Figure 1.
The typical visual appearance of an idiopathic focal eosinophilic enteritis IFEE lesion at laparotomy.
The lesion is grossly hyperaemic and spans all or part of the circumference of the small intestine (small bowel). Palpably the tissues are markedly thickened at the site of the lesion and most commonly there is obstruction of ingesta proximal to the lesion(s) resulting in a simple obstruction of the bowel.
Figure 2.
Frequency histograms of horse age, month and year.
Histograms depicting the frequency distributions of the ages of the horses (top), the year of surgery (middle) and month of surgery (bottom) for cases (left) and controls (right). The frequencies for the years' 2000 and 2010 are circa half the size of those of the other years as the period of study spans July 2000 to June 2010.
Figure 3.
Geographic locations, x = (x1, x2) = (Easting, Northing), of case and control horses.
The point map depicts the geographical location of the 85 cases (red triangles) of idiopathic focal eosinophilic enteritis (IFEE) and 848 randomly selected controls (‘+’) in the present study. The green circle shows the location of the Philip Leverhulme Equine Hospital (PLEH).
Figure 4.
Graphical illustration of the estimated relationship (smooth) between the log odds of IFEE (‘Effect’) and age.
The estimate derives from a Generalised Additive Model formulation; the smooth of horse age adjusted for seasonality (parametric), day in year (parametric) and the geographical location of the horse/owner (smooth). The dotted horizontal line is at log-odds = 0.
Figure 5.
Graphical illustration of the estimated relationship between the log odds of IFEE (‘contribution to log odds’) and day of year.
The seasonal estimate (parametric) derives from a Generalised Additive Model formulation and is adjusted for horse age (smooth) and the geographical location of the horse/horse owner (smooth). The dotted horizontal line is at log-odds = 0.
Figure 6.
Contour plot of the smooth estimate of residual spatial variation in the log odds of IFEE.
This is adjusted for day in year (parametric day of year and season effects) and horse age (smooth). The closed circular contours centred at Easting = x1 = 370000 and Northing = x2 = 4 25000 indicates an increase in the log odds in this region. A zero contour value corresponds to an odds of 1, positive values correspond to odds in excess of one and negative values to odds of less than one. The green circle shows the location of the Philip Leverhulme Equine Hospital (PLEH).
Table 1.
Parameter estimates relating to the time (day in year) and seasonal effects for the final fitted model.
Table 2.
Minimum and maximum values of the estimated parameters and associated p-values resulting from GAM model fits to the five sets of randomly permuted location data.
Figure 7.
Contour plots of the smooth estimates of the residual spatial variation in the log odds of IFEE.
These were obtained when using the observed location data of the owner/carer location (top left) and also when using each of the five perturbed sets of co-ordinates.