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Surve AA, Hwang JY, Manian S, Onono JO, Yoder J. Economics of East Coast fever: a literature review. Front Vet Sci 2023; 10:1239110. [PMID: 37771945 PMCID: PMC10526366 DOI: 10.3389/fvets.2023.1239110] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/12/2023] [Accepted: 08/22/2023] [Indexed: 09/30/2023] Open
Abstract
East Coast fever (ECF) is a cattle disease caused by a protozoan parasite called Theileria parva (T. parva). Theileria parva is transmitted among cattle by ticks. It is endemic in parts of central, eastern, and southern Africa and imposes an economic burden through illness and death of approximately a half of a billion U.S. dollars annually. This paper reviews existing science on the economics of ECF. We utilize a conceptual model that defines primary categories of economic costs due to ECF and use it to organize a synthesis of the literature on aggregate and micro level direct costs of the disease and the costs and benefits related to various ECF management strategies. We then identify knowledge gaps to motivate for future research.
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Affiliation(s)
- Aditi A. Surve
- School of Economic Sciences, Washington State University, Pullman, WA, United States
| | - Jae Young Hwang
- School of Economic Sciences, Washington State University, Pullman, WA, United States
| | - Shanthi Manian
- School of Economic Sciences, Washington State University, Pullman, WA, United States
- School for Global Health, Washington State University, Pullman, WA, United States
| | - Joshua Orungo Onono
- Department of Public Health Pharmacology and Toxicology, University of Nairobi, Nairobi, Kenya
| | - Jonathan Yoder
- School of Economic Sciences, Washington State University, Pullman, WA, United States
- School for Global Health, Washington State University, Pullman, WA, United States
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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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Efficacy, T cell activation and antibody responses in accelerated Plasmodium falciparum sporozoite chemoprophylaxis vaccine regimens. NPJ Vaccines 2022; 7:59. [PMID: 35641527 PMCID: PMC9156686 DOI: 10.1038/s41541-022-00473-1] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2021] [Accepted: 03/18/2022] [Indexed: 11/08/2022] Open
Abstract
Repeated direct venous inoculation of Plasmodium falciparum sporozoites (PfSPZ) together with antimalarial chemoprophylaxis (PfSPZ-CVac) is the most potent way to induce sterile immunity against P. falciparum infection in malaria-naive volunteers. However, established schedules are complex and long. Here, we tested two accelerated three-dose schedules (28- and 10-day regimen) assessing efficacy by controlled human malaria infection (CHMI) against placebo, comparing vaccine-specific T cell and antibody responses by antigen-reactive T cell enrichment (ARTE) and protein microarray, respectively. Both regimens were similarly efficacious (67 and 63% vaccine efficacy) but different in the induction of vaccine-specific T cells and antibodies. The 10-day regimen resulted in higher numbers of antigen-specific CD4+ effector memory pro-inflammatory T cells and a broader antibody response compared with the 28-day regimen. Usually in nature, P. falciparum liver stage lasts about 6.5 days. The short vaccination-interval of the 10-day regimen prolongs the time of continuous exposure to liver-stage parasites, which may explain the stronger response. Besides dose and number of vaccinations, duration of liver-stage exposure is a factor to optimize PfSPZ-CVac immunogenicity.
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Muleya W, Atuhaire DK, Mupila Z, Mbao V, Mayembe P, Kalenga S, Fandamu P, Namangala B, Salt J, Musoke AJ. Sequence Diversity of Tp1 and Tp2 Antigens and Population Genetic Analysis of Theileria parva in Unvaccinated Cattle in Zambia's Chongwe and Chisamba Districts. Pathogens 2022; 11:114. [PMID: 35215058 PMCID: PMC8879479 DOI: 10.3390/pathogens11020114] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2021] [Revised: 01/07/2022] [Accepted: 01/16/2022] [Indexed: 12/10/2022] Open
Abstract
East Coast Fever (ECF), caused by Theileria parva, is a major constraint to improved livestock keeping in east and central Africa, including Zambia. To understand the dynamics and determine the candidates for immunization in Zambia's Chongwe and Chisamba districts, a combination of Tp1 and Tp2 gene sequencing and microsatellite analysis using nine markers was conducted from which an abundance of Muguga, Kiambu, Serengeti and Katete epitopes in the field samples was obtained. Phylogenetic analysis showed six (Tp1) and three (Tp2) clusters with an absence of geographical origin clustering. The majority of haplotypes were related to Muguga, Kiambu, Serengeti and Katete, and only a few were related to Chitongo. Both antigens showed purifying selection with an absence of positive selection sites. Furthermore, low to moderate genetic differentiation was observed among and within the populations, and when vaccine stocks were compared with field samples, Chongwe samples showed more similarity to Katete and less to Chitongo, while Chisamba samples showed similarity to both Katete and Chitongo and not to Muguga, Kiambu or Serengeti. We conclude that the use of Katete stock for immunization trials in both Chongwe and Chisamba districts might produce desirable protection against ECF.
