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Willow Smallbone


Willow Smallbone

I graduated from Cardiff University in July 2014 with a degree in Zoology, which included a Professional Training Year where I worked with the Cardiff University Otter Project team as a research assistant focusing on the biotic and abiotic factors influencing Toxoplasma gondii infection in Eurasian Otters (Lutra lutra). My final year project with Prof. Jo Cable and Dr. Alberto Macedo Veiga assessed the toxicity of nitrates in the guppy (Poecilia reticulata)-parasite (Gyrodactylus turnbulli) system. I am currently doing a PhD between Cardiff University and University of East Anglia.



Location: Cardiff School of Biosciences, The Sir Martin Evans Building, Museum Avenue, Cardiff, CF10 3AX Room: C6.15


PhD: To assess how the MHC-linked mutational load affects the fitness and life-history of a vertebrate model, the guppy (Poecilia reticulata).

Supervisors: Prof. Jo Cable, Dr. Cock van Oosterhout; School of Environmental Sciences, University of East Anglia.

Funding: The Leverhulme trust

GuppyA central question in biology is how selection on genetic variation affects fitness. For decades, the Major Histocompatibility Complex (MHC) genes of vertebrates have been used as a model system to study positive selection. However, the MHC genes also tend to accumulate many deleterious mutations and transposable elements that are selectively non-neutral. The aims of my PhD are: 1) to determine how the MHC-linked mutational load influences fish fitness, fertility and longevity of both the parent and their offspring; 2) identify whether MHC heterozygous fish have superior parasite resistance compared to MHC homozygous individuals; 3) ascertain female mate choice regarding MHC. Does a female fish choose a mate that is most MHC dissimilar to increase offspring heterozygosity? Guppy strains that are fixed for alleles at their MHC will be crossed to create second-generation (F2) hybrids. These F2s will be genotyped to identify how much variation in the fitness, longevity, parasite resistance and mate choice can be explained by MHC genotype (homozygous vs heterozygous). This is the first study to analyse the effect of MHC on fitness.


Final Year Project (FYP) and Summer internship – Fisheries Society of the British Isles: Assessing the toxicity of nitrates in the Guppy (Poecilia reticulata)-parasite (Gyrodactylus turnbulli) system. Collaboration with Dr Alberto Macedo Veiga and Prof. Jo Cable.

The increased discharge of organic matter into aquatic systems contributes to the widespread phenomenon of man-made eutrophication. The toxicity of ammonia and nitrites has been widely documented on aquatic species, but nitrates have received comparatively little attention as a water quality hazard. As well as being harmful in their own right, nitrates may increase fish susceptibility to infectious diseases. Nitrogenous waste is a particular concern in recirculating aquaculture, with water changes and filter systems needed to maintain safe thresholds of these compounds to maximise fish production. Determining the effects of parasites on wild populations has important consequences for the protection and management of freshwater fisheries. The well-studied fish pathogens, gyrodactylids, have devastating consequences on wild and captive fish populations. Experimental tests of the acute (FYP) and chronic (FSBI internship) effects of nitrates on fish immune reaction, parasite performance, disease susceptibility and pathology (FSBI) are essential for understanding the consequence of nitrate exposure on host-health and as a driving force of host-parasite interactions in wild fish populations. This study has assessed the susceptibility of guppies to disease under ecologically relevant concentrations of nitrate using experimental infections and histopathological examination of key tissues involved in the immune response of fish.


Professional Training Year at Cardiff University Otter Project: Biotic and abiotic factors influence Toxoplasma gondii infection in Eurasian Otters (Lutra lutra). Collaboration with Prof. Jo Cable, Prof. Edward Guy, Drs Liz Chadwick, Sarah Perkins and Ellie Sherrard-Smith.

Toxoplasma gondii oocyst

Toxoplasma gondii oocyst

Toxoplasma gondii, a zoonotic parasite of global importance, has the ability to infect all endothermic vertebrates, with potentially devastating health implications. The prevalence of this parasite is seldom monitored in wildlife. In this study, a semi-aquatic keystone species, widespread Eurasian otter (Lutra lutra) in England and Wales was used to assess the effect of meteorological factors, land use and biotic factors on T. gondii seroprevalence in British wildlife. Overall, this study found that the key abiotic and biotic factors affecting seroprevalence of T. gondii in otters were those that increased the number of viable oocysts in the environment and that older otters are more likely to be infected due to an increased exposure time.



Smallbone WA, Sherrard-Smith E, Chadwick EA, Francis J, Guy, E, Perkins SE, Cable J (2013) Biotic and abiotic factors influence Toxoplasma gondii infection in Eurasian Otters (Lutra lutra). British Society of Parasitology Spring meeting, Bristol University, UK. Oral presentation 8th – 11th April 2013.

Smallbone WA, Sherrard-Smith E, Chadwick EA, Francis J, Guy, E, Perkins SE, Cable J (2013) Biotic and abiotic factors influence Toxoplasma gondii infection in Eurasian Otters (Lutra lutra). Eurasian Otter Workshop Cork, Ireland. Oral presentation 23rd – 28th April 2013.

Smallbone WA, Moorhouse-Gann RJ, Chadwick EA (2013) Long term monitoring of a sentinel species of freshwaters. Eurasian Otter Workshop Cork, Ireland. Poster presentation 23rd – 28th April 2013.


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