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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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2
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Iles R, Choi Y, Kagundu S, Gatumu H. Estimating Willingness-to-Pay for a Livestock Vaccine Among the Marginalized: The Role of Reflective Thought in Discrete Choice Experiments. Prev Vet Med 2022; 201:105592. [DOI: 10.1016/j.prevetmed.2022.105592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2021] [Revised: 12/23/2021] [Accepted: 02/02/2022] [Indexed: 11/26/2022]
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3
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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: 17] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [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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Abstract
Background: Livestock mortality impacts farmer livelihoods and household nutrition. Capturing trends in livestock mortality at localised or national levels is essential to planning, monitoring and evaluating interventions and programs aimed at decreasing mortality rates. However, livestock mortality data is disparate, and indicators used have not been standardised. This review aims to assess livestock mortality indicator definitions reported in literature, and define the ages where mortality has greatest impact. Methods: A systematic review was conducted, limited to articles focussed on mortality of cattle, sheep and goats. Peer-reviewed articles in Web of Science until year 2020 were assessed for inclusion of age-based definitions for mortality indicators and data on age distribution of mortality. Indicator definitions for each species were collated and similar terms and age groups most targeted were compared. The cumulative distribution of age at mortality was compared across studies graphically where possible; otherwise, age patterns for mortality were collated. Results: Most studies reported mortality risk rather than rate, and there was little agreement between indicator definitions used in the literature. The most common indicators reported were perinatal and neonatal mortality in cattle, and for perinatal, neonatal and pre-weaning mortality indicators for sheep and goats. Direct comparison of age distribution of mortality was only possible for cattle, which found that approximately 80% of all mortalities within the first 12 months had occurred by six months of age. A significant finding of the study is the variation in age groups for which mortality is reported, which impedes the comparison of mortality risk across studies, particularly for sheep and goats. Conclusions: This study demonstrates the importance and value of standardising mortality risk indicators for general use, including a young stock mortality risk indicator measuring mortality in the highest risk period of birth to six months of age in cattle, sheep and goats.
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Affiliation(s)
- Johanna T. Wong
- Supporting Evidence-Based Interventions - Livestock, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Ciara Vance
- Supporting Evidence-Based Interventions - Livestock, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
| | - Andrew Peters
- Supporting Evidence-Based Interventions - Livestock, University of Edinburgh, Easter Bush, Midlothian, EH25 9RG, UK
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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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Nanteza A, Obara I, Kasaija P, Mwega E, Kabi F, Salih DA, Njahira M, Njuguna J, Odongo D, Bishop RP, Skilton RA, Ahmed J, Clausen PH, Lubega GW. Antigen gene and variable number tandem repeat (VNTR) diversity in Theileria parva parasites from Ankole cattle in south-western Uganda: Evidence for conservation in antigen gene sequences combined with extensive polymorphism at VNTR loci. Transbound Emerg Dis 2020; 67 Suppl 1:99-107. [PMID: 32174038 DOI: 10.1111/tbed.13311] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2019] [Revised: 06/28/2019] [Accepted: 07/22/2019] [Indexed: 12/23/2022]
Abstract
Theileria parva is a tick-transmitted apicomplexan protozoan parasite that infects lymphocytes of cattle and African Cape buffalo (Syncerus caffer), causing a frequently fatal disease of cattle in eastern, central and southern Africa. A live vaccination procedure, known as infection and treatment method (ITM), the most frequently used version of which comprises the Muguga, Serengeti-transformed and Kiambu 5 stocks of T. parva, delivered as a trivalent cocktail, is generally effective. However, it does not always induce 100% protection against heterologous parasite challenge. Knowledge of the genetic diversity of T. parva in target cattle populations is therefore important prior to extensive vaccine deployment. This study investigated the extent of genetic diversity within T. parva field isolates derived from Ankole (Bos taurus) cattle in south-western Uganda using 14 variable number tandem repeat (VNTR) satellite loci and the sequences of two antigen-encoding genes that are targets of CD8+T-cell responses induced by ITM, designated Tp1 and Tp2. The findings revealed a T. parva prevalence of 51% confirming endemicity of the parasite in south-western Uganda. Cattle-derived T. parva VNTR genotypes revealed a high degree of polymorphism. However, all of the T. parva Tp1 and Tp2 alleles identified in this study have been reported previously, indicating that they are widespread geographically in East Africa and highly conserved.
