Worms, sheep and environment: integrating ecological perspectives into anthelmintic resistance management.

Lead Research Organisation: University of Glasgow
Department Name: College of Medical, Veterinary &Life Sci

Abstract

Keywords: Resistance evolution, worms, genomics, ecology, adaptive management

Abstract:
The purpose of this multidisciplinary studentship is to integrate fundamental and applied perspectives on a research problem with direct societal relevance but which also informs key questions in evolutionary ecology and parasitology. The development of resistance to chemical control measures is a key concern in human and veterinary medicine and in agricultural production systems. To increase the efficiency and effectiveness of chemical control measures in the face of resistance, adaptive management approaches have been proposed that customise intervention strategies to the biology and ecology of the particular target pathogens and their hosts. However, these would ideally consider the specific mechanisms of the control agent, genetics of resistance, rates of migration between susceptible and resistant populations, and the strength of selection imposed by the control agents, while taking into account other types of environmental variation, such as the type of pasture that hosts feed on, the community of hosts that share pastures, and how isolated hosts are from new infections. This requires integration of ecology, evolution, genetics/genomics, parasitology, veterinary science, quantitative analyses of "big data", and mathematical modelling, which has not often been achieved.

The overall aim of this studentship is to take a multidisciplinary approach to investigate the nature and consequences of anthelmintic resistance in an important parasite of sheep, the nematode Haemonchus contortus. The project will focus on resistance to ivermectin, which is one of the key anthelmintics for controlling livestock parasites. The student will benefit from support and resources provided by a large UK-wide consortium investigating anthelmintic resistance (https://bugconsortium.wordpress.com). The project will involve four main elements but there will be flexibility for the student to take the project in different directions: 1) using previously developed crosses between resistant and susceptible parasites to test the genetic basis of resistance; 2) examining 'real life' fitness (e.g. ability to establish infection, competition, mating success) and the influence of mating preferences, by genotyping the adults and progeny resulting from mixed infections; 3) testing the segregation of resistance markers in previously established lines of a free-living nematode model system (Caenorhabditis remanei) that was selected for ivermectin resistance to test whether there is a common basis of resistance and similar phenotypic consequences; and 4) using deep sequencing approaches to genotype individuals from agricultural environments that differ in resistance management practices to test predictions about expected rates of resistance evolution.

Publications

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