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Affiliation(s)
- Walter Muleya
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia; (W.M.); (Z.M.)
| | | | - Zachariah Mupila
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia; (W.M.); (Z.M.)
| | - Victor Mbao
- Eastern and Southern Africa Regional Office, International Development Research Centre, Nairobi 00200, Kenya;
| | - Purity Mayembe
- Department of Veterinary Services, Ministry of Fisheries and Livestock, Lusaka 50060, Zambia; (P.M.); (S.K.); (P.F.)
| | - Sydney Kalenga
- Department of Veterinary Services, Ministry of Fisheries and Livestock, Lusaka 50060, Zambia; (P.M.); (S.K.); (P.F.)
| | - Paul Fandamu
- Department of Veterinary Services, Ministry of Fisheries and Livestock, Lusaka 50060, Zambia; (P.M.); (S.K.); (P.F.)
| | - Boniface Namangala
- Department of Paraclinical Studies, School of Veterinary Medicine, University of Zambia, Lusaka 10101, Zambia;
| | - Jeremy Salt
- Global Alliance for Livestock Veterinary Medicines, Pentlands Science Park, Bush Loan, Penicuik EH26 0PZ, UK;
| | - Antony Jim Musoke
- LMK Medical Laboratories and Consultancies, Kampala P.O. Box 33686, Uganda;
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Teufel N, Korir L, Hammond J, van Wijk M, Kiara H. Farm and Livelihood Characteristics After ITM Vaccination Against East Coast Fever in Tanzania. Front Vet Sci 2021; 8:639762. [PMID: 34859079 PMCID: PMC8632140 DOI: 10.3389/fvets.2021.639762] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2020] [Accepted: 07/12/2021] [Indexed: 11/30/2022] Open
Abstract
East Coast Fever is a critical cattle disease in East and Southern Africa which is currently mainly controlled through frequent chemical removal of ticks, the disease vector. However, a vaccine conveying life-long immunity has existed for some time, known as the infection and treatment method (ITM), although it has so far not been widely adopted because of its cost, demanding distribution system and regulatory reservations. Also, despite having proved effective on the animal level, the promoters of the vaccine have not been able to show much evidence of its benefits on the herd, farm and household levels. This study, based on a cross-sectional survey of 994 cattle keepers throughout Tanzania, aims to provide such evidence by comparing indicators of herd productivity, of farm management and success as well as of household livelihoods between households that have adopted the ITM vaccine for some years with those that have only recently adopted it. Econometric models identify the contribution of ITM adoption to indicator values together with various other determining factors amongst 277 long-term adopters of ITM and the control group of 118 recent adopters as well as 118 matched farmers without access to ITM. The results confirm that ITM adoption is positively associated with all three indicators of herd-productivity considered in this study. However, it does not support any of the three indicators of farm management and only one out of four indicators representing farm success. Nevertheless, the adoption of ITM shows a positive association with all four indicators of household livelihood. Investigating the chain of intermediate outcomes, indicators of herd productivity, such as milk yield, are significantly linked to higher feed expenses, contributing to increased livestock productivity and ultimately income and food availability. Overall, these results therefore support the promotion of ITM as a beneficial technology for the sustainable development of rural livestock keepers.
