People

Meet our group members.

Professor Amy B. Pedersen FRSE

Photo of Amy with blue skies and a hilly landscape with houses and trees in the background

Principal Investigator

C.V.

  • 2022 - present: Personal Chair in Disease Ecology, School of Biological Sciences, University of Edinburgh
  • 2017 - 2022: Reader,  School of Biological Sciences, University of Edinburgh
  • 2013 - 2018: Chancellor's Fellow,  School of Biological Sciences, University of Edinburgh
  • 2009 - 2013: Advanced Research Fellow, Wellcome Trust funded Centre for Immunity, Infection & Evolution, Institute of Evolutionary Biology,  School of Biological Sciences, University of Edinburgh
  • 2006 - 2009: Royal Society International Independent Research Fellow, Department of Animal and Plant Sciences, University of Sheffield
  • 2005 - 2006: Postdoctoral Research Associate, Institute of Ecology, University of Georgia (Adviser: Prof Sonia Altizer)
  • 2000 - 2005: Ph.D., Department of Biology, University of Virginia, Thesis: Intestinal parasites, acorn masts, and population dynamics of Peromyscus (Adviser: Prof Janis Antonovics),
  • 1995 - 1999: B.S. Biology, George Washington University, USA

Research interests

My research focuses on the importance of multi-host parasites and in particular on the factors that drive disease emergence. Much research in disease ecology and evolution focuses on the one host–one parasite framework. And yet, in natural systems, hosts are usually co-infected by multiple parasites, and many parasites can infect several host species. I focus on understanding host-parasite interactions in this realistic context. My past and current work has sought to significantly expand this perspective by (i) evaluating the interactions that occur between co-infecting parasites and their implications for host health and (ii) to advance our knowledge of how multi-host parasites contribute to disease emergence.

Publications

Lab Personnel

Sarah Wolf

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Postdoctoral Research Associate 

C.V.

  • 05/2023 – present: Postdoctoral Research Associate, School of Biological Sciences, University of Edinburgh, position funded by NERC grant “The environmental drivers of senescence: an experimental test in the wild” (to TJ Little, AB Pedersen).
  • 09/2022 – 04/2023: Postdoctoral Fellow, Biobehavioral Health, Pennsylvania State University, position funded by NIH T32 “Pathways Training” Fellowship, working on an NIEHS-funded grant “The Comparability and Reproducibility of Telomere Length Measurements for Population-based Studies” (to I Shalev).
  • 09/2016 – 06/2022: PhD in Biology, Indiana University, Supervisor: Dr Kimberly Rosvall.
  • 08/2014 – 08/2016: M.Sc., Biology, William & Mary, Supervisor: Dr Dan Cristol.
  • 08/2010 – 05/2014: B.S., Biology, Minor: Spanish, Centre College.

Research interests

I study why animals age at different rates in the wild, combining molecular biology, ecology, and hands-on field experiments. I completed my MSc at William & Mary and my PhD at Indiana University, where I spent several years working with wild birds to link telomeres, hormones, and gene expression to life-history and environmental variation. At Pennsylvania State University, I extended this work to human telomere dynamics and ageing. I am now a postdoctoral researcher at the University of Edinburgh, where I developed a DNA methylation-based “epigenetic clock” for the wild wood mouse that can accurately predict chronological age. This tool lets us ask new questions about how environmental stressors, pregnancy, and microbes accelerate or slow epigenetic ageing in nature. By bringing cutting-edge epigenetic tools into wild systems, my research connects ageing biology to global change, disease ecology, and animal welfare.

swolf2@ed.ac.uk

Rivka Lim

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Postdoctoral Research Associate

Rivka is a postdoctoral researcher affiliated with the University of Glasgow and the University of Edinburgh. As part of the Pedersen lab, she is working within the BBSRC-funded project examining superspreaders, the small proportion of individuals responsible for a disproportionate share of transmission, and what drives their outsized role in parasite dynamics within wildlife populations. She is also investigating intensity-dependent effects of anthelmintic treatment in wild wood mice (Apodemus sylvaticus) infected with Heligmosomoides polygyrus, asking when treatment helps, when it is neutral, and when it may carry unexpected costs.

Rivka’s background is in infectious disease epidemiology with research that combines field data, causal inference methods, and statistical modelling to understand how host-parasite dynamics shape population-level outcomes, and what that means for designing effective control strategies. She completed a Wellcome Trust PhD on the epidemiology of Schistosoma mansoni control programmes, and prior to that worked as a research assistant in parasite immunoepidemiology, with a consistent focus on the quantitative side of host-parasite biology.

