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  1. Article ; Online: Seasonality and pathogen transmission in pastoral cattle contact networks

    Kimberly VanderWaal / Marie Gilbertson / Sharon Okanga / Brian F. Allan / Meggan E. Craft

    Royal Society Open Science, Vol 4, Iss

    2017  Volume 12

    Abstract: Capturing heterogeneity in contact patterns in animal populations is essential for understanding the spread of infectious diseases. In contrast to other regions of the world in which livestock movement networks are integral to pathogen prevention and ... ...

    Abstract Capturing heterogeneity in contact patterns in animal populations is essential for understanding the spread of infectious diseases. In contrast to other regions of the world in which livestock movement networks are integral to pathogen prevention and control policies, contact networks are understudied in pastoral regions of Africa due to the challenge of measuring contact among mobile herds of cattle whose movements are driven by access to resources. Furthermore, the extent to which seasonal changes in the distribution of water and resources impacts the structure of contact networks in cattle is uncertain. Contact networks may be more conducive to pathogen spread in the dry season due to congregation at limited water sources. Alternatively, less abundant forage may result in decreased pathogen transmission due to competitive avoidance among herds, as measured by reduced contact rates. Here, we use GPS technology to concurrently track 49 free-roaming cattle herds within a semi-arid region of Kenya, and use these data to characterize seasonal contact networks and model the spread of a highly infectious pathogen. This work provides the first empirical data on the local contact network structure of mobile herds based on quantifiable contact events. The contact network demonstrated high levels of interconnectivity. An increase in contacts near to water resources in the dry season resulted in networks with both higher contact rates and higher potential for pathogen spread than in the wet season. Simulated disease outbreaks were also larger in the dry season. Results support the hypothesis that limited water resources enhance connectivity and transmission within contact networks, as opposed to reducing connectivity as a result of competitive avoidance. These results cast light on the impact of seasonal heterogeneity in resource availability on predicting pathogen transmission dynamics, which has implications for other free-ranging wild and domestic populations.
    Keywords network analysis ; infectious disease ; animal movement ; ecology ; pathogen ; Science ; Q
    Language English
    Publishing date 2017-01-01T00:00:00Z
    Publisher The Royal Society
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  2. Article: GPS tracking cattle as a monitoring tool for conservation and management

    Schieltz, Jennifer M / Brian F Allan / Daniel I Rubenstein / Sharon Okanga

    African journal of range & forage science. 2017 July 3, v. 34, no. 3

    2017  

    Abstract: The emergence of GPS technology has resulted in significant advances in the ease and flexibility of studying animal movement patterns, yet barriers remain to the widespread use of GPS units for animal tracking. Here, we developed a low-cost, logistically ...

    Abstract The emergence of GPS technology has resulted in significant advances in the ease and flexibility of studying animal movement patterns, yet barriers remain to the widespread use of GPS units for animal tracking. Here, we developed a low-cost, logistically simple approach, deploying small and inexpensive GPS units to monitor cattle movements and habitat use and to assess the impact of cattle grazing on vegetation. Cattle were collared with i-gotU loggers to track fine-scale and broad-scale movements within an integrated ecosystem (cattle and wildlife) in Laikipia, central Kenya. At the fine scale, cattle exerted a significant impact on vegetation quantity and quality; increasing grazing intensity showed a negative relationship to grass height, but a positive correlation to green-up after rain. At the broad scale, cattle movement density varied notably by herd type and habitat availability, with acacia woodland and savanna grassland habitats used most predominantly. Overall, these small GPS loggers provided a flexible and relatively cheap method of tracking cattle movements, and demonstrated potential for collaring of cattle as a tool for monitoring ecosystem health and assisting management decisions.
    Keywords Acacia ; cattle ; ecosystems ; environmental health ; global positioning systems ; grasses ; grasslands ; grazing intensity ; habitat preferences ; habitats ; herds ; monitoring ; rain ; savannas ; wildlife ; woodlands ; Kenya
    Language English
    Dates of publication 2017-0703
    Size p. 173-177.
    Publishing place Taylor & Francis
    Document type Article
    ZDB-ID 1160792-0
    ISSN 1727-9380 ; 1022-0119 ; 0256-6702
    ISSN (online) 1727-9380
    ISSN 1022-0119 ; 0256-6702
    DOI 10.2989/10220119.2017.1387175
    Database NAL-Catalogue (AGRICOLA)

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    In stock of ZB MED Bonn / Germany

    Z 5057: Show issues

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  3. Article ; Online: Correction

    Sharon Okanga / Graeme S Cumming / Philip A R Hockey / Lisa Nupen / Jeffrey L Peters

    PLoS ONE, Vol 10, Iss 5, p e

    Host specificity and co-speciation in avian haemosporidia in the Western Cape, South Africa.