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Affiliation(s)
- Nils Teufel
- Policies, Institutions and Livelihoods, International Livestock Research Institute, Nairobi, Kenya
| | - Luke Korir
- Policies, Institutions and Livelihoods, International Livestock Research Institute, Nairobi, Kenya
| | - James Hammond
- Sustainable Livestock Systems, International Livestock Research Institute, Nairobi, Kenya
| | - Mark van Wijk
- Sustainable Livestock Systems, International Livestock Research Institute, Nairobi, Kenya
| | - Henry Kiara
- Animal and Human Health, International Livestock Research Institute, Nairobi, Kenya
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Allan FK, Peters AR. Safety and Efficacy of the East Coast Fever Muguga Cocktail Vaccine: A Systematic Review. Vaccines (Basel) 2021; 9:vaccines9111318. [PMID: 34835249 PMCID: PMC8623010 DOI: 10.3390/vaccines9111318] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 10/27/2021] [Accepted: 10/29/2021] [Indexed: 12/04/2022] Open
Abstract
Immunisation of livestock with high quality vaccines is considered an essential approach to controlling many animal diseases. The only currently available commercial vaccine to protect cattle from East Coast fever (ECF), a tick-borne disease caused by Theileria parva, is an unconventional “infection and treatment method” (ITM) involving administration of a combination of live T. parva isolates, referred to as the “Muguga cocktail”, and simultaneous treatment with long-acting oxytetracycline. Veterinary vaccine research and development typically involves studies designed to demonstrate vaccine quality, safety, and efficacy; however, as there were no such purpose-designed registration studies conducted for the Muguga cocktail, evidence for safety and efficacy is solely based on that which is available in the clinical literature. An extensive systematic review was conducted to analyse the evidence available in the literature in order to establish the safety and efficacy of the Muguga cocktail vaccine. A combination of meta-analyses and narrative summaries was conducted. A total of 61 studies met the criteria to be included in the systematic review. The majority of studies demonstrated or reported in favour of the vaccine with regards to safety and efficacy of the Muguga cocktail vaccine. Proximity to buffalo often resulted in reduced vaccine efficacy, and reports of shed and transmission of vaccine components affected the overall interpretation of safety. Better understanding of control options for this devastating livestock disease is important for policymakers and livestock keepers, enabling them to make informed decisions with regards to the health of their animals and their livelihoods.
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Allan FK, Sindoya E, Adam KE, Byamungu M, Lea RS, Lord JS, Mbata G, Paxton E, Mramba F, Torr SJ, Morrison WI, Handel I, Morrison LJ, Auty HK. A cross-sectional survey to establish Theileria parva prevalence and vector control at the wildlife-livestock interface, Northern Tanzania. Prev Vet Med 2021; 196:105491. [PMID: 34562810 PMCID: PMC8573586 DOI: 10.1016/j.prevetmed.2021.105491] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/09/2021] [Revised: 09/02/2021] [Accepted: 09/09/2021] [Indexed: 11/28/2022]
Abstract
East Coast fever (ECF) in cattle is caused by the protozoan parasite Theileria parva, transmitted by Rhipicephalus appendiculatus ticks. In cattle ECF is often fatal, causing annual losses >$500 million across its range. The African buffalo (Syncerus caffer) is the natural host for T. parva but the transmission dynamics between wild hosts and livestock are poorly understood. This study aimed to determine the prevalence of T. parva in cattle, in a 30 km zone adjacent to the Serengeti National Park, Tanzania where livestock and buffalo co-exist, and to ascertain how livestock keepers controlled ECF and other vector-borne diseases of cattle. A randomised cross-sectional cattle survey and questionnaire of vector control practices were conducted. Blood samples were collected from 770 cattle from 48 herds and analysed by PCR to establish T. parva prevalence. Half body tick counts were recorded on every animal. Farmers were interviewed (n = 120; including the blood sampled herds) using a standardised questionnaire to obtain data on vector control practices. Local workshops were held to discuss findings and validate results. Overall prevalence of T. parva in cattle was 5.07% (CI: 3.70-7.00%), with significantly higher prevalence in older animals. Although all farmers reported seeing ticks on their cattle, tick counts were very low with 78% cattle having none. Questionnaire analysis indicated significant acaricide use with 79% and 41% of farmers reporting spraying or dipping with cypermethrin-based insecticides, respectively. Some farmers reported very frequent spraying, as often as every four days. However, doses per animal were often insufficient. These data indicate high levels of acaricide use, which may be responsible for the low observed tick burdens and low ECF prevalence. This vector control is farmer-led and aimed at both tick- and tsetse-borne diseases of livestock. The levels of acaricide use raise concerns regarding sustainability; resistance development is a risk, particularly in ticks. Integrating vaccination as part of this community-based disease control may alleviate acaricide dependence, but increased understanding of the Theileria strains circulating in wildlife-livestock interface areas is required to establish the potential benefits of vaccination.
