A mechanistic model of developing immunity to Teladorsagia circumcincta infection in lambs

Singleton, D.R., Stear, M.J. and Matthews, L. (2011) A mechanistic model of developing immunity to Teladorsagia circumcincta infection in lambs. Parasitology, 138(3), pp. 322-332. (doi:10.1017/S0031182010001289)

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Abstract

Acquired immunity influences the severity of parasitic disease, but modelling the effects of acquired immunity in helminth infections has proved challenging. This may be due to a lack of suitable immunological data, or to the perceived complexity of modelling the immune response. We have developed a model of T. circumcincta infection in domestic sheep that incorporates the effects of acquired immunity on parasite establishment and fecundity. A large data set from commercially managed populations of Scottish Blackface sheep was used, which included relationships between IgA activity and worm length, and between worm length and fecundity. Use was also made of a recently published meta-analysis of parasite establishment rates. This realistic but simple model of nematode infection emulates observed patterns of faecal egg counts. The end-of-season faecal egg counts are remarkably robust to perturbations in the majority of the parameters, possibly because of priming of the immune system early in the season, reducing parasite establishment and growth and, therefore, faecal egg counts. Lowering the amount of early infection leads to higher end-of-season egg counts. The periparturient rise in egg counts in ewes appears to have an important role in supplying infection for the priming of the immune response. This feedback in the immune priming suggests that nematode infections may be difficult to eliminate.

Item Type:Articles
Status:Published
Refereed:Yes
Glasgow Author(s) Enlighten ID:Stear, Professor Michael and Matthews, Professor Louise and Singleton, Dr Darran
Authors: Singleton, D.R., Stear, M.J., and Matthews, L.
Subjects:Q Science > QR Microbiology > QR180 Immunology
S Agriculture > SF Animal culture > SF600 Veterinary Medicine
College/School:College of Medical Veterinary and Life Sciences > Institute of Biodiversity Animal Health and Comparative Medicine
College of Medical Veterinary and Life Sciences > Institute of Infection Immunity and Inflammation
Journal Name:Parasitology
Publisher:Cambridge University Press
ISSN:0031-1820
ISSN (Online):1469-8161
Published Online:15 October 2010

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Project CodeAward NoProject NamePrincipal InvestigatorFunder's NameFunder RefLead Dept
468351The effect of selection for nematode resistance on mhc class II diversiityMichael StearBiotechnology and Biological Sciences Research Council (BBSRC)BB/F015313/1Institute of Infection Immunity and Inflammation