Joint FAO/International Atomic Energy Agency (IAEA) Programme of Nuclear Techniques in Food and Agriculture, Insect Pest Control Sub-Programme, Vienna, Austria
| | - Giovanni Cattoli
- Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, Animal Production and Health Sub-Programme, Vienna, Austria
| | - Gerrit J Viljoen
- Joint FAO/IAEA Programme of Nuclear Techniques in Food and Agriculture, Animal Production and Health Sub-Programme, Vienna, Austria
| | | | - Jérémy Bouyer
- Unité Mixte de Recherche INTERTRYP, Centre de Coopération Internationale en Recherche Agronomique pour le Développement (CIRAD), Montpellier, France; Unité Mixte de Recherche "Animal, Santé, Territoires, Risques et Ecosystèmes" (ASTRE), CIRAD, Montpellier, France
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25
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Tchamdja E, Kulo AE, Vitouley HS, Batawui K, Bankolé AA, Adomefa K, Cecchi G, Hoppenheit A, Clausen PH, De Deken R, Van Den Abbeele J, Marcotty T, Delespaux V. Cattle breeding, trypanosomosis prevalence and drug resistance in Northern Togo. Vet Parasitol 2017; 236:86-92. [PMID: 28288771 DOI: 10.1016/j.vetpar.2017.02.008] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Revised: 01/05/2017] [Accepted: 02/10/2017] [Indexed: 11/30/2022]
Abstract
African Animal Trypanosomosis (AAT) is a major disease of cattle in Togo and its control is essentially based on chemotherapy. However, because of excessive use of trypanocides during the past decades, chemo-resistance in the parasites has developed. In order to assess the current situation of AAT and resistance to trypanocidal drugs in Northern Togo, a study was conducted on cattle from December 2012 to August 2013 in the regions of Kara and Savanes. An initial cross-sectional survey was carried out in 40 villages using the Haematocrit Centrifugation Technique (HCT). Out of these, 5 villages with a trypanosome prevalence of >10% were selected for a block treatment study (BT) with diminazene diaceturate (DA: 3.5mg/kg for a 14-day follow-up) and isometamidium chloride (ISM: 0.5mg/kg for a 28-day follow-up). Positive blood samples collected during the parasitological surveys and an equivalent number of negatives were further analyzed by PCR-RFLP for trypanosome species confirmation and molecular diagnosis of resistance to DA in Trypanosoma congolense. The results from 1883 bovine blood samples confirmed a high overall trypanosome prevalence of 10.8% in Northern Togo. PCR-RFLP revealed that T. congolense is the dominant pathogenic trypanosome species (50.5%) followed by T. vivax (27.3%), and T. brucei (16.2%). The BT showed varying levels of treatment failures ranging from 0 to 30% and from 0 to 50% for DA and for ISM respectively, suggesting the existence of resistant trypanosome populations in the study area. Our results show that AAT still represents a major obstacle to the development of cattle husbandry in Northern Togo. In areas of high AAT risk, a community-based integrated strategy combining vector control, rational use of trypanocidal drugs and improving the general condition of the animals is recommended to decision makers.