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Affiliation(s)
- Fiona K Allan
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, United Kingdom.
| | - Emmanuel Sindoya
- Minstry of Livestock and Fisheries, Serengeti District Livestock Office, Mugumu, Tanzania
| | - Katherine E Adam
- Innogen Institute, Science Technology and Innovation Studies; School of Social and Political Science, University of Edinburgh, Old Surgeons' Hall, High School Yards, Edinburgh, United Kingdom
| | | | - Rachel S Lea
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Jennifer S Lord
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - Geofrey Mbata
- Vector and Vector-borne Diseases Research Institute, Tanga, Tanzania
| | - Edith Paxton
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, United Kingdom
| | - Furaha Mramba
- Tanzania Veterinary Laboratory Agency, Dar es Salaam, Tanzania
| | - Stephen J Torr
- Department of Vector Biology, Liverpool School of Tropical Medicine, Liverpool, United Kingdom
| | - W Ivan Morrison
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, United Kingdom
| | - Ian Handel
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, United Kingdom
| | - Liam J Morrison
- Roslin Institute, Royal (Dick) School of Veterinary Studies, University of Edinburgh, Midlothian, EH25 9RG, United Kingdom
| | - Harriet K Auty
- Institute of Biodiversity, Animal Health & Comparative Medicine, College of Medical, Veterinary & Life Sciences, University of Glasgow, United Kingdom (Previously Epidemiology Research Unit, SRUC, Inverness, United Kingdom)
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Cook EAJ, Sitt T, Poole EJ, Ndambuki G, Mwaura S, Chepkwony MC, Latre de Late P, Miyunga AA, van Aardt R, Prettejohn G, Wragg D, Prendergast JGD, Morrison WI, Toye P. Clinical Evaluation of Corridor Disease in Bos indicus (Boran) Cattle Naturally Infected With Buffalo-Derived Theileria parva. Front Vet Sci 2021; 8:731238. [PMID: 34660767 PMCID: PMC8511504 DOI: 10.3389/fvets.2021.731238] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/26/2021] [Accepted: 08/25/2021] [Indexed: 11/17/2022] Open
Abstract
Corridor disease (CD) is a fatal condition of cattle caused by buffalo-derived Theileria parva. Unlike the related condition, East Coast fever, which results from infection with cattle-derived T. parva, CD has not been extensively studied. We describe in detail the clinical and laboratory findings in cattle naturally infected with buffalo-derived T. parva. Forty-six cattle were exposed to buffalo-derived T. parva under field conditions at the Ol Pejeta Conservancy, Kenya, between 2013 and 2018. The first signs of disease observed in all animals were nasal discharge (mean day of onset was 9 days post-exposure), enlarged lymph nodes (10 days post-exposure), and pyrexia (13.7 days post-exposure). Coughing and labored breathing were observed in more than 50% of animals (14 days post-exposure). Less commonly observed signs, corneal edema (22%) and diarrhea (11%), were observed later in the disease progression (19 days post-exposure). All infections were considered clinically severe, and 42 animals succumbed to infection. The mean time to death across all studies was 18.4 days. The mean time from onset of clinical signs to death was 9 days and from pyrexia to death was 4.8 days, indicating a relatively short duration of clinical illness. There were significant relationships between days to death and the days to first temperature (chi2 = 4.00, p = 0.046), and days to peak temperature (chi2 = 25.81, p = 0.001), animals with earlier onset pyrexia died sooner. These clinical indicators may be useful for assessing the severity of disease in the future. All infections were confirmed by the presence of macroschizonts in lymph node biopsies (mean time to parasitosis was 11 days). Piroplasms were detected in the blood of two animals (4%) and 20 (43%) animals seroconverted. In this study, we demonstrate the successful approach to an experimental field study for CD in cattle. We also describe the clinical progression of CD in naturally infected cattle, including the onset and severity of clinical signs and pathology. Laboratory diagnoses based on examination of blood samples are unreliable, and alternatives may not be available to cattle keepers. The rapid development of CD requires recognition of the clinical signs, which may be useful for early diagnosis of the disease and effective intervention for affected animals.