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Affiliation(s)
- Anne Nanteza
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Isaiah Obara
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Paul Kasaija
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Elisa Mwega
- Faculty of Veterinary Medicine, Sokoine University of Agriculture, Morogoro, Tanzania
| | - Fredrick Kabi
- College of Natural Sciences, Makerere University, Kampala, Uganda
| | | | - Moses Njahira
- Biosciences East and Central Africa (BecA), Nairobi, Kenya
| | - Joyce Njuguna
- Biosciences East and Central Africa (BecA), Nairobi, Kenya
| | - David Odongo
- School of Biological Sciences, University of Nairobi, Nairobi, Kenya
| | - Richard P Bishop
- Department of Veterinary Microbiology and Pathology, Washington State University, Pullman, WA, USA
| | - Rob A Skilton
- Biosciences East and Central Africa (BecA), Nairobi, Kenya
| | - Jabbar Ahmed
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
| | - Peter-Henning Clausen
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - George W Lubega
- College of Veterinary Medicine, Animal Resources and Biosecurity, Makerere University, Kampala, Uganda
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Kimeli P, VanLeeuwen J, Gitau GK, Heider LC, McKenna SL, Greenwood SJ. Management factors associated with time-to-onset and fecal egg/oocyst counts of gastrointestinal parasites in heifer calves on Kenyan smallholder farms. Vet Parasitol 2020; 283:109174. [PMID: 32629206 DOI: 10.1016/j.vetpar.2020.109174] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2020] [Revised: 06/20/2020] [Accepted: 06/22/2020] [Indexed: 01/27/2023]
Abstract
A prospective cohort study on zero-grazed smallholder dairy farms was conducted to determine factors associated with onset and counts of gastrointestinal parasitism in heifer calves. The researchers recruited 187 newborn heifer calves from 150 farms in Kenya. Over 16 months, farm visits every two months were used to collect rectal fecal samples and animal- and farm-level measures. Fecal samples underwent centrifugal fecal flotation with Sheather's sugar to determine counts of strongyle-type eggs and coccidia oocysts. Cox proportional hazard (Cox PH) analysis and mixed-effects negative binomial (MeNB) regression determined factors associated with time-to-onset and counts of strongyle-type eggs and coccidia oocysts, respectively (P < 0.05). The incidence rate of strongyles was 0.0011 cases/animal-day while coccidia was 0.0073 cases /animal-day. Incidence risks of strongyles and coccidia over the study period were 28.3 % (53/187) and 87.7 % (164/187), respectively. For infected calves, median time-to-onset for strongyles and coccidia was 78 (interquartile-range: IQR 38-117) and 43 (IQR 29-92) days, respectively. In the final Cox PH model for strongyles, breed (Ayrshires and Jerseys) and weaned calves had a greater hazard of infection than Friesians and preweaned calves, respectively. Calf tethering outside the pen was associated with a higher hazard of strongyle infection. In the final Cox PH model for coccidia, calves with watery and/or hemorrhagic diarrhea had a higher hazard compared with those with hard or soft feces. Weaning status and birth weight (kg) were time-varying covariates, leading to increased hazard over time. In the final MeNB model for strongyles, weaned animals had higher counts than those still on milk. In an interaction variable, the predicted strongyle-type egg counts increased with longer duration of farm operation when herd size was less than five cattle, but decreased when herd size was more than five. In the final MeNB model for coccidia, calves sometimes tethered outside their pens had higher counts than those continuously enclosed in the pen. Calf pen floors with either scant manure or moderate slurry had higher predicted counts than those on a clean pen floor. Calves with watery or hemorrhagic diarrhea and fed fresh Napier grass (Pennisetum purpureum) had higher counts compared with soft or hard feces and those not given fresh Napier, respectively. In an interaction variable, calves experiencing diarrhea and raised on elevated slatted floors had lower oocyst counts compared with those having diarrhea but not on elevated floors. The identified management practices associated with onset and counts of gastrointestinal parasitism should be considered in control efforts.
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Affiliation(s)
- P Kimeli
- Department of Health Management, Atlantic Veterinary College, UPEI, Canada.
| | - J VanLeeuwen
- Department of Health Management, Atlantic Veterinary College, UPEI, Canada
| | - G K Gitau
- Department of Clinical Studies, Faculty of Veterinary Medicine, University of Nairobi, Kenya
| | - L C Heider
- Department of Health Management, Atlantic Veterinary College, UPEI, Canada
| | - S L McKenna
- Department of Health Management, Atlantic Veterinary College, UPEI, Canada
| | - S J Greenwood
- Department of Biomedical Sciences, Atlantic Veterinary College, UPEI, Canada
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Reflections on IDEAL: What we have learnt from a unique calf cohort study. Prev Vet Med 2020; 181:105062. [PMID: 32615453 PMCID: PMC7456772 DOI: 10.1016/j.prevetmed.2020.105062] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/29/2020] [Revised: 05/07/2020] [Accepted: 06/10/2020] [Indexed: 11/20/2022]
Abstract
The year 2020 marks a decade since the final visit was made in the ‘Infectious Diseases of East African Livestock’ (IDEAL) project. However, data generation from samples obtained during this ambitious longitudinal study still continues. As the project launches its extensive open-access database and biobank to the scientific community, we reflect on the challenges overcome, the knowledge gained, and the advantages of such a project. We discuss the legacy of the IDEAL project and how it continues to generate evidence since being adopted by the Centre for Tropical Livestock Genetics and Health (CTLGH). We also examine the impact of the IDEAL project, from the authors perspective, for each of the stakeholders (the animal, the farmer, the consumer, the policy maker, the funding body, and the researcher and their institution) involved in the project and provide recommendations for future researchers who are interested in running longitudinal field studies.
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9
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Obara I, Ahmed J, Bishop R, Clausen PH. Towards wider and more efficient deployment of live vaccines for control of Theileria parva and Theileria annulata infections in cattle in eastern, central and northern Africa. Transbound Emerg Dis 2020; 67 Suppl 1:5-7. [PMID: 32174042 DOI: 10.1111/tbed.13359] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/30/2019] [Revised: 09/02/2019] [Accepted: 09/10/2019] [Indexed: 11/29/2022]
Affiliation(s)
- Isaiah Obara
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Jabbar Ahmed
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
| | - Richard Bishop
- Department of Veterinary Microbiology & Pathology, Washington State University, Pullman, Washington
| | - Peter-Henning Clausen
- Institute for Parasitology and Tropical Veterinary Medicine, Freie Universität Berlin, Berlin, Germany
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Hines SA, Brandvold J, Mealey RH, Call DR, Graça T. Exposure to ambient air causes degradation and decreased in vitro potency of buparvaquone and parvaquone. Vet Parasitol 2020; 277S:100023. [PMID: 32904749 PMCID: PMC7458381 DOI: 10.1016/j.vpoa.2020.100023] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2019] [Revised: 02/04/2020] [Accepted: 02/05/2020] [Indexed: 02/04/2023]
Abstract
Buparvaquone and parvaquone are used to treat livestock infected with Theileria spp. Air exposure had a significant impact on the stability of buparvaquone and parvaquone. Parvaquone was more stable than buparvaquone. Drug degradation was related with loss of potency by an in vitro viability assay.
