A multilevel study of the environmental determinants of swine ascariasis in England.

Ascariasis is considered a common parasitosis of swine worldwide. The disease causes significant economic losses due to its effect on feed conversion ratio and liver condemnations at slaughter (liver milk spots). This study aimed to characterise the between-farm and spatial variance in porcine ascariasis in England and to assess the association between the percentage of infected animals and potential environmental risk factors, including production system, socioeconomic deprivation, soil characteristics (pH, topsoil bulk density, topsoil organic matter, topsoil texture class, soil water regime, topsoil available water capacity, and elevation), and climatic conditions (relative humidity, air temperature, and rainfall) before slaughter.