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Affiliation(s)
- Elizabeth A. J. Cook
- Livestock Genetics, International Livestock Research Institute (ILRI), Nairobi, Kenya
- Centre for Tropical Livestock Genetics and Health (CTLGH), International Livestock Research Insitute (ILRI) Kenya, Nairobi, Kenya
| | - Tatjana Sitt
- Livestock Genetics, International Livestock Research Institute (ILRI), Nairobi, Kenya
| | - E. Jane Poole
- Livestock Genetics, International Livestock Research Institute (ILRI), Nairobi, Kenya
| | - Gideon Ndambuki
- Livestock Genetics, International Livestock Research Institute (ILRI), Nairobi, Kenya
| | - Stephen Mwaura
- Livestock Genetics, International Livestock Research Institute (ILRI), Nairobi, Kenya
| | - Maurine C. Chepkwony
- Livestock Genetics, International Livestock Research Institute (ILRI), Nairobi, Kenya
- Centre for Tropical Livestock Genetics and Health (CTLGH), International Livestock Research Insitute (ILRI) Kenya, Nairobi, Kenya
| | - Perle Latre de Late
- Livestock Genetics, International Livestock Research Institute (ILRI), Nairobi, Kenya
- Centre for Tropical Livestock Genetics and Health (CTLGH), International Livestock Research Insitute (ILRI) Kenya, Nairobi, Kenya
| | - Antoinette A. Miyunga
- Livestock Genetics, International Livestock Research Institute (ILRI), Nairobi, Kenya
| | | | | | - David Wragg
- The Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, United Kingdom
- Centre for Tropical Livestock Genetics and Health (CTLGH), Easter Bush Campus, Roslin, United Kingdom
| | - James G. D. Prendergast
- The Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, United Kingdom
- Centre for Tropical Livestock Genetics and Health (CTLGH), Easter Bush Campus, Roslin, United Kingdom
| | - W. Ivan Morrison
- The Roslin Institute, University of Edinburgh, Easter Bush Campus, Roslin, United Kingdom
| | - Philip Toye
- Livestock Genetics, International Livestock Research Institute (ILRI), Nairobi, Kenya
- Centre for Tropical Livestock Genetics and Health (CTLGH), International Livestock Research Insitute (ILRI) Kenya, Nairobi, Kenya
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Evaluating farm-level livestock interventions in low-income countries: a scoping review of what works, how, and why. Anim Health Res Rev 2020; 21:108-121. [PMID: 33261710 DOI: 10.1017/s1466252320000146] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
Livestock interventions can improve nutrition, health, and economic well-being of communities. The objectives of this review were to identify and characterize livestock interventions in developing countries and to assess their effectiveness in achieving development outcomes. A scoping review, guided by a search strategy, was conducted. Papers needed to be written in English, published in peer-reviewed journals, and describe interventions in animal health and production. Out of 2739 publications systematically screened at the title, abstract, and full publication levels, 70 met our inclusion criteria and were considered in the study. Eight relatively high-quality papers were identified and added, resulting in 78 reviewed publications. Only 15 studies used randomized controlled trial designs making it possible to confidently link interventions with the resulting outcomes. Eight studies had human nutrition or health as outcomes, 11 focused on disease control, and four were on livestock production. Eight interventions were considered successful, but only four were scalable. We found good evidence that livestock-transfer programs, leveraging livestock products for nutrition, and helping farmers manage priority diseases, can improve human well-being. Our report highlights challenges in garnering evidence for livestock interventions in developing countries and provides suggestions on how to improve the quantity and quality of future evaluations.
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Atuhaire DK, Muleya W, Mbao V, Bazarusanga T, Gafarasi I, Salt J, Namangala B, Musoke AJ. Sequence diversity of cytotoxic T cell antigens and satellite marker analysis of Theileria parva informs the immunization against East Coast fever in Rwanda. Parasit Vectors 2020; 13:452. [PMID: 32894166 PMCID: PMC7487574 DOI: 10.1186/s13071-020-04322-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Accepted: 08/30/2020] [Indexed: 11/21/2022] Open
Abstract
Background East Coast fever (ECF) caused by Theileria parva is endemic in Rwanda. In this study, the antigenic and genetic diversity of T. parva coupled with immunization and field challenge were undertaken to provide evidence for the introduction of ECF immunization in Rwanda. Methods Blood collected from cattle in the field was screened for T. parva using ELISA and PCR targeting the p104 gene. Tp1 and Tp2 gene sequences were generated from field samples and from Gikongoro and Nyakizu isolates. Furthermore, multilocus genotype data was generated using 5 satellite markers and an immunization challenge trial under field conditions using Muguga cocktail vaccine undertaken. Results Out of 120 samples, 44 and 20 were positive on ELISA and PCR, respectively. Antigenic diversity of the Tp1 and Tp2 gene sequences revealed an abundance of Muguga, Kiambu and Serengeti epitopes in the samples. A further three clusters were observed on both Tp1 and Tp2 phylogenetic trees; two clusters comprising of field samples and vaccine isolates and the third cluster comprising exclusively of Rwanda samples. Both antigens exhibited purifying selection with no positive selection sites. In addition, satellite marker analysis revealed that field samples possessed both shared alleles with Muguga cocktail on all loci and also a higher proportion of unique alleles. The Muguga cocktail (Muguga, Kiambu and Serengeti) genotype compared to other vaccine isolates, was the most represented in the field samples. Further low genetic sub-structuring (FST = 0.037) coupled with linkage disequilibrium between Muguga cocktail and the field samples was observed. Using the above data to guide a field immunization challenge trial comprising 41 immunized and 40 control animals resulted in 85% seroconversion in the immunized animals and an efficacy of vaccination of 81.7%, implying high protection against ECF. Conclusions Antigenic and genetic diversity analysis of T. parva facilitated the use of Muguga cocktail vaccine in field conditions. A protection level of 81.7% was achieved, demonstrating the importance of combining molecular tools with field trials to establish the suitability of implementation of immunization campaigns. Based on the information in this study, Muguga cocktail immunization in Rwanda has a potential to produce desirable results.![]()
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Affiliation(s)
| | - Walter Muleya
- Department of Biomedical Sciences, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka, 10101, Zambia.
