Classification and Regression Tree (CART) analysis is a potentially powerful tool for
identifying risk factors associated with contagious caprine pleuropneumonia (CCPP) and the important
interactions between them. Our objective was therefore to determine the seroprevalence
and identify the risk factors associated with CCPP using CART data mining modeling in the most
densely sheep- and goat-populated governorates. A cross-sectional study was conducted on 620
animals (390 sheep, 230 goats) distributed over four governorates in the Nile Delta of Egypt in 2019.
The randomly selected sheep and goats from different geographical study areas were serologically
tested for CCPP, and the animals’ information was obtained from flock men and farm owners. Six
variables (geographic location, species, flock size, age, gender, and communal feeding and watering)
were used for risk analysis. Multiple stepwise logistic regression and CART modeling were used
for data analysis. A total of 124 (20%) serum samples were serologically positive for CCPP. The
highest prevalence of CCPP was between aged animals (>4 y; 48.7%) raised in a flock size 200
(100%) having communal feeding and watering (28.2%). Based on logistic regression modeling
(area under the curve, AUC = 0.89; 95% CI 0.86 to 0.91), communal feeding and watering showed
the highest prevalence odds ratios (POR) of CCPP (POR = 3.7, 95% CI 1.9 to 7.3), followed by age
(POR = 2.1, 95% CI 1.6 to 2.8) and flock size (POR = 1.1, 95% CI 1.0 to 1.2). However, higher-accuracy
CART modeling (AUC = 0.92, 95% CI 0.90 to 0.95) showed that a flock size >100 animals is the most
important risk factor (importance score = 8.9), followed by age >4 y (5.3) followed by communal
feeding and watering (3.1). Our results strongly suggest that the CCPP is most likely to be found
in animals raised in a flock size >100 animals and with age >4 y having communal feeding and
watering. Additionally, sheep seem to have an important role in the CCPP epidemiology. The CART
data mining modeling showed better accuracy than the traditional logistic regression. |