Rivka.lim@ed.ac.uk

Alex Vavrik

Photo of Alex sitting outdoor, in the sun, on a step in front of a wall

Alex Vavrik - Research Assistant

CV

  • 2023 - present – Research assistant, University of Edinburgh
  • 2019-2023 – BSc Zoology (Honours), University of Edinburgh

Research interests

I moved to Edinburgh to study Biological Sciences and after graduating, I became a field assistant on the epigenetic ageing project. I quickly learned that I really enjoyed fieldwork (with all of its challenges)! I then led both field and lab work for the Superspreader project, investigating what could make a wood mouse host particularly good at spreading worms. This project gave me the opportunity to conduct some analysis as well, in which I looked at the effects of anthelminthic treatment on wild wood mice. As of 2026, I am joining the Buck lab to work on a helminth vaccine project. This will introduce me to some immunology, which I look forward to. Outside of work, I enjoy cooking, baking, and bouldering!

avavrik@ed.ac.uk

Aniela Dexter

Photo of Aniela standing in front of a vast green landscape

PhD Student

C.V.

  • 2024-present: PhD student, Institute of Ecology and Evolution, University of Edinburgh (Principal supervisors: Prof. Amy Pedersen and Prof. Sarah Reece)
  • June-August 2023: Amgen Scholar, Goto Lab, Graduate School of Agricultural and Life Sciences, University of Tokyo
  • July-August 2022: Research Intern, Bailey Lab, School of Biology, University of St Andrews
  • 2020-2024: BSc (Hons) Biology, School of Biology, University of St Andrews

Research interests

Circadian clocks maximise fitness by functionally anticipating cyclical changes in the environment such that biological activities from the molecular to behavioral level are scheduled appropriately throughout the 24-hour day. While the timekeeping of biological clocks is buffered against change, the output rhythms they produce are expected to exhibit plasticity depending on the environmental context.

My PhD research aims to understand the evolutionary ecology of daily and seasonal rhythms in wild wood mice (Apodemus sylvaticus). I am interested in how ecological factors including food availability, parasitic infection, demographics, and atmospheric conditions impact rhythms, and whether changes to rhythms reflect adaptive plasticity or maladaptive disruption. I combine lab and field-based approaches to rigorously test hypotheses and ensure findings maintain relevance under real-world ecological scenarios.

LinkedInORCiDaniela.dexter@ed.ac.uk 

Caroline Faircloth

Photo of Caroline outdoors holding a small bird with a black and yellow-striped head

PhD Student

Research interests

I am a PhD student working with Amy Pedersen and Iris Mair investigating the relationship between skin microbiome and ectoparasite infestations in wild mouse populations (Mus musculus domesticus on the Isle of May and Apodemus sylvaticus in the woodlands surrounding Edinburgh). I am part of the Hosts, Pathogens, and Global Health Wellcome Trust Programme. My background is primarily in evolutionary biology and disease ecology.

C.E.P.Faircloth@sms.ed.ac.uk

Indra Warr

Headshot of Indra

Research interests

Hi, I’m Indra! I completed a BA in Biological Natural Sciences (Pathology) at the University of Cambridge and an MSc by Research in Biomedical Sciences from the University of Edinburgh before starting my PhD in the Pedersen group in 2024.

My PhD project aims to investigate which environmental and demographic factors shape Regulatory T cell biology (Treg) in a free-living population of house mice. The immune system has the challenge of balancing effective defence against pathogens whilst needing to maintain tolerance to harmless self and environmental antigens. Treg are central to this process, and their dysfunction in humans can lead to autoimmune, inflammatory, and allergic disease. Laboratory mice are widely regarded as the ‘gold standard’ for identifying immune mechanisms relevant to human health. However, these controlled models often do not fully capture the complexity of immune responses in natural settings. My project aims to address this gap by investigating how immune regulation, particularly mediated by Treg, is shaped in free-living mice compared to their laboratory counterparts. By integrating ecological, nutritional, and immunological data from free-living mice that inhabit the Isle of May, Scotland, I aim to reveal how environmental and demographic factors affect Treg phenotype at critical barrier sites such as the gut.

Publications

S. H Chong1, L. A Burns1, T. K. M Cheng1, I. S Warr1, J. C Kenyon, A Review of COVID Vaccines: success against a moving target, Br Med Bull, 2022 Dec 12;144(1):12-44. Doi;10.1093/bmb/ldac025

1These authors contributed equally

Professional Memberships

  • Member, British Society for Immunology
  • Member, Royal Society of Biology
ORCHiDLinkedInI.S.Warr@sms.ed.ac.uk

Olivia Fleming

Photo of Olivia in graduation gown, standing in front of a wooden door

PhD student

C.V.

  • 2023—2026  Wellcome Trust PhD student, Hosts, Pathogens and Global Health Programme, Institute of Ecology and Evolution, University of Edinburgh
  • 2022—2023  MRes in Hosts, Pathogens and Global Health, Institute of Ecology and Evolution, University of Edinburgh
  • 2021—2022 Research assistant, Institute of Genetics and Cancer, University of Edinburgh
  • 2017—2020  MA Biological Natural Sciences, Department of Zoology, University of Cambridge

Research interests

I am interested in disease ecology, statistics and parasitology. In my PhD, I am investigating the efficacy of different methods of treating parasitic worms, and the effects of treatment in wild populations. My research combines experimental methods and statistical analyses of long-term datasets. I have focused on how well novel vaccine candidates translate from conventional laboratory models, and the effects of food supplementation and anthelmintic treatment on demography, individual health, and parasite burden in wild wood mice. I am also very passionate about science communication, and I enjoy teaching and outreach.