Buparvaquone and parvaquone are hydroxynaphthoquinone compounds commonly used to treat livestock infected with Theileria species such as T. parva and T. annulata. In many (sub)tropical regions, chromatic changes in medicines can result from extreme environmental conditions and improper drug storage or handling, raising the possibility of drug degradation and loss of potency. We evaluated the effects of UV light, elevated temperature, and atmospheric air on the stability and potency of both buparvaquone and parvaquone by using a combination of high performance liquid chromatography (HPLC) and a T. equi based in vitro parasite growth inhibition assay (to measure potency). Aliquots (1 ml; 3 replicates per treatment) of each compound were subjected to a variety of treatments that varied in duration and intensity followed by HPLC and potency assays. Exposure to ambient air for 50 days was correlated with a significant loss of potency for both buparvaquone (4535%, P < 0.05) and parvaquone (247%, P < 0.05), while elevated temperature (37°C) and UV light exposure (24 h) had no significant impact (P > 0.05). The decrease in potency of both buparvaquone and parvaquone correlated with drug degradation (r = -0.74 and -0.88, respectively) as measured by HPLC. In practice, if there is headspace present in the vial, then ambient air will invariably enter the vial and contribute to degradation of these compounds. Such degradation may contribute to increasing drug resistance, economic losses for farmers, and animal welfare concerns for animals that are treated for Theileria infections.
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Affiliation(s)
- Siddra A Hines
- Department of Veterinary Microbiology and Pathology, Pullman, WA 99164-7090, USA
| | - Jacob Brandvold
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164-7090, USA
| | - Robert H Mealey
- Department of Veterinary Microbiology and Pathology, Pullman, WA 99164-7090, USA
| | - Douglas R Call
- Department of Veterinary Microbiology and Pathology, Pullman, WA 99164-7090, USA; Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164-7090, USA
| | - Telmo Graça
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164-7090, USA.
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Cheruiyot EK, Bett RC, Amimo JO, Zhang Y, Mrode R, Mujibi FDN. Signatures of Selection in Admixed Dairy Cattle in Tanzania. Front Genet 2018; 9:607. [PMID: 30619449 PMCID: PMC6305962 DOI: 10.3389/fgene.2018.00607] [Citation(s) in RCA: 38] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/06/2018] [Accepted: 11/19/2018] [Indexed: 01/07/2023] Open
Abstract
Multiple studies have investigated selection signatures in domestic cattle and other species. However, there is a dearth of information about the response to selection in genomes of highly admixed crossbred cattle in relation to production and adaptation to tropical environments. In this study, we evaluated 839 admixed crossbred cows sampled from two major dairy regions in Tanzania namely Rungwe and Lushoto districts, in order to understand their genetic architecture and detect genomic regions showing preferential selection. Animals were genotyped at 150,000 SNP loci using the Geneseek Genomic Profiler (GGP) High Density (HD) SNP array. Population structure analysis showed a large within-population genetic diversity in the study animals with a high degree of variation in admixture ranging between 7 and 100% taurine genes (dairyness) of mostly Holstein and Friesian ancestry. We explored evidence of selection signatures using three statistical methods (iHS, XP-EHH, and pcadapt). Selection signature analysis identified 108 candidate selection regions in the study population. Annotation of these regions yielded interesting genes potentially under strong positive selection including ABCG2, ABCC2, XKR4, LYN, TGS1, TOX, HERC6, KIT, PLAG1, CHCHD7, NCAPG, and LCORL that are involved in multiple biological pathways underlying production and adaptation processes. Several candidate selection regions showed an excess of African taurine ancestral allele dosage. Our results provide further useful insight into potential selective sweeps in the genome of admixed cattle with possible adaptive and productive importance. Further investigations will be necessary to better characterize these candidate regions with respect to their functional significance to tropical adaptations for dairy cattle.
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Affiliation(s)
- Evans Kiptoo Cheruiyot
- Department of Animal Production, College of Agriculture and Veterinary Sciences, University of Nairobi, Nairobi, Kenya.,USOMI Limited, Nairobi, Kenya
| | - Rawlynce Cheruiyot Bett
- Department of Animal Production, College of Agriculture and Veterinary Sciences, University of Nairobi, Nairobi, Kenya
| | - Joshua Oluoch Amimo
- Department of Animal Production, College of Agriculture and Veterinary Sciences, University of Nairobi, Nairobi, Kenya
| | - Yi Zhang
- College of Animal Science and Technology, China Agricultural University, Beijing, China
| | - Raphael Mrode
- International Livestock Research Institute, Nairobi, Kenya.,Scotland's Rural College, Edinburgh, United Kingdom
| | - Fidalis D N Mujibi
- USOMI Limited, Nairobi, Kenya.,Nelson Mandela African Institute of Science and Technology, Arusha, Tanzania
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Mcelwain TF, Thumbi SM. Animal pathogens and their impact on animal health, the economy, food security, food safety and public health. REV SCI TECH OIE 2018; 36:423-433. [PMID: 30152474 DOI: 10.20506/rst.36.2.2663] [Citation(s) in RCA: 27] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022]
Abstract
Animal pathogens attract attention in both the livestock and public health sectors for their impacts on socio-economics, food safety and security, and human health. These impacts are felt at the household, national, regional and global levels. Whereas the World Organisation for Animal Health (OIE) has identified 118 animal diseases as notifiable, based on their potential for impact on trade, there is a selected subset that have been classified as posing a greater threat to countries due to unique characteristics, such as being highly transmissible, spreading rapidly within and between countries, and requiring cooperation between several countries to control their spread or exclude them. While these 'transboundary diseases' are endemic in much of the world, particularly the developing nations, many countries are classified as disease free. Following the terrorist events of 11 September 2001 in the United States, a small group of zoonotic pathogens and a group of animal-specific pathogens (those that cause what are referred to as `high-consequence foreign animal diseases'), were classified as high-risk, biothreat 'select agents'. Rather than providing a comprehensive review of all animal pathogens, the authors briefly review the impact of these high-risk biothreat agents on animal health, the economy, food security and safety, and public health, using highly pathogenic avian influenza, foot and mouth disease and brucellosis as examples. They focus on the impact of these diseases in the context of high-income countries and low- and middle-income countries, comparing and contrasting their impact at the national and individual household levels.
