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Livestock movement informs the risk of disease spread in traditional production systems in East Africa. Sci Rep 2021; 11:16375. [PMID: 34385539 PMCID: PMC8361167 DOI: 10.1038/s41598-021-95706-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2021] [Accepted: 07/01/2021] [Indexed: 11/22/2022] Open
Abstract
In Africa, livestock are important to local and national economies, but their productivity is constrained by infectious diseases. Comprehensive information on livestock movements and contacts is required to devise appropriate disease control strategies; yet, understanding contact risk in systems where herds mix extensively, and where different pathogens can be transmitted at different spatial and temporal scales, remains a major challenge. We deployed Global Positioning System collars on cattle in 52 herds in a traditional agropastoral system in western Serengeti, Tanzania, to understand fine-scale movements and between-herd contacts, and to identify locations of greatest interaction between herds. We examined contact across spatiotemporal scales relevant to different disease transmission scenarios. Daily cattle movements increased with herd size and rainfall. Generally, contact between herds was greatest away from households, during periods with low rainfall and in locations close to dipping points. We demonstrate how movements and contacts affect the risk of disease spread. For example, transmission risk is relatively sensitive to the survival time of different pathogens in the environment, and less sensitive to transmission distance, at least over the range of the spatiotemporal definitions of contacts that we explored. We identify times and locations of greatest disease transmission potential and that could be targeted through tailored control strategies.
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Squarzoni-Diaw C, Arsevska E, Kalthoum S, Hammami P, Cherni J, Daoudi A, Karim Laoufi M, Lezaar Y, Rachid K, Seck I, Ould Elmamy B, Yahya B, Dufour B, Hendrikx P, Cardinale E, Muñoz F, Lancelot R, Coste C. Using a participatory qualitative risk assessment to estimate the risk of introduction and spread of transboundary animal diseases in scarce-data environments: A Spatial Qualitative Risk Analysis applied to foot-and-mouth disease in Tunisia 2014-2019. Transbound Emerg Dis 2021; 68:1966-1978. [PMID: 33174371 DOI: 10.1111/tbed.13920] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/01/2020] [Revised: 10/22/2020] [Accepted: 11/01/2020] [Indexed: 12/01/2022]
Abstract
This article presents a participative and iterative qualitative risk assessment framework that can be used to evaluate the spatial variation of the risk of infectious animal disease introduction and spread on a national scale. The framework was developed through regional training action workshops and field activities. The active involvement of national animal health services enabled the identification, collection and hierarchization of risk factors. Quantitative data were collected in the field, and expert knowledge was integrated to adjust the available data at regional level. Experts categorized and combined the risk factors into ordinal levels of risk per epidemiological unit to ease implementation of risk-based surveillance in the field. The framework was used to perform a qualitative assessment of the risk of introduction and spread of foot-and-mouth disease (FMD) in Tunisia as part of a series of workshops held between 2015 and 2018. The experts in attendance combined risk factors such as epidemiological status, transboundary movements, proximity to the borders and accessibility to assess the risk of FMD outbreaks in Tunisia. Out of the 2,075 Tunisian imadas, 23 were at a very high risk of FMD introduction, mainly at the borders; and 59 were at a very high risk of FMD spread. To validate the model, the results were compared to the FMD outbreaks notified by Tunisia during the 2014 FMD epizootic. Using a spatial Poisson model, a significant alignment between the very high and high-risk categories of spread and the occurrence of FMD outbreaks was shown. The relative risk of FMD occurrence was thus 3.2 higher for imadas in the very high and high spread risk categories than for imadas in the low and negligible spread risk categories. Our results show that the qualitative risk assessment framework can be a useful decision support tool for risk-based disease surveillance and control, in particular in scarce-data environments.
