title: A model to assess the efficacy of vaccines for control of liver fluke infection.
abstract: Fasciola hepatica, common liver fluke, infects cattle and sheep causing disease and production losses costing approximately $3 billion annually. Current control relies on drugs designed to kill the parasite. However, resistance is evident worldwide and widespread in some areas. Work towards a vaccine has identified several antigens of F. hepatica that show partial efficacy in terms of reducing worm burden and egg output. A critical question is what level of efficacy is required for such a vaccine to be useful? We have created the first mathematical model to assess the effectiveness of liver fluke vaccines under simulated field conditions. The model describes development of fluke within a group of animals and includes heterogeneity in host susceptibility, seasonal exposure to metacercariae and seasonal changes in temperature affecting metacercarial survival. Our analysis suggests that the potential vaccine candidates could reduce total fluke burden and egg output by up to 43% and 99%, respectively, on average under field conditions. It also suggests that for a vaccine to be effective, it must protect at least 90% of animals for the whole season. In conclusion, novel, partial, vaccines could contribute substantially towards fasciolosis control, reducing usage of anthelmintics and thus delaying the spread of anthelmintic resistance.
authors.affiliation: Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst Campus, Chester High Road, Neston, CH64 7TE, UK.
authors.forename: Joanne
authors.initials: J
authors.lastname: Turner
authors.affiliation: Department of Infection Biology, Institute of Infection and Global Health, Liverpool Science Park IC2, 146 Brownlow Hill, Liverpool, L3 5RF, UK.
authors.forename: Alison
authors.initials: A
authors.lastname: Howell
authors.affiliation: Department of Infection Biology, Institute of Infection and Global Health, Liverpool Science Park IC2, 146 Brownlow Hill, Liverpool, L3 5RF, UK.
authors.forename: Cathy
authors.initials: C
authors.lastname: McCann
authors.affiliation: Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Waterhouse Building, Liverpool, L69 3GL, UK.
authors.forename: Cyril
authors.initials: C
authors.lastname: Caminade
authors.affiliation: Department of Mathematical Sciences, University of Liverpool, Mathematical Sciences Building, Liverpool, L69 7ZL, UK.
authors.forename: Roger G
authors.initials: RG
authors.lastname: Bowers
authors.affiliation: Department of Infection Biology, Institute of Infection and Global Health, Liverpool Science Park IC2, 146 Brownlow Hill, Liverpool, L3 5RF, UK.
authors.forename: Diana
authors.initials: D
authors.lastname: Williams
authors.affiliation: Department of Epidemiology and Population Health, Institute of Infection and Global Health, University of Liverpool, Leahurst Campus, Chester High Road, Neston, CH64 7TE, UK.|NIHR Health Protection Research Unit in Emerging and Zoonotic Infections, Liverpool, L69 7BE, UK.
authors.forename: Matthew
authors.initials: M
authors.lastname: Baylis
mesh_terms: D000818:Animals; D002417:Cattle; D002418:Cattle Diseases / Q000469:parasitology / Q000517:prevention & control; D005210:Fasciola hepatica / Q000187:drug effects; D005211:Fascioliasis / Q000517:prevention & control* / Q000662:veterinary*; D008954:Models, Biological; D016052:Protozoan Vaccines / Q000494:pharmacology*; D012756:Sheep; D012757:Sheep Diseases / Q000469:parasitology / Q000517:prevention & control
chemical_list: D016052:Protozoan Vaccines