Bronsvoort, Mark

Callaby, Rebecca

Kruuk, Loeske

Woolhouse, Mark

Edinburgh Research Explorer

     Edinburgh Research Explorer                                      Evidence for pathogen-pathogen assocaitions in East AfricanZebu cattleCitation for published version:Callaby, R, Kruuk, L, Bronsvoort, M & Woolhouse, M 2014, 'Evidence for pathogen-pathogen assocaitionsin East African Zebu cattle' British Society of Parasitology Autumn Symposium, Salford, United Kingdom,17/09/14 - 18/09/14, .Link:Link to publication record in Edinburgh Research ExplorerDocument Version:Early version, also known as pre-printGeneral rightsCopyright for the publications made accessible via the Edinburgh Research Explorer is retained by the author(s)and / or other copyright owners and it is a condition of accessing these publications that users recognise andabide by the legal requirements associated with these rights.Take down policyThe University of Edinburgh has made every reasonable effort to ensure that Edinburgh Research Explorercontent complies with UK legislation. If you believe that the public display of this file breaches copyright pleasecontact openaccess@ed.ac.uk providing details, and we will remove access to the work immediately andinvestigate your claim.Download date: 05. Apr. 2019Background: • Associations between pathogens may be important determinants of dynamics of infections, but comprehensive data on full pathogen burdens are rare. Little is about whether such associations are generally positive or negative, and about the time scale on which they operate.  • We use the unique longitudinal study, called the Infectious Diseases in East Africa Livestock (IDEAL) Project1 to track the fine-scale dynamics of coinfection by multiple pathogen species to determine: 1. The nature of concurrent associations and of lagged effects, both over short and relatively longer term. 2. The extent to which such associations are driven by other characteristics of either the calf or its environment. Methods: • 548 shorthorn zebu calves in West Kenya were screened every five weeks for the first year of life and the sequence of infections monitored  • 455 survived until 51 weeks of age • Generalised linear mixed models  was built to answer the following question: Aim 1: Is  infection with pathogen A at the present time point (T0) associated with infection with pathogen B at the present time point (T0) or at a previous time point (T-X) or other pathogens (pathogen C etc.) at the present and multiple time points?   • Potential environmental confounders were added into the model to evaluate the extent to which pathogen-pathogen associations are driven by characteristics of the calf or its environment (Aim 2). Summary: 1. 40% of associations between all possible pairwise combinations of pathogens were statistically significant.  2. Both positive (55.6%) and negative (44.4%) associations between pathogens exist.  3. Most associations occurred over short periods of time rather than long-term carry-over effects.  4. The same associations between pathogens remained after accounting for environmental and calf variation. 5. Concurrent or previous infection with the alternative pathogens is associated with a higher risk (or level of protection) for infection with the pathogen of interest than the characteristics of the calf or its environment References: 1Bronsvoort et al. (2013) BMC Veterinary Research Evidence for pathogen-pathogen  associations in East African Zebu cattle  Rebecca Callaby1,2, Loeske Kruuk1, Mark Bronsvoort3, Mark Woolhouse1 1Institute of Evolutionary Biology, University of Edinburgh, UK; 2The James Hutton Institute, Aberdeen, UK;  3The Roslin Institute, University of Edinburgh, UK  rebecca.callaby@ed.ac.uk www.epigroup.biology.ed.ac.uk Study Area Acknowledgements: This work was supported by the Wellcome Trust [WT079445MF] and by a NERC CASE studentship to RC. The IDEAL project was  a collaboration between the Universities of Edinburgh, Pretoria and Nottingham and ILRI, Nairobi.  Descriptive Results: Figure 1: Fraction of calves infected with the pathogen at each age       Figure 2: Cumulative fraction of calves ever infected by the pathogen up until the age stated Results:         Figure 3: A schematic diagram showing the significant associations between pathogens identified from the analysis of pathogen presence at the current visit (T0) or at previous time point, 5 or 10 weeks prior to the current visit (T-5 and T-10, respectively) before accounting for the characteristics of either the calf or its environment  • Positive associations (risk factors, OR >1): Significant at P<0.01 and P<0.001 • Negative associations (protective factors, OR < 1): Significant at P<0.01 and P<0.001 • Arrows: Explanatory variable                    Response variable                                      Interspecific associations                                      Intraspecific associations Figure 4: A schematic diagram showing the significant associations between pathogens identified from the analysis of pathogen presence at the current visit (T0) or at previous time point, 5 or 10 weeks prior to the current visit (T-5 and T-10, respectively) after accounting for the characteristics of either the calf or its environment • Positive associations (risk factors, OR > 1): Significant at P<0.01 and P<0.001 • Negative associations (protective factors, OR <1): Significant at P<0.01 and P<0.001 • Arrows: Explanatory variable                    Response variable                                      Interspecific associations                                      Intraspecific associations                                      Characteristics of either the calf or its environment • Numbers represent the odds ratio and are followed by the 95% confidence interval Aim 2:  Aim 1:  

Evidence for pathogen-pathogen assocaitions in East African Zebu cattle

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Evidence for pathogen-pathogen assocaitions in East African Zebu cattle

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