    2015  Volume 0129188

    Keywords Medicine ; R ; Science ; Q
    Language English
    Publishing date 2015-01-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  4. Article ; Online: Host specificity and co-speciation in avian haemosporidia in the Western Cape, South Africa.

    Sharon Okanga / Graeme S Cumming / Philip A R Hockey / Lisa Nupen / Jeffrey L Peters

    PLoS ONE, Vol 9, Iss 2, p e

    2014  Volume 86382

    Abstract: Host and pathogen ecology are often closely linked, with evolutionary processes often leading to the development of host specificity traits in some pathogens. Host specificity may range from 'generalist', where pathogens infect any available competent ... ...

    Abstract Host and pathogen ecology are often closely linked, with evolutionary processes often leading to the development of host specificity traits in some pathogens. Host specificity may range from 'generalist', where pathogens infect any available competent host; to 'specialist', where pathogens repeatedly infect specific host species or families. Avian malaria ecology in the region remains largely unexplored, despite the presence of vulnerable endemic avian species. We analysed the expression of host specificity in avian haemosporidia, by applying a previously developed host specificity index to lineages isolated from wetland passerines in the Western Cape, South Africa. Parasite lineages were isolated using PCR and identified when possible using matching lineages deposited in GenBank and in MalAvi. Parasitic clades were constructed from phylogenetic trees consisting of Plasmodium and Haemoproteus lineages. Isolated lineages matched some strains of Plasmodium relictum, P. elongatum, Haemoproteus sylvae and H. lanii. Plasmodium lineages infected a wide range of hosts from several avian families in a generalist pattern of infection. Plasmodium spp. also exhibited an infection trend according to host abundance rather than host species. By contrast, Haemoproteus lineages were typically restricted to one or two host species or families, and displayed higher host fidelity than Plasmodium spp. The findings confirm that a range of host specificity traits are exhibited by avian haemosporidia in the region. The traits show the potential to not only impact infection prevalence within specific host species, but also to affect patterns of infection at the community level.
    Keywords Medicine ; R ; Science ; Q
    Language English
    Publishing date 2014-01-01T00:00:00Z
    Publisher Public Library of Science (PLoS)
    Document type Article ; Online
    Database BASE - Bielefeld Academic Search Engine (life sciences selection)

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  5. Article: Can integrating wildlife and livestock enhance ecosystem services in central Kenya?

    Allan, Brian F / Heather Tallis / Rebecca Chaplin‐Kramer / Steven Huckett / Virginia A Kowal / Jessica Musengezi / Sharon Okanga / Richard S Ostfeld / Jennifer Schieltz / Charles M Warui / Spencer A Wood / Felicia Keesing

    Frontiers in ecology and the environment. 2017 Aug., v. 15, no. 6

    2017  

    Abstract: Because wildlife and livestock compete for grazing resources, biodiversity conservation and livestock ranching typically have been portrayed as conflicting uses of African savannas. Here, we offer an alternative perspective by describing a savanna ... ...

    Abstract Because wildlife and livestock compete for grazing resources, biodiversity conservation and livestock ranching typically have been portrayed as conflicting uses of African savannas. Here, we offer an alternative perspective by describing a savanna ecosystem in central Kenya where wildlife and livestock exhibit a suite of potential positive interactions. For example, treating livestock with an acaricide offers the unintended benefit of removing ticks from the landscape, a result that has now been shown to occur at both large and small scales. When humans derive financial benefits both from wildlife (through tourism) and from livestock (through food production), they may achieve greater economic stability than when income is derived solely from one source. The integrated management of wildlife and livestock can simultaneously improve human health and wildlife conservation. Optimization of human and wildlife benefits will require the management of ecological and socioeconomic trade‐offs when conflicts occur between stakeholders.
    Keywords acaricides ; biodiversity conservation ; ecosystem services ; ecosystems ; food production ; grazing ; human health ; humans ; income ; landscapes ; livestock ; ranching ; savannas ; stakeholders ; ticks ; tourism ; wildlife ; wildlife management ; Kenya
    Language English
    Dates of publication 2017-08
    Size p. 328-335.
    Publishing place John Wiley & Sons, Ltd
    Document type Article
    Note JOURNAL ARTICLE
    ZDB-ID 2110853-5
    ISSN 1540-9309 ; 1540-9295
    ISSN (online) 1540-9309
    ISSN 1540-9295
    DOI 10.1002/fee.1501
    Database NAL-Catalogue (AGRICOLA)

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    In stock of ZB MED Bonn / Germany

    Z 7542: Show issues

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    This service is chargeable due to the Delivery terms set by subito. Orders including an article and supplementary material will be classified as separate orders. In these cases, fees will be demanded for each order.

    Inter-library loan at ZB MED

    Your chosen title can be delivered directly to ZB MED Cologne location if you are registered as a user at ZB MED Cologne.

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