Overview
Diagnostic testing plays an important role for parasite management in livestock. The increased number of reports of drug resistance has led to a ’test don’t guess’ approach being advocated by animal health experts that promotes diagnostic testing for appropriate targeted treatments to minimise selection for drug resistance, which can also reduce environmental exposure to drug residues.
About this opportunity
Fasciolosis is a major parasitic disease of livestock globally, significantly impacting animal productivity, contributing to the challenges of efficient and sustainable livestock production. It is caused by two parasites, Fasciola hepatica and Fasciola gigantica that are found across the world in temperate and tropical climates, respectively. However, there are also areas where the two species overlap, such as across Africa, resulting in hybrid forms with potential for increased genetic diversity that may impact the spread and severity of disease.
Liver fluke diagnostic tools play important roles in parasite control strategies on farm, as well as parasite prevalence studies that determine which Fasciola spp. are circulating, allowing the potential spread of infection/disease to be monitored within both animals and people. A range of tools are available, detecting the presence of the parasite in faeces, detecting the host response to infection via circulating anti-Fasciola antibodies and molecular assays. To date, commercially available serological diagnostic assays are focused on F. hepatica, which may be impacted on in areas where F. hepatica co-exists with F. gigantica, resulting in potential species hybrids, negating effective diagnostic testing.
The aim of this PhD project is to evaluate the impact of Fasciola species-specific differences on diagnostic tools using a dual comparative bioinformatic approach of F. hepatica and F. gigantica omics datasets and laboratory analyses of serological assays.
Key areas of investigation will include:
a. Evaluation of Fasciola species-specific differences will be carried out using a comparative genomics approach at the genome and gene level. Intraspecies differences across the Fasciola spp. genomes will be determined, with a specific focus on the nuclear molecular markers. This data will also be used to identify and develop novel markers for Fasciola species determination. Bioinformatic analyses will also be carried out to explore the diversity within Fasciola spp. gene families, including the cathepsin peptidases that form the basis of several serological diagnostic assays
b. Current diagnostic tools, including a new lateral flow test developed at the University of Liverpool, will be evaluated using samples collected from F. gigantica-infected animals from fieldwork in Africa. Based on the results from the bioinformatics part of the project, a serological ELISA will be developed and evaluated for pan Fasciola spp. diagnosis.
Further reading
1. Komal M, Afshan K, Firasat S, Hodgkinson JE, Cwiklinski K. Multi-marker analysis of Fasciola gigantica from cattle and buffalo across Pakistan reveals high levels of genetic diversity and novel haplotypes. Parasitol. 2025.1-10. doi: 10.1017/S0031182025100693.
2. Beesley NJ, Cwiklinski K, Allen K, Hoyle RC, Spithill TW, La Course EJ, Williams DJL, Paterson S, Hodgkinson JE. A major locus confers triclabendazole resistance in Fasciola hepatica and shows dominant inheritance. PLoS Pathog. 2023. 19(1):e1011081. doi: 10.1371/journal.ppat.1011081.
3. Cwiklinski K, Dalton JP. Exploiting comparative omics to understand the pathogenic and virulence-associated protease: Anti-protease relationships in the zoonotic parasites Fasciola hepatica and Fasciola gigantica. Genes (Basel). 2022. 13(10):1854. doi: 10.3390/genes13101854.
4. López Corrales J, Cwiklinski K, De Marco Verissimo C, Dorey A, Lalor R, Jewhurst H, McEvoy A, Diskin M, Duffy C, Cosby SL, Keane OM, Dalton JP. Diagnosis of sheep fasciolosis caused by Fasciola hepatica using cathepsin L enzyme-linked immunosorbent assays (ELISA). Vet Parasitol. 2021. 298:109517. doi: 10.1016/j.vetpar.2021.109517.
5. Walsh TR, Ainsworth S, Armstrong S, Hodgkinson J, Williams D. Differences in the antibody response to adult Fasciola hepatica excretory/secretory products in experimentally and naturally infected cattle and sheep. Vet Parasitol. 2021. 289:109321. doi: 10.1016/j.vetpar.2020.109321.