title: A statistically derived index for classifying East Coast fever reactions in cattle challenged with Theileria parva under experimental conditions.
abstract: A statistically derived disease reaction index based on parasitological, clinical and haematological measurements observed in 309 5 to 8-month-old Boran cattle following laboratory challenge with Theileria parva is described. Principal component analysis was applied to 13 measures including first appearance of schizonts, first appearance of piroplasms and first occurrence of pyrexia, together with the duration and severity of these symptoms, and white blood cell count. The first principal component, which was based on approximately equal contributions of the 13 variables, provided the definition for the disease reaction index, defined on a scale of 0-10. As well as providing a more objective measure of the severity of the reaction, the continuous nature of the index score enables more powerful statistical analysis of the data compared with that which has been previously possible through clinically derived categories of non-, mild, moderate and severe reactions.
authors.affiliation: International Livestock Research Institute, Nairobi, Kenya. j.rowlands@cgiar.org
authors.forename: G J
authors.initials: GJ
authors.lastname: Rowlands
authors.forename: A J
authors.initials: AJ
authors.lastname: Musoke
authors.forename: S P
authors.initials: SP
authors.lastname: Morzaria
authors.forename: S M
authors.initials: SM
authors.lastname: Nagda
authors.forename: K T
authors.initials: KT
authors.lastname: Ballingall
authors.forename: D J
authors.initials: DJ
authors.lastname: McKeever
mesh_terms: D000818:Animals; D000953:Antigens, Protozoan / Q000276:immunology; D015415:Biomarkers; D002417:Cattle; D004797:Enzyme-Linked Immunosorbent Assay / Q000662:veterinary; D015800:Protozoan Proteins / Q000276:immunology; D016052:Protozoan Vaccines / Q000276:immunology*; D016797:Theileria parva / Q000276:immunology*; D013801:Theileriasis / Q000276:immunology* / Q000517:prevention & control*
chemical_list: D000953:Antigens, Protozoan; D015415:Biomarkers; D015800:Protozoan Proteins; D016052:Protozoan Vaccines; C114309:p67 antigen, Theileria