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Affiliation(s)
- E Tchamdja
- Direction de l'Elevage, BP 4041, Lomé, Togo
| | - A E Kulo
- Ecole Supérieure d'Agronomie, Université de Lomé, BP 1515, Lomé, Togo
| | - H S Vitouley
- Centre International de Recherche-Développement sur l'Elevage en Zone Subhumide (CIRDES), 01BP454 Bobo Dioulasso 01, Burkina Faso
| | - K Batawui
- Direction de l'Elevage, BP 4041, Lomé, Togo
| | | | - K Adomefa
- Direction de l'Elevage, BP 4041, Lomé, Togo
| | - G Cecchi
- Food and Agriculture Organization of the United Nations, Sub-Regional Office for Eastern Africa, Addis Ababa, Ethiopia
| | - A Hoppenheit
- Freie Universitaet Berlin, Institute of Parasitology and Tropical Veterinary Medicine, Robert-von-Ostertagstr. 7-13, 14163 Berlin, Germany
| | - P H Clausen
- Freie Universitaet Berlin, Institute of Parasitology and Tropical Veterinary Medicine, Robert-von-Ostertagstr. 7-13, 14163 Berlin, Germany
| | - R De Deken
- Institute of Tropical Medicine, Biomedical Sciences Department, Veterinary Entomology, Nationalestraat 155, B-2000 Antwerp, Belgium
| | - J Van Den Abbeele
- Institute of Tropical Medicine, Biomedical Sciences Department, Veterinary Protozoology, Nationalestraat 155, B-2000 Antwerp, Belgium
| | - T Marcotty
- Veterinary Epidemiology, Risk-analysis and Diagnosis Research & Development, VERDI - R&D (asbl), Rue du gravier, 7, B-4141 Louveigné, Belgium
| | - V Delespaux
- Vrije Universiteit Brussel, Faculty of Sciences and Bioengineering Sciences, Pleinlaan 2, B-1050 Brussels, Belgium.
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Meyer A, Holt HR, Selby R, Guitian J. Past and Ongoing Tsetse and Animal Trypanosomiasis Control Operations in Five African Countries: A Systematic Review. PLoS Negl Trop Dis 2016; 10:e0005247. [PMID: 28027299 PMCID: PMC5222520 DOI: 10.1371/journal.pntd.0005247] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/05/2016] [Revised: 01/09/2017] [Accepted: 12/12/2016] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Control operations targeting Animal African Trypanosomiasis and its primary vector, the tsetse, were covering approximately 128,000 km2 of Africa in 2001, which is a mere 1.3% of the tsetse infested area. Although extensive trypanosomiasis and tsetse (T&T) control operations have been running since the beginning of the 20th century, Animal African Trypanosomiasis is still a major constraint of livestock production in sub-Saharan Africa. METHODOLOGY/PRINCIPAL FINDINGS We performed a systematic review of the existing literature describing T&T control programmes conducted in a selection of five African countries, namely Burkina Faso, Cameroon, Ethiopia, Uganda and Zambia, between 1980 and 2015. Sixty-eight documents were eventually selected from those identified by the database search. This was supplemented with information gathered through semi-structured interviews conducted with twelve key informants recruited in the study countries and selected based on their experience and knowledge of T&T control. The combined information from these two sources was used to describe the inputs, processes and outcomes from 23 major T&T control programmes implemented in the study countries. Although there were some data gaps, involvement of the target communities and sustainability of the control activities were identified as the two main issues faced by these programmes. Further, there was a lack of evaluation of these control programmes, as well as a lack of a standardised methodology to conduct such evaluations. CONCLUSIONS/SIGNIFICANCE Past experiences demonstrated that coordinated and sustained control activities require careful planning, and evidence of successes, failures and setbacks from past control programmes represent a mine of information. As there is a lack of evaluation of these programmes, these data have not been fully exploited for the design, analyses and justification of future control programmes.