| | - Victor Mbao
- International Development Research Centre, Eastern and Southern Africa Regional Office, Nairobi, Kenya
| | | | | | - Jeremy Salt
- Global Alliance for Livestock Veterinary Medicines, Doherty Building, Pentlands Science Park, Bush Loan, Penicuik, Edinburgh, EH26 0PZ, Scotland, UK
| | - Boniface Namangala
- Department of Paraclinical Studies, School of Veterinary Medicine, University of Zambia, P.O. Box 32379, Lusaka, 10101, Zambia
| | - Antony Jim Musoke
- LMK Medical laboratories and consultancies, P.O. Box 33686, Kampala, Uganda
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Bishop RP, Odongo D, Ahmed J, Mwamuye M, Fry LM, Knowles DP, Nanteza A, Lubega G, Gwakisa P, Clausen PH, Obara I. A review of recent research on Theileria parva: Implications for the infection and treatment vaccination method for control of East Coast fever. Transbound Emerg Dis 2020; 67 Suppl 1:56-67. [PMID: 32174044 DOI: 10.1111/tbed.13325] [Citation(s) in RCA: 21] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/26/2019] [Revised: 07/17/2019] [Accepted: 08/05/2019] [Indexed: 12/29/2022]
Abstract
The infection and treatment (ITM) live vaccination method for control of Theileria parva infection in cattle is increasingly being adopted, particularly in Maasai pastoralist systems. Several studies indicate positive impacts on human livelihoods. Importantly, the first detailed protocol for live vaccine production at scale has recently been published. However, quality control and delivery issues constrain vaccination sustainability and deployment. There is evidence that the distribution of T. parva is spreading from endemic areas in East Africa, North into Southern Sudan and West into Cameroon, probably as a result of anthropogenic movement of cattle. It has also recently been demonstrated that in Kenya, T. parva derived from cape buffalo can 'breakthrough' the immunity induced by ITM. However, in Tanzania, breakthrough has not been reported in areas where cattle co-graze with buffalo. It has been confirmed that buffalo in northern Uganda national parks are not infected with T. parva and R. appendiculatus appears to be absent, raising issues regarding vector distribution. Recently, there have been multiple field population genetic studies using variable number tandem repeat (VNTR) sequences and sequencing of antigen genes encoding targets of CD8+ T-cell responses. The VNTR markers generally reveal high levels of diversity. The antigen gene sequences present within the trivalent Muguga cocktail are relatively conserved among cattle transmissible T. parva populations. By contrast, greater genetic diversity is present in antigen genes from T. parva of buffalo origin. There is also evidence from several studies for transmission of components of stocks present within the Muguga cocktail, into field ticks and cattle following induction of a carrier state by immunization. In the short term, this may increase live vaccine effectiveness, through a more homogeneous challenge, but the long-term consequences are unknown.
