title: Use of a 14.2 kDa recombinant Cooperia oncophora protein in an ELISA for herd health monitoring of nematode infections in first grazing season calves.
abstract: An ELISA using a recombinant 14.2kDa excretory/secretory Cooperia oncophora protein (CoES14.2 ELISA) was evaluated for estimating level of cumulative exposure to infective Cooperia larvae in first grazing season calves. Data from one experiment were used to obtain a quantitative relationship between IgG levels and cumulative exposure. That relationship was validated against data from another experimental study and from natural field studies. The latter included different pasture management strategies with or without an anthelmintic treatment. Validation involved 'predicting' cumulative exposure for the groups of calves in the latter two datasets based on observed IgG levels measured with the CoES14.2 ELISA, and subsequently comparing those 'predictions' with observed cumulative exposures. Generally, 'predicted' cumulative exposures correlated well to observed exposures (r values of 0.7-0.9). However, 'predicted' cumulative exposures underestimated observed exposures in the natural field studies. Anthelmintic treatments in some of the groups of the natural field studies reduced the 'prediction' accuracy of the CoES14.2 ELISA. This suggests that cumulative exposure in relation to IgG levels is more accurately defined by the total amount of host-parasite contact than by the cumulative number of larvae ingested. It is concluded that IgG levels measured with the CoES14.2 ELISA allow evaluating how much exposure to infection calves have experienced in the first grazing season.
authors.affiliation: Department of Parasitology and Tropical Veterinary Medicine, Utrecht University, P.O. Box 80.165, 3508 TD, Utrecht, Netherlands.
authors.forename: J B
authors.initials: JB
authors.lastname: Githiori
authors.forename: F N
authors.initials: FN
authors.lastname: Kooyman
authors.forename: C
authors.initials: C
authors.lastname: Kruitwagen
authors.forename: H W
authors.initials: HW
authors.lastname: Ploeger
authors.forename: M
authors.initials: M
authors.lastname: Eysker
mesh_terms: D000818:Animals; D000947:Antigens, Helminth / Q000276:immunology*; D002417:Cattle; D002418:Cattle Diseases / Q000175:diagnosis*; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D007074:Immunoglobulin G / Q000032:analysis; D011994:Recombinant Proteins / Q000276:immunology; D012621:Seasons; D014251:Trichostrongyloidea / Q000276:immunology*; D014252:Trichostrongyloidiasis / Q000175:diagnosis / Q000662:veterinary*
chemical_list: D000947:Antigens, Helminth; D007074:Immunoglobulin G; D011994:Recombinant Proteins