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Affiliation(s)
- Cécile Squarzoni-Diaw
- CIRAD, UMR ASTRE, Sainte Clotilde, La Réunion, France.,ASTRE, Univ Montpellier, CIRAD, INRAE, Montpellier, France
| | - Elena Arsevska
- ASTRE, Univ Montpellier, CIRAD, INRAE, Montpellier, France.,CIRAD, UMR ASTRE, Montpellier, France
| | - Sana Kalthoum
- Centre national de veille zoosanitaire (CNVZ), Tunis, Tunisia
| | - Pachka Hammami
- CIRAD, UMR ASTRE, Sainte Clotilde, La Réunion, France.,ASTRE, Univ Montpellier, CIRAD, INRAE, Montpellier, France
| | - Jamel Cherni
- Centre national de veille zoosanitaire (CNVZ), Tunis, Tunisia
| | - Assia Daoudi
- Ministry of Agriculture and Rural Development, Alger, Algeria
| | | | - Yassir Lezaar
- Office National, Sécurité Sanitaire des Produits Alimentaires (ONSSA), Rabat, Morocco
| | - Kechna Rachid
- Office National, Sécurité Sanitaire des Produits Alimentaires (ONSSA), Rabat, Morocco
| | - Ismaila Seck
- Food and Agricultural organization of the United Nations (FAO), Regional Office for Africa (RAF), Accra, Ghana.,Ministère de l'Élevage et des Productions Animales, Dakar, Sénégal
| | - Bezeid Ould Elmamy
- Office National de Recherche et de Développement de l'Elevage (ONARDEL), Nouakchott, Mauritania.,Regional Diseases Surveillance System Enhancement (REDISSE) in West Africa, Nouakchott, Mauritania
| | - Barry Yahya
- Office National de Recherche et de Développement de l'Elevage (ONARDEL), Nouakchott, Mauritania
| | - Barbara Dufour
- USC EPIMAI Unit, Anses, Ecole Nationale Vétérinaire d'Alfort, Maisons-Alfort, France
| | - Pascal Hendrikx
- CIRAD, UMR ASTRE, Montpellier, France.,ENSV-France Vétérinaire International, Lyon 69, France
| | - Eric Cardinale
- CIRAD, UMR ASTRE, Sainte Clotilde, La Réunion, France.,ASTRE, Univ Montpellier, CIRAD, INRAE, Montpellier, France
| | - Facundo Muñoz
- ASTRE, Univ Montpellier, CIRAD, INRAE, Montpellier, France.,CIRAD, UMR ASTRE, Montpellier, France
| | - Renaud Lancelot
- ASTRE, Univ Montpellier, CIRAD, INRAE, Montpellier, France.,CIRAD, UMR ASTRE, Montpellier, France
| | - Caroline Coste
- ASTRE, Univ Montpellier, CIRAD, INRAE, Montpellier, France.,CIRAD, UMR ASTRE, Montpellier, France
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Omondi GP, Obanda V, VanderWaal K, Deen J, Travis DA. Animal movement in a pastoralist population in the Maasai Mara Ecosystem in Kenya and implications for pathogen spread and control. Prev Vet Med 2021; 188:105259. [PMID: 33453561 DOI: 10.1016/j.prevetmed.2021.105259] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/12/2020] [Revised: 12/28/2020] [Accepted: 12/31/2020] [Indexed: 12/13/2022]
Abstract
Livestock movements are important drivers for infectious disease transmission. However, paucity of such data in pastoralist communities in rangeland ecosystems limits our understanding of their dynamics and hampers disease surveillance and control. The aim of this study was to investigate animal movement networks in a pastoralist community in Kenya, and assess network-based strategies for disease control. We used network analysis to characterize five types of between-village animal movement networks. We then evaluated implications of these networks for disease spread and control by quantifying topological changes in the network associated with targeted and random removal of nodes. To construct these networks, data were collected using standardized questionnaires (N = 165 households) from communities living within the Maasai Mara Ecosystem in southwestern Kenya. Our analyses show that the Maasai Mara National Reserve (MMNR), a protected wildlife area, was critical for maintaining village connectivity in the agistment network (dry season grazing), with MMNR-adjacent villages being highly utilized during the dry season. In terms of disease dynamics, the network-based basic reproduction number, R0, was sufficient to allow disease invasion in all the five networks, and removal of villages based on degree or betweenness was not efficient in reducing R0. However, we show that villages with high degree or betweenness may play an important role in maintaining network connectivity, which may not be captured by assessment of R0 alone. Such villages may function as potential "firebreaks." For example, targeted removal of highly connected village nodes was more effective at fragmenting each network than random removal of nodes, indicating that network-based targeting of interventions such as vaccination could potentially disrupt transmission pathways in the ecosystem. In conclusion, this work shows that animal movements have the potential to shape patterns of disease transmission in this ecosystem, with targeted interventions being a practical and efficient measure for disease control.