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Affiliation(s)
- Richard P Bishop
- Department of Veterinary Microbiology & Pathology, Washington State University, Pullman, WA, USA
| | - David Odongo
- School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Jabbar Ahmed
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Micky Mwamuye
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Lindsay M Fry
- Department of Veterinary Microbiology & Pathology, Washington State University, Pullman, WA, USA.,Animal Disease Research Unit, Agricultural Research Service, US Department of Agriculture, Pullman, WA, USA
| | - Donald P Knowles
- Department of Veterinary Microbiology & Pathology, Washington State University, Pullman, WA, USA
| | - Anne Nanteza
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - George Lubega
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Paul Gwakisa
- Genome Science Laboratory, College of Veterinary Medicine and Biomedical Sciences, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Peter-Henning Clausen
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Isaiah Obara
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
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Patel E, Mwaura S, Di Giulio G, Cook EAJ, Lynen G, Toye P. Infection and treatment method (ITM) vaccine against East Coast fever: reducing the number of doses per straw for use in smallholder dairy herds by thawing, diluting and refreezing already packaged vaccine. BMC Vet Res 2019; 15:46. [PMID: 30704455 PMCID: PMC6357393 DOI: 10.1186/s12917-019-1787-y] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2018] [Accepted: 01/17/2019] [Indexed: 11/23/2022] Open
Abstract
Background The Infection and Treatment Method (ITM) of vaccination is the only immunization procedure currently available to protect cattle against East Coast fever (ECF), a tick-transmitted disease responsible for losses of several hundreds of millions of dollars per year in sub-Saharan Africa. The vaccine comprises a homogenized preparation of infected ticks packaged in straws and stored in liquid nitrogen. The current manufacturing protocol results in straws containing 30–40 doses (ILRI 0804), which is impractical for immunizing small herds as found in dairy and smallholder farming systems. The ILRI 0804 SD stabilate was prepared as a 1:5 dilution of the parent stabilate, with the aim of producing vaccine stabilate straws containing between four to eight doses and thus suitable for smallholder farming systems. Infectivity of the diluted stabilate was assessed and the protective efficacy of the diluted stabilate was determined by performing experimental and field immunizations. Results Two groups of six cattle were inoculated with 1 ml of the diluted stabilate at 1:20 (equivalent to the recommended field dose for ILRI 0804, assuming no loss of sporozoite viability during thawing and refreezing) and 1:14 (assuming 30–35% loss of sporozoite viability). Schizonts were detected in all 12 animals, showing viability of sporozoites. Ten animals from the infectivity study and two control animals not previously exposed to T. parva were challenged with the parental ILRI 0804 stabilate. The results show that the two control animals displayed severe ECF reactions and were treated 14 days after challenge. Of the previously infected animals, only one underwent a severe reaction following challenge, a result in accord with the challenge experiments performed previously with the parent stabilate [Ticks Tick-Borne Dis 7:306-314, 2016]. The animal that displayed a severe reaction had no detectable schizonts and did not seroconvert following the initial inoculation with ILRI 0804 SD. In addition, 62 animals immunized under field conditions showed a mean seroconversion rate of 82%. Conclusion The results presented in this article demonstrate that it is possible to prepare straws suitable for use in smallholder herds by thawing, diluting and refreezing already packaged vaccine.
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Affiliation(s)
- Ekta Patel
- International Livestock Research Institute, P.O.Box 30709-00100, Old Naivasha Road, Nairobi, Kenya.
| | - Stephen Mwaura
- International Livestock Research Institute, P.O.Box 30709-00100, Old Naivasha Road, Nairobi, Kenya
| | | | - Elizabeth A J Cook
- International Livestock Research Institute, P.O.Box 30709-00100, Old Naivasha Road, Nairobi, Kenya
| | - Godelieve Lynen
- International Livestock Research Institute, P.O.Box 30709-00100, Old Naivasha Road, Nairobi, Kenya
| | - Philip Toye
- International Livestock Research Institute, P.O.Box 30709-00100, Old Naivasha Road, Nairobi, Kenya.