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13
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Cross-sectional prevalence of gastrointestinal helminth parasites in cattle in Lira District, Uganda. Trop Anim Health Prod 2018; 50:1599-1604. [PMID: 29704091 DOI: 10.1007/s11250-018-1600-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/20/2017] [Accepted: 04/19/2018] [Indexed: 10/17/2022]
Abstract
The prevalence of gastrointestinal helminth parasite infections and associated risk factors was studied in traditionally reared East African short-horned zebu cattle in Lira District, Uganda. Fecal samples were collected from 205 cattle and coprologically examined for the presence of helminth parasites using the simple salt flotation method complemented with the sedimentation method. The overall prevalence of gastrointestinal helminth parasites (GITPs) in cattle in Adekokwok, Lira District, was 32.2%. Of these, 12 (18.18%) were cases of mixed infections mainly of Amphistomes and other GITPs. Paramphistomum was the most prevalent parasite contributing up to 45.5% of infections, followed by Fasciola, Toxocara, strongyles, Trichuris, and Nematodirus, in descending order of abundance. GITP infections were not influenced by the sex of cattle, while infection with Toxocara was associated with cattle age. The mean body condition score (BCS) for all animals studied was 2.37 ± 0.07. A low BCS was associated with gastrointestinal helminth infections. Nevertheless, other factors such as nutritional stress are likely to augment the effects of parasites in the traditional agro-pastoral system particularly in the dry season and should therefore be considered when using the cattle body condition as an indicator of parasitism.
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Leahy E, Bronsvoort B, Gamble L, Gibson A, Kaponda H, Mayer D, Mazeri S, Shervell K, Sargison N. Proof of concept of faecal egg nematode counting as a practical means of veterinary engagement with planned livestock health management in a lower income country. Ir Vet J 2017; 70:16. [PMID: 28588763 PMCID: PMC5457739 DOI: 10.1186/s13620-017-0094-9] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 05/30/2017] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND The wellbeing and livelihood of farmers in impoverished regions of the world is intrinsically linked to the health and welfare of their livestock; hence improved animal health is a pragmatic component of poverty alleviation. Prerequisite knowledge and understanding of the animal health challenges facing cattle keepers in Malawi is constrained by the lack of veterinary infrastructure, which inevitably accompanies under-resourced rural development in a poor country. METHODS We collaborated with public and private paraveterinary services to locate 62 village Zebu calves and 60 dairy co-operative calves dispersed over a wide geographical area. All calves were visited twice about 2 to 3 weeks apart, when they were clinically examined and faecal samples were collected. The calves were treated with 7.5 mg/kg of a locally-available albendazole drench on the first visit, and pre- and post- treatment trichostrongyle and Toxocara faecal egg counts were performed using a modified McMaster method. RESULTS Our clinical findings point towards a generally poor level of animal health, implying a role of ticks and tick-transmitted diseases in village calves and need for improvement in neonatal calf husbandry in the dairy co-operative holdings. High faecal trichostrongyle egg counts were not intuitive, based on our interpretation of the animal management information that was provided. This shows the need for better understanding of nematode parasite epidemiology within the context of local husbandry and environmental conditions. The albendazole anthelmintic was effective against Toxocara, while efficacy against trichostrongyle nematodes was poor in both village and dairy co-operative calves, demonstrating the need for further research to inform sustainable drug use. CONCLUSIONS Here we describe the potential value of faecal nematode egg counting as a platform for communicating with and gaining access to cattle keepers and their animals, respectively, in southern Malawi, with the aim of providing informative background knowledge and understanding that may aid in the establishment of effective veterinary services in an under-resourced community.