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Affiliation(s)
- Anne Meyer
- Department of Production and Population Health, Royal Veterinary College, Hatfield, United Kingdom
| | - Hannah R. Holt
- Department of Production and Population Health, Royal Veterinary College, Hatfield, United Kingdom
| | - Richard Selby
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Javier Guitian
- Department of Production and Population Health, Royal Veterinary College, Hatfield, United Kingdom
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Welburn SC, Bardosh KL, Coleman PG. Novel Financing Model for Neglected Tropical Diseases: Development Impact Bonds Applied to Sleeping Sickness and Rabies Control. PLoS Negl Trop Dis 2016; 10:e0005000. [PMID: 27855156 PMCID: PMC5113866 DOI: 10.1371/journal.pntd.0005000] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/02/2022] Open
Affiliation(s)
- Susan Christina Welburn
- Division of Infection and Pathway Medicine, Edinburgh Medical School: Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Chancellor’s Building, United Kingdom
- * E-mail:
| | - Kevin Louis Bardosh
- Division of Infection and Pathway Medicine, Edinburgh Medical School: Biomedical Sciences, College of Medicine and Veterinary Medicine, The University of Edinburgh, Chancellor’s Building, United Kingdom
| | - Paul Gerard Coleman
- Department of Disease Control, Faculty of Infectious and Tropical Diseases, London School of Hygiene & Tropical Medicine, Keppel Street, Bloomsbury, London, United Kingdom
- H2O Venture Partners, United Kingdom
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28
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Abstract
Pathogenic animal trypanosomes affecting livestock have represented a major constraint to agricultural development in Africa for centuries, and their negative economic impact is increasing in South America and Asia. Chemotherapy and chemoprophylaxis represent the main means of control. However, research into new trypanocides has remained inadequate for decades, leading to a situation where the few compounds available are losing efficacy due to the emergence of drug-resistant parasites. In this review, we provide a comprehensive overview of the current options available for the treatment and prophylaxis of the animal trypanosomiases, with a special focus on the problem of resistance. The key issues surrounding the main economically important animal trypanosome species and the diseases they cause are also presented. As new investment becomes available to develop improved tools to control the animal trypanosomiases, we stress that efforts should be directed towards a better understanding of the biology of the relevant parasite species and strains, to identify new drug targets and interrogate resistance mechanisms.
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29
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Ahmed SK, Rahman AH, Hassan MA, Salih SEM, Paone M, Cecchi G. An atlas of tsetse and bovine trypanosomosis in Sudan. Parasit Vectors 2016; 9:194. [PMID: 27056678 PMCID: PMC4825090 DOI: 10.1186/s13071-016-1485-6] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2016] [Accepted: 03/31/2016] [Indexed: 11/11/2022] Open
Abstract
Background After a long period of neglect, initiatives are being implemented in Sudan to control tsetse and trypanosomosis. Their planning, execution and monitoring require reliable information on the geographic distribution of the disease and its vectors. However, geo-referenced and harmonized data at the national level are lacking, despite the fact that a number of epidemiological studies were conducted over the years. The Atlas of tsetse and bovine trypanosomosis in Sudan tries to fill this gap. Methods The present study includes both a review of historical datasets on tsetse flies and bovine trypanosomosis, as well as the results of recent, targeted field investigations. The review includes both published and unpublished datasets collected in Sudan from 1960 onwards. Targeted field investigations were conducted for trypanosomosis in Blue Nile (2011) and Gezeira States (2012), for tsetse flies in South Darfur (2012) and Blue Nile States (2009 and 2011), and for other trypanosomosis vectors in seven States (Khartoum, Gezeira, White Nile, Blue Nile, North Kordofan, Kassala and Gadarif). The latter surveys, conducted from 2010 to 2012, also enabled us to confirm the absence of tsetse flies in a number of locations. Results Tsetse fly infestation in Sudan appears to be limited to two relatively small areas at the south-western and south-eastern tips of the Country (South Darfur and Blue Nile State respectively). Glossina morsitans submorsitans is present in both areas, whilst G. fuscipes fuscipes is found only in the latter. In contrast, bovine trypanosomosis is widespread, its presence having being confirmed in eleven States and suspected in all the others. Both mechanical transmission by non-cyclical vectors and animal movement contribute to this broad distribution of trypanosomosis. This is especially the case for Trypanosoma vivax, which was found even in sedentary cattle at hundreds of kilometres of the tsetse belt. Conclusions The Atlas provides a spatially-explicit synthesis of the current knowledge of tsetse and bovine trypanosomosis in Sudan. Its various epidemiological outputs are being used to target both trypanosomosis control activities and further data collection exercises. Activities are ongoing to expand the Atlas to non-cyclical vectors and hosts other than cattle. Electronic supplementary material The online version of this article (doi:10.1186/s13071-016-1485-6) contains supplementary material, which is available to authorized users.
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Affiliation(s)
| | | | | | | | - Massimo Paone
- Food and Agriculture Organization of the United Nations, Animal Production and Health Division, Rome, Italy
| | - Giuliano Cecchi
- Food and Agriculture Organization of the United Nations, Sub-Regional Office for Eastern Africa, Addis Ababa, Ethiopia.
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