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Svitek N, Saya R, Awino E, Munyao S, Muriuki R, Njoroge T, Pellé R, Ndiwa N, Poole J, Gilbert S, Nene V, Steinaa L. An Ad/MVA vectored Theileria parva antigen induces schizont-specific CD8 + central memory T cells and confers partial protection against a lethal challenge. NPJ Vaccines 2018; 3:35. [PMID: 30245859 PMCID: PMC6134044 DOI: 10.1038/s41541-018-0073-5] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2018] [Revised: 06/22/2018] [Accepted: 07/02/2018] [Indexed: 01/03/2023] Open
Abstract
The parasite Theileria parva is the causative agent of East Coast fever (ECF), one of the most serious cattle diseases in sub-Saharan Africa, and directly impacts smallholder farmers’ livelihoods. There is an efficient live-parasite vaccine, but issues with transmission of vaccine strains, need of a cold chain, and antibiotics limit its utilization. This has fostered research towards subunit vaccination. Cytotoxic T lymphocytes (CTL) are crucial in combating the infection by lysing T. parva-infected cells. Tp1 is an immunodominant CTL antigen, which induces Tp1-specific responses in 70–80% of cattle of the A18 or A18v haplotype during vaccination with the live vaccine. In this study, human adenovirus serotype 5 (HAd5) and modified vaccinia Ankara (MVA) were assessed for their ability to induce Tp1-specific immunity. Both viral vectors expressing the Tp1 antigen were inoculated in cattle by a heterologous prime-boost vaccination regimen. All 15 animals responded to Tp1 as determined by ELISpot. Of these, 14 reacted to the known Tp1 epitope, assayed by ELISpot and tetramer analyses, with CTL peaking 1-week post-MVA boost. Eleven animals developed CTL with specific cytotoxic activity towards peripheral blood mononuclear cells (PBMC) pulsed with the Tp1 epitope. Moreover, 36% of the animals with a Tp1 epitope-specific response survived a lethal challenge with T. parva 5 weeks post-MVA boost. Reduction of the parasitemia correlated with increased percentages of central memory lymphocytes in the Tp1 epitope-specific CD8+ populations. These results indicate that Tp1 is a promising antigen to include in a subunit vaccine and central memory cells are crucial for clearing the parasite. A vaccine expressing parasitic proteins offers more convenient East Coast fever prophylaxis. Current vaccination for the cattle disease, caused by the parasite Theileria parva and a detriment to sub-Saharan African farmers, involves inconvenient injection with live parasites before antibiotic treatment (ITM). A collaboration led by Nicholas Svitek, of the Kenyan International Livestock Research Institute, designed a candidate to provoke cellular immune responses against the parasitic antigen Tp1—an ITM vaccine candidate. In tests on cattle, 93% created Tp1-targeting T cells, and 33% survived a lethal dose of T. parva. The East Coast fever reduction seen in animals in this research outperformed a recent study and was able to generate the same immune memory cells that ITM inspires to provide long-lasting protection. Future research might integrate more antigens with this Tp1 vaccine to provide more comprehensive protection.
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Affiliation(s)
- Nicholas Svitek
- 1International Livestock Research Institute (ILRI), P.O. Box 30709, 00100 Nairobi, Kenya
| | - Rosemary Saya
- 1International Livestock Research Institute (ILRI), P.O. Box 30709, 00100 Nairobi, Kenya
| | - Elias Awino
- 1International Livestock Research Institute (ILRI), P.O. Box 30709, 00100 Nairobi, Kenya
| | - Stephen Munyao
- 1International Livestock Research Institute (ILRI), P.O. Box 30709, 00100 Nairobi, Kenya
| | - Robert Muriuki
- 1International Livestock Research Institute (ILRI), P.O. Box 30709, 00100 Nairobi, Kenya
| | - Thomas Njoroge
- 1International Livestock Research Institute (ILRI), P.O. Box 30709, 00100 Nairobi, Kenya
| | - Roger Pellé
- 1International Livestock Research Institute (ILRI), P.O. Box 30709, 00100 Nairobi, Kenya
| | - Nicholas Ndiwa
- 1International Livestock Research Institute (ILRI), P.O. Box 30709, 00100 Nairobi, Kenya
| | - Jane Poole
- 1International Livestock Research Institute (ILRI), P.O. Box 30709, 00100 Nairobi, Kenya
| | - Sarah Gilbert
- 2The Jenner Institute, University of Oxford, Old Road Campus Research Building, Roosevelt Drive Oxford, OX3 7DQ UK
| | - Vishvanath Nene
- 1International Livestock Research Institute (ILRI), P.O. Box 30709, 00100 Nairobi, Kenya
| | - Lucilla Steinaa
- 1International Livestock Research Institute (ILRI), P.O. Box 30709, 00100 Nairobi, Kenya
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Byaruhanga C, Oosthuizen M, Collins N, Knobel D. Using participatory epidemiology to investigate management options and relative importance of tick-borne diseases amongst transhumant zebu cattle in Karamoja Region, Uganda. Prev Vet Med 2015; 122:287-97. [DOI: 10.1016/j.prevetmed.2015.10.011] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Revised: 10/18/2015] [Accepted: 10/19/2015] [Indexed: 10/22/2022]
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Kasozi KI, Matovu E, Tayebwa DS, Natuhwera J, Mugezi I, Mahero M. Epidemiology of Increasing Hemo-Parasite Burden in Ugandan Cattle. ACTA ACUST UNITED AC 2014. [DOI: 10.4236/ojvm.2014.410026] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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