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Affiliation(s)
- Eithne Leahy
- Worldwide Veterinary Service, 14 Wimborne Street, Cranborne, Dorset BH21 5PP UK
| | - Barend Bronsvoort
- Royal (Dick) School of Veterinary Studies, Easter Bush Veterinary Centre, University of Edinburgh, Roslin, Midlothian EH25 9RG UK.,The Epidemiology, Economics and Risk Assessment (EERA) Group, The Roslin Institute, Easter Bush, Roslin, Midlothian EH26 9RG UK
| | - Luke Gamble
- Worldwide Veterinary Service, 14 Wimborne Street, Cranborne, Dorset BH21 5PP UK
| | | | - Henderson Kaponda
- Blantyre District Agricultural Development Office, Kunthembwe EPA, Malawi
| | - Dagmar Mayer
- Worldwide Veterinary Service, 14 Wimborne Street, Cranborne, Dorset BH21 5PP UK
| | - Stella Mazeri
- Royal (Dick) School of Veterinary Studies, Easter Bush Veterinary Centre, University of Edinburgh, Roslin, Midlothian EH25 9RG UK.,The Epidemiology, Economics and Risk Assessment (EERA) Group, The Roslin Institute, Easter Bush, Roslin, Midlothian EH26 9RG UK
| | | | - Neil Sargison
- Royal (Dick) School of Veterinary Studies, Easter Bush Veterinary Centre, University of Edinburgh, Roslin, Midlothian EH25 9RG UK
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Ward JM, Youssef SA, Treuting PM. Why Animals Die: An Introduction to the Pathology of Aging. Vet Pathol 2017; 53:229-32. [PMID: 26936750 DOI: 10.1177/0300985815612151] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022]
Affiliation(s)
- J M Ward
- Global VetPathology, Montgomery Village, MD, USA
| | - S A Youssef
- Dutch Molecular Pathology Center, Faculty of Veterinary Medicine, Department of Pathobiology, Utrecht University, Utrecht, The Netherlands
| | - P M Treuting
- School of Medicine, Department of Comparative Medicine, University of Washington, Seattle, WA, USA
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16
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Marsh TL, Yoder J, Deboch T, McElwain TF, Palmer GH. Livestock vaccinations translate into increased human capital and school attendance by girls. SCIENCE ADVANCES 2016; 2:e1601410. [PMID: 27990491 PMCID: PMC5156515 DOI: 10.1126/sciadv.1601410] [Citation(s) in RCA: 31] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/21/2016] [Accepted: 10/26/2016] [Indexed: 05/22/2023]
Abstract
To fulfill the United Nation's Sustainable Development Goals (SDGs), it is useful to understand whether and how specific agricultural interventions improve human health, educational opportunity, and food security. In sub-Saharan Africa, 75% of the population is engaged in small-scale farming, and 80% of these households keep livestock, which represent a critical asset and provide protection against economic shock. For the 50 million pastoralists, livestock play an even greater role. Livestock productivity for pastoralist households is constrained by multiple factors, including infectious disease. East Coast fever, a tick-borne protozoal disease, is the leading cause of calf mortality in large regions of eastern and Southern Africa. We examined pastoralist decisions to adopt vaccination against East Coast fever and the economic outcomes of adoption. Our estimation strategy provides an integrated model of adoption and impact that includes direct effects of vaccination on livestock health and productivity outcomes, as well as indirect effects on household expenditures, such as child education, food, and health care. On the basis of a cross-sectional study of Kenyan pastoralist households, we found that vaccination provides significant net income benefits from reduction in livestock mortality, increased milk production, and savings by reducing antibiotic and acaricide treatments. Households directed the increased income resulting from East Coast fever vaccination into childhood education and food purchase. These indirect effects of livestock vaccination provide a positive impact on rural, livestock-dependent families, contributing to poverty alleviation at the household level and more broadly to achieving SDGs.
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Affiliation(s)
- Thomas L. Marsh
- School of Economic Sciences, Washington State University, Pullman, WA 99164, USA
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164, USA
- Corresponding author.
| | - Jonathan Yoder
- School of Economic Sciences, Washington State University, Pullman, WA 99164, USA
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164, USA
| | - Tesfaye Deboch
- School of Economic Sciences, Washington State University, Pullman, WA 99164, USA
| | - Terry F. McElwain
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164, USA
| | - Guy H. Palmer
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164, USA
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17
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Byaruhanga C, Collins NE, Knobel D, Kabasa W, Oosthuizen MC. Endemic status of tick-borne infections and tick species diversity among transhumant zebu cattle in Karamoja Region, Uganda: Support for control approaches. VETERINARY PARASITOLOGY- REGIONAL STUDIES AND REPORTS 2016; 1-2:21-30. [PMID: 31018404 DOI: 10.1016/j.vprsr.2015.11.001] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2015] [Revised: 11/13/2015] [Accepted: 11/30/2015] [Indexed: 10/22/2022]
Abstract
We conducted a study to investigate tick species diversity, seroprevalence of antibodies to Anaplasma marginale and Theileria parva, and the risk factors for these infections among cattle under a transhumant production system in Karamoja Region, Uganda, from November 2013 through January 2014. Twenty herds were randomly selected from 20 purposively-selected superherds. Semi-structured interviews and piling for annual proportion of tick-borne disease (TBD) cases in different age groups, with pastoralist groups, clinical examinations and field observations were employed to obtain information related to the epidemiology of TBDs. Ticks were collected and identified from whole body inspections of at least seven systematically selected cattle in each herd. Concurrently, serum was collected from 397 cattle. Antibodies to A. marginale were detected by MSP-5 competitive inhibition enzyme-linked immunosorbent assay, and to T. parva by indirect fluorescent antibody test. Clinical examinations and informant interviews showed that TBDs affected all age groups of cattle. Tick species that have not been reported in recent studies from other parts of Uganda were collected, namely Amblyomma lepidum, Hyalomma truncatum, Amblyomma gemma, and Rhipicephalus pulchellus. Out of the 10,923 ticks collected, Rhipicephalus appendiculatus (54.4%) was the most abundant species followed by Rhipicephalus (Boophilus) decoloratus (17.7%), Amblyomma variegatum (12%) and A. lepidum (11.6%). Two-thirds of the sampled cattle had moderate (37.3%, 11-50 ticks) to abundant (28.6%, >50 ticks) numbers of ticks. Seroprevalence of A. marginale was high (86.6%, 95% confidence interval [CI] 80.8%-91.8%), while that of T. parva was low (14.6%, 95% CI 7.1%-22.4%). Cattle of 5-12months (18.3%, Odds ratio [OR]=4.1) and 13-24months (30.3%, OR=8.0) were more likely to be seropositive for T. parva than those >24months. For A. marginale, cattle of 13-24months (92.4%, OR=2.7) and >24months (89.7%, OR=2.0) were more likely to be seropositive than those 5-12months. There was a significant difference (p<0.001, OR=6.5) in the proportion of T. parva seropositive animals between Moroto (24.5%) and Kotido districts (4.8%), but not for A. marginale. In conclusion, the low seroprevalence for T. parva, possibly due to limited exposure in calves, may suggest a high likelihood of ECF in cattle. High seroprevalence for A. marginale suggests that a high proportion of cattle were exposed to infection. The findings provide knowledge of epidemiology of TBDs in Karamoja cattle and support for strategic control and improvement of cattle productivity.