Publications

Patrick KA Kearns; Charles Dixon; Mihaly Badonyi; Kim Lee; Rafal Czapiewski; Olivia Fleming et al. (2024) Structural epitope profiling identifies antibodies associated with critical COVID-19 and long COVID.

Mattia Marenda; Davide Michieletto; Rafal Czapiewski; Jon Stocks; Sophie M Winterbourne; Jamilla Miles; Olivia CA Fleming et al. (2024 pre-print, in review) Nuclear RNA forms an interconnected network of transcription-dependent and tunable microgels.

Frederik Dahl Madsen, Olivia C.A. Fleming et al. (2026) Environmental Science Exploration Days: Breaking the Barriers, and Widening Participation in the Scottish Capital

ORCiDLinkedIno.fleming@sms.ed.ac.uk

Rhoslyn Howroyd

Photo of Rhoslyn standing on a bridge in front of a woodland landscape

PhD Student

C.V.

  • 2024 - Present: PhD student, Institute of Ecology and Evolution, University of Edinburgh (Supervisors: Prof. Amy Pedersen, Prof. Andy Fenton, Dr Simon Babayan, Dr Amy Sweeny)
  • January - March 2025: NERC Placement, Frontierra, Edinburgh
  • June - August 2023: Student internship, Pedersen group, University of Edinburgh
  • 2020 - 2024: BSc. (Hons) Ecology (First class), School of Biological Sciences, University of Edinburgh

Research interests

Not all individuals transmit infection equally, and hosts who are responsible for an aggregated proportion of disease transmission are termed superspreaders. Superspreading typically follows the Pareto Principle, wherein 20% of individuals are responsible for 80% of secondary infections, and their importance in driving pandemics has been well documented, including both SARS-CoV-1 and SARS-CoV-2 pandemics. These superspreaders can be overdispersed in terms of their shedding of pathogenic particles into the environment, or can have highly aggregated social contacts in which to transmit pathogens and parasites to their conspecifics. We aim to identify whether individuals with overdispersed shedding (‘supershedders’) or individuals with overdispersed contacts (‘supercontactors’) are the main drivers of parasite transmission.

My PhD focuses on determining how supershedders and supercontactors differ. Specifically, I am interested in whether these two groups differ in their social behaviour and activity, their genetic resistance to parasite infection, and their demographics. Using these results, we aim to more readily identify supershedders and supercontactors in wild animal populations, allowing for targeted treatment of infections. We use Apodemus sylvaticus (wood mice) and their gastrointestinal helminth Heligmosomoides polygyrus in the wild as a study system, which allows us to experimentally determine how targeted treatment of superspreaders reduces population wide infection, and the differences in superspreader hosts within ecologically realistic environments.  

LinkedInORCIDr.c.howroyd@sms.ed.ac.uk   

Nitara Wijayatilake

Photo of Nitara sitting in front of a large wooden door

PhD Student

C.V.

  • 2023-2027 PhD Institute of Ecology & Evolution, University of Edinburgh (Supervisors: Matthew Silk, Amy Pedersen)
  • 2022-2023 MSc Biodiversity & Global Change, UCL, Natural History Museum and ZSL
  • 2019-2022 BSc Biological Sciences, Imperial College London

Research interests

My research focuses on how animal social network structure shapes pathogen spread. Right now, I am looking at the emergence of superspreading. I work with large comparative datasets across many different species and build simulation-based disease models to link behavioural structure to epidemic dynamics. Alongside this, I’m developing a citizen-science game to generate behavioural data for model calibration. I’m especially interested in transmission heterogeneity, network structure, and the trade-offs between information and pathogen spread.

LinkedInORCiDN.Wijayatilake@sms.ed.ac.uk

NamePositionCurrent workplace
Lisa GecchelePhD StudentImperial College London - PostDoc
Dishon MuloiPhD studentAnimal & Human Health department Nairobi - PostDoc
Melanie ClercPhD studentUniversity of Edinburgh, Bogaert group - PostDoc
Liam BrierleyPhD studentUniveristy of Liverpool - MRC Skills Development Fellow
Evie RynkiewiczPostDocFashion Insitute of Technology - Assistant Proffessor
Godefroy DeveveyPostDocCentro de Ciências do Mar
Sarah KnowlesPostDocUniversity of Oxford - Assistant Proffessor
Susan WithenshawTechnicianUniversity of Liverpool - Technician
Julia McIverField AssistantUniversity of Dundee - Technician
Maddy HodgemanField AssistantThe Glasgow School of Art- Student

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