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Affiliation(s)
- George P Omondi
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States; Ahadi Veterinary Resource Center, P.O. Box 51002, 00200, Nairobi, Kenya.
| | - Vincent Obanda
- Ahadi Veterinary Resource Center, P.O. Box 51002, 00200, Nairobi, Kenya; Veterinary Services Department, Kenya Wildlife Service, P.O. Box 40241, 00100, Nairobi, Kenya
| | - Kimberly VanderWaal
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - John Deen
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
| | - Dominic A Travis
- Department of Veterinary Population Medicine, College of Veterinary Medicine, University of Minnesota, St. Paul, MN, United States
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de Glanville WA, Davis A, Allan KJ, Buza J, Claxton JR, Crump JA, Halliday JEB, Johnson PCD, Kibona TJ, Mmbaga BT, Swai ES, Uzzell CB, Yoder J, Sharp J, Cleaveland S. Classification and characterisation of livestock production systems in northern Tanzania. PLoS One 2020; 15:e0229478. [PMID: 33378382 PMCID: PMC7773236 DOI: 10.1371/journal.pone.0229478] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/06/2020] [Accepted: 12/07/2020] [Indexed: 01/03/2023] Open
Abstract
Livestock keepers in sub-Saharan Africa face a range of pressures, including climate change, land loss, restrictive policies, and population increase. Widespread adaptation in response can lead to the emergence of new, non-traditional typologies of livestock production. We sought to characterise livestock production systems in two administrative regions in northern Tanzania, an area undergoing rapid social, economic, and environmental change. Questionnaire and spatial data were collected from 404 livestock-keeping households in 21 villages in Arusha and Manyara Regions in 2016. Multiple factor analysis and hierarchical cluster analysis were used to classify households into livestock production systems based on household-level characteristics. Adversity-based indicators of vulnerability, including reports of hunger, illness, and livestock, land and crop losses were compared between production systems. Three distinct clusters emerged through this process. The ethnic, environmental and livestock management characteristics of households in each cluster broadly mapped onto traditional definitions of 'pastoral', 'agro-pastoral' and 'smallholder' livestock production in the study area, suggesting that this quantitative classification system is complementary to more qualitative classification methods. Our approach allowed us to demonstrate a diversity in typologies of livestock production at small spatial scales, with almost half of study villages comprising more than one production system. We also found indicators of change within livestock production systems, most notably the adoption of crop agriculture in the majority of pastoral households. System-level heterogeneities in vulnerability were evident, with agro-pastoral households most likely to report hunger and pastoral households most likely to report illness in people and livestock, and livestock losses. We demonstrate that livestock production systems can provide context for assessing household vulnerability in northern Tanzania. Policy initiatives to improve household and community well-being should recognise the continuing diversity of traditional livestock production systems in northern Tanzania, including the diversity that can exist at small spatial scales.
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Affiliation(s)
- William A. de Glanville
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Alicia Davis
- School of Social and Political Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Kathryn J. Allan
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Joram Buza
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - John R. Claxton
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - John A. Crump
- Centre for International Health, University of Otago, Dunedin, New Zealand
- Division of Infectious Diseases and International Health, Duke University Medical Center, Durham, NC, United States of America
- Duke Global Health Institute, Duke University, Durham, NC, United States of America
- Kilimanjaro Christian Medical University College, Tumaini University, Moshi, Tanzania
| | - Jo E. B. Halliday
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Paul C. D. Johnson
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Tito J. Kibona
- Nelson Mandela African Institution of Science and Technology, Arusha, Tanzania
| | - Blandina T. Mmbaga
- Duke Global Health Institute, Duke University, Durham, NC, United States of America
- Kilimanjaro Christian Medical University College, Tumaini University, Moshi, Tanzania
- Kilimanjaro Clinical Research Institute, Moshi, Tanzania
| | - Emmanuel S. Swai
- Department of Veterinary Services, Ministry of Livestock and Fisheries, Dhaka, Tanzania
| | - Christopher B. Uzzell
- School of Geographical and Earth Sciences, University of Glasgow, Glasgow, United Kingdom
| | - Jonathan Yoder
- School of Economic Sciences, Washington State University, Pullman, WA, United States of America
| | - Jo Sharp
- School of Geography and Sustainable Development, University of St Andrews, St Andrews, United Kingdom
| | - Sarah Cleaveland
- Institute of Biodiversity, Animal Health and Comparative Medicine, College of Medical, Veterinary and Life Sciences, University of Glasgow, Glasgow, United Kingdom
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