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Affiliation(s)
- C Byaruhanga
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa; National Agricultural Research Organisation, P.O. Box 259, Entebbe, Uganda.
| | - N E Collins
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - D Knobel
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - W Kabasa
- College of Veterinary Medicine, Animal Resources and Bio-security, Makerere University, P.O. Box 7062, Kampala, Uganda
| | - M C Oosthuizen
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
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Woolhouse MEJ, Thumbi SM, Jennings A, Chase-Topping M, Callaby R, Kiara H, Oosthuizen MC, Mbole-Kariuki MN, Conradie I, Handel IG, Poole EJ, Njiiri E, Collins NE, Murray G, Tapio M, Auguet OT, Weir W, Morrison WI, Kruuk LEB, Bronsvoort BMDC, Hanotte O, Coetzer K, Toye PG. Co-infections determine patterns of mortality in a population exposed to parasite infection. SCIENCE ADVANCES 2015; 1:e1400026. [PMID: 26601143 PMCID: PMC4643819 DOI: 10.1126/sciadv.1400026] [Citation(s) in RCA: 43] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/10/2014] [Accepted: 02/11/2015] [Indexed: 05/11/2023]
Abstract
Many individual hosts are infected with multiple parasite species, and this may increase or decrease the pathogenicity of the infections. This phenomenon is termed heterologous reactivity and is potentially an important determinant of both patterns of morbidity and mortality and of the impact of disease control measures at the population level. Using infections with Theileria parva (a tick-borne protozoan, related to Plasmodium) in indigenous African cattle [where it causes East Coast fever (ECF)] as a model system, we obtain the first quantitative estimate of the effects of heterologous reactivity for any parasitic disease. In individual calves, concurrent co-infection with less pathogenic species of Theileria resulted in an 89% reduction in mortality associated with T. parva infection. Across our study population, this corresponds to a net reduction in mortality due to ECF of greater than 40%. Using a mathematical model, we demonstrate that this degree of heterologous protection provides a unifying explanation for apparently disparate epidemiological patterns: variable disease-induced mortality rates, age-mortality profiles, weak correlations between the incidence of infection and disease (known as endemic stability), and poor efficacy of interventions that reduce exposure to multiple parasite species. These findings can be generalized to many other infectious diseases, including human malaria, and illustrate how co-infections can play a key role in determining population-level patterns of morbidity and mortality due to parasite infections.
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Affiliation(s)
- Mark E. J. Woolhouse
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Ashworth Laboratories, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, UK
- Corresponding author. E-mail:
| | - Samuel M. Thumbi
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Ashworth Laboratories, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, UK
- Paul G. Allen School for Global Animal Health, Washington State University, Pullman, WA 99164–7090, USA
| | - Amy Jennings
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, The Roslin Building, Easter Bush, Midlothian EH25 9RG, UK
- The Roslin Institute, University of Edinburgh, The Roslin Building, Easter Bush, Midlothian EH25 9RG, UK
| | - Margo Chase-Topping
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Ashworth Laboratories, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, UK
| | - Rebecca Callaby
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Ashworth Laboratories, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, UK
- The James Hutton Institute, Craigiebuckler, Aberdeen AB15 8QH, UK
| | - Henry Kiara
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
| | - Marinda C. Oosthuizen
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Mary N. Mbole-Kariuki
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
- School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Ilana Conradie
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Ian G. Handel
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, The Roslin Building, Easter Bush, Midlothian EH25 9RG, UK
- The Roslin Institute, University of Edinburgh, The Roslin Building, Easter Bush, Midlothian EH25 9RG, UK
| | - E. Jane Poole
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
| | - Evalyne Njiiri
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
| | - Nicola E. Collins
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Gemma Murray
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Ashworth Laboratories, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, UK
| | - Miika Tapio
- Natural Resources Institute Finland (Luke), Green technology, FI-31600 Jokioinen, Finland
| | - Olga Tosas Auguet
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Ashworth Laboratories, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, UK
| | - Willie Weir
- Henry Wellcome Building, Institute of Biodiversity, Animal Health and Comparative Medicine, Garscube Campus, College of Medical, Veterinary and Life Sciences, University of Glasgow, Bearsden Road, Glasgow G61 1QH, UK
| | - W. Ivan Morrison
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, The Roslin Building, Easter Bush, Midlothian EH25 9RG, UK
- The Roslin Institute, University of Edinburgh, The Roslin Building, Easter Bush, Midlothian EH25 9RG, UK
| | - Loeske E. B. Kruuk
- Centre for Immunity, Infection and Evolution, University of Edinburgh, Ashworth Laboratories, Kings Buildings, West Mains Road, Edinburgh EH9 3JT, UK
- Division of Evolution, Ecology and Genetics, Research School of Biology, The Australian National University, Canberra, Australian Capital Territory 0200, Australia
| | - B. Mark de C. Bronsvoort
- Royal (Dick) School of Veterinary Studies, University of Edinburgh, The Roslin Building, Easter Bush, Midlothian EH25 9RG, UK
- The Roslin Institute, University of Edinburgh, The Roslin Building, Easter Bush, Midlothian EH25 9RG, UK
| | - Olivier Hanotte
- School of Life Sciences, University of Nottingham, University Park, Nottingham NG7 2RD, UK
| | - Koos Coetzer
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Philip G. Toye
- International Livestock Research Institute, P.O. Box 30709, Nairobi 00100, Kenya
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Abstract
Parasite burden varies widely between individuals within a population, and can covary with multiple aspects of individual phenotype. Here we investigate the sources of variation in faecal strongyle eggs counts, and its association with body weight and a suite of haematological measures, in a cohort of indigenous zebu calves in Western Kenya, using relatedness matrices reconstructed from single nucleotide polymorphism (SNP) genotypes. Strongyle egg count was heritable (h2 = 23·9%, s.e. = 11·8%) and we also found heritability of white blood cell counts (WBC) (h2 = 27·6%, s.e. = 10·6%). All the traits investigated showed negative phenotypic covariances with strongyle egg count throughout the first year: high worm counts were associated with low values of WBC, red blood cell count, total serum protein and absolute eosinophil count. Furthermore, calf body weight at 1 week old was a significant predictor of strongyle EPG at 16–51 weeks, with smaller calves having a higher strongyle egg count later in life. Our results indicate a genetic basis to strongyle EPG in this population, and also reveal consistently strong negative associations between strongyle infection and other important aspects of the multivariate phenotype.
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20
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Gorsich EE, Ezenwa VO, Jolles AE. Nematode-coccidia parasite co-infections in African buffalo: Epidemiology and associations with host condition and pregnancy. Int J Parasitol Parasites Wildl 2014; 3:124-34. [PMID: 25161911 PMCID: PMC4142258 DOI: 10.1016/j.ijppaw.2014.05.003] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2014] [Revised: 05/06/2014] [Accepted: 05/28/2014] [Indexed: 01/13/2023]
Abstract
Co-infections are common in natural populations and interactions among co-infecting parasites can significantly alter the transmission and host fitness costs of infection. Because both exposure and susceptibility vary over time, predicting the consequences of parasite interactions on host fitness and disease dynamics may require detailed information on their effects across different environmental (season) and host demographic (age, sex) conditions. This study examines five years of seasonal health and co-infection patterns in African buffalo (Syncerus caffer). We use data on two groups of gastrointestinal parasites, coccidia and nematodes, to test the hypothesis that co-infection and season interact to influence (1) parasite prevalence and intensity and (2) three proxies for host fitness: host pregnancy, host body condition, and parasite aggregation. Our results suggest that season-dependent interactions between nematodes and coccidia affect the distribution of infections. Coccidia prevalence, coccidia intensity and nematode prevalence were sensitive to factors that influence host immunity and exposure (age, sex, and season) but nematode intensity was most strongly predicted by co-infection with coccidia and its interaction with season. The influence of co-infection on host body condition and parasite aggregation occurred in season-dependent manner. Co-infected buffalo in the early wet season were in worse condition, had a less aggregated distribution of nematode parasites, and lower nematode infection intensity than buffalo infected with nematodes alone. We did not detect an effect of infection or co-infection on host pregnancy. These results suggest that demographic and seasonal variation may mediate the effects of parasites, and their interactions, on the distribution and fitness costs of infection.
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Affiliation(s)
- Erin E. Gorsich
- Department of Integrative Biology, Oregon State University, Corvallis, USA
| | - Vanessa O. Ezenwa
- Odum School of Ecology and Department of Infectious Diseases, College of Veterinary Medicine, University of Georgia, Athens, USA
| | - Anna E. Jolles
- Department of Integrative Biology, Oregon State University, Corvallis, USA
- Department of Biomedical Sciences, Oregon State University, Corvallis, USA
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VanderWaal K, Omondi GP, Obanda V. Mixed-host aggregations and helminth parasite sharing in an East African wildlife-livestock system. Vet Parasitol 2014; 205:224-32. [PMID: 25086496 DOI: 10.1016/j.vetpar.2014.07.015] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2013] [Revised: 05/20/2014] [Accepted: 07/10/2014] [Indexed: 10/25/2022]
Abstract
Parasitic infections transmitted between livestock and wildlife pose a significant risk to wildlife conservation efforts and constrain livestock productivity in tropical regions of the world. Gastrointestinal helminths are among the most ubiquitous parasites, and many parasites within this taxon can readily infect a wide range of host species. Factors shaping bidirectional transmission of parasites in wildlife-livestock systems are understudied. In this study, we investigate the prevalence and diversity of helminth infections in an East African community of wild and domestic ungulates. We also identify pairs of host species between which transmission may be possible based on shared parasite taxa, and explore the role of multi-host aggregations in shaping patterns of parasite sharing. Helminth taxa detected included Trichostrongylus, Trichuris, Paramphistomum, Skrjabinema, Strongyloides, Strongylus spp., and other strongyle-type nematodes. We found that nearly 50% of individuals harbored at least one species of helminth, but certain species, such as zebra and impala, exhibited higher prevalence than others. High canopy feeders, like giraffe, had lower prevalence than hosts feeding at medium and low foraging heights. For helminths, patterns of parasite sharing likely emerge from shared space use, which is mediated in part by mixed-species aggregations. The frequency with which host species associated together in mixed-species aggregations was positively correlated with the number of parasite taxa shared. We suggest that variation among species in their tendency to form mixed-species aggregations creates heterogeneity in transmission opportunities, and consequently, parasite sharing across ungulate species. These results enhance our understanding of the role of spatiotemporal relationships among host species in shaping parasite communities in mixed wildlife-livestock grazing systems.
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Affiliation(s)
- Kimberly VanderWaal
- Animal Behavior Graduate Group, University of California, Davis, 1 Shields Avenue, Davis, CA 95616, USA; Wangari Maathai Institute for Peace and Environmental Studies, University of Nairobi, PO Box 29053-00625, Nairobi, Kenya.
| | - George Paul Omondi
- Wildlife Management Department, Ol Pejeta Conservancy, Private Bag - 10400, Nanyuki, Kenya
| | - Vincent Obanda
- Veterinary Services Department, Kenya Wildlife Service, P.O. Box 40241-00100, Nairobi, Kenya
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A longitudinal assessment of the serological response to Theileria parva and other tick-borne parasites from birth to one year in a cohort of indigenous calves in western Kenya. Parasitology 2014; 141:1289-98. [PMID: 24838078 PMCID: PMC4113304 DOI: 10.1017/s003118201400050x] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
Abstract
Tick-borne diseases are a major impediment to improved productivity of livestock in sub-Saharan Africa. Improved control of these diseases would be assisted by detailed epidemiological data. Here we used longitudinal, serological data to determine the patterns of exposure to Theileria parva, Theileria mutans, Babesia bigemina and Anaplasma marginale from 548 indigenous calves in western Kenya. The percentage of calves seropositive for the first three parasites declined from initial high levels due to maternal antibody until week 16, after which the percentage increased until the end of the study. In contrast, the percentage of calves seropositive for T. mutans increased from week 6 and reached a maximal level at week 16. Overall 423 (77%) calves seroconverted to T. parva, 451 (82%) to T. mutans, 195 (36%) to B. bigemina and 275 (50%) to A. marginale. Theileria parva antibody levels were sustained following infection, in contrast to those of the other three haemoparasites. Three times as many calves seroconverted to T. mutans before seroconverting to T. parva. No T. parva antibody response was detected in 25 calves that died of T. parva infection, suggesting that most deaths due to T. parva are the result of acute disease from primary exposure.
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Parasite co-infections and their impact on survival of indigenous cattle. PLoS One 2014; 9:e76324. [PMID: 24586220 PMCID: PMC3930515 DOI: 10.1371/journal.pone.0076324] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2013] [Accepted: 08/23/2013] [Indexed: 12/14/2022] Open
Abstract
In natural populations, individuals may be infected with multiple distinct pathogens at a time. These pathogens may act independently or interact with each other and the host through various mechanisms, with resultant varying outcomes on host health and survival. To study effects of pathogens and their interactions on host survival, we followed 548 zebu cattle during their first year of life, determining their infection and clinical status every 5 weeks. Using a combination of clinical signs observed before death, laboratory diagnostic test results, gross-lesions on post-mortem examination, histo-pathology results and survival analysis statistical techniques, cause-specific aetiology for each death case were determined, and effect of co-infections in observed mortality patterns. East Coast fever (ECF) caused by protozoan parasite Theileria parva and haemonchosis were the most important diseases associated with calf mortality, together accounting for over half (52%) of all deaths due to infectious diseases. Co-infection with Trypanosoma species increased the hazard for ECF death by 6 times (1.4-25; 95% CI). In addition, the hazard for ECF death was increased in the presence of Strongyle eggs, and this was burden dependent. An increase by 1000 Strongyle eggs per gram of faeces count was associated with a 1.5 times (1.4-1.6; 95% CI) increase in the hazard for ECF mortality. Deaths due to haemonchosis were burden dependent, with a 70% increase in hazard for death for every increase in strongyle eggs per gram count of 1000. These findings have important implications for disease control strategies, suggesting a need to consider co-infections in epidemiological studies as opposed to single-pathogen focus, and benefits of an integrated approach to helminths and East Coast fever disease control.
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Toye P, Handel I, Gray J, Kiara H, Thumbi S, Jennings A, van Wyk IC, Ndila M, Hanotte O, Coetzer K, Woolhouse M, Bronsvoort M. Maternal antibody uptake, duration and influence on survival and growth rate in a cohort of indigenous calves in a smallholder farming system in western Kenya. Vet Immunol Immunopathol 2013; 155:129-34. [PMID: 23838470 PMCID: PMC3740236 DOI: 10.1016/j.vetimm.2013.06.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2013] [Revised: 05/31/2013] [Accepted: 06/03/2013] [Indexed: 11/07/2022]
Abstract
The passive transfer of antibodies from dams to offspring via colostrum is believed to play an important role in protecting neonatal mammals from infectious disease. The study presented here investigates the uptake of colostrum by 548 calves in western Kenya maintained under smallholder farming, an important agricultural system in eastern Africa. Serum samples collected from the calves and dams at recruitment (within the first week of life) were analysed for the presence of antibodies to four tick-borne haemoparasites: Anaplasma marginale, Babesia bigemina, Theileria mutans and Theileria parva. The analysis showed that at least 89.33% of dams were seropositive for at least one of the parasites, and that 93.08% of calves for which unequivocal results were available showed evidence of having received colostrum. The maternal antibody was detected up until 21 weeks of age in the calves. Surprisingly, there was no discernible difference in mortality or growth rate between calves that had taken colostrum and those that had not. The results are also important for interpretation of serosurveys of young calves following natural infection or vaccination.
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Affiliation(s)
- Philip Toye
- The International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya
| | - Ian Handel
- The Roslin Institute, University of Edinburgh, Easter Bush EH25 9RG, UK
| | - Julia Gray
- College of Veterinary Medicine, Cornell University, Ithaca, NY 14853, USA
| | - Henry Kiara
- The International Livestock Research Institute (ILRI), P.O. Box 30709, Nairobi 00100, Kenya
| | - Samuel Thumbi
- Centre for Immunology, Infection & Evolution, University of Edinburgh, EH9 3JT, UK
| | - Amy Jennings
- Centre for Immunology, Infection & Evolution, University of Edinburgh, EH9 3JT, UK
| | - Ilana Conradie van Wyk
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Mary Ndila
- School of Biology, University of Nottingham, Nottingham NG7 2RD, UK
| | - Olivier Hanotte
- School of Biology, University of Nottingham, Nottingham NG7 2RD, UK
| | - Koos Coetzer
- Department of Veterinary Tropical Diseases, Faculty of Veterinary Science, University of Pretoria, Private Bag X04, Onderstepoort 0110, South Africa
| | - Mark Woolhouse
- Centre for Immunology, Infection & Evolution, University of Edinburgh, EH9 3JT, UK
| | - Mark Bronsvoort
- The Roslin Institute, University of Edinburgh, Easter Bush EH